Access Transmission Upgrade

Dr.Attila HILT, Péter PETRÁSDean EMSLEY, Grzegorz RYBARCZYK

Nokia Siemens Networks,NPO, Network Planning and Optimization

H-1092 Budapest, Köztelek utca 6. Hungary, [email protected]

ACCESS TRANSMISSION NETWORK UPGRADE IN A NATIONWIDE MOBILE NETWORK MODERNIZATION

PROJECT FOR EDGE DEPLOYMENT

1 © 2008 Nokia Siemens Networks - HILT Attila - Budapest , 1-Oct-2008.

INTRODUCTION• there is a continuous demand for capacity increase :

new sites, new services, deployment of EDGE, UMTS

• microwave access networks become very dense

• most of the networks expanded historically – not optimal

• planning rules were not always kept - planning mistakes

• several access networks are tipically 5…10 years old

• modernization & network optimization projects

• to meet subscribers‘ expectations

• better spectral efficiency – reduced frequency fees

• to adopt changing regulations, stricter standards

• to increase quality and reliability of the network


UNOFFICIAL INTRODUCTION

no complicated equationsbefore coffe break please…


“real life”

project

learnings

I tE E

E E t E t

E Et E t

PDopt R F

R F opt R FR F

R F

R F optopt R F

R Fopt

( ) cos cos

cos( ) cos

=+

+ + +

+ ± +

2 2 2

2

22 2

2

22

22

ω ω

ω ω ω

( ) ( )I k E E kP D R F o u t j o p t j o u t j k o p t j R Fk

N j

j

N( ) , ,

*, ,ω ω ω ω= ++

=

−

=∑∑

01

NETWORK MODERNIZATION & OPTIMIZATION• GSM networks developed originally for voice –data was not supported• most of the GSM networks are tipically 5…15 years old

• example of nationwide modernization of operator‘s GSM network• simultaneous deployment of EDGE (in parallel with UMTS roll-out)• operator‘s goal was to achive a high speed mobile data network

not technology specific (EGDE or UMTS) but service oriented

• modernization projects offer the possibility of network optimization• in RF: high mobile data rates (100…120 kbit/s typical), better KPIs• in TRS: massive capacity upgrades meanwhile:

• adopting changing regulations, stricter standards, • NW assessment, increasing quality and reliability• removing “historical” constraints/planning mistakes

•in RF&TRS: less interference, better spectral efficiency


GSM Network Architecture – EGPRS supports data

GnGGSN

Gb

SGSN

A.bis

MSC (or MSS)BSC

A

Core Network

BTS

BTS

Access Transmission

Network

Radio Network

EDGE : Enhanced Data Rates for GSM Evolution


Evolution of Mobile Data Rates : 1997-

UMTS

2002

2003

GPRS

General Packet Radio Service EDGE

Enhanced Data Rates for GSM Evolution

High Speed Circuit Switched DataWireless Application Protocol

Universal Mobile Telecommunication Services

ShortMessage

Service

SMS

1997

1999

1998~40 kbit/s

48 kbit/s(CS.2)

High Speed Downlink/UplinkPacket Access

HSUPA

GSM Evolution

2000WAP, HSCSD 236.8 kbit/s(MCS.9)

HSDPA

3.6 Mbit/s

2007

384 kbit/s

2008


EDGE – Modulation and Throughput

(0,0,1)

(1,0,1)

(0,0,0) (0,1,0)(0,1,1)

(1,1,1)

(1,1,0)(1,0,0)

8 PSK

(0,0)

(0,1)

(1,1)

(1,0)

GMSK

236.856Max.user TP/air-4TSL [kbit/s]59.214User TP/air-TSL [kbit/s]69.622.8Gross rate/air-TSL [kbit/s]348114Air IF burst size [bits]

270.833270.833Symbol rate [ksymbol/s]31Number of bits [bit/symbol]

8-PSKGMSKModulation methodEDGEGPRS


1.) Software upgrade/activationof existing, EDGE capable TRXs in existing UltraSites

2.) TRX upgradesin existing UltraSites(EDGE capable TRXs)

3.) Swap of entire BTS cabinet:Citytalk→ UltraSite and Flexitalk→ EDGE capable MetroSite

EDGE upgrade : SW activation or HW swap


Network Modernization Example : Site Swaps/Upgrades

more than 2000 BTS were swapped and/or upgradedred dots :

EDGE deloyment

on existing

TRS NW (D1)

green squares :

TRS NW upgrade

was necessary

(D2…D7)


Swap/Upgrade of the Base Stations for EDGE

very fast roll-out : 800 Sites in Phase 1, 1200 Sites in Phase 2

Sites swapped per week

0

10

20

30

40

50

60

70

80

Week No

Sites Swapped 0 1 0 1 2 2 8 11 23 23 22 16 21 13 39 25 38 40 29 42 52 51 71 62 61 58 28 0 0 0 5 13 18 17 20 19 15 20 12 29 32 21 24 29 34 33 42 24 37 35 31 42 45 27 27 15 11 4 10 16 26 37 41 35 37 33 42 41 44 39 39

5/26

5/

2

7

5/

2

8

5/

2

9

5/

3

0

5/

3

1

5/

3

2

5/

3

3

5/

3

4

5/

3

5

5/

3

6

5/

3

7

5/

3

8

5/

3

9

5/

4

0

5/

4

1

5/

4

2

5/

4

3

5/

4

4

5/

4

5

5/

4

6

5/

4

7

5/

4

8

5/

4

9

5/

5

0

5/

5

1

5/

5

2

6/

1

6/

2

6/

3

6/

4

6/

5

6/

6

6/

7

6/

8

6/

9

6/

1

0

6/

1

1

6/

1

2

6/

1

3

6/

1

4

6/

1

5

6/

1

6

6/

1

7

6/

1

8

6/

1

9

6/

2

0

6/

2

1

6/

2

2

6/

2

3

6/

2

4

6/25

6/

2

6

6/

2

7

6/

2

8

6/

2

9

6/

3

0

6/

3

1

6/

3

2

6/

3

3

6/

3

4

6/

3

5

6/

3

6

6/

3

7

6/

3

8

6/

3

9

6/

4

0

6/

4

1

6/

4

2

6/

4

3

6/44

10 © 2008 Nokia Siemens Networks - HILT Attila - Budapest , 1-Oct-2008

Concept of Dynamic A-bis Pool (EDAP)

Two sites of 2+2+2 configuration groomed into 1 E1

BTS1 ungroomed, space for future TRX upgrade, 6 TSL EDAP

BTS2 ungroomed, space for future TRX upgrade, 6 TSL EDAP

1 BTS per 1E1, 1 new 2 Mbit/s A-bis channel required

2 BTS sharing 1E1 (2Mbit/s)


• D1 : “Easy swap” site. Existing TRS capacity is sufficient to activate EDGE after the site is swapped or upgraded. No additional E1 required.

• D2 : New 2 Mbit/s path must be patched.Patching means remote electrical or local physical cross connections via cables on sites. Existing physical TRS capacity is sufficient, but the entire 2Mbit/s path must be estabilished and checked between BSC and BTS (A-bis) before EDGE activation. Typical example is “un-grooming” of sites, where sites sharing the same E1, but there is no available A-bis TSL for EDAP (EDGE Dynamic A-bis Pool)

•D3 : SDH upgrade is required.A-bis path contains SDH section, where 2 Mbit/s upgrade is needed for the BTS. SDH upgrade require activation of existing physical interfaces or insertion of new cards may be required

• D4 : MW link must be swapped or upgraded.• D5 : Leased Line upgrade required.• D6 : BSC problem :

No more free ET card available in actual BSC, PCU full-up,frozen BSC : BSC rehoming or BSC SW upgrade.

• D7 : Core NW upgrade is requiredE.g. SGSN, or Gb interface capacity upgrade.

Classification of possible problems in EDGE upgrade of sites


Statistics of TRS problems/upgrades – required for EDGE


0

100

200

300

400

500

D2patching

D3SDH

D4MW

D5LL

D6BSC

21

.3%

13

.3%

10

.9%

2.4% 3.5%

TRS problems Total % of sitesD1 1486 74.2%D2 427 21.3%D3 267 13.3%D4 219 10.9%D5 48 2.4%D6 70 3.5%

No of problems 2517 125.7%

Statistics of TRS problem sites

Conclusions : Number of sites are not equal with the number of TRS problems.One single site may suffer several TRS problemsSolution of a single TRS problem can solve the TRS problem

of several sites☺


TRS problem SitesD2 81 4.0%D2D3 110 5.5%D2D3D4 97 4.8%D2D3D4D6 7 0.3%D2D3D5 22 1.1%D2D3D6 30 1.5%D2D4 26 1.3%D2D4D6 7 0.3%D2D5 25 1.2%D2D5D6 1 0.0%D2D6 26 1.3%D4 84 4.2%TRS Problem sites 516 25.8%Sites without TRS problem 1486 74.2%Total 2002 100%

Total

0

50

100

150

D2D2D

3D2D

3D4

D2D3D

4D6

D2D3D

5D2D

3D6

D2D4

D2D4D

6

D2D5

D2D5D

6

D2D6 D4

Network Modernization Example : Topology, MW links (D4)


Modernization of MW Access Networks

Nokia Radio TypeCapacity 8x2 16x2 8x2 16x2 8x2 16x2 Mbit/sBandwidth 7 14 14 28 14 28 MHzPout (nominal TX power) 18 18 18 18 17 17 dBmVHP2-220A (60 cm) antenna 40.1 40.1 dBiVHLP2-220 (60 cm) antenna 40.1 40.1 dBiVHLP2-23 (60 cm) antenna 40.4 40.4 dBiBER=10-3 threshold, guaranteed -82 -79 -86 -83 -79 -76 dBmBER=10-6 threshold, guaranteed -79 -76 -83 -80 -75 -72 dBmSystem Gain, (BER=10-3) 100 97 104 101 96 93 dBSystem Gain, (BER=10-6) 97 94 101 98 92 89 dBSystem & 2xAnt.Gain, (BER=10-3) 180.8 177.8 184.2 181.2 176.2 173.2 dBSystem & 2xAnt.Gain, (BER=10-6) 177.8 174.8 181.2 178.2 172.2 169.2 dBGain increase compared to DH 4.6 4.6 8 8 0 0 dBGain increase compared to DH 5.6 5.6 9 9 0 0 dB

FlexiHopperPlus FlexiHopper DynaHopper

increased system gain

23 GHz example :

better antenna gain

double capacity in same bandwidth


Basic Rules of Dense MW Access NW Design

set transmit power as low as possible

proper use offrequency bands

use high gainantennas

select properlink polarization

avoid High-Low conflict on sites

use high qualityMW radios

balance Received SignalLevels at sites

monitorthe results

30

70


Polarization and Distance Rule

Distance(km) 0.15 1 3 5 6 7.5 10 12 15

Vertical

Horizontal Vertical

Horizontal Vertical

Horizontal Vertical

23 GHz

13 GHz

52 or 58 GHz

38 GHz

• always select the proper frequency band :

• long links → lower frequency bands (e.g. 13 or 15 GHz),

• short links → as high frequencies as possible (23, 26, 38 or 58 GHz).

• in several countries there are local regulations forcing all network

operators for efficient band selection.

• Swiss regulation is shown as an example:


ETSI defines RF channel raster and duplex distance in each frequency band.

(In some bands e.g. 15 GHz more duplex distances are standardized.)

1A 2A 3A 4A 5A 6A 7A 1B 2B 3B 4B 5B 6B 7B

Duplex (go-return) distancef

Low sub-band High sub-band

Tx=4A

Tx=4B

L (Low TX)

H (High TX)

Rx=4BRx=4A

High and Low TX Radios


H

HH L

L

near interferenceshould be avoided

H

HL

L

new freq. bande.g. 32 or 38 GHz

new link must be added :

Solution 1 :add one more site into the loop

Solution 2 :introduce new frequency band

H

HL

Avoiding High - Low Conflicts (near field interference)

H/L

HH L

L

High / Low TX channel allocation, all links are in the same band e.g. 23 GHz


• only high

output power

• high and low

output power

Preferably try to use low output power

but high gain antennas, if possible.

Setting Transmit Power Properly

LLH

L

high outputpower

low outputpower

low outputpower

HL

LH

L

high outputpower

low outputpower

low outputpower

H

L

LH

LH

high outputpower high output

powerhigh output

power

interference path

L

LH

LH


powerhigh output

power

interference path

LLH

L

high outputpower

low outputpower

low outputpower

HL

LH

L

high outputpower

low outputpower

low outputpower

H

L

LH

LH


powerhigh output

power

interference path

L

LH

LH


powerhigh output

power

interference path

L

LH

LH


powerhigh output

power

interference path

L

LH

LH


powerhigh output

power

interference path


Selecting High Gain and High Performance Antennae

high performance antennahas better gain in main directionand smaller sidelobes in unwanted directions

StandardHigh

Performance

5-15 dB

Interfered site

Standard antenna

Un-interfered site

High Performance antenna


OSS Monitoring of the Link Parameters•Pout

•RSL

•frequency

•modulation mode

•2Mbit/s cross

connections

•IDU configuration


Roll-Out Speed of Access Network Modernization

links planned

linksswappedorupgraded

linksfrequency licenced

linksto beswapped or upgraded

MW Link Swaps, Upgrades & New Links

1.Sep.

29.Sep.

27.Oct.2005

24.Nov.

22.Dec.

19.Jan.2006

16.Feb.

16.Mar.

13.Apr.

11.May.2006

8.Jun.

6. 3.Aug.

31.Aug.2006

28.Sep.

26.Oct.

23.Nov.2006

Jul.

PLANNED MW LINKS

FREQUENCY APPROVED LINKS

IMPLEMENTED MW LINKS

LINKS TO BE BUILT / SWAPPED

PLANNED MW LINKS




PLANNED MW LINKS




Num

ber o

f mic

row

ave

links

0

100

200

300

400

500

0

100

200

300

400

500

1. 29.


Topology of Repeater “VS803”Optimized for Access

Capacity Increase


Repeater Optimization for Access Capacity IncreaseOllon Chavalon Chavalon VD954 Territet Chavalon Gion Chavalon La Chiesaz Chavalon Sully Chavalon Legier Chavalon Corseaux Chavalon Pelerin Chavalon Mollie Margo ChavalonVD431 VS803 VS803 VD954 VD422 VS803 VD454 VS803 VD406 VS803 VD417 VS803 VD411 VS803 VD881 VS803 VD804 VS803 VD801 VS803

H:12 12912/13178V:13 12926/1319223429

53 22375.523383.5

Link 9 Link 10Link 5 Link 6 Link 7 Link 8

14.7 17.25 26.08

Site nameSite ID

Link number Link 1 Link 2 Link 3 Link 4

new fr. band 23 GHz 23 GHz 23 GHz 23 GHz 23 GHz 23 GHz

Vertical

FHP

FHPFH FHP FH

23 GHz

23 GHz 23 GHz 23 GHz 23 GHzold fr. band 23 GHz 23 GHz 23 GHz

yes yes yes no

16x2 16x2 16x2

Interference yes no no yes yes yes

4x2 4x2 4x2 8x2old capacity 4x2 4x2 4x2

Vertical Vertical VerticalVertical Vertical Vertical Vertical

FH FH FHFH FH DH FH

OLD

old radio FH DH

old polarization Vertical Vertical

FHP X-polar FHP

Horizontal X-polar Vertical

23 GHz 13 GHz 13 GHz

new radio FH FHP FH

Horizontal Vertical Horizontal Verticalnew polarization Vertical Horizontal Vertical

16x2

new channel [MHz] 11 128981316423404.5

22375.523383.5 30 22421

new capacity 4x2 8x2 4x2 4x2 8x2 4x2 8x2

no

old channel [MHz]

interference

22431.523439.5 64 22452.5

23460.5 56 22396.5

no no nono no no

hop length [km] 11.03 9.4 9.11 11.33 14.49

NEW

11.29

22382.523390.5 57 22403.5

23411.5 61

13.25

23 GHz 23 GHz

no no no

16x2 32x2

53

FHP

13

52 22368.523376.5 57 22403.5 65 22459.5

23411.5 23467.5 49 22347.523355.5 59 22417.5 66 22466.5

23425.5 23474.5 14 22386 16 22442 6 1290523394 23450 13171

59 22417.523425.5 54

• links marked with yellow had interference (all links were Vertical)• some links were out of channel range preferred by Authority• several links arriving to the repeater in a narrow angle• by systematic order of swapping link polarizations between

Horizontal and Vertical (H, V, H, V, …) and by swapping out 5 links : • access capacity increased from 80x2 Mbit/s up to 104x2 Mbit/s


How shouldn’t we plan microwave links ?

Strong wind may “influence”the network quality…

e.g. by changing polarization from vertical to horizontal


Sometimes the problem

may arise when the

wind does not blow…

How shouldn’t we plan microwave links ?


Try to keep the first Fresnel zone clear…

The link was implemented first…building reconstruction came later


CONCLUSION

• several GSM networks are typically 5…15 years old

• modernization with EDGE deployment in GSM networks

• results of a successful EDGE deployment for a Swiss mobile operator

• due to mobile systems microwave access networks became very dense

• continuous demand for capacity increase

• statistics of the required TRS network upgrades were presented

• several rules of dense access network design

• modernization projects give opportunity also for network optimization

• network optimization example of a repeater showed 24x2 Mbit/s

capacity increase for a microwave transmission node

Thank You for Your Attention !30 © 2008 Nokia Siemens Networks - HILT Attila - Budapest , 1-Oct-2008.

High altitude FlexiHopper radio : JungfrauJoch

FHP radio

at

3571 m


Documents

Access Transmission Upgrade