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RAN Planning Guidelines
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RADIO NETWORKPLANNING GUIDELINES
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INDEX
RADIO NETWORK PLANNING GUIDELINES ............................................................. 11 Introduction ................................................................................................................ 52 Spectrum & frequency planning ........................................................................... 6
2.1 Channel allocation .................................................................................................62.2 Carrier separation ..................................................................................................62.3 Carrier planning .....................................................................................................7
2.3.1 Multi-site towns .............................................................................................. 72.3.2 Single site towns............................................................................................ 8
2.4 Spectrum Utilization Efficiency (SUE) ................................................................93 Carrier dimensioning ............................................................................................. 104 Coverage levels ....................................................................................................... 14
4.1 Link Budgets.........................................................................................................144.1.1 900 MHz band (for reference) ................................................................... 154.1.2 1800 MHz band (for reference) ................................................................. 16
4.2 Roaming sensitive locations ..............................................................................165 Antenna & Feeder cables ...................................................................................... 17
5.1 Antennas ...............................................................................................................175.2 Feeder cables ......................................................................................................18
6 Dual Band (900/1800) planning............................................................................ 197 BTS.............................................................................................................................. 22
7.1 Site types ..............................................................................................................227.1.1 Outdoor/Indoor............................................................................................. 227.1.2 Macro/Micro.................................................................................................. 227.1.3 Tower top BTS ............................................................................................. 227.1.4 Street pole BTS ........................................................................................... 22
7.2 BTS Capacity Optimization ................................................................................237.3 Handover and Power Control ............................................................................24
7.3.1 Handover Types .......................................................................................... 247.3.2 Handover Criteria ........................................................................................ 257.3.3 Adjacencies .................................................................................................. 25
7.4 Data network configuration ................................................................................267.4.1 Timeslot configuration ................................................................................ 267.4.2 DAP Pool capacity ...................................................................................... 267.4.3 PCU capacity ............................................................................................... 267.4.4 Gb Link capacity .......................................................................................... 27
8 BSC ............................................................................................................................. 288.1 Location.................................................................................................................288.2 BSC Capacity .......................................................................................................29
8.2.1 Trigger points for BSC enhancement....................................................... 30
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8.3 BSC Capacity optimization ................................................................................318.4 Location Area Design..........................................................................................31
8.4.1 Paging vs. Location Updating Traffic ....................................................... 328.4.2 LAC size and border ................................................................................... 33
8.5 BSS Parameters ..................................................................................................359 Transcoder ................................................................................................................ 36
9.1 Location.................................................................................................................369.2 Capacity ................................................................................................................369.3 Pool configurations ..............................................................................................38
9.3.1 Trigger points for enhancement ................................................................ 3810 Site Planning...................................................................................................... 39
10.1 Radio planning .....................................................................................................3910.2 Transmission network planning.........................................................................4110.3 Pre - planning .......................................................................................................4110.4 Nominal Planning ................................................................................................42
10.4.1 Pre-Survey / SARF...................................................................................... 4210.4.2 Site Survey ................................................................................................... 4310.4.3 Site Acquisition Report ............................................................................... 4310.4.4 Site Pre-Validation ...................................................................................... 4310.4.5 Technical Site Survey Report .................................................................... 4410.4.6 Site Validation & Deviation ........................................................................ 44
10.5 Detailed Network Planning.................................................................................4510.5.1 Radio Planning ............................................................................................ 4510.5.2 Transmission Planning ............................................................................... 4610.5.3 Co-site Planning .......................................................................................... 47
10.6 Site Implementation Data ...................................................................................4710.6.1 Site Implementation Report ....................................................................... 4810.6.2 Site Integration Data ................................................................................... 4810.6.3 Site Verification............................................................................................ 48
10.7 Site passive infrastructure sharing (with other operator) ..............................4911 Capacity planning ............................................................................................ 50
11.1 Capacity Requirements ......................................................................................5011.2 Capacity rollout tracking .....................................................................................51
12 Network enhancement features ................................................................... 5212.1 Coverage enhancement solutions ....................................................................52
12.1.1 ICE (Intelligent Coverage Enhancement) ................................................ 5212.1.2 SRC (Smart Radio Concept) ..................................................................... 5212.1.3 Two (2) Port Antenna Combiner By-pass ............................................... 5412.1.4 Four (4) Port Antenna Combiner By-pass ............................................... 5512.1.5 High Gain Antenna [20dBi, 65°] ................................................................ 5612.1.6 TMA ............................................................................................................... 5712.1.7 TMB ............................................................................................................... 5712.1.8 Tower Top BTS............................................................................................ 5712.1.9 Repeaters ..................................................................................................... 57
12.2 Abis Compression solution ................................................................................5912.3 VSAT Abis connectivity ......................................................................................61
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12.4 Mobile BTS station ..............................................................................................6213 Energy Saving Guidelines ............................................................................. 64
13.1 ULTRA EDGE BTS .............................................................................................6413.1.1 Shiner –Frisco Trx ....................................................................................... 6413.1.2 LTCD (Low Traffic Controlled Disconnect) ............................................. 6613.1.3 Hybrid Solution (Ultra 2/2/2 to Flexi 4/4/4) .............................................. 6813.1.4 Co-Siting Solution (Ultra 4/4/4 to Flexi 6/6/6) ......................................... 69
13.2 FLEXI EDGE BTS ...............................................................................................7014 Network Optimisation...................................................................................... 72
14.1 Key Performance Indicators ..............................................................................7214.2 Performance Evaluation .....................................................................................7514.3 Interference Reduction .......................................................................................85
14.3.1 Antenna tilting /reorientation /beamwidth reduction............................... 8914.3.2 Discontinuous transmission/reception (DTX) ......................................... 8914.3.3 Frequency hopping (FH) ............................................................................ 9014.3.4 Power control (PC)...................................................................................... 9114.3.5 Adaptive antennas ...................................................................................... 9214.3.6 Dynamic channel allocation algorithms ................................................... 9314.3.7 Antenna Hopping......................................................................................... 9414.3.8 Bi-Sector Antennas - TenXc ...................................................................... 9714.3.9 SAIC (Single Antenna Interference Cancellation)................................ 10214.3.10 STIRC (Space Time Interference Rejection Combining) .................... 104
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1 IntroductionThis document lists out various radio network guidelines in planning,performance enhancement, optimization, efficiencies (capax & opex.) to beadhered to all VF-IN circles with NSN BSS equipment. Any deviation fromthese guidelines would require specific approvals.
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2 Spectrum & frequency planning
2.1 Channel allocationChannel allocation for GSM system given in table below
BAND GSM 900 GSM1800 E-GSM 900Uplink 890 – 915 1710 – 1785 880 - 890
Downlink 935 – 960 1805 – 1880 925 - 935Channel 1 - 124 512 - 885 975 - 1023
2.2 Carrier separation
Guidelines for minimum separation between carriers:
BCCH carriers
1) Separation between BCCH carriers within same site : 600 KHz2) Separation in BCCH carriers between different sites in same cluster : 400 KHz3) co-channel C/I : ≥ 12 dB4) adjacent channel C/A : ≥ -9 dB
TCH carriers
1) Synthesized Frequency Hopping (SFH) with 1/1 frequency reuse pattern to beused to increase the network capacity. 1/1 frequency planning means that allhopping TCH frequencies are used in all cells.
600KHz
400KHz
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2) Frequency plan for hopping layer should be generated based on actual C/I fieldmeasurements data captured from OSS over a period of 7 days. Frequency planshould include new sites and/or new TRX planned over next 1 month. Appropriateadvanced frequency planning tools capable of carrying out non-uniform frequencyplans to be used.
3) MA List (Mobile Allocation List): To be allocated per cell & decided locallydepending on frequency planning tool used and & no of TCH channels available.
4) HSN (Hopping Sequence Number): To be allocated per site from the GSMstandards.
2.3 Carrier planning
2.3.1 Multi-site towns
Since BCCH (Broadcast Channel) is required to be continuously available, nofrequency hopping can be deployed on this channel. 4/12 reuse is recommendedfor optimum performance. This means a cluster of 12 cells (4 sites) will have a setof BCCH frequencies to be used within that cluster and the same plan is replicatedin all such clusters of 12 cells each.
Frequency loading
In frequency hopping, each frequency is used by a fraction of the time. Thisfraction of time is dependent on number of hopping frequencies. Frequencyload indicates the fraction of time a frequency is being transmitted by a cell.The frequency load is defined as:
FRload = Average (Erlangcell) / (8 x #Hopping Frequencies)
BCCH traffic should be excluded for calculation. BCCH is always radiating &therefore there is 100% frequency load on BCCH.
Following table gives maximum configuration & corresponding frequency load percell:
Spectrum(MHZ)
Totalcarriers
No ofBCCH
carriers
No ofcarriers
for guardband
No ofcarriersleft forTCH
BTSconfiguration
(max)
TotalErlangper site
(FR)
Designedfrequencyload (%)
4.4 22 12 1 9 3/3/2 38.00 10.8%6.2 31 12 2 17 4/4/4 63.12 12.2%7.2 36 12 2 22 5/5/4 77.54 11.8%8.2 41 12 2 27 6/6/5 97.61 13.1%9.2 46 12 2 32 7/6/6 111.48 13.1%
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10.2 51 12 3 36 7/7/7 126.36 13.3%11.2 56 12 3 41 8/8/8 146.10 14.0%12.2 61 12 3 46 9/9/8 161.24 13.8%13.2 66 12 3 51 10/10/9 182.15 14.3%14.2 71 12 3 56 11/10/10 196.49 14.2%15.0 75 12 3 60 11/11/11 211.83 14.3%
BCCH carriers for micro/Ibs can be use for macro BCCH plan if required.Circles may have variations due to use of more carriers for micro, Ibsand/or guard band. All such variations can be considered for frequencyplanning.All networks to make sure that loading as per the above guidelines isachieved before new “capacity only” sites are planned in the network.
It is not technically feasible to load all sites in a town with max possibleconfiguration indicated above. Doing such will result in high interferenceand hence degrade the network quality. Therefore typical traffic loadingshould be 84% of maximum capacity & the frequency load for a clustershould not more than 10% to 12%
2.3.2 Single site towns
For single site towns, there is no cluster for frequency re-use & therefore it ispossible to have higher site loading. Frequency hopping is not required.
The following figure gives the carrier planning for single site town.
Spectrum(MHZ)
TotalARFCN
BCCHcarriers(Nos.)
No ofcarriersforguardband
TCHcarriers(Nos.)
TRXconfiguration(max.))
Erlangper site(FR)
3.4 17 3 5 9 3/3/3 44.674.0 20 3 5 12 3/3/4 50.814.4 22 3 5 14 4/3/4 56.956.2 31 3 5 23 5/5/6 91.187.2 36 3 5 28 6/6/6 104.048.2 41 3 5 33 7/7/7 126.369.2 46 3 5 38 8/7/8 139.52
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2.4 Spectrum Utilization Efficiency (SUE)
As a measure to monitor how efficiently the spectrum is used and loaded in anetwork, following formula provides an objective method of calculating thesame:
SUE = Offered erlang / (Spectrum in MHz x Area in Sq. Km)
SUE is measured in terms of erlang / MHz / Sq Km
This value is to be calculated for top-5 towns of a circle under followingcategories
Peak spectrum utilization efficiency
One square Km polygon of dense part of the town is to be considered. OfferedFR capacity of all cells (macro/micro/IBS etc) within that 1 sq km to be taken.
Average spectrum utilization efficiency
Eight square Km. polygon of the town having maximum traffic is to beconsidered and offered FR capacity of all cells (macro/micro/IBS etc) withinthat polygon area to be considered.
Townname Parameter Nos. of sites Offered
capacity (FR)SUE(Erl/MHz/Sq Km)
Town-1 Peak SUE Within 1 Sq KmAverage SUE Within 8 Sq Km
Town-2 Peak SUE Within 1 Sq KmAverage SUE Within 8 Sq Km
These values will be benchmark against global standards
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3 Carrier dimensioning
SDCCH dimensioning:
SDCCH capacity of every cell should be planned is such a way that maximum SDCCHblocking should not exceed 1% GoS.
The below table comprises the recommended SDCCH configuration per cell
TRX per cell(Nos.)
Number ofSDCCH
SDCCHconfiguration
Number ofSDCCH sub
channels
SDCCHcapacity@1%GoS
[Erl.]1 0 Combined 3 0.452 1 Non-combined 7 2.503 1 Non-combined 7 2.504 2 Non-combined 15 8.115 2 Non-combined 15 8.116 3 Non-combined 23 14.477 3 Non-combined 23 14.478 4 Non-combined 31 21.199 4 Non-combined 31 21.1910 5 Non-combined 39 28.1211 5 Non-combined 39 28.1212 6 Non-combined 47 35.12
One signalling sub-channel is taken account for cell broadcast service (CBCH)
Note:
1) For cells on LAC borders, additional SDCCH capacity may be configure on need basis.2) Dynamic SDCCH allocation feature should be enabled3) Above indicated signalling capacity (SDCCH) is assuming a max of 20% HR traffic
carried. However, networks having > 20% HR traffic may require higher SDCCHcapacity.
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TCH dimensioning:
The TCH capacity of every cell should planned in such a way that within the TCHbusy hour the TCH blocking does not exceed 2% GoS.
The below table comprises the recommended TCH capacity per cell at differentdedicated time slots for data:
TRX per cell(Nos.)
Number ofSDCCH
TCH capacity@2%Gos [Erl.]
0 Data TS 1 Data TS 2 Data TSL1 0 2.93 2.27 1.652 1 8.2 7.4 6.613 1 14.89 14.04 13.184 2 21.03 20.15 19.265 2 28.25 27.34 26.436 3 34.68 33.75 32.837 3 42.12 41.18 40.258 4 48.7 47.75 46.819 4 56.27 55.32 54.37
10 5 62.94 61.98 61.0311 5 70.06 69.64 68.6812 6 77.34 76.37 75.41
Half rate configuration
20% capacity gain due to half rate should be considered.
Total capacity = Capacity (FR) + HR gain
The voice capacity of a cell should plan in such a way that within the TCH busyhour, TCH traffic should not exceed 40% half rate.
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HR gain = x HR Traffic ~20%
(Busy hour HR fraffic + Busy hour AMR_HR Traffic)x100Total Busy hour trafficHR Traffic (%) =
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Example:
Consider two TRX cell with one dedicated data TS
Configuration without HR
BC SD T T T T T TT T T T T T T DD
Offered FR capacity (excluding Data) = 7.40 ErlangOffered FR + HR capacity (excluding Data) = 7.40 x 1.2 = 8.88 Erlang
TCH requirement (8.88@2%GoS) ~15
Configuration with HR (20% extra HR-capacity)
BC SD T T T T T TT T T T T DR DR DD
BC: BCCHSD: SDCCHT : TCH FRDD: Dedicated dataDR: TCH Dual rateFR: Full rateHR: Half Rate
By making 2 FR timeslots as Dual Rate in this example, it is possible to get 20% half ratecapacity gain. However HR trigger thresholds (FRU & FRL in case of Nokia) need to besuitably optimized. In the above example, setting FRU = 80% is enough to achieve 20% softcapacity. Similar implementation to be done for higher cell configurations
In Abis interface as a normal practice, 16 Kbps LAPD signalling is sufficient in caseof any TRX having upto 18 channels (SD + TCH). However in case any TRX exceedsthis limit of 18 channels, 32 Kbps LAPD needs to be configured.
In TCSM AMR pool to be suitably configured to support all of AMR traffic.
Recommendation:
Total traffic (Busy hour)x 100Capacity(FR)
Capacity Utilization (FR) = <=84%
Total traffic (Busy hour)x 100Capacity(FR) + HR gain
Capacity Utilization (FR+HR) = <=70%
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BTS expansions:
Delta erlang capacity calculation for enhancement of existing BTS configurations betaken as differential of higher and existing configuration.
Example: To calculate erlang added due to expansion of BTS from 3/3/3 to 4/4/4:3/3/3 capacity = 44.7 erlang; 4/4/4 capacity = 63.12 erlangAdditional capacity obtained due to expansion = 18.42 erlang
Some typical expansion configurations are:
Current BTS Expanded BTS Delta additionErl/TRX
achievedconfigurationErlang
capacity(V+D)
configurationErlang
capacity(V+D)
TRX Erlang(V+D)
1/1/1 8.82 2/2/2 24.60 3 15.78 5.262/2/2 24.60 3/3/3 44.70 3 20.1 6.703/3/3 44.70 4/4/4 63.12 3 18.42 6.144/4/4 63.12 5/5/5 84.75 3 21.63 7.215/5/5 84.75 6/6/6 104.04 3 19.29 6.436/6/6 104.04 7/7/7 126.36 3 22.32 7.44
For all other expansions not listed above, similar method of delta erlang calculationto be follow based on erlang table.
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4 Coverage levelsSignal levels (on road) recommended for various clutters is as below:
Clutter type On road RSSI^ Probability900 band 1800 band Voice Data
Dense Urban* -65 dBm -62 dBm 95% 90%Urban -70 dBm -68 dBm 95% 90%Industrial -75 dBm -72 dBm 95% 90%Suburban -75 dBm -75 dBm 95% 90%Rural / open -85 dBm -85 dBm 95% 90%
* includes CBD, high-rise buildings and old city areas with narrow roads and thickbuilding walls.^ Receive Signal Strength Indicator
4.1 Link Budgets
Typical radio link budgets to be used for 900 & 1800 MHz networks are as below.Any variations from these need prior approval.
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4.1.1 900 MHz band (for reference)
RADIO LINK POWER BUDGETMS
CLASS 4MS
CLASS 4MS
CLASS 4MS
CLASS 4MS
CLASS 4MS
CLASS
GENERAL INFO System: GSM GSM GSM GSM GSMFrequency (MHz): Frequency 900 900 900 900 900
RECEIVING END: BS MS BS MS BS MS BS MS BS MS BSRX RF-input sensitivity (TU50, RA250, HT100) dBm -112.5 -104.0 -112.5 -104.0 -112.5 -104.0 -112.5 -104.0 -112.5 -104.0 -112.5Fast fading margin + BTS power limit dB 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0Cable loss + connector dB 1.5 0.0 1.8 0.0 2.0 0.0 2.0 0.0 2.7 0.0 0.0Body proximity loss 0.0 3.0 0.0 3.0 0.0 3.0 0.0 3.0 0.0 3.0 0.0Rx antenna gain dBi 17.0 0.0 17.0 0.0 17.0 0.0 17.0 0.0 17.0 0.0 17.0Diversity gain dB 4.0 0.0 4.0 0.0 4.0 0.0 5.5 3.0 5.5 3.0 5.5Isotropic power dBm -132.0 -101.0 -131.7 -101.0 -131.5 -101.0 -133.0 -104.0 -132.3 -104.0 -135.0Field strength dBµV/m 4.3 35.3 4.6 35.3 4.8 35.3 3.3 32.3 4.0 32.3 1.3
TRANSMITTING END: MS BS MS BS MS BS MS BS MS BS MSTX RF output peak power W 1.3 37.2 1.3 37.2 1.3 37.2 1.3 37.2 1.3 37.2 1.3(mean power over RF cycle) dBm 31.0 45.7 31.0 45.7 31.0 45.7 31.0 45.7 31.0 45.7 31.0Isolator + combiner + filter dB 0.0 3.2 0.0 0.0 0.0 0.0 0.0 3.2 0.0 3.2 0.0RF-peak power, combiner output dBm 31.0 42.5 31.0 45.7 31.0 45.7 31.0 42.5 31.0 42.5 31.0Cable loss + connector dB 0.0 1.5 0.0 1.8 0.0 2.0 0.0 2.0 0.0 2.7 0.0Body proximity loss 3.0 0.0 3.0 0.0 3.0 0.0 3.0 0.0 3.0 0.0 3.0TX-antenna gain dBi 0.0 17.0 0.0 17.0 0.0 17.0 0.0 17.0 0.0 17.0 0.0Peak EIRP W 0.6 631.0 0.6 1230.3 0.6 1174.9 0.6 562.3 0.6 478.6 0.6(EIRP = ERP + 2dB) dBm 28.0 58.0 28.0 60.9 28.0 60.7 28.0 57.5 28.0 56.8 28.0Isotropic path loss dB 160.0 159.0 159.7 161.9 159.5 161.7 161.0 161.5 160.3 160.8 163.0
159.0 159.7 159.5 161.0 160.3 163.0CELL SIZES
COMMON INFO Urban Urban Urban Rural Rural RuralMS antenna height (m): 1.5 1.5 1.5 1.5 1.5 1.5BS antenna height (m): 25.0 35.0 50.0 50.0 80.0 110.0Standard Deviation (dB): 7.0 7.0 7.0 7.0 7.0 7.0OKUMURA-HATA (OH)Area Type Correction (dB) -3.0 -3.0 -3.0 -12.0 -12.0 -12.0INDOOR (In-car) COVERAGEPropagation Model OH OH OH OH OH OHSlow Fading Margin + BPL (dB): 18.3 18.3 18.3 13.3 13.3 13.3Coverage Threshold (dBµV/m): 53.6 53.6 53.6 45.6 45.6 45.6Coverage Threshold (dBm): -82.7 -82.7 -82.7 -90.7 -90.7 -90.7Location Probability over Cell Area(L%): 85.0% 85.0% 85.0% 85.0% 85.0% 85.0%
Cell Range (km): 2.8 3.5 4.1 11.9 15.3 23.1Cell Area (sqkm) 15.6 23.6 33.2 274.8 455.4 1044.7
OUTDOOR COVERAGEPropagation Model OH OH OH OH OH OHSlow Fading Margin (dB): 7.4 7.4 7.4 7.4 7.4 7.4Coverage Threshold (dB?V/m): 11.6 11.9 12.1 10.6 11.3 8.6Coverage Threshold (dBm): -124.6 -124.3 -124.1 -125.6 -124.9 -127.6
UltraSite rooftop+pole
UltraSite 35mcomb by-pass
UltraSite 50m1_5/8" c. by-
UltraSite +SRC80m 1_5/8"
UltraSite +SRC50m 1_5/8"
UltraSite MHA+SRC 110m
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4.1.2 1800 MHz band (for reference)
RADIO LINK POWER BUDGETMS
CLASS 1MS
CLASS 1MS
CLASS 1MS
CLASS 1MS
CLASS 1MS
CLASS
GENERAL INFO System: GSM1800 GSM1800 GSM1800 GSM1800 GSM1800Frequency (MHz): Frequency 1800 1800 1800 1800 1800
RECEIVING END: BS MS BS MS BS MS BS MS BS MS BSRX RF-input sensitivity (TU50, RA250, HT100) dBm -112.0 -102.0 -112.0 -102.0 -112.0 -102.0 -112.5 -102.0 -112.5 -102.0 -112.5Fast fading margin + BTS power limit dB 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0Cable loss + connector dB 1.5 0.0 2.9 0.0 2.7 0.0 0.0 0.0 0.0 0.0 0.0Body proximity loss 0.0 3.0 0.0 3.0 0.0 3.0 0.0 3.0 0.0 3.0 0.0Rx antenna gain dBi 18.0 0.0 18.0 0.0 18.0 0.0 18.0 0.0 18.0 0.0 18.0Diversity gain dB 4.0 0.0 4.0 0.0 4.0 0.0 3.0 3.0 3.0 3.0 3.0Isotropic power dBm -132.5 -99.0 -131.1 -99.0 -131.3 -99.0 -133.5 -102.0 -133.5 -102.0 -133.5Field strength dBµV/m 9.8 43.3 11.2 43.3 11.0 43.3 8.8 40.3 8.8 40.3 8.8
TRANSMITTING END: MS BS MS BS MS BS MS BS MS BS MSTX RF output peak power W 1.0 28.2 1.0 28.2 1.0 28.2 1.0 28.2 1.0 28.2 1.0(mean power over RF cycle) dBm 30.0 44.5 30.0 44.5 30.0 44.5 30.0 44.5 30.0 44.5 30.0Isolator + combiner + filter dB 0.0 3.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0RF-peak power, combiner output dBm 30.0 41.4 30.0 44.5 30.0 44.5 30.0 44.5 30.0 44.5 30.0Cable loss + connector dB 0.0 1.5 0.0 2.9 0.0 2.7 0.0 2.6 0.0 3.9 0.0Body proximity loss 3.0 0.0 3.0 0.0 3.0 0.0 3.0 0.0 3.0 0.0 3.0TX-antenna gain dBi 0.0 18.0 0.0 18.0 0.0 18.0 0.0 18.0 0.0 18.0 0.0Peak EIRP W 0.5 616.6 0.5 912.0 0.5 955.0 0.5 977.2 0.5 724.4 0.5(EIRP = ERP + 2dB) dBm 27.0 57.9 27.0 59.6 27.0 59.8 27.0 59.9 27.0 58.6 27.0Isotropic path loss dB 159.5 156.9 158.1 158.6 158.3 158.8 160.5 161.9 160.5 160.6 160.5
156.9 158.1 158.3 160.5 160.5 159.5CELL SIZES
COMMON INFO Urban Urban Urban Rural Rural RuralMS antenna height (m): 1.5 1.5 1.5 1.5 1.5 1.5BS antenna height (m): 25.0 35.0 50.0 50.0 80.0 110.0Standard Deviation (dB): 7.0 7.0 7.0 7.0 7.0 7.0BPL Average (dB): (and Car) 15.0 15.0 15.0 10.0 10.0 10.0Standard Deviation indoors (dB): 8.0 8.0 8.0 8.0 8.0 8.0OKUMURA-HATA (OH)Area Type Correction (dB) -3.0 -3.0 -3.0 -12.0 -12.0 -12.0INDOOR (In-car) COVERAGEPropagation Model OH OH OH OH OH OHSlow Fading Margin + BPL (dB): 12.3 12.3 12.3 7.3 7.3 7.3Coverage Threshold (dBµV/m): 55.6 55.6 55.6 47.6 47.6 47.6Coverage Threshold (dBm): -86.7 -86.7 -86.7 -94.7 -94.7 -94.7Location Probability over Cell Area(L%): 65.0% 65.0% 65.0% 65.0% 65.0% 65.0%
Cell Range (km): 1.9 2.5 3.0 8.9 11.9 13.7
C100 rooftop +poleC100 35m comb
by-passC100 50m 1 5/8"comb by-pass
C100 MHA +SRC80m 1 5/8"
C100 MHA +SRC50m 1 5/8"
C100 MHA +SRC110m 1 5/8"
4.2 Roaming sensitive locations
For locations like airports, railway stations, highway entry points, hotels etc, whereroaming traffic is high, following guidelines are to be adhered to:
a. Receive signal strength in idle mode must be always better than -85 dBm at allthe sensitive location.
b. Number of BCCH carriers should be equal or more than any other competitivenetwork in that area.
c. BSS parameter (RXP) on min signal strength of access should be set to -110dBm.
It is required that periodic comparative network testing is carried out at all roamingcritical locations to ascertain adherence to the above norms. Some of thetechniques by which more BCCH carriers can be added into a particular area are:
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a. Adding new sites (macro or IBS)b. Adding additional sectors within same sites (upto 6 sectors possible)c. By splitting a sector (which is non-serving the roaming area) to provide coverage.d. Changing antennas to high gain for sectors of neighbouring cells having lower
BCCH levels.
5 Antenna & Feeder cables5.1 Antennas
Antenna is a very critical part of the overall radio network design and hence properselection of antennas is important to meet the planning objectives. Following antennamodels are recommended for use in various clutter / coverage conditions described:
Note:
a. The above guidelines are indicative only for the type of application. However,specific antenna models not listed above can be used after prior approval.
b. All antennas to be used are of Electrical down tilt (continuously variable) only.c. Detailed antenna models and vendors are as per Hutch approval process.
Sl.No. Clutter HBW( ˚ ) VBW( ˚ ) Gain(dBi) Application1
Option 1 65˚ 30˚ 12 dBiOption 2 65˚ 9.5˚ 17 dBiOption 3 65˚ 14˚ 15.6 dBiOption 1 65˚ 7˚ 18/21 dBiOption 2 65˚ 4˚ 21 dBiOption 1 65˚ 7˚ 18/21 dBiOption 2 65˚ 4˚ 21 dBiOption 1 90˚ 14.5˚ 14 dBiOption 2 90˚ 7˚ 16.5 dBiOption 3 65˚ 7˚ 21dBiOption 4 65˚ 4˚ 21dBi
Option 5 45˚ 5˚ 22 dBiFor targetting extended coverage towards
specific Clutter
Option 1 45˚ 5˚ 22 dBi
For targetting extended coverage towardsspecific Clutter along the Highway/Rail
LineOption 2 30˚ 7˚ 21dBiOption 3 33˚ 5˚ 22 dBiOption 1 65˚/65˚ 30˚/20˚ 12/13 dBiOption 2 65˚/65˚ 15˚/8˚ 14/16 dBiOption 3 65˚/65˚ 10˚/6˚ 16/17.8 dBiOption 4 65˚/65˚ 9˚/9˚ 17/17.5 dBi
Dense Urban
3
2
b)
a)
Highways/Railway route
Dual Band (900 & 1800)6
5
Lower Vertical BW's for Low RiseBuildings
High Gains for better signal Penetrations
Lower Vertical BW's for Low RiseBuildings
For extended Coverage alongRailway/Highways
Higher Vertical BW's for High RiseStructures
For clutter evenly distributed closer to thesite
For extended coverages and unevenclutter distribution
Higher Vertical BW's for High RiseStructures
GUIDELINES IN SELECTION OF ANTENNAS FOR DIFFERENT CLUTTERS
High Rise Buidings
Low Rise Buildings
Urban
Sub-Urban/Rural
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5.2 Feeder cables
Following feeder types are recommended for various feeder lengths at sites in both900 & 1800 bands. This calculation is based on requirement of max 3.0 dB insertionloss of the feeder system,
GUIDELINES IN SELECTING FEEDER TYPE FOR DIFFERENT LENGTHS
Sr.No.
Length Of theFeeder
CableLoss(dB/100Mtr.)
Connectorization andJumperlosses(dB)
Feeder type Band
1 Up to 20 Mtr. 11.6 0.5 dB* 1/2" Super flexible Foam Dielectric 900 MHz2 20 Mtr. to 35 Mtr. 7.12 0.5 dB* 1/2" Foam Dielectric 900 MHz3 35 Mtr. to 50 Mtr. 4.02 1 dB 7/8" Foam Dielectric 900 MHz4 50 Mtr. to 70 Mtr. 2.87 1 dB 1 1/4" Foam Dielectric 900 MHz5 70 Mtr. to 90 Mtr. 2.38 1 dB 1 5/8" Foam Dielectric 900 MHz6 Beyond 90 Mtr. 2.06 1 dB 2 1/4" Foam Dielectric 900 MHz7 Up to 15 Mtr. 16.6 0.5 dB* 1/2" Super flexible Foam Dielectric 1800 MHz8 15 Mtr. to 25 Mtr. 10.1 0.5 dB* 1/2" Foam Dielectric 1800 MHz9 25 Mtr. to 35 Mtr. 5.75 1 dB 7/8" Foam Dielectric 1800 MHz10 35 Mtr.to 50 Mtr. 4.15 1 dB 1 1/4" Foam Dielectric 1800 MHz11 50 Mtr. to 70 Mr. 3.45 1 dB 1 5/8" Foam Dielectric 1800 MHz12 Beyond 70 Mtr. 3.05 1 dB 2 1/4" Foam Dielectric 1800 MHz
* no jumpersrecommended
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6 Dual Band (900/1800) planningDual Band:
Circles having licenses in two frequency bands are able to support the use of multiband mobile stations in both bands with use of the Dual Band feature. This isrequired especially when frequencies of one single band are limited.
Common BCCH Control:
The Common BCCH Control feature allows the integration of resources fromdifferent frequency bands into one cell. TRX of different frequency bands can beconfigure in the same cell by letting them share a common BCCH allocated fromone of the frequency band used in the cell and resources across all bands are co-located and synchronized.
Segmentation:
Common BCCH Control & Dual Band utilizes the segment architecture, whichintroduces a segment radio network object (SEG). A segment may consist of oneor more BTS objects. A BTS in a segment is a group of similar TRX in onefrequency band onlyThe operator sees common BCCH segment as single cell even thoughparameterization and management has been partly separated between the BTSsof the segment. The MS also sees the segment as one BCCH frequency band cellbecause it has no knowledge of the other frequency bands in a segment due to thefact that these bands have no BCCH. The BSC allows up to 36 TRX and 32 BTSobjects in a segment.
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The band where the BCCH carrier is in the common BCCH controlled segmentsmust be the same throughout the whole network. This ensures that the support forsingle band mobile stations remains in at least one of the frequency bands ofoperation. It is also possible that there are single band cells, in the networksimultaneously with the multi-band common BCCH segments and the service tomobile stations is offered via these single band cells as well.
In a multi-band Common BCCH segment the Initial SDCCH channel for a call set-upis always allocated in the frequency band where also the segment’s BCCH is.
The multi-band MS and the multi-band network shall support Frequency Hoppingwithin each band of operation. Frequency Hopping between the bands of operationis not supported.
The introduction of Common BCCH Control feature has not affected the basicstructure of statistics. The measurements are still collected per BTS in the segmentenvironment. The possibility to have frequency band-specific statistics and segment-specific statistics based on the BTS-specific measurements is offered by networkservice and OSS system.
Introducing the segment concept and the possibility to have several BTS objects inone cell causes changes in the data collection of some cell level activities and in theBTS-specific counter interpretation in the segment environment. The featureintroduces some new counters for the supervision of intra-segment
TCH handover based on load, intra-segment TCH handover based on signal level,intra-segment handover between frequency bands and for the supervision of inter-segment handovers that are also handovers between separate frequency bands.These are implemented in the handover measurement and the BSC level clear code(PM) measurement.
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Following are some NSN Major Parameters required to take care along with DualBand, Common BCCH & Segment Feature to make Dual Functionality properly.Same parameters can be optimized to take full advantage of additional spectrum.
Parameters Range NSNDefault Recommended
multiBandCell (DBC) No YesearlySendingIndication No YesmultiBandCellReporting 1 1nonBcchLayerOffset –40 to +40 dBm 0 dBmBTSLoadInSEG 0...100 (%) 70%MsTxPwrMaxGsm For GSM 800 and
GSM 900: 5..39 dBm 33
MsTxPwrMaxGsm1x00 For GSM 1800 0...36dBm with 2 dBm step 30
nonBCCHLayerAccessThreshold –90 dBmnonBCCHLayerExitThreshold –95 dBmnonBCCHLayerExitThresholdPx 2nonBCCHLayerExitThresholdNx 5...39 dBm with 2
dBm step 33 3
intraSegSdcchGuard 0 - 255 (s) 255
Example:Additional Capacity Gain due to availability of GSM 1800 spectrum
Spectrum Bandwidth No. ofChannels
BCCHLayer
SiteConfiguration
Max. SiteConfiguration
GSM 900 8.2 MHz 41 Yes 6/5/57/7/7
GSM 1800 2.0 MHz 10 No 1/2/2
Note: However to achieve better voice quality, some networks may limit number ofTRX loaded on 900 band to 5/5/5 & increase 1800 band loading.
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7 BTS7.1 Site types
7.1.1 Outdoor/Indoor
Following aspects should be taken into consideration before choosing indoor /outdoor BTS models:
Availability of adequate space for shelter Environment of use. Shared sites Far off / rural / highway sites If that site is a transmission hub site OR a BSC location, shelter is required to
be set up. Outdoor BTS on tower top for better coverage.
Capacity considerations
Indoor BTS with 1 level of combiner shall be planned in areas wherein thecapacity shall go beyond 12 TRX in any site within 1 Year or is part of DU,Urban and SU areas.
Outdoor BTS without any Combiner shall be planned in all new towns , HW ,Rail Routes and also sites that will be less than or equal to 12 TRX /site in 2Years.
7.1.2 Macro/Micro
Macro BTS: In areas of high traffic. ( ~12 TRX) Micro BTS: Used for (a) small coverage footprint to offload macro sites, (b) In
areas of low traffic (<4 TRX) & (c) In-building solutions where space is aconstraint. Micro BTS are usually used for infill sites to cover the coverageholes & capacity requirements.
7.1.3 Tower top BTS
Tower Top BTS shall be planned in highways and peripheral sites wherein thecapacity shall be less than 4 TRX/site for 2 years.
7.1.4 Street pole BTS
Street pole BTS are pole mounted BTS & shall be planned for road coverage,flyovers & highways.
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7.2 BTS Capacity Optimization
TRX Addition
New TRX to be added If the Average Utilization (FR+20%HR) of any fivedays of the week is more than 80%
New Capacity Site
New capacity site to be added when it is not possible to add more TRX tothe BTS due to spectrum, space and power limitation.
All necessary capacity enhancement techniques (refer to section 12)available in market and approved by VF corporate needs to be deployedbefore new capacity sites are planned.
TRX Deletion
TRX to be removed from the sites with more than two TRX and havingutilization less than 20% in consultation with Marketing department
Capacity for neighbouring sites must be optimized before planning a new capacitysite in a location. The given template should be followed for planning & tracking anew capacity site.
Capacity siteapproval form
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7.3 Handover and Power Control
For controlling the MS in dedicated mode, two main sets of parameters have to becarefully defined:
Power Control parameters, threshold definitions to trigger power controlcommands, as well as the power range of the MS (UL power control) andBTS (DL power control if enabled)
Handover Control parameters, threshold definitions to trigger handovercommands, for every type of handovers.
7.3.1 Handover Types
Handover is a basic functionality of cellular networks. Handovers can bedistinguished as either intra-cell, inter-cell or inter-BSC handovers. Handovers withina single cell (i.e. changing timeslots and/or carrier frequencies) can be handledautonomously by the controlling BSC. Handovers between cells of the same BSCcan also be handled by the BSC. Handovers between cells of different BSC must behandled by the initiating MSC. Handovers between networks (national orinternational) are mostly supported only when roaming or between two differentkinds of networks.
Figure: Handovers
• Intracell same cell, other carrier or timeslot• Intercell between cells (normal case)• Inter-BSC between BSC areas
• inter-MSC between MSC areas• inter- PLMN (only when roaming)
intracellintercell
inter-BSC
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7.3.2 Handover Criteria
Interference, UL and DL Bad C/I ratio Uplink quality Downlink quality Uplink level Downlink level Distance Rapid field drop MS speed Better cell, i.e. periodic check (power budget, umbrella handovers) Good C/I ratio PC: lower quality/level thresholds (DL/UL) PC: upper quality/level thresholds (DL/UL)
Note:The adjacent cell parameters must be specified in order to allow the handovers.
7.3.3 Adjacencies
A mobile cannot hand over to a cell, which has not been defined as an adjacent cellto the serving cell. Therefore, all possible adjacencies should be defined in order toensure successful handovers. In the beginning, it is a good idea to define all possibleadjacencies and later on, the unnecessary ones can be removed. Note, thathandover control parameters affect all handovers from the cell, whereas adjacentcell parameters only affect one connection.
Note:Always remember to define the adjacencies to both directions!
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7.4 Data network configuration
Within radio network, various data dimensioning points / nodes are indicated below.
7.4.1 Timeslot configuration
This defines the number of dedicated & dynamic timeslots to be configured per cell(sector).
Top Ten Cities : 2 dedicated + 4 dynamicRest of Network : 1 dedicated + 2 dynamic
However the above guidelines can vary based on local business requirements.
7.4.2 DAP Pool capacity
Top Ten Cities : 256 Kbps (64 x 4 TS)Rest of Network : 128 Kbps (64 X 2TS)
The above DAP size depends of traffic flow and also availability of TS in accesstransmission network.
7.4.3 PCU capacity
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No of sites per PCU card (logical) in Nokia BSS:
Top Ten Cities : 6Rest of Network : 12
BSC (660TRX) is delivered with 6 PCU-2 cards (12 logical PCU cards); however useof each PCU card should be in line with the above guidelines. Use of multiple PCUcards without fully loading them with the above defined sites will result in lowthroughputs to user due to high PCU reselections, in addition to more Gbrequirement.
7.4.4 Gb Link capacity
Gb – Frame relay
Top Ten Cities : upto 256 Kbps per logical PCU cardRest of Network : upto 128Kbps per logical PCU card
However Gb link capacity to be optimized based on quarterly performance reportsand analysis on actual carried traffic and utilization levels.
Gb over IP
As per implementation guidelines of VF data core & transmission groups.
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8 BSC8.1 Location
Locating BSC in the BSS network is flexible. BSC can be colocated or non-colocatedwith the MSC and the Transcoder.
The best location depends mainly on tariff structure / availability of transmissionmedia. For example, if the tariff correlates strongly with the distance of thetransmission line, the best location for a BSC is normally non-colocated with the MSCand the Transcoder. Transmission lines can be saved on the A interface by sub-multiplexing and concentrating the traffic on fewer lines. Concentration can save a lotof expenses because the number of lines can be dimensioned according to theexpected volume of traffic.
The start of the whole BSS design procedure relies on BSS traffic handlingrequirements.
The specific information needed in planning and dimensioning the network includesthe following items:
BTS locations and sizes BSC location MSC location Transcoder equipment location Available transmission media
The design starts from the BTS information, followed by the BSC, the Transcoder andthe MSC.
For the transmission part of the network, the following input data is needed fordimensioning:
The number of traffic channels on the A interface per BSS, full rate (FR/EFR), halfrate (HR), High Speed Circuit Switched Data (HSCSD), General Packet Radio Service(GPRS) and the number of EDGE TRX
The number of Transcoder units, their capacities and BSC A interface connectionscan be deduced from this number.
HSCSD will set special requirements for Ater capacity depending on how manyHSCSD circuits are used and how many parallel time slots are supported by thetranscoder. A given transcoder pool may support both FR/EFR/HR and multi-slotHSCSD.
Each HSCSD channel occupies an entity of 64 Kbit/s (one time slot) at the A interface.However, the data stream itself may be carried by less than 8 bits of the time slot.
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GPRS service is implemented by plug-in unit (PCU) in the BSC. The capacity of BSCto SGSN interface (Gb) is up to 31 x 64 Kbit/s per logical PCU, which is an entityhandling the same functionality in the BSC as a physical PCU plug-in unit in olderNokia BSC models.
The total number of TRX controlled by the BSC
If the dual band feature is in use, the TRX operate in different frequency bands.The capability of the BSC processing can be deduced from this number.
The total number of 2 Mbit/s links on the BSC Abis interface
The number of BSC Abis 2 Mbit/s connections can be deduced from this number.EDGE TRX can be connected using a shared Dynamic Abis pool which allowsdynamic allocation of capacity wherever it is needed.
8.2 BSC Capacity
BSC is to be dimensioned based on following limiting conditions:
Nos. of TRX Erlang carrying capacity BCSU Planning Nos. of Signalling links towards Transcoder and Abis (E1 ports) Nos. of BTS/BCF BHCA
Following are the limits in current version of NSN BSC
BSCmodel
Maxnos.of
TRX
Max no ofBTS/BCF
Max Erlcarryingcapacity(FR+HR)
No of SS7signalling
linksBHCA Remarks
BSC3i 660 248 3920 16 x 64Kbps 117K
Has 6 BCSU,each with 110TRX capacity
BSC3i –Hi cap 2000 2000 11880
10 X 2 MOR 16 X
512K354K
Has 10 BCSU,each with 200TRX capacity
Product Specific Information.
High Cap BSC 3iPD.pdf
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BSC3i (660 TRX)
No. of BCSUsTRXCapacity
ErlangCapacity BHCA Capacity
1 110 653 107,500
2 220 1,307 215,000
3 330 1,960 322,500
4 440 2,613 430,000
5 550 3,267 537,500
6 660 3,920 645,000
BSC3i (2000 TRX)
No. of BCSUsTRXCapacity
ErlangCapacity BHCA Capacity
1 200 1,188 194,400
2 400 2,376 388,800
3 600 3,564 583,200
4 800 4,752 777,600
5 1000 5,940 972,000
6 1200 7,128 1,166,400
7 1400 8,316 1,360,800
8 1600 9,504 1,555,200
9 1800 10,692 1,749,600
10 2000 11,880 1,944,000
8.2.1 Trigger points for BSC enhancement
Trigger points for BSC enhancement to be based on following 4 limits, whichever isreached first:
80% of total TRX capacity 80% of Erlang capacity 100% of BCF/BTS 100% of E1 port capacity 80% of BHCA
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For example, in the case of Nokia BSC3i with 660 TRX capacity should bedimensioned to be loaded for 528 TRX OR 3136 Erlang traffic OR 248 BCF OR 93.6KBHCA
Minimum BSC configuration of 400 TRX & to be considered in planning. Higher BSC capacities on beyond 1000 TRX to be considered in locations where
good backhaul media / capacity is available. Considering HR traffic, at least 2 signalling links per BCSU to be dimensioned in
view of HR traffic.
Note:Any new BSC location planned in the circle based on above guidelines requireapproval from VF corporate as per attached template.
New BSC locationrequest form
8.3 BSC Capacity optimization
BSC capacity to be optimized with neighbouring BSC before reaching the thresholdlimits as described above considering the traffic growth, TRX availability, new siteplanned & transmission availability
BSC capacity can be optimized by Re-parenting sites BCSU reshuffling
BCSU reshuffling should be done in such a way that after reshuffling new TRX loadingof parent BSC should not exceed 65%.
8.4 Location Area Design
A location area, as defined in GSM specifications, is the smallest area, into which aterminating call towards a mobile subscriber will be paged. Also, a location area isthe area in which a mobile needs not to update its location with its home locationregister.Location update is performed in idle mode when the mobile is roaming into a cellhaving a different location area code (LAC). In connected mode, the mobile willupdate its location with the network as soon as it becomes idle again, i.e. after callcompletion.While handover boundaries affect only mobiles that are in “connected mode”,location area boundaries affect all mobiles in the network, including the (many) idlemobiles.
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Location updating causes signaling and processing load across the entire networkhierarchy up to the mobile’s HLR. In case of foreign roaming mobiles (tourists), thisis often even international signaling traffic. Therefore planning of location areaboundaries should be considered with some thought, such as to avoid “oscillating”location updates along a heavily frequented road.Different MSCs cannot use the same LAC; otherwise, the BSC will not know to whichMSC the mobile belongs.When planning a dual band or a microcellular network, LACs should be very carefullydesigned. It is recommended to define the co-located GSM900 and GSM1800 cells(the normal situation) in the same LAC – and of course in the same MSC. This canavoid additional location updates, which would cause very high SDCCH blocking.Some networks, which have more than one vendor, might have separate MSC forGSM900 and GSM1800 respectively. Then, to a dual band MS; every cell is at theLAC border. This implies that the amount of location updates is very large andconsumes a large amount of SDCCH and signaling resources. More SDCCH needsto be assigned to the cells.
8.4.1 Paging vs. Location Updating Traffic
In a location area, there is a trade-off between paging traffic and location updatingtraffic. This means that concatenating e.g. a large city into a single location area willavoid any location updating traffic, but on the other hand causes a maximum inpaging traffic, since every single terminating call within the area is broadcast to everysingle cell in the area. (Even several times per call attempt, depending on networkparameters). This can cause significant traffic loads within the network.The task is to find the optimum compromise between paging and location updatingtraffic. This is not trivial, since it is a function of call distribution, user mobility and callarrival statistics. This problem has been studied in literature. There is in fact ananalytic minimum of signaling traffic. This minimum however is time-variant, afunction of user densities, user mobility and call arrival rates. Therefore, it is noteasily calculated. Figure 12 shows the basic dependency of paging and locationupdating traffic.
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Figure: Trade-off between location update and paging traffic
8.4.2 LAC size and border
Optimal LA size is a balance between PCH load and Location Updates (LU). If the LAsize is too large, paging channels and capacity will be saturated due to limited LAPDAbis or radio interface CCCH paging capacity. On the other hand, with large locationareas there will be a smaller number of location updates (LU) performed and viceversa. The same applies to paging coming via the Gs- and Gb-interfaces: the MSCsends the paging message to the SGSN with the LA info and the SGSN defines it toa more accurate area: cell, routing area (RA), LA or BSS. If within the SGSN areathere are cells that do not support GPRS services, the SGSN will group these cellsunder a 'null RA'. The SGSN will perform the paging procedure described above withinboth the RA(s) derived from the location information and the 'null RA'
Example
LA size for medium size cells (4+4+4 configuration)
In this example it is assumed that we have a configuration with 4 TRX per cell. If weuse 2 % blocking in the radio interface, we can see from the Erlang B-table that 21.9Erlang will be served on cell basis. This can be converted to 876 subscribers per cell(25mErlang/sub). If one site consists of 4+4+4 as a configuration, 23 sites togetherwill serve some 1511.1 Erlang or 60.444 K subscribers.
Note: The LA size for medium size cells (4+4+4) configuration with 276 TRX couldthen be as follows:
Total number of subscribers 60.444 (in 69 cells, each 876 subs.)TRX in LA 276 (in 69 cells, each 4 TRX)
Paging LocUp
# of cells in Loc. area
signallingtraffic
optimum numberof cells in Loc. area
function of user density,cell size, call arrival rate ...function of
user mobility
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Cell configuration 4+4+4CCCH channel structure NONCOMBINED (for example large cell)
total CCCH 9typical PCH 7
typical AGCH 2Number of Multiframes BetweenPaging
5 (does not effect PCH capacity, but MSbattery life time
Max. Pages per hour (in Air) 147.063 (TMSI2 60%, IMSI1 40%)Pages per hour with BSC nominal callmix 29 829
Max. Pages per hour (in Air) 147.063 (TMSI2 60%, IMSI1 40%)Pages per hour with BSC nominal callmix 29 829
LAC size should be restricted to 50000 subs.
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8.5 BSS Parameters
Following are recommended values for critical BSS parameters:BSS Parameters Recommended Value
CELL BARRED (BAR) "No"
BTS HOPPING (HOP)RF hopping (SFH) to be used in all cells with >1 TRX ; Decision forIBS sites to be taken on case-to-case basis
DR in use (DR) "YES"Trunk Reservation Used (TR) "No"Call Reestablishment Allowed (RE) "YES"Allow IMSI attach/detach (ATT) "YES"DTX mode (DTX) "SHALL"
RxLev Access Min (RXP)
a) -110 dBm for roaming entry cells & b) -105 dBm for all remainingcells
Radio Link Timeout (RTL)
Recommended value is 20 SACCH frames. However depending onspecific cell requirement and congestion levels in that cell, it can beset lower upto 12 SACCH Frames. Note: T 3109 timer should begreater than radioLinkTimeOut x 0.48 (in seconds).
Number of Blocks for AGCH (AG)
a) 1 AG Block for cells with Combined mode(BCCH+3*CCCH+SDCCH/4) & b) 2 AG Blocks for cells with NonCombined (BCCH+9*CCCH)
MS TxPower Max GSM (PMAX1) 33 dBmMS TxPower Max GSM 1800/1900 (PMAX2) 30 dBm
MS TxPower Min (PMIN)a) for 900 network : 5 dBm & b) for 1800 networks : 0 dBm
Max Number of Repetition (NY1)5
Max Number of Retransmission (RET)4
Number of Multiframes (MFR)4
Timer for Periodic MS LUP (PER)
Between 4 and 8 Hours depending on No. of LACs, size of eachLAC, Subscribers per LAC, No. of Pages per LAC & MSC Proc. Load.
GPRS enabled (GENA) "YES" (depends on requirement)
Any variations from the above need to be pre-approved.
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9 Transcoder
9.1 LocationTranscoders are usually collocated with the MSC to minimize the need for additionaltransmission media cost. In cases where the transcoders are utilized to 100%, thetransmission media from the MSC can be extended to a remote Transcoder torelieve temporary congestion across the interfaces.
This chapter does not address TCSM capacity in case it is part of R4 MGW. That isaddressed in Core network planning.
9.2 CapacityTranscoder is to be dimensioned for the busy hour (BH) traffic on the radio interfacewith following considerations:
Total carried traffic should include FR + HR calls. 90% of Transcoder resources utilization to be considered. GoS on ‘A’ interface at 0.1%.
Any variations needed to these dimensioning guidelines need to be discussed andmutually agreed.
Following TCSM, models are available:
TCSM model Channels E1 towardsMSC
E1 towardsBSC Capacity step
TCSM2i 960 32 8 120 Ch
BSC3i combinedwith TCSM3i 11,358 384 96 960 Ch
TCSM3i 11,520 384 96 960 Ch
Product Specific Information.
High Cap TCSMSheet.pdf
Example of TCSM capacity calculation
No of E1 towards Abis : 8 No of E1 towards A : 32
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Total circuits : 960 Total voice circuits available : 896 excluding signalling overheads.
Transcoder to be dimensioned for 90% capacity utilization of circuits. Hence, oneTCSM is planned to support upto 806 circuits or 742 Erlang at 0.1% GoS, whichtranslates to 23.2 Erlangs/E1 towards MSC.
However it must be borne in mind that Transcoder can handle traffic upto 100%capacity.
AMR circuit pool needs to utilize 100% as any overflow calls get directed to EFR/ FRpool.
Example:For a network requiring additional 100 BTS (2/2/2) of radio capacity, following shouldbe the Transcoder dimensioning:
Total radio voice capacity of the network = 22,200 Erlang Assuming 20% additional capacity due to HR, total offered radio capacity is equal
to 26,640 Erlang. Assuming 70% utilization of Radio capacity in BH, traffic = 18,648 Erlang
Transcoder should be catered for supporting 18,648 Erlang of traffic. Transcoderutilization. Taking 742 Erlang/TCSM, no of TCSM required is 25 nos of 32E1 capacity
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9.3 Pool configurations
At present following pools are being used in the network
CIRCUIT POOL NO 7 FR speech version 1 FR speech version 2 FR data (12, 6, 3.6 kbit/s) HR speech version 1 HR data (6, 3.6 kbit/s)
CIRCUIT POOL NO 23 FR speech version 3 HR speech version 3
9.3.1 Trigger points for enhancement
When AMR pool reaches 100% utilization, additional capacity to be added intoAMR pool from EFR.
When EFR pool is 90% utilized, then additional TCU or new TCSM is to beplanned.
Note:Transcoder are not required for NSN circles with R4 deployment. NSN circles withcore in R4 deployed, above transcoder guidelines will not be applicable
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10 Site Planning10.1 Radio planning
Radio coverage is frequently perceived to be the most important measurement fornetwork quality. Radio coverage planning plays a major role in GSM network planning,because it decides extent of coverage area, speech quality, mobility and customersatisfaction. Various forms of inputs and limitations from the customer in terms ofspectrum availability, network dimensions, frequency planning, network growth, localwireless regulations and finally the RF environment itself plays an important role incoverage planning. The approach for the coverage plan needs to be well definedsince, it requires to accommodate various phases of network growth across timewithout any compromise on service quality goal. Some of the major steps involved inthe cell planning are shown in figure below.
Site Planning Consists of Three stages:
Pre - Planning
Oriented at support from Customer Account Team. Involves BoQ finalization
Traffic &coverageanalysis
Systemdesign
Systemtuning
Nominalcell plan
Surveys
Implementation
CellPlanningProcess
40
Nominal Planning
Decide Planning Strategy & Set Criteria for Planning Prepare Nominal Coverage Plans
Detailed Planning
Site Surveys Finalize Site Locations & Physical Parameters Finalize Cell Configuration & Capacity Prepare final Coverage Plots Prepare Frequency Plans & Set Parameters Perform Pre-launch Optimization Site Implementation Data Site Implementation Report Site Integration Data Site Verification Report
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10.2 Transmission network planning
Consists of Three stages:
Pre - Planning Oriented at support Customer Account Team. Involves BoQ finalization
Nominal Planning
Decide Planning Strategy & Set Criteria for Planning Prepare Nominal Transmission Plans (Network Topology) Finalize BSC Locations
Detailed Planning
Site Surveys Finalize Site Locations & Physical Parameters Finalize Link Configuration & Capacity Prepare final PCM Plans Prepare Frequency Plans & Set Parameters
10.3 Pre - planning
Contains Network Dimensioning & System Configuration BoQ is Finalised based on the inputs from the customer Subscriber Forecast Total Erlang to be built in the year Traffic / User during Busy Hour (mErl) VLR / HLR Ratio BBH / NBH Ratio Utilization Factor Half Rate Usage Guidelines New Towns to be covered Subscribers forecast for the new towns GPRS Data Traffic in Hot Spots Coverage Requirements Frequency Spectrum Network Availability for designing Transmission Network Availability of leased lines if any Blocking Probabilities
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10.4 Nominal Planning
Performance of existing network is analyzed methods to rectify critical issues are identified Nominal Coverage Plot is generated Antenna System & Site Configurations are defined Tentative Transmission Network Topology is drawn MSC & BSC locations are defined Nominal Plan is generated based on the Following Inputs No. of BTS to be deployed TRX Configurations Coverage requirements as defined in Pre-planning Frequency Planning Strategy Network Performance Data Inputs on use of Special Features Inputs on Use of Ancillary Equipment (TMA, TMB, etc) Repeaters must avoided as far as possible
Results of Nominal Planning
Nominal Coverage Plan• Nominal Co-ordinate in UTM format• Site Code• Physical Parameters of the Site (Antenna Ht, Orientation, Tilt, etc)
Transmission Network Diagram• Media Selection• Capacity Requirement• 2 Mb/s Plan & TS Plan
10.4.1 Pre-Survey / SARF
Tentative site locations & search rings are given. Planning Team & Sales agree on the Coverage requirement and sign on the
area map• Hot Spots to be covered• Area to be covered
Preliminary checks are done in the planning tool to identify possible LoS
SARF
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10.4.2 Site Survey
Enables the planners to familiarize themselves with actual clutter / terrain• At least three preferred candidates to be identified• Obstructions to be check in all directions.• Panoramic photographs of the LoS is a must• Line of site to be check for all radio links• Preferred tower/pole locations to be identified & sketched
Make changes to proposed Nominal plan if necessary
Site Survey Report
10.4.3 Site Acquisition Report
Provided by the Site Acquisition coordinator to the Planning Team based on theSARF & contains
• Site Code• Correct Site Address• Building Height• SARF map indicating the site• Sketch of Roof area• Access to roof Photos• SAR is rejected / redone if information is incomplete• If all candidates are rejected, another option is found. This means• Changing the search ring if required• Revisiting the area• Redoing certain adjacent sites along with the revised SARF• GPS Co-ordinates, Addresses and Photos are a must for all options
SAR
10.4.4 Site Pre-Validation
Site candidates from SAR are prioritized and acceptance / rejection is givenaccordingly• Can also be done based on SARF – Pre-visiting of sites needs to be done• Planners are recommended to visit the site before this report is generated• Desktop Pre-validation is allowed only if the planner is extremely familiar with
the area Following information is checked while selecting the candidates
• Clutter type / Terrain• Coverage requirements in the area• Capacity requirements in the area• Map studies to confirm LoS
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• Surrounding Area• Site Location in itself• Antenna Locations• Cable Lengths• Obstructions in the main lobe of the antenna
Site Pre-validationReport
10.4.5 Technical Site Survey Report
• Run for all active candidates in descending order of priority for the given site• Representatives from all departments should be present during this exercise• Planners would perform all required verification / tests• Check / review LoS• Antenna Height & Orientations• Radio Propagation Measurements (if needed)• Structural stability of the candidate• Capture information about other operators details in the same site if any –
Co-siting• Photographs are a must (every 30deg starting from 0deg and obstructions if
any)
TSSR
10.4.6 Site Validation & Deviation
Done together with all relevant departments• Antenna System configuration is frozen• All site drawing are prepared
In case the site falls outside the search ring of RF Planner or does not meet thedesign criteria, the planners prepare a site deviation form and get it signed bythe concerned parties responsible the deviation along with all other membersof the TSSR
Site Deviation form
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10.5 Detailed Network Planning
Starts as and when a site is acquired Objective is to fix various Radio & TRS related parameters with the following
- Site locations- Type of equipment- Configurations- Use of special features
Final Coverage plan is generated Final Capacity is also generated Frequency Plan is finalized Interference analysis are performed & Interference plots are generated Parameters are planned Transmission plan is frozen 2 Mb/s plan is finalized Transmission network Capacity & Topology plans are generated
10.5.1 Radio Planning
Coverage Plan• Contracted Site Locations• Antenna Directions• Cable Losses• Antenna Types• Antenna Heights• Indoor Coverage Plan• Outdoor Coverage Plan• Special BSS Features used
Capacity Plan• Contracted Site Locations• Dynamic Hot Spots• Verified Hot Spots• Additional Fill-in sites if required
Frequency Plan• Allocated Spectrum• Frequency Hopping• Band for different layers• Plan for different layers• Reuse Pattern• Measurements• Location Areas• BSIC Planning• Special BSS Features used
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Interference Analysis• Adjacencies• Spectrum distribution• Hopping Frequencies• Guard Bands
Parameter Planning• Default set of parameters are defined• Emphasis on creating the correct parameters given by the planner to avoid
frequent optimisation later• Includes the following parameters• BSC, BTS, Cell, TRX Identification parameters
a) LACb) Cell Selection / Re-selection parametersc) Handover parametersd) Power Control parameterse) Adjacent Cell parametersf) Control of advanced system failures
• Traffic distribution between layers to get optimal results• Handovers to be minimised to reduce load
10.5.2 Transmission Planning(detailed guidelines to be issued by VF corporate Transmission team)
Microwave Link Planning• Performance calculations are made• Path Profile analysis is done• Frequency planning• Required Repeater locations are identified• LoS surveys are performed both on maps & on actual links
Results of this would includea) Antenna heights and sizesb) Antenna directionsc) Power levels (Tx / Rx)d) Hop lengthse) Performance calculations
2 Mb/s Planning• Traffic Routing across various nodes is done• Defines the traffic route through base stations / access network on a 2 Mb/s
level
Results of this would includea) Transmission Network diagram on a 2 Mb/s level
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b) Time slot & Cross-connect Planningc) Time Slot usage is defined at the transport linkd) Needed branching and Cross-connections are plannede) Time Slot allocation of transmission linksf) Branching & Cross-connection tables for the equipment with cross-
connect functionality
Synchronisation Network Planning
Synchronisation plan is prepared based on the following inputs• Network infrastructure• Network architecture• National Clock distribution information
Results of this would include
• Timing sources & hierarchy level definitions• Network timing distribution definitions
Management Network Planning
Knowledge on management regions, existing infrastructure & detailedtransmission network implementation plan are the input. Results would includenetwork management diagram including
• Information on management buses• Addressing of Managed Equipment
10.5.3 Co-site Planning
Extra care to be taken by the planner in this situation• Possible interference from other carriers to be analysed• Antenna heights & locations should be proposed in such a way that they do
not obstruct each other• Site visit along with Radio Planner is a must
10.6 Site Implementation Data
Upon completion of detailed planning, planning team provides the implementation datato the following personnel
• Logistics coordinator• Implementation Engineer• BSC Engineer
Planning team should ensure that data on the same site is being given to the variousdepartments
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10.6.1 Site Implementation Report
Submitted to the planning team by the implementation teams so that they can verify ifthe site has been implemented in accordance with the plan
• Care should be taken to implement the site in strict accordance with the planto avoid frequent optimisation and network degradation
• Drive test teams are deputed based on this form• If changes are made to the original plan between the time implementation
data was released and actual implementation, latest information to beshared with all the teams
10.6.2 Site Integration Data
During Site Implementation phase or immediately afterwards, Planning & BSCteams will create the site in the BSC database correctlyPlanning team provides the Site Integration Data to the BSC / OSS team. It containsof
• RF parameters• Neighbour relations• Necessary PCM information
10.6.3 Site Verification
After site integration, drive test teams perform drive tests and check the following• Coverage of the planned site• Call set-up & Call hold• HO Performance• Interference in the neighbourhood
Drive test teams should carry a coverage plot of the area and it is mandatory that arigger must accompany the team.
Physical optimisation if any should be done before the site is put on airPhysical optimisation of neighbouring cells should also necessarily be performedbefore the site is put on airThe Planner also checks the dump from the BSC / OSS to ensure that the site hasbeen created with the correct parameter settingsAny anomalies found should be immediately reported by the planner and he gets itrectified
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10.7 Site passive infrastructure sharing (with other operator)
GSM Antenna: 900 MHz and 1800 MHz antenna shall be placed at least 0.3m distance.
GSM Antenna and CDMA Antenna: Vertical Antenna Separation of 3m is recommended.
BTS Equipments inside the Shelter can be placed next to each other.
Feeder Cable laying shall be done in such a way that no Sharp bends are observed. Nocompromise on this aspect is allowed.
Future Capacity Enhancement requirement shall be considered while sharing the sites.Space for at least one additional cabinet for our Own BTS be available after sharing.
Sharing Partner’s Future expansion plan shall be considering before acceptingTechnical Feasibility.
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11 Capacity planning
11.1 Capacity Requirements
mErl/sub Calculations
Offered radio erlang capacity per subscriber to be calculated taking intoconsideration following parameters.
BBH / NBH Ratio VLR (Active) / Marketing subscribers NBH Erlang traffic / VLR (Active) % NBH Radio capacity utilisation % Half Rate traffic in NBH Data network capacity (dedicated only)
Following formula to be used for offered Erlang capacity calculations
Definitions of various parameters used in the formula:
NBH Traffic: Maximum value of radio traffic in 1 hour across 24 Hrs a day. The hourto be considered will be same across all BSCs in that network.
In each hour of the day, radio traffic recorded from each BSC will be aggregatedacross the network. The hour (out of 24 Hrs) in which this aggregated radio trafficvalue is highest will be the NBH traffic value.
BBH Traffic: This is the aggregation of maximum radio traffic carried by each cell inthe network in its busy 1 hour of the day.
VLR (Active): It is equal to VLR (Attached- own) + In roamers into the network. It isto be taken at the NBH time period of the day.
Reported Subs: It is the number of subscribers reported by marketing.
NBH Traffic VLR (Active) BBH TrafficOffered mErl/Sub = ----------------- x ----------------- x ---------------
VLR (Active) Reported subs NBH Traffic
_________________________________________ x (1 + % Data config)
(% Radio NBH utilization)
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Data Configuration: It is percentage dedicated data capacity defined across thenetwork. Recommended value for this parameter is 8%.
Radio NBH Utilization %: It is the radio capacity utilization (FR) calculated in theNBH time of the date. It varies from 50% - 75% across circles. Recommended valueis 70%.
Example:
Assumptions:
NBH Traffic : 40,000 ErlangBBH Traffic : 51,000 ErlangVLR (Active) : 1,400,100 subsReported Subs : 1,800,500 subsData config % : 6%Radio NBH Util % : 70%
Ratios calculated are:
BBH/NBH Ratio : 1.275NBH/VLR (Active) : 28.57 mEr/subVLR (Active)/Mktg Subs : 0.78
mErl/sub (offered) = 28.57 x 0.78 x 1.275 x 1.08----------------------------------------------- = 43.83 mErl/sub
0.7
11.2 Capacity rollout tracking
Monthly tracking of capacity forecasted / budgeted & actual rolled out is to befollowed. Attached is the template for the same.
Capacity tracker
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12 Network enhancement features
12.1Coverage enhancement solutions
With a view to get the maximum coverage out of current sites before a new site isplanned, especially in suburban/rural areas, following are some of the main featuresto be considered for capex savings into budget as per their applicability:
12.1.1 ICE (Intelligent Coverage Enhancement)
This feature helps in maintaining same coverage footprint even when BTS sitecapacity is enhanced from 2/2/2 upto 4/4/4. Useful for rural areas where coverageshrinks due to 3rd TRX addition.
12.1.2 SRC (Smart Radio Concept)
This uses 2 TRX units in single density mode and provides coverage extension onhighways/rural areas by upto 3 Kms depending on terrain. Hence a 4/4/4 site can beconfigured as a 2/2/2 site with higher coverage levels with a TMA in the uplink. Butthis solution should be restricted to areas where capacity requirements are less than2/2/2 for at least 6 months. For capacities more than 2/2/2, this solution is notcommercially viable.
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12.1.3 Two (2) Port Antenna Combiner By-pass
Description
2 Port regular antennas can be used in combiner by-pass mode to gain 3dB power in the LinkBudget. Coverage footprint increased with this implementation. Solution can be used in ruralarea, towns with single site and up to 2 TRXs per sector.
Implementation
By-pass the combiner of 2 TRXs & provide direct Tx/Rx inputs to AntennaPort
Dependencies
Regular 2 Port antenna required
Advantages
Gain of 3dB in Link Budget Enhanced coverage footprint for Rural Single site towns
Recommendations
Use of 2 Port Regular Antennas for Sector up to 2 Trx in Combiner Bypassmode.
Use 4 Port Antenna for More than 2 Trx Sector to keep the Trx in Uncombinedmode
2 Port Antenna (Combiner Bypass)
Tx1 Tx2
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12.1.4 Four (4) Port Antenna Combiner By-pass
Description
4 Port antennas can be used in combiner by-pass mode to gain 3dB power in the LinkBudget. Coverage footprint increased with this implementation. Solution can be used inrural area, sites with 3 and 4 TRXs per sector.
Implémentation By-pass the combiner of 3-4 TRXs & provide direct Tx/Rx inputs to
Antenna Port
Dependencies 4 Port antenna required
Advantages Gain of 3dB in Link Budget Enhanced Coverage footprint for Rural single Site towns Savings on pole mount with use of 4 Port Antenna No loss of coverage moving from uncombined 2/2/2 configuration to
Higher configuration of 4/4/4
Recommendations Use of 4 Port Antenna for sector having more than 2 Trx up to 4 Trx in
Combiner Bypass mode
4 Port Antenna (Combiner Bypass)
Tx1 Tx2 Tx3 Tx4
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12.1.5 High Gain Antenna [20dBi, 65°]
Description
20dBi, 65° High Gain antennas can be used to increase coverage footprint in rural andHighway/Railway sites. High Gain antennas can provide up to 6dB gain in link budget withcombiner by-pass mode.
Implémentation Implement 20dBi High Gain antenna in either Combine mode or
Combiner By-pass Mode
Dependencies 20dBi High Gain Antenna Required
Advantages Up to 6dB Gain in Link Budget Enhanced coverage footprint for Rural Single site towns
Recommendations Use of 20dBi High Gain Antenna
with combiner bypass for <2 TRX sector with combiner for >2 TRX sector
20dBi High Gain Antenna
Tx1 Tx2
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12.1.6 TMA
TMA to be used on for sites in suburban/rural areas where BTS downlink power isenhanced using special techniques as discussed in section 7 above. Typically linkbudget is balanced within ± 5 dB with default configuration deployment. DualDuplexed TMA units only to be used.
12.1.7 TMB
TMB provides Gain I both directions (uplink & downlink) and hence is to be usedonly when there is a requirement to increase coverage footprint while maintainingthe link budget balance. It is mostly used in in- building solutions where micro BTSis used for coverage.
It is not recommended for macrosites in view of higher cost involved.
12.1.8 Tower Top BTS
In a macrosite link budget, typically a 3dB feeder loss is considered. However inlocations where coverage enhancement is critical like in highway locations, BTSequipment can be installed on top of tower to avoid 3 dB feeder loss. This willresult in coverage enhancement and also capex saving on account of feeder.However due to higher tower loading involved, such solutions are recommendedto use micro BTS solutions like Metrosite & mini-Ultra models.
12.1.9 Repeaters
GSM Repeater systems are typically used in following
To extend coverage beyond BTS footprint To improve in-building coverage in urban areas. To create a dominant channel in an area to improve C/I and hence quality
Repeater types (based on power)
Low power repeaters (upto + 16 dBm output) Medium power repeaters ( upto + 27 dBm output) High power repeaters ( more than +27 dBm output)
Repeater types (based on application)
Pico repeaters (for home applications) Multi band repeaters
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Frequency shift repeaters Channel selective repeaters (do not support freq hopping) Band selective repeaters OFC fed repeaters (with separate central & remote heads)
Recommended vendors for various repeater models are as per Hutchrecommendations. However Frequency shift repeaters are not recommended in viewof disadvantaged cost model w.r.t micro BTS solutions.
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12.2 Abis Compression solution
Detailed field evaluation of Abis compression solutions offered by various vendors iscarried out. Salient features of the solution are:
Maximum 2:1 compression is obtained (in view of Abis links already compressedby 4:1)
Upto 100 Erlangs traffic per compressed link possible. 24 TRXs or more can bemapped onto 1 E1, depending on total carried traffic.
Data calls supported (GPRS & EDGE) AMR & HR supported. No perceivable MOS deterioration observed at peak traffic on the compressed
link. Solution is BSS vendor specific, in view of proprietary Abis configuration. Testing
completed on Nokia and Ericsson Abis only. NMS available
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Considering the current TRAI guidelines on leased bandwidth charges and alsoprevailing discounts offered by various NLD providers, use of this solution isrecommended for following cases:
Where additional E1 capacity for either new sites or existing capacityenhancements is not available from any BW vendor.
Where minimum of 2E1 links are required / used currently. Where chargeable distance is at least 100 Kms.
However this solution is not to be used for links with 6 or more E1s currently used orrequired within 1 year in view of lower bandwidth charges for higher E1 links.
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12.3 VSAT Abis connectivity
This solution for Abis connectivity is recommended only if all of the following conditionsare met:
BTS configuration shall not exceed 4/4/4 (including all chained sites to parentVSAT site)
At least two or more microwave repeater stations needed to connect BTS from thenearest Hutch site.
No leased bandwidth available from any vendor at least for next 1 year. Data traffic not required. (VSAT cannot support data calls in current software
version). However, SMS is supported. Space for installation of 2.4 Mts diameter VSAT antenna with clear sky visibility at
site.
Recommendation:
Based on the current cost structure of VSAT system for GSM Abis, at least 15 VSATremote sites per central Hub in a circle network are required to make this system costeffective, both in terms of Capex & Opex.
In current regulatory environment for VSAT approvals, a lead time of at least 6months to be considered for commercial launch from the date of PO.
CentralOffice
MSC
BSCE1
s SATModems
E1
RemoteSite
E1
Optimization box
BTS
SATModem
RemoteSite
E1
Optimization box
BTS
SATModem
A-BIS
1:2 Abis optimisationequipment
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12.4 Mobile BTS station
Following pros and cons of this system are to be considered:
Pros: Provide short term coverage and capacity in hot spots like convention
centers, exhibition grounds and sports complexes where a permanentsite is not required / possible due to various reasons.
Provide short term capacity & coverage in areas where new siteimplementations are delayed due to various reasons.
To study subscriber response in a suburban/rural area before committinga new BTS site. << good for circle operations >>
Can be used as testing Lab for new BTS products or features beforeimplementing network wide.
Cons: Need sufficient parking space to install the system and also require
advance coordination with local agencies. They are prone to accidents if not properly handled and installed. Require LOS to nearest cell site. Difficult in CBD areas with high rise
buildings. GSM Frequency plan changes required at short notice in neighboring
sites to bring up the mobile BTS. Require to arrange a vehicle to pull the trolley to the parking slot.
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Sufficient planning required on route taken to move the trolley. Narrowand temporary roads with low height over bridges cannot be used.
SACFA approval for temporary siting and height clearance required. Site may add localized microwave interference due to short term addition
of new hop into the network. Need sufficient training for BSS team to install the tower May not be used throughout the year, leading to a non-performing asset
in the network.
Recommendation:
To take a decision based on above considerations.
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13 Energy Saving Guidelines13.1 ULTRA EDGE BTS
13.1.1 Shiner –Frisco Trx
Description
Re arrange Shiner TRX as BCCH and Frisco TRX as non BCCH e.g. TRX 1,5,9 in4/4/4 Ultra can be Shiners and rest all can be Frisco. These TRX can be configuredas "preferred BCCH TRX" in the BSC. BCCH TRX always radiates at full power. Thereduction in power consumption comes from Frisco TRX in which the PA is shut downin idle time
Implementation
Simple implementation with re-arranging the Shiner & Frisco Trxs. Identification of Shiner & Frisco TRX Log into the BTS Manager Pickup HW version data for the BTS as Shown in Text A Seek the Version numbers of the Trx in Use FRISCO TRX : Version 209 and above SHINER TRX: Version up to 208
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Dependencies
Shiner/Frisco TRXs required
Advantages Frisco consumes less power than shiner TRXs Utilizes Idle time PA shutdown in Frisco Trx Lowers power consumption of the BTS Savings of up to 30 w per Trx
Recommendation Rearrange Shiner TRX as BCCH & Frisco in TCH in Ultra Site to lower
the power consumption of BTS.
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13.1.2 LTCD (Low Traffic Controlled Disconnect)
DescriptionIn large installations where more than 1 cabinet is used to form a cell it is
often the case that at times of low traffic a single cabinet offers sufficient capacity.The 2nd cabinet is hence surplus to requirements and can be turned off in order tosave power from the mains supply. A solution has been devised which utilizes amodified LVLD switch which is placed in the 48V supply line to the BTS cabinet andthe ‘Calendar’ SW tool in the BSC to switch of a 2nd auxiliary or slave cabinet underthe control of the ‘Master’ cabinet.
LTCD Hardware Specification
ImplementationLTCD box to be installed between power system and the two Ultra Site
cabinets
DependenciesThe solution can only be used when more than 1 cabinet is used, the cabinet
which is turned off to save power will not usable and should not carry any trafficwhich cannot be turned off. It is expected that all BCCH’s and traffic while movedonto the ‘Master’ cabinet before the 2nd cabinet is turned off.It is important to note that the cabinet which has been turned off will have none of itsenvironmental control systems running during the period it has no power applied toit. In outdoor applications particularly in area’s of high humidity there is a risk thatthe inside of the cabinet may go past the dew point as it cools and water dropletsmay form inside the cabinet. If this is likely to be the case then the extreme conditionsgasket kit (469996A - D-CONNECTOR ENHANCEMENT KIT) should be added tothe cabinet.The BSC command calendar executes events based on the system time. If the BTSis not operational when the calendar is due to either turn on or turn off the 2nd cabinetthen the event will not occur until 24 hours later. It is important that if the ‘master’cabinet is being reset or is off line when the event is due (particularly the turn oncommand) that the command is manually activated by the engineer who has beenworking on the master cabinet.
Advantages Power savings based on the expansion cabinet Trx Loading
Dimension (HxWxD in mm) 300x230x110 mmWeight (Kgs) 2 KgsVolume (Ltr) 7.6 Ltr
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For a 8/8/8 site with LTCD, 50% savings in power consumption duringTraffic Lean Hrs
Recommendation Identify Low Traffic Periods at Night Implement an External Switch connecting Expansion Cabinet to Main
Cabinet Run a Script for the BTS to switch off in the Lean Traffic Window set in the
Script. Ensure The Cabinet switches on at the end of the Time Window specified
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13.1.3 Hybrid Solution (Ultra 2/2/2 to Flexi 4/4/4)
DescriptionExpand existing 2/2/2 Ultra BTS to 4/4/4 with 2/2/2 Flexi in the lower half of
the same cabinet. The Flexi dTRXs can be shut down in low traffic hours.
ImplementationTrained BTS engineer needed on site insert the expansion kit and rearrange
the TRXs
Dependencies The configuration needs to be standardized and tested in all future releases Complex Cabling & O&M activity Hardware Kit Required to install flexi BTS
Advantages 120 w Savings in power consumption with respect to 4/4/4 Ultra Site
consumption Ease of Implementation within the same cabinet
Recommendation Use of up to 2/2/2 Flexi for Expansion of 2/2/2 Ultra Site Flexi Expansion Module placement within unused space in the Ultra Site
Itself Most Suitable for Expansion from 2/2/2 to up to 4/4/4 saving both Space
and power.
Existing Ultra site Cabinet
• Expand existing 2/2/2 Ultra site with2/2/2 Flexi
• FMUB to be installed along with thenew RF cables
• Possibility to power down the FlexiDTRXs in low traffic hours gives around120 W saving per site
• Feasibility study ongoing by using UltraMulti couplers (without Flexi DDUs)
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13.1.4 Co-Siting Solution (Ultra 4/4/4 to Flexi 6/6/6)
DescriptionFlexi EDGE can serve as an extension for Ultra Site cabinet. TRXs from both the
BCFs can be combined in same sector or the TRXs can be re arranged so that all FlexiEDGE TRXs are in the same sector.
ImplementationIt would be just like Multi BCF with 2 Ultra Site cabinets.
Dependencies Enables modernization with the latest product. All latest Flexi EDGE features can
be used in the Flexi BCF.
Advantages 120W Savings in power consumption with respect to 4/4/4 Ultra Site Use of single Synchronization cable between cabinets
Recommendation Use of up to 2/2/2 Flexi for Expansion of 4/4/4 Ultra Site Flexi Expansion Module(2/2/2) co-sited with Ultra site(4/4/4) Most Suitable for Expansion from 4/4/4 to up to 6/6/6 saving power.
.
2 x UltraSite EDGE BTS UltraSite EDGE BTS +Flexi EDGE BTS
GSM/ EDGE 6+6 GSM / EDGE 6
GSM/EDGE 6+6+6
GSM/ EDGE 4+4+4 GSM / EDGE 2+2+2
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13.2 FLEXI EDGE BTS
1. Script Based TRX Shutdown
Description
Flexi EDGE dTRU cab be switched off during low traffic period. The Time windowshould be identified for low traffic hours and script needs to be activated in OSS toshutdown the dTRU. Approx 295 to 335 W power saving observed per dTRUshutdown.
ImplementationTime Window needs to identify based on traffic pattern and Script should beactivated in OSS.
DependenciesScript based TRX Shutdown and Antenna Hopping feature can worktogether after following modification only.
Configuration at BSC
TRX 1 is the BCCH TRX BTS 2 is locked prior to locking DTRX 2 (TRX 3 and 4) using a script *due of antenna
hopping in use* TRX 1 and TRX 2 continue to be working on separate antennas with antenna hopping
– see next slide
Reconfiguration for TX cabling on site TX 1 and TX 3 on Antenna 1 TX 2 and TX 4 on antenna 2 DTRX 2 (TRX 3 and 4) to be powered off during low traffic hours DTRX 1 will supply power to DDU TRX 1 will be on Antenna 1 and TRX 2 will be on antenna 2 -> antenna hopping can
still be used
TRX-1
TRX-3
TRX-4
SEG-1BTS-1 BTS-2
BCCH
TRX-2
• BTS-1: TX1 and TX2 on separate antennas• BTS-2: TX3 and TX 4 on separate antennas
DTRX 1 DTRX 2
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Advantages Approx 10% Savings in power consumption with script based Trx shutdown.
Recommendation Use of Script to force calls onto BCCH Trx from TCH Trx On TCH getting freed, switches off P.A of TCH Trx Identify Lean traffic period for Flexi BTS Activate script for the BTS in BSS with time window set. Switch off & switch on of dTRU based on timings set in Time window.
DTRX 1(TRX 1 &2)
DTRX 2(TRX 3 &4) Antenna 2
TX 1 TX 2
TX 3 TX 4
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14 Network OptimisationThe network optimization process consists of the network performance evaluation andthe subsequent actions to improve them. The main tools used for network optimizationbelong to three classes:
planning tools radio measurements tools (drive test and propagation) OMC data analysis
14.1 Key Performance IndicatorsTo evaluate the performance of a network it is necessary to define some referencevalues, the so-called KPIs (Key Performance Indicators). KPIs are calculated after apost processing of NMS data or drive test measurement data. Usually one short-termtarget and one long-term target are defined for each KPI.
Every network produces periodically a report with the KPIs status to check the networkevolution and which targets are achieved and which not, this leads to the definition ofnew action points to improve the poorest indicators. KPIs calculated with NMS data,represent the network performance from the system side. KPIs from drive test figureout the performance on the subscribers’ side. Usually network quality is evaluatedaccording to some predefined KPIs figures like drop call rate and average downlinkquality.
The most reliable KPIs to evaluate the network performance with NMS are: Drop call rate [%], which is the percentage of call ended without a subscriber request
SDCCH and TCH congestion time, which is the sum of the partial time when all theresources of a cell are busy in the reference period (1 hour usually).
Call set-up success rate, which is the percentage of call attempts that leads to a TCHseizure.
Handover failure and/or success rate [%], which is the percentage of handover failure orhandover success in the reference period.
Average quality DL and UL, which is the mean value of all the quality samples uplink anddownlink.
Blocking percentage [%], which is the percentage of call attempts failure due to lack ofcapacity resource
All these figures can be collected on different network element basis (TRX, Cell, BTS,BSC…, PLMN).
Drive Test Measurements
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Drive test measurements and their analysis is a powerful means to evaluatenetwork performance from the subscriber point of view. It is possible to collectsome KPIs information like DL quality, call success rate, handover success rate,DL signal level from the drive test results, but the results are not statistically asreliable as NMS information. The real adding value of drive test measurementcompared to NMS data analysis is the following information:
find out the geographical position of problems like bad DL quality to look for apossible interference source in the area
compare the performance of different networks display the signal level on the digital maps to individuate areas with lack of
coverage and eventually improve the propagation model verify the neighbour list parameter plan.There are no strict processes for optimization because the activity is driven by thenetwork evolution.
Optimization Targets
In a new town launch area, the primary target is normally the coverage. In this phase,usually there is a massive use of drive test measurement both to check the signal andthe performance of the network
In a capacity driven network the primary targets are quality indicators like drop call rate,average quality, handover failures. In this phase, it is very important use the informationfrom NMS because they give a general view of the network performance. Drive testmeasurements are still used but not in a massive way, they are performed in areaswhere new sites are on air, or where interference and similar problems are pointed outby NMS data analysis.
The targets value, measurement time and measurement period for our network isshown below:
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KPIMeasurement Time Measurement
Period
Target
Top Cities Rest of NW TopCities Rest of NW
Switch KPISuccessful Call Rate (NBH) Network Busy Hour Daily >=99%Paging Success Rate per MSC (NBH) Network Busy Hour Daily >=92%Network Availability (Switch) 24 Hours Daily >=99.99%Network Availability (IN) 24 Hours Daily >=99.99%SS7 Signaling Load (NBH) Network Busy Hour Daily <=40%
Network level KPISDCCH Completion Rate (NBH) Network Busy Hour Daily >=98.8%TCH Completion Rate (NBH) Network Busy Hour Daily >=98.5%Handover Success Rate (NBH) Network Busy Hour Daily >=97%SDCCH Assignment Success (NBH) Network Busy Hour Daily >=99.5%TCH Assignment Success (NBH) Network Busy Hour Daily >=98%RX Quality DL (0-5) (NBH) Network Busy Hour Daily >=97%Radio Network Availability 24 Hours Daily >=99.95% >=99.5%
Cell Level KPI (% of cells meeting KPI)SDCCH Completion Rate(BBH) >98%
SDCCH Completion Rate(BBH) >98% Bouncing Busy hour Daily >=95% >=90%
TCH Completion Rate(BBH) >=98%
TCH Completion Rate (BBH)>=97.5% Bouncing Busy hour Daily >=95% >=90%
Handover Success Rate(BBH) >= 95%
Handover Success Rate(BBH) >= 95% Bouncing Busy hour Daily >=95% >=90%
SDCCH AssignmentSuccess (BBH) >=99%
SDCCH Assignment Success(BBH) >=99% Bouncing Busy hour Daily >=95% >=90%
TCH Assignment Success(BBH) >= 97%
TCH Assignment Success(BBH) >= 97% Bouncing Busy hour Daily >=95% >=90%
RX Quality DL (0-5) (BBH)>=96%
RX Quality DL (0-5) (BBH)>=94% Bouncing Busy hour Daily >=95% >=90%
Random Access SuccessRate (BBH) >=95%
Random Access SuccessRate (BBH) >=95% Bouncing Busy hour Daily >=95% >=90%
EDHE / GPRS KPIEDGE DL Average Throughput per TBF (DBH) Data Busy Hour Daily >=90 Kbps >=45 KbpsGPRS DL Average Throughput per TBF (DBH) Data Busy Hour Daily >=27 KbpsTBF Success Rate (DBH) Data Busy Hour Daily >=93%DL Multislot Assignment Success (DBH) Data Busy Hour Daily >=95%
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14.2 Performance Evaluation
Network Quality test for new coverage site / new town launch
Drive test is conducted before launching the network commercially for new towns. Atthis stage, the default parameter set should be used for all sites. In addition to that,the network planner gives the neighbor definitions for the site. The frequencies, BSIC,LACs and BCC are also defined.
The purpose of the measurements is to verify that the basic parameters have beengiven correctly and everything is functioning properly. This means that the frequenciesand handovers to all neighbors need to be checked. For this, radial measurementroutes into the neighbor cell areas have to be defined. In addition to that the coveragerange of the cell should be checked and compared with the predicted one.
Performance / Drive Test
Performance tests represent the subscriber's view of the network. Thesemeasurements are conducted in a live network on regular basis. During themeasurements, calls are generated e.g. every 2 minutes. The number of calls shouldbe high enough to be statistically reliable. A random route should be defined once andused repeatedly for the measurements. This enables the comparison of themeasurement data and hence the development of the network can be traced. Thehandover success rate, call set-up success rate and call completion success rate canbe obtained as a result from these measurements. This information is secondary tothe OMC information for the KPIs. However, performance measurements givegeographical information about the problem areas and hence give additionalinformation to the OMC data.
Optimization Process
An optimization process should not start without a previous Network Audit, in order tostate the starting point, that is, how is performing now the network that must beoptimized.
The Network Optimization itself could be divided in many ways, depending on thecriteria used. One extended criteria separates three main tasks: these are theParameters and Configurations Consistency Checks, the Performance Monitoring andReporting and the Performance Analysis and Troubleshooting. In a first phase, thismust be also the order or the three steps, but after a first iteration, all of them mustrun in parallel and in a recurrent way.
As the output result of each round, the solutions found for the identified problems andthe improvements suggested must be put in form of Change Request for itsimplementation in the network.
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Parameters &Configurations
Parameters &Configurations
PerformanceAnalysis and
Troubleshooting
PerformanceAnalysis and
Troubleshooting
PerformanceMonitoringNetwork
Optimization
Network Audit
Change Request
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Parameters & Configurations Checks
The consistency of the network must be checked initially, before any monitoring oranalysis, and periodically during the whole duration of the project, so that it matchesthe planned hardware configuration and parameter set. The checking list follows inthe paragraphs below. Obviously, some points have no sense in a project other thana replacement; it is the case of the first one.
o Hardware configuration vs plan: Sector configuration: number of TRXs and output power. The OMC engineer
should check this Antenna configuration: azimuth and tilt. To check by drive tests.
o Software configuration vs. plan, and consistency of values: Frequency plan. To check by drive tests and by consistency checks running in
Network Doctor Adjacency plan. To check in the same way. Parameter set. To check in the same way.
o Alarm status: check that there are no critical and performance-affecting alarms inany network element. The OMC engineer should check this using Network Doctor(menu 1 Fault Management).
o Parameter correctness, not in relation to the plan, but according to the differentstrategies, using for example Network Doctor Handover control and adjacencies strategy. Power control strategy. Dimensioning strategy (regarding signaling or GPRS capacity). Active features correct implementation. Traffic management strategy (between different layers, bands or cell types).
Performance Monitoring
o Statistics monitoring, using any of the reporting tools mentioned before:
Collecting the selected target KPIs at region level, in order to identify the genericproblems, and to follow up the project objectives and for reporting purposes.
Making worst cells lists, in order to detect the ones to focus the optimization in. Collecting a wider range of performance reports and Performance Indicators at
cell level, for troubleshooting purposes.
Performance Analysis & Troubleshooting
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Searching for specific problems and for ways to fix them is a continuous must, bothat area level and at specific cell level. The other permanent issue is trying to findways to improve crucial aspects of the network performance, namely the overallDrop Call Rate or Blocking Rate, by means of, for example, activating some featureor optimizing some parameter or dimensioning rule. A list of mandatory stepsfollows below:
o Finding generic area problems, by means of statistical analysis. For example: Wrong setting in handover thresholds. Feature not working due to wrong parameter set.
o Analysis of worst cells in the most critical indicators: using the Network Doctorreports can identify them.
Dropped Call Rate. Handover Failure Rate. TCH/SDCCH Blocking Rate.
o Identifying coverage problems, meaning both areas with bad coverage and cellscovering less or more than wanted: to check from drive tests.
o Finding interference and bad quality: to check from drive tests for geographicalapproach and from Network Doctor reports for cell specific approach.
o Detecting adjacency problems: to check from detailed analysis of drive tests andrunning Consistency Checks.
Missing neighbors. Unnecessary or unwanted neighbors. Incorrectly defined adjacencies.
o Finding hardware problems: the effects can be detected from statistics, andsome from drive test analysis. Further checking on-site by the implementationengineers is necessary.
Crossed sectors. Mixed antenna lines. Faulty units (TRXs, BBUs, etc). Imbalance problems (e.g., due to ROE in cables or jumpers).
The last step of the performance analysis, and only in case it is included in thescope of the project, is the traffic analysis and balance. The objective is to avoidblocking situations and to get a homogeneous distribution of the traffic among cells,or a traffic distribution according to the pre-defined traffic strategy between layersor/and between frequency bands.
o Analysis of worst cells: TCH/SDCCH Congestion Time. Cells with less traffic.
o Detection of strong imbalances between sectors of same site and betweenneighbor cells.
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o Unsatisfactory behavior of the different strategies of traffic distribution: Macro layer – micro layer – umbrella layer. Overlay layer – underlay layer (if IUO is used). GSM band – DCS band. Slow moving / fast moving MSs distribution.
Optimization Process Outputs
The whole optimization process must produce continuous and/or periodic results,with a double objective: a number of Change Requests, for operational purposes,and a periodic Performance Report, for follow-up purposes.
Change Requests
Right after producing a solution for a found problem a Performance engineer mustproduce a Change Request for every change he wants to introduce in the networkin order to fix the mentioned problem. The possible changes requested can be:
o Software changes: Changing a frequency. Changing a parameter. Adding/deleting/correcting an adjacency definition. Activating/deactivating a feature.
o Hardware changes: Modifying an antenna direction or tilt. Checking and fixing a detected hardware problem.
CRF Format
CRF_CRF no_Circlename_VEL_date
The full process from the CR form is produced until the changed is implementedmust be perfectly clear, as mentioned before. An example of procedure is shownin the figure below.
Perf .Eng .produces & sendsChange Request
Operator NwPResponsibleapproves CR
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After making any major changes the network elements are to be keptunder observation for some time for any deteriorate in the network KPI.
Performance Reports
Performance Engineer has to produce a periodic Performance Report, in additionto the final Performance Report. The periodic report, focused in the follow up andthe work in progress, could be weekly and should include most of the followingitems:
o Resume of the main KPIs, at circle Network level, for the reported period andevolution from the beginning of the project.
o List of worst cells for few critical KPIs, usually Drop Ratios and Block Ratios.o Graphs from the Drive Tests done (RxLev, RxQual, events), if agreed.o Resume of status of most critical active alarms.o Detected problems during the period.o Solutions: troubleshooting made.
The Final Performance Report will be more focused in summarizing theachievements of the established target KPI values. It could also include a resumeof the main troubleshooting works, grouped by type.
NetworkNetwork
EOSFLXEOSFLX
MiscTARGET InterferenceInterf. & qual CoverageMiscel. FaultsCapacity
KPIs values DTs plot s Upl ink Downlink Coverage Adjacencies Traf.distr. Redimensioning
Network ChangesNetwork Changes
EOSFLXPerformance Monitoring andAnalysis
Report
Extraction
Orange ProcessOperator ProcessSolution Deployment
NetworkNetwork
EOSFLXEOSFLX
MiscTARGET InterferenceInterf. & qual CoverageMiscel. FaultsCapacity
KPIs values DTs plot s Upl ink Downlink Coverage Adjacencies Traf.distr. Redimensioning
Network ChangesNetwork Changes
EOSFLXPerformance Monitoring andAnalysis
Report
Extraction
Orange ProcessOperator ProcessSolution Deployment
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ND reports
In the Nokia OSS ND reports can be generated to get the specific information aboutnetwork health. It provides ready-made textual reports for analyzing theperformance of the network. Reports are based on the collected from differentareas, such as configuration, performance and fault management with a specialfocus on the needs of network planning and O&M. Reports support the networkoperations scope from BSS level down to cell level The list of major ND reportsand its description is given Below
Report DescriptionReport 020 Report 020: Alarm statistics 221Report 023 Report 023: Alarm-specific statistics for each BTS 222Report 024 Report 024: Active BCCH missing alarms 223Report 025 Report 025: BTS alarm sum time by cells 224Report 027 Report 027: BTS outage breakdown over 10 days 159Report 030 Report 030: BSC alarm breakdown 158Report 034 Report 034: Alarm types and counts 218Report 035 Report 035: Alarm types and counts for BSC 219Report 036 Report 036: Number of alarms per object 221Report 041 Report 041: All base station sites per maintenance region 225Report 042 Report 042: All radio network sorted out by BSC, BCF, BTS 70Report 043 Report 043: All cells with LAC and CI 226Report 044 Report 044: Find BS sites having the given character string in the name 227Report 045 Report 045: Find cells having the given CI and LAC 227Report 046 Report 046: Find cells having an adjacent cell with the given CI and LAC 227Report 047 Report 047: Find cells having the given frequency 215Report 050 Report 050: Find locked BCFs, BTSs, TRXs and channels 103Report 051 Report 051: Find cells having GPRS enabled TRXs 266Report 053 Report 053: AMR parameters 288Report 054 Report 054: Segment configuration 210Report 055 Report 055: EGPRS parameters 270Report 060 Report 060: Adjacency discrepancies 76Report 061 Report 061: Non-symmetrical adjacencies 78Report 062 Report 062: Frequency check of adjacent cells 78Report 063 Report 063: BTS audit 93Report 065 Report 065: Adjacencies to non-existing or foreign cells 74Report 066 Report 066: Non-unique CI and LAC 82Report 067 Report 067: Handover synchronization 80Report 068 Report 068: BTS parameter survey 85Report 069 Report 069: Adjacent cell double frequencies 81Report 070 Report 070: BTSs with maximum number of adjacencies 94Report 071 Report 071: Cells with minimum number of adjacencies 94Report 072 Report 072: Defined, undefined and used adjacencies of a cell 98Report 073 Report 073: Undefined adjacent cells 99Report 074 Report 074: Adjacencies of cells 94
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Report DescriptionReport 080 Report 080: Number of named parameter sets 229Report 081 Report 081: Named sets used 230Report 082 Report 082: Allocation of a named set 231Report 089 Report 089: BSC option statistics 207Report 090 Report 090: Network configuration summary 68Report 090 Report 090: Network configuration summary 205Report 091 Report 091: Maintenance regions 207Report 092 Report 092: BSCs 208Report 093 Report 093: MSCs 208Report 094 Report 094: HLRs 208Report 095 Report 095: Base station sites of a maintenance region 209Report 096 Report 096: Location areas 209Report 097 Report 097: PLMNs 210Report 099 Report 099: BCF software and hardware type statistics 212Report 103 Report 103: Routing areas 266Report 110 Report 110: Occurrence of frequencies 213Report 111 Report 111: Frequency plan 101Report 121 Report 121: First and last measurement record times for each BSC 56Report 122 Report 122: Records for a measurement type, over BTS area 62Report 124 Report 124: TCH and SDCCH observation records 63Report 126 Report 126: Records for a measurement type, over BSC 55Report 127 Report 127: Last BSS measurement record times 54Report 130 Report 130: Cells having SDCCH congestion 133Report 131 Report 131: Unavailability classification per BSC 177Report 132 Report 132: Cells having SMS establishment failures 327Report 134 Report 134: Cells having RACH rejections 326Report 135 Report 135: Cells having TCH congestion 136Report 138 Report 138: Cells having high TCH raw blocking 138Report 139 Report 139: Cells having unavailable radio time slots 179Report 150 Report 150: Cells having high HO failure ratio 122Report 151 Report 151: Common BCCH, Multi-BCF HO 313Report 153 Report 153: Adjacencies having high HO failure ratio 123Report 154 Report 154: HO attempt cause distribution by cells 318Report 155 Report 155: TRHO handovers (AMH) 124Report 155 Report 155: TRHO handovers 307Report 156 Report 156: DADLB handovers 125Report 157 Report 157: Cells having high HO attempts/call ratio 326Report 158 Report 158:Intra BSS HO observation statistics 309Report 159 Report 159: WCDMA adjacencies having high HO failure ratio 310
Report 075 Report 075: BTSs with maximum number of adjacencies between LAs 100Report 076 Report 076: Adjacent cells having the same NCC, BCC and BCCH frequency 82Report 077 Report 077: BSC parameter survey 91Report 078 Report 078: BTS state conflict between BSC and MSC 104
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Report 160 Report 160: TCH drop call statistics by days across area 111Report 162 Report 162: TCH drop call statistics per day in each BSC 112Report 163 Report 163: Cells having high TCH drop call ratio 114Report 164 Report 164: Transcoder failures 324
Report DescriptionReport 166 Report 166: SDCCH drop ratio per cell 108Report 167 Report 167: Cells having high drop call count in handovers 327Report 180 Report 180: TCH traffic ( Erlang) per hour for each BSC or MR 141Report 181 Report 181: Daily TCH traffic profile for a BTS 147Report 182 Report 182: Busy hour traffic for all cells 139Report 183 Report 183: Low traffic cell check-up 324Report 184 Report 184: BSC unit load for each BSC 148Report 185 Report 185: Cells having maximum TCH traffic 144Report 186 Report 186: Cells having maximum paging traffic 149Report 187 Report 187: Cell location updates 149Report 188 Report 188: Cells having peak RACH load 150Report 189 Report 189: Cells sorted out by SDCCH or TCH holding time 150Report 190 Report 190: Cells having UL interference, 24-hour/10-day breakdowns 187Report 191 Report 191: Cells having bad link balance 302Report 196 Report 196: UL and DL quality and UL interference per TRX, 24-hour/10- day breakdowns 295Report 197 Report 197: UL and DL quality per TRX 296Report 198 Report 198: Cells by dominant link balance range 305Report 199 Report 199: Link balance of an area 301Report 200 Report 200: Daily sums of traffic in report 200, Performance statistics (benchmark) 141Report 202 Report 202: Cells having most delete indications and PImm. Ass.NACK 151Report 203 Report 203: Location update success ratio per BSC 129Report 205 Report 205: BTS GSM KPI/PI table, dynamic object and time aggregation 340Report 206 Report 206: TRX level GSM KPI/PI table, dynamic time aggregation 341Report 208 Report 208: Link balance per cell 304Report 213 Report 213: Performance statistics 268Report 215 Report 215: Availability per BSC unit 181Report 217 Report 217: SDCCH, TCH and BSC out HO observation statistics 116Report 220 Report 220: Clear code statistics 322Report 221 Report 221: Base station site check 345Report 222 Report 222: Call distribution per LA 142Report 225 Report 225: Drop call trace 118Report 226 Report 226: (E)GPRS KPIs 245Report 228 Report 228: Cells by multislot requests and allocations 250Report 229 Report 229: GPRS KPIs 241Report 231 Report 231: Cells by dominant distance range 314Report 232 Report 232: Distance range distribution per cell 315Report 233 Report 233: Cells by M 306Report 235 Report 235: GPRS counters 262Report 236 Report 236: Cells having max. HTCH traffic 233
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Report DescriptionReport 237 Report 237: UL PS traffic 246Report 238 Report 238: DL PS Traffic 247Report 239 Report 239: Territory upgrade, downgrade 248Report 240 Report 240: Frame relay, detailed 254Report 241 Report 241: HSCSD counters 330Report 242 Report 242: HSCSD KPIS 331Report 243 Report 243: Frame relay, short 256Report 244 Report 244: Distribution of call samples by codecs and quality classes, S10 (BER) 278Report 245 Report 245: Distribution of call samples by codecs and quality classes, S10 (FER) 281Report 246 Report 246: AMR call time and quality, dynamic time and object aggregation 282Report 247 Report 247: Transcoder failure ratio 283Report 248 Report 248: Codec set modification failure ratio 284Report 249 Report 249: AMR counters summary 287Report 250 Report 250: Cells by call success ratio 155Report 251 Report 251: Call success profiles of a cell 156Report 254 Report 254: TBF PI 252Report 255 Report 255: PBCCH availability 272Report 257 Report 257: Sleeping GPRS BTSs 276Report 260 Report 260: Position Based Services (PBS) 290Report 270 Report 270: Quality of service 273Report 275 Report 275: EGPRS RLC statistics 267Report 278 Report 278: WPS PI 333Report 280 Report 280: Dynamic Abis 269Report 400 Report 400: IUO counters of a cell 200Report 401 Report 401: Cells by average traffic absorption to super TRXs 191Report 402 Report 402: Cells by busy hour traffic absorption to super TRXs 192Report 403 Report 403: KPI statistics for IUO cells 201Report 404 Report 404: IUO measurement data per BTS 201Report 405 Report 405: Adjacent cells with the same or adjacent frequency, IUO super TRX excluded 202Report 407 Report 407: C/I statistics 202Report 512 Report 512: Log statistics 39Report 513 Report 513: Network Doctor use statistics 40Report 515 Report 515: DMR profile 164Report 516 Report 516: DN2 profile 164Report 517 Report 517: TRU profile 165Report 518 Report 518: Transmission statistics 163Report 522 Report 522: BSC ET profile 171Report 523 Report 523: BSC TCSM profile 174Report 525 Report 525: TRE profile 175Report 526 Report 526: TRE-SEL profile 175Report 700 Report 700: Cell related SGSN counters 264Report 800 Report 800: Quality survey 292
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14.3Interference Reduction
Interference is the sum of all signal contributions that are neither noise nor thewanted signal.Carrier-to-Interference Concept: Signal quality is largely determined by the ratio ofcarrier-to-interference (C/I). GSM specifies a minimum C/I of 9 dB to ensure nominalbit error rates under static propagation conditions.
Figure 1. Carrier to interference
Interference causes degradation of signal quality. This introduces bit errors in thereceived signal. Bit errors are partly recoverable by means of channel coding anderror correction mechanisms. There are also irreducible bit errors caused by phasedistortions of the radio signal (random FM noise).The interference situation is – as opposed to field strength – not reciprocal in uplinkand downlink direction. Mobile station and base station are exposed to very differentinterference situations. The ratio of Carrier-to-Interference (C/I) is a key figure forassessing the quality of a radio signal.Signal quality classification in GSM is based on detected bit error rates before allchannel coding and error correction takes place. GSM-specified parameter RXQUALranges from 0 (excellent) to 7 (bad) in logarithmic steps.
• Signal quality =sum of all wanted signals carriersum of all unwanted signal interference=
wanted signal atmosphericnoise
other signals
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Figure 2. GSM quality classes
Sources of Interference
The main source of interference is the re-use of own frequencies. Other contributionsto interference come from multipath components of the very same signal, i.e. longdelayed echoes that are outside the equaliser window of 16 microseconds. Externalinterference is caused by spurious emissions from other frequency bands.A network will practically always be limited in its performance by interference ratherthan by coverage. Interference is unavoidable due to re-use of frequencies.However, the radio planner’s goal will always be to push the interference limits asfar out as possible.
Co-Channel Interference
Co-channel interference comes from the re-use of own (limited) frequencyresources. It is therefore unavoidable in a network and the major contribution to totalinterference. Dense re-use of frequencies provides high capacity and also highinterference levels. Scarce frequency re-use provides excellent interference-freenetworks but with very low capacity. So, once again, it is the planner’s task to findthe compromise.The optimum layout of cell patterns, providing the best compromise betweenintroduced interference and achieved capacity, has been studied in depth inliterature. For illustration reasons often regular hexagonal cell patterns are used asa simplified case. Applicability of a model that greatly simplified is, however, doubtful.
DOCUMENTTYPE
TypeUnitOrDepartmentHereTypeYourNameHere TypeDateHere
R
D
Ancient concept !for demonstration only
CI
RD
6*
f2
f3
f4f5
f6
f7
f3
f4f5
f6
f2
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f4f5
f6f2
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f4f5f2
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Figure 3. Co-channel interference
where the carrier is R- and the interferers 6*(D- ).
RXQUAL Mean BER BER rangeclass (%) from... to0 0,14 < 0,2%1 0,28 0,2 ... 0,4 %2 0,57 0,4 ... 0,8 %3 1,13 0,8 ... 1,6 %4 2,26 1,6 ... 3,2 %5 4,53 3,2 ... 6,4 %6 9,05 6,4 ... 12,8 %7 18,1 > 12,8 %
usable signal
unusablesignal
good
acceptable
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There is a trade-off between C/I, frequency efficiency and network capacity. Whileanalogue systems feature a rather “graceful degradation” of signal quality andintelligibility with decreasing C/I; digital systems such as GSM will maintain a goodsignal quality by means of error correction codes down to rather low values of C/I.From a certain threshold, when error correction capabilities are exhausted signalquality will deteriorate rapidly and become unbearable ("cliff effect"). This isnoticeably the case under severe interference conditions.
Adjacent Channel Interference
It is possible that an adjacent channel causes interference problems. It is specifiedin recommendations that certain bit error performance requirements have to be metin conditions of static adjacent channel interference ratio of –9 dB (adjacent channel9 dB stronger than serving one). This is therefore typically considered as requiredC/IA ratio and normally adjacent channel interference is not a problem. After all,handover to this interfering channel is likely to be made before it begins to interfereseverely. However, in certain conditions adjacent channel interference may be a realproblem and it should be taken into account.
Figure 4. Relation of signal quality and C/I ratio
Long Delayed Echoes
A contribution to interference is caused by excessive multipath delays. Partial wavestaking long detours (e.g. by reflecting off a distant mountain) will arrive at the receiverwith a delay of more than the 16 sec equaliser window specified by GSM. Theselong delays act as interferers even in otherwise reuse-interference-free environment,since they will cause inter-symbol interference with the next transmitted symbol.Whether these effects cause noticeable interference also depends on theimplementation of the channel equaliser in the BTS and in the mobile station,respectively. (Equalisers may also be designed to cope with longer delays thanspecified in GSM)
6 9 12 15 18
C/ I ratio (dB)
quality
analog systems
digital systems
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Figure 5. Multipath echoes
Noise
Noise is the unavoidable companion and the “natural enemy” of the wanted signal.Main contributions to noise are: Physics: N = k * T * B
k = Boltzmann's constant = 1.38x10-23 J/K, T= temperature (Kelvin) and B issignal bandwidth. Noise floor for a GSM radio channel (at 25°C) is ~ -120.8dBm.
Technology: Amplifiers, filters, oscillators, mixers etc. add their noisefigures to the wanted signal
Interference Reduction Methods
The simplest method of interference control is proper location of base station sites.Sites on hilltops should be avoided in very most cases, since radio waves willpropagate unhindered across very large distances. Placing base stations in valleys,surrounding hills can be positively used as natural barriers for limiting both, coveragerange and interfered area.
equaliser window 16 s
amplitude
delay time (sec)
long echos, out of equaliser window:==> interference contributions
direct path
nearby scatterers• 1 sec delay = 300m16 sec delay = 4800m max. excess distance
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TypeUnitOrDepartmentHereTypeYourNameHere
bad location
good location
Figure 6. Number one method to reduce interference is to selectproper site locations
In a network capacity shall always be limited by interference rather than bycoverage. This limitation shall also appear at the latest possible point in the network’slife cycle.Some "add-on" methods for interference reduction are:
14.3.1 Antenna tilting /reorientation /beamwidth reduction
The first method greatly reduces interference probability and slightly improves spotcoverage. The second method is not so recommended because it may haveunwanted side effects (unpredictable interference towards other sites). The thirdmethod is a good one and it should be a common practice in designing cellularnetworks even from scratch (e.g. using 65° horizontal beamwidth instead of 120°).
14.3.2 Discontinuous transmission/reception (DTX)
It is a method for battery lifetime improvement and interference reduction. DTX is atranscoder function. When speech pauses, the transmitters in base station andmobile is switched off, as there is no useful information to transmit. Every 480 mssome “silence descriptors” are transmitted, informing the remote transcoder functionabout the characteristics of the background noise ("comfort noise") to be producedtowards the other caller.
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Figure 7. Discontinuous transmission
14.3.3 Frequency hopping (FH)
Frequency hopping is mainly a diversity technique against fast fading effects, bywhich some interference reduction can be expected as a (useful) side-effect. This ismost effective for static or slow moving mobiles, which may be hovering in a localfading dip for some seconds. Local fading dips are caused by destructiveinterference of two partial waves (multipath propagation!) of same amplitudes, butwith opposite phases. These fading dips can lead to practical elimination of the signalin an area of the order of half a wavelength (10... 15 cm for GSM900). This localfading dip is very frequency dependent, i.e. it would not exist for a different frequencyat the same location. And that is the basic idea behind frequency hopping. Thediversity effect caused by frequency hopping rapidly decreases with higher mobilespeeds, as the mobiles pass through the local fading dips quickly enough due totheir own velocity. As a side-effect frequency hopping produces an interferenceaveraging, since the interference patterns will be changing with the hoppingsequence: therefore interference conditions, if they exist, will be only for very shorttime periods (ratio 1:N, where N is number of frequencies used in HoppingSequence).
• Switch transmitter off in speech pauses and silenceperiods
• both sides transmit only “ silence updates” (SIDframes)
• “ comfort noise” generated by transcoder• VAD: Voice Activity Detection
• transcoder function• Transcoder is informed on use of DTX/ VAD
(in call set-up)
Battery savinginterference reduction
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Figure 8. Frequency hopping
14.3.4 Power control (PC)
It is a method for battery lifetime improvement and interference reduction. Powercontrol is controlled by the BSC and performed in both base station and mobilestation. It can be applied in uplink and downlink direction. When in connected mode,the mobile reports on a regular basis (every 480 msec) received signal power of theserving cell to he base station. BS commands the mobile to reduce/ increase itstransmit power in incremental steps of 2 dB. The aim is to maintain a good link qualityat lowest possible transmit powers. This reduces network interference and increasesbattery lifetime in the mobile. Power control can be level-based, quality based orboth. Level-based power control means the BS aims for a target RX level (parameteris set from OMC) of e.g. -88 dBm. Transmit power of mobiles and BS is regulatedsuch, that the received signal is always near the target level. Note that Power controlmay not be used on the entire BCCH carrier, since the mobiles for detecting a BCCHcarrier in the power-up procedure need a constant carrier signal. Quality-basedpower control means, that signal level is regulated such, that signal quality is justabout to deteriorate (due to low level or interference). This may be even at levels farlower than the simply level-based algorithm. There is no effect of power control onthe link balance, since both ends of the link regulate powers symmetrically. The linkalways remains balanced. In case of power control the maximum allowable path lossis not exploited to full extent.
• Diversi ty technique• frequency diversi ty against fast fading
ef fectsuseful• for static or slow-moving mobiles
• Base Band Hopping• signal hops between TRX s, (min. 2 TRX )• not on BCCH timeslot
• Radio Frequency (Synthesised) Hopping• timeslots hop between dif ferent f requencies• not on 1st TRX (BCCH) needs a wideband
combiner
Frequency diversity for static mobilesside-ef fect: interference averaging
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Figure 9. Power control
14.3.5 Adaptive antennas
It is a catchword describing actively steered antenna array constellations. Alsoknown as “Intelligent or smart antennas” or phased array antennas. Virtually anykind of radiation pattern can be achieved by phase-shifting the input signals fed tothe individual dipole elements of an array antenna. Antenna beams are formed toconcentrate their main lobe energy towards the direction of the user. The directionof the user is extracted from the uplink signal by means of “direction-of-arrival”algorithms. These are very heavy in computational load and involve analysing thecomplex uplink signal as received by 10s of elementary dipole elements of theantenna array. The critical ratio defining link quality is the C/I of the received signal.Instead of concentrating the main lobe towards the desired user (i.e. increasing the“C” part of the term), C/I can also be improved by reducing the “I”, that is theinterference. The “nulls” of the antenna pattern are directed towards the maininterferers, thereby significantly reducing the received energy from that direction.While main lobes are in the order of 20..30° in angle, the antenna pattern Nulls arevery distinct, reducing signals by some 20 dB within a few angular degrees only.Intelligent antenna algorithms involve very high computational power, severalparallel workstations are still needed to perform calculations in real-time. Antennapatterns can be switched within microseconds, i.e. a different antenna pattern canbe applied on a per-timeslot basis, if the controlling computers can keep up with thespeed. Several prototype antennas have been demonstrated also under liveconditions in GSM networks. However, only a single timeslot (1 out of 8) was activelysteered, the other 7 used the antenna’s static radiation pattern.
• GSM : 15 power steps à 2 dB each• BSC in command• level or quality-driven• Use power control in both uplink &
downlink• no affect in L ink Balance• M inimise interference in network• Save battery l i fe-time
PC not allowedon BCCH carrier
time
signallevel target level
e.g. -85 dm
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14.3.6 Dynamic channel allocation algorithms
Dynamic channel (frequency) allocation schemes are presently an area of greatscientific interest and research. The basic idea is as follows: every base stationconstantly measures the interference situation in the entire allocated band. Radiochannels are assigned to call requests on a per-call basis. The best suitable channelpermitting to maintain the minimum quality requirements is assigned to the mobile.“Best” channel can also be interpreted as the “best suitable” channel. This meansthat a mobile arriving with a strong signal may be assigned to a channel with a ratherhigh interference level, as long as the C/I minimum criterion is met. Therebychannels with less interference levels can be kept in stock for mobiles arriving withweak signals, where an “interference-free” channel is crucial for call success. Thepattern of interfering channels is constantly under change, depending on the mobiledistributions, call arrival statistics and user mobility. Dynamic frequency allocationeliminates the need for a fixed allocation. In principle every frequency may be usedin every cell without restriction (hardware permitting; combiners ...). This allows formaximum network capacity. Ultimately this becomes a “spread spectrum” situation,where every channel is re-used in every cell, i.e. the frequency re-use rate convergestowards unity. (re-use rate of 1)
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14.3.7 Antenna Hopping
Description
Antenna Hopping is a downlink performance enhancement feature designedto improve link performance where frequency hopping is not in use or noteffective due to high correlation between frequencies. In a typical sectorwhere you have the BCCH and hopping layer, the BCCH layer has nodownlink diversity since it is only one frequency transmitting over a singleantenna. This makes it more susceptible to noise, interference and fading.The hopping layer however has the advantage that it is “hopping” from onefrequency to creating phase diversity where it combats long term fading andfrequency related interference.This feature enables the TRXs in an RF hopping BTS to transmit with all theTX antennas in the BTS using the existing BB (Baseband) hoppingfunctionality in the BTS. With AH the improvement is more substantial on thenon-hopping layer because we bring it to almost equal link performance withthe hopping layer (Fig.1 and Fig 2). This translates to gain on the non-hoppinglayer that will improve existing coverage and RSSI levels. This feature wouldalso be very beneficial in interference-limited areas.
Implementation
Set parameter Antenna Hopping (AHOP) to Y AHOP is BTS level
Modification: BTS must be locked.Range: Y/NMML default: NDescription: With this parameter you define whether antenna hopping is used
in the BTS.
BCCH TRX Coverage
Hopping TRX Coverage
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Relatedcommand(s):
EQE, EQO
Note: OPTIONAL (ANTENNA_HOPPING_USAGE
Activating Antenna Hopping for UltraSite BTS
Lock the BTSs so that the Antenna Hopping for UltraSite BTS parametercan be modified (EQS)
ZEQS:BTS=1:L;
Take the Antenna Hopping in use in the BTS (EQE)
ZEQE:BTS=1:AHOP=Y;
Unlock the BTS (EQS)
ZEQS:BTS=1:U;
Dependencias
Prerequisites BSS S11, OSS 3.1 & UltraSite CX4.0-3 ULTRASITE EDGE HW EDGE TRX (non-EDGE TRX can be used in the same cabinet if it is in a
non-hopping or RF Hopping mode) Minimum of 2 TRXs per BTS (or cell) where both are used for antenna
hopping Antenna Hopping groups can include the BCCH
RestrictionsThe following features cannot be used together with Antenna Hopping: Cannot be used with Remote Tune Combiner (RTC) Cannot be used with Baseband Hopping (BB) in the same BTS Cannot be used with IDD in the same BTS (IDD uses the same BB
hopping module for AH)
The feature is OFF in the BTS if: TRX(s) are down The number of working TRXs fall below 2 TRXs/BTS
The following tests are not possible when Antenna Hopping is in use TRX test for Nokia Ultra Site TRX loop test
KNOWN ISSUES WITH ANTENNA HOPPING
Transmission outage causes some TRXs in a BTS to trigger “TRX faulty” alarmincorrectly causing the TRXs to become blocked out of service until a BTSreset was performed. This issue has been brought up with Nokia Product Linefor resolution.
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Advantages
Marginal increase in Traffic Good improvement in KPIs except DL Quality Improvement in signal penetration, Improved coverage
footprint
Recommendations
Use antenna hopping in close coordination with optimizationteam and with monitoring of basic KPIs wherever required.
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14.3.8 Bi-Sector Antennas - TenXc
Description 4 Port Antenna Small adjacent sector overlap reducing handovers Better match of original tri-sector coverage Increased capacity with HOS Dual split sector, increased capacity Seamless hotspot site deployments Avoid cell splitting with new sector adds Back to back BCCH frequencies used to increase the spectral
efficiencies
Implementation
Planning Consideration
Implementation Considerations
Site Numbering Strategy Strict replacement strategy: A replaced by A&D, B by B&E and C
by C&FWhy? Need to allow for growth from 3 to 4, 5 and 6 Sectors Minimize reconfiguration between 3 and 4, 5 and 6 sector sites Maintains Sector statistics as much as possible Allows for Back-to-Back (B2B) BCCH allocations
Two Fixed directional beams in one
In planning tool each beam needs tobe entered separately at +- 18 degreesdeployed direction.
Offsets can not be changed Separate LEFT and RIGHT beam
patterns need to be assigned correctly. Any mechanical tilt apply to both
sectors Electrical tilt can be applied
independently
Deployment Orientation
Left Orientation Right Orientation
TenXcBi-Sector
Array
RF Cables
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Back-to-Back (B2B) BCCH Allocation
How? Unique asymmetrical shape of BSA coupled
With high Front to Back ratio allows for BCCHTo be allocated twice per site
A&E, D&C, B&F are paired on same BCCH. For multiple sites reuse patterns can be used
To maintain separation Optimizer upgrades to support B2B are being
Pursued
BCCH Frequency Planning Considerations
Overall Strategy Use existing Frequency Planning allocations and strategy Optimize using Optimizer/Schema tool to deliver best results For 6.2MHz use 6 BCCH per site Only use B2B BCCH for 4.4MHz Use standard 4/3 reuse with B2B for multiple site deployments
TCH Frequency Planning Considerations
Overall Strategy Use existing Frequency Planning allocations and strategy Optimize using Optimizer/Schema tool to deliver best results For 6.2MHz use ad-hoc planning and Optimizer For 4.4MHz use 1/1 reuse
A
D
B
EBF
A DB
ECF
4/3 Back-to-Back Reuse
4.4 MHz 6.2 MHz orGreater
B2B BCCHNeeded
B2B BCCHNeeded
- Use Existing 3-sector BCCHS- Use AFP tools or display toolsto assign Best BCCH in B2B
- Assign three additional BCCHusing AFP tools or display tools
- Run Optimizertool after five days
of data
- Freeze BSA sites BCCHalloaction
- Use 4/3 reuse for multiple sites
- Run Optimizertool after five days
of data
YES NO
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Neighbour Cell Planning Considerations
Overall Strategy Disable B2B handovers: ‘A’ should not be a candidate of ‘E’, etc Restrict HO to adjacent sectors only if B2B BCCH is used Reuse existing 3-sector list: ‘Old list A’ should be used on both A and D Optimize once MS based measurements or drive testing is performed
Sector A D B E C FHandoverCandidate F,D A,B D,E B,C E,F A,C
Dependencies
Item Requirement CheckAvailability of space for additional cabinet for higherTRX Configuration. 2 Cabinets
Availability of Transmission Resources ( Additional E1)for higher TRX counts
2 E1 for 24TRX
Upgrading of power resources suitable for highercapacity configurations As required
Feeder Lines to be planned for additional sectors. 2 Per Sector
Suitability of existing pole to replace existing antennawith TenXc antenna
5 to 12 cmmount
VSWR of all feeders and TenXc antennas validationand readings meeting the specifications <1.4 Required
4.4 MHz 6.2 MHz orGreater
- Use 1/1 or 1/3 reuse planning- Assign three additional TCHallocations using AFP tools ordisplay tools
- Run Optimizertool after five days
of data
C B
A
A
E
D
C
BF
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Advantages & Recommendations To achieve High Capacity in High Traffic Cells Better Interference Containment and Traffic Balance Use of Higher Order Sectorization in High capacity Sites Relieve congestion Enhance Spectral Efficiencies Use of Back to Back BCCH frequencies Overcome constraint of adding Trx in spectrum limited Networks with use of
Back to Back BCCH Improve in building coverage
A) High Traffic Hot Spot Sectors B) Site and Cluster• Single sector having High Blocking in
Peak Hrs• Limitation in further addition of TRX’s
due to Spectrum Constraint or Sectorat maximum TRX allocation
• Spare TRX expansion due to lowertraffic on other sectors
• Having sufficient Transmission andpower back up resources for Higherconfigurations
• Multiple sector having High Blocking inPeak Hrs
• High Dense areas with High growthprojections and constraints in addingsites
• Limitation in further addition of TRX’s dueto Spectrum Constraint
• Relieve congestion from surroundingSites as well within the Cluster
• Having sufficient Transmission andpower back up resources for Higherconfigurations
Use of 3 Sectors. Maximum Configuration possible is
4/4/3 with Frequency Hopping. Maximum Traffic Offered with 4/4/3
Configuration is 54 full Rate Erl persite
Addition of Trx beyond 4/4/3 is notadvisable and will deteriorate theKPI’s
Additional Traffic is absorbed byaddition of New sites in Adjoiningareas
Use of Higher no. Sectors ranging from 4 to6.
Maximum Configuration possible is 4+4 /4+4 / 4+4 with BSA
Maximum Traffic Offered with 4+4 / 4+4 /4+4 Configuration is 120 Full Rate Erl persite
Addition of Trx beyond 4/4/3 is Possiblewith BSA
Additional Traffic is absorbed by addition ofsectors in the same site
CURRENT SCENARIO – 6.2 MHz WITH BSA – 6.2 MHz
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14.3.9 SAIC (Single Antenna Interference Cancellation)
Description
SAIC enables the interference cancellation without exploiting a second antenna
Two Major Approaches Blind Interference Cancellation (BIC): Only demodulate the desired signal.
They are mainly applied to GMSK modulation. Works in both Sync andUnsync NWs
Joint Detection (JD): Demodulate both desired and interfering signals. Although currently SAIC is for GMSK, conceptually JD methods also apply to
8PSK modulation SAIC methods are very sensitive to the amount of different interferers
overlapping the desired signal. Synchronized NWs are preferred since the timeslot alignment across the NW ensures that the set of interferers remainunchanged during the duration of a burst.
Expected Gain (Dependent non-linearly upon SAIC MS penetration) For low to moderate terminal penetrations, SAIC is provides its primary benefit
in terms of immediate improvement in call quality (and GPRS throughput) ofSAIC-enabled terminals, with the secondary benefit of modest system capacitygain (2.7% capacity gain with 20% penetration with specific networkconfiguration).
For high terminal penetration rates, SAIC provides both, improvement in callquality of SAIC-enabled terminals as well as large gain in overall systemcapacity. (50% capacity gain with 100% penetration in simulation with specificNW configuration)
NeighbourBTS
User 1
ServingBTS
OwnCell
User 2Interference
SAIC is digital signal processingtechnique, which uses the correlation
properties of a GMSK modulatedsignal to perform an active
cancellation of the interfering signals.
In today's network the vast amountof traffic is GMSK modulated!
GMSK modulated interferer’s SAIC gain!
8-PSK modulated interfererNo SAIC gain/NolossGains on both synchronized and non-synchronized networks (performs better in SyncNW).SAIC does not improve coverage.
GMSK
FR, HR and EFRspeechAMR speechGPRSEDGE (MCS1-4)Control channel
8-PSK EDGE (MCS5-4)
MODULATIONS
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Implementation SAIC can be enable at BSC level by loading the license file Various counter definition should be enable in BSC where SAIC is
implemented to get the SAIC related counter values
Dependencies BSS12 OSS 4.2 to measure SAIC Counters SAIC License
Advantages SAIC improves network capacity. The capacity gain due to SAIC
depends on Type of Environment Penetration of SAIC capable Handsets Ratio of GMSK Vs 8-PSK Traffic Geographical factors & Interference characteristics
SAIC improves network downlink performance
Recommendation SAIC can be used to improve downlink performance. The best system performance is achieved with SAIC when the uplink and
downlink interference cancellation is balanced. This can be achieved byusing Interference Rejection Combining (IRC) or Space TimeInterference Rejection Combining (ST-IRC) in the uplink (in the BTS)
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14.3.10 STIRC (Space Time Interference Rejection Combining)
Description
STIRC is an enhancement to Interference Rejection Combining (IRC) that isimplemented in NSN Flexi EDGE, EDGE Ultra Site, and EDGE Metro Site BTSs
In a multiple-antenna receiver, there is a strong correlation in the interferencebetween different branches (normal and diversity) and samples for each symbolperiod. Usually, the interference correlation is different from the correlation of thedesired signal.
IRC is a set of diversity combining, digital signal processing methods that removesinterference by taking these cross correlations into account. These methods can beconsidered as whitening the interference (there is no correlation) between theindividual branches and samples of each symbol which, if done perfectly, optimizesthe performance of the receiver, in particular the bit (0/1) detection process.
Implementation STIRC can be implemented in BSC via loading the license file and enable the
feature. STIRC related counter definition should be loaded in BSC to get the counter
values.
Dependencies STIRC License BSS 12, OSS 4.2 Due to the nature of the interference rejection algorithms, IRC and STIRC perform
best in synchronized networks
Advantages STIRC improves network uplink performance STIRC improves the adjacent channel and co-channel interference rejection
capability (in UL only) of the Flexi EDGE, NSN EDGE Ultra Site, and Metro SiteTRXs.
Recommendation STIRC can be used to improve uplink performance Best results when used with SAIC and with Synchronized network
Whitening
Whitening
Whitening,jointly
estimated
Space Time InterferenceCombining STIRC
Interference RejectionCombining (IRC)
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These methods can be used to fine-tune the interference conditions achieved so far.A bad frequency plan, however, cannot be substantially improved with these “add-on” methods. The main and decisive factor for interference reduction is thereforealways a good and proper frequency allocation plan to start with. Fixed frequencyallocation is implemented in most network planning tools. These algorithms assumestatic, worst case interference conditions and allocate frequencies to cells followinga heuristic allocation strategy. There is no closed-form, analytical solution to thefrequency allocation problem. Many different allocation strategies have been studiedin literature and are further under development. A good allocation plan still heavilyrelies on intelligent planner’s guidance. There also is no fully automatic allocationprocedure, but it is rather an iterative procedure between the planner and thecomputer.
Figure 10. Effects of interference reduction methods
Gains achieved by diversity, power control, frequency hopping and DTX are nophysical gains in terms of increased signal levels. They are “equivalent gains”instead. A gain of X dB means that the bit error rate found with usage of (e.g.)diversity corresponds to the bit error rate that could achieved with a carrier with XdB stronger, but without use of diversity.
Interference Planning
A main dimensioning criterion for the network is the amount of tolerated outage area.While “blocking” is a call-oriented network failure, caused e.g. by overload situations,“outage” describes a purely physical reason for network failure, e.g. power supplybreakdown, no coverage due to shadowing or interference.Network functionality can be provided if (area is covered) AND (area is notinterfered). Values for max. acceptable outage area is defined by the operator,typically 5 ...10%.The cell’s actual useful service area is calculated by:
% of areawith acceptableinterference level
# of radiochannels used
low high
80
100
90
design goal
tight re-use
power control
frequencyhopping
DTX
use largerbandwidth
good frequencyplanning
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(1- uncovered_area) * (1- interfered_area)
Figure :. Outage probability
• Dimensioning criterion :“How much of area to be covered is tolerated to be interfered?”
• Calculate total cell outage area :outage area = 1 - serviced_areaservice_area = (1 - interfered_area) * (1 - uncovered_area)
8%3%
4%Service_area = 93% * 92%
Outage area = 1 - 0,8556 =14,4%
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