04 RN2010EN20GLN00 Radio Resource Management v1.0 [Compa

8/2/2019 04 RN2010EN20GLN00 Radio Resource Management v1.0 [Compa

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BSSPAR1: Chapter 4

Radio Resource Management

1 Nokia Siemens Networks


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Module Objectives

Give an overview about the signalling to establish and release a call Discuss the standard and maximum acceptable interference level

algorithm used for TCH allocation

Explain prioritised TCH allocation

Give an overview about the parameter settings applied to queuing

Explain how the queue is entered and left, and how these processes


Discuss the algorithms to verify call drop and re-establish a call

Explain TCH allocation and queuing for Wireless Priority of Service(WPS)


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Channel request (RACH)MS NETWORK

Immediate assignmentImmediate assignment (AGCH)

Service request (SDCCH)

Service request

Authentication request (SDCCH)

Authentication response (SDCCH) Authentication

Ciphering mode command (SDCCH)

Signaling (Mobile Originating Call)


Setup (SDCCH)

Call initiationCall proceeding (SDCCH)

Assignment command (SDCCH)

Assignment complete (FACCH) Assignment of traffic channel

Alert (FACCH)

Call confirmation

Connect (FACCH)

Connect acknowledged (FACCH) Call accepted


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Page request (PCH)MS NETWORK

Immediate assignmentChannel request (RACH)

Page response (SDCCH)

Service request

Authentication request (SDCCH)

Authentication response (SDCCH) Authentication

Ciphering mode command (SDCCH)

Immediate assignment (AGCH)

Signaling (Mobile Terminating Call)


Ciphering mode complete (SDCCH) Ciphering mode setting

Setup (SDCCH)

Call initiationCall confirmation (SDCCH)

Assignment command (SDCCH)

Assignment complete (FACCH) Assignment of traffic channel

Alert (FACCH)

Call confirmation

Connect (FACCH)

Connect acknowledged (FACCH) Call accepted


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DisconnectMS NETWORK

Call clearingRelease

Channel release

Release complete

Network initiated

Signaling (Call Release)


DisconnectMS NETWORK

Call clearingRelease

Channel release

Release

Release complete

MS initiated


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MS capabilities

Channel rate : full, half, dual, multi rateSpeech codecs : normal FR, normal HR, EFR, AMR FR, AMR HR, Double HR(OSC)

MSC demands

A interface circuit allocated for call

Standard TCH Allocation (General Criteria)


BTS demands

Speech codec capabilitiesTCH configurationCurrent resources

Homogeneous use of TRXs and radio time slotsLarge free groups of radio time slots for high loaded HSCSD BTS


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Measurement of uplink receive level on idle channels = uplink interference

Averaging over interferenceAveragingProcessAverPeriod (AP)(6) = 1..32 SACCHperiods

Classification into interference bands based on interferenceAveragingProcess(BO1..BO4) = -110..-47 dBm

Standard TCH Allocation(Interference Bands)


BSC tries to allocate TCH from best interference band (can be requested by MSC)If not available, BSC tries to take TCH from next band

0 71 2 3 4 5 6

rxLevUL = -75 dBm

BO5 47 (fixed)

BO0 110 (fixed)

BO4 -90

BO3 -95

BO1 -105BO2 -100


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Measurement Coding

RxLev Coding

-110dBm 0-109 1

-108 2

BER(%) Coding

< 0.2 00.2-0.4 10.4-0.8 2

I Interf.(dBm) Band

-110 to -105 0

-104 to -100 1

LEVEL QUALITY INTERFERENCE


. .

. .- 49 61- 48 62

- 47dBm 63

0.8-1.6 31.6-3.2 43.2-6.4 5

6.4-12.8 6> 12.8 7

-99 to -95 2-94 to -90 3-89 to -47 4


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Standard algorithm

Does not avoid allocation of strongly interfered channels-> dropped calls-> channels allocated again with same consequence

Maximum interference level algorithm

BSC tries to allocate TCH from interference band into which MAX INTF LEV falls

Maximum Interference Level(Call Set Up + Intra Cell Handover)


MAX_INTF_LEV = RXLEV_UL - cNThreshold + (msTxPwrMax - MS_TXPWR)

_ _-> TCH usually from better band than according the standard algorithm

Parameters

RXLEV_UL current uplink receive levelcNThreshold (CNT)0..63 dB desired C/N ratioMS_TXPWR current MS output powermsTxPwrMax maximum allowed MS output power in serving cell


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MAX_INTF_LEV = RXLEV_DL - rxLevBalance - cNThreshold

RXLEV_DL is current downlink receive level

Maximum Interference Level(Inter Cell Handover)


BSC tries to allocate TCH in target cell from interference band, into which MAX_INTF_LEV falls

MOClass

AbbreviatedName

Range And Step Description Defaultvalue

BSC - MMLName

BSC rxLevBalance 0...20 dB, step 1

dB

Balance between the DL signal level and

the UL signal level within the BSCcoverage area. DL is considered RXBALdB stronger than UL.

5 dB RXBAL

BTS cnThreshold 0...63, step 1 The minimum acceptable C/N(carrier/noise) ratio when selecting a timeslot to be allocated for a call or handover.

0 CNT


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Priority for TCH from BCCH TRX

BCCH is transmitted permanently -> no additional interference in networkPlanned to be least interfered channels

Prioritized TCH Allocation

Whole band , 50 channels 1 ch=200kHz

BCCH, 30 channels TCH, 20 channels

All 50 channels for BCCH and TCH

Case1

Case2


Priority for TCH from other TRX

BCCH TRX does not hop in case of RF hopping -> hopping gain only for other TRX

Parameter

trxPriorityInTCHAlloc (TRP) 0 = no priority1 = priority for BCCH TRX2 = priority for other TRX3 = priority for BCCH TRX for non-AMR users,

priority for other TRX for AMR users


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Priorities

No TCH available for call set up / handover -> request put into queueDifferent kinds of requests can have different priorities

queuePriorityUsed (QPU) Y/N enables use of priorities

queueingPriorityCall (QPC)(10) 1..14 priority for call set up requestqueuePriorityNonUrgentHo (QPN)(9) 1..14 priority for non urgent handover (power budget,

umbrella, slow moving MS, traffic reason)

Queuing (Parameters)


request

queueingPriorityHandover (QPH)(9) 1..14 priority for urgent handover (all other) request

Queue length and time

maxQueueLength (MQL)(50) 0..100% percentage of number of TCHs handled by BTStimeLimitCall (TLC)(10) 0..15 s time a call set up request is kept in the queue

0 = queuing is disabledtimeLimitHandover (TLH)(5) 0..10 s time a handover request is kept in the queue

0 = queuing is disabled


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Conditions

Timers set to values > 0Use of priorities enabledQueue not full with requests of equal or higher priority than the current one

Queuing of call set up requests

Queuing (Entering the Queue)


Reservation of SDCCH resources-> SDCCH easily overbooked-> blocking of services like SMS or location update


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With TCH allocation

Release of busy TCH Check of queue from top to bottom for best matching request If TCH allocation possible, request removed from queue

Without TCH allocation

Queuing (Leaving the Queue)


Queuing timer expiresRequest of higher priority enters full queue


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Directed Retry Timer maxTimeLimitDirectedRetry expires

call cleared, even if still in queue

Queuing timer expires

target cell evaluation continues, if directed retry timer is still running

Queuing (Together with Directed Retry)



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BTS does not receive measurement report onSACCH for running call for the first time

Counter initialised with value of radioLinkTimeout(4,8,..64 SACCH periods)(20)

SACCH not received again SACCH received again

Dropped Call ControlRadio Link Timeout


Counter decremented by 1 Counter incremented by 2(but not beyond initial value)

Counter has value 0

Call release due to radio linktime out

Example: short tunnel


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RLT is based on SACCH deletion but SACCH is though not using adynamic codec like voice in AMR, which means:

Using the EFR RLT value an AMR customer can have the call droppedbecause RLT = 0 when still the FER is good

RLT is not anymore reliable with the same value in AMR as in EFR

Due to the fact that the FER performance is different when comparing AMR

Dropped Call ControlRadio Link Timeout


,for AMR

The Radio Link Timeout parameters for AMR are ARLT and AHRLT. Theprinciple of these are the same as in the RLT but they are used only for theAMR capable mobile stations. ARLT & AHRLT are not supported in TalkFamily base stations.


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Radio link timeout occurscallReestablishmentAllowed (RE) set to Y

Receive level of BCCH measured for serving and adjacent cellAveraged over 5 s

Strongest cell considered Example: long tunnel

Dropped Call ControlCall Reestablishment


BCCH decodedC1 cell selection criterion fulfilledCell not barred

Cell belongs to selected PLMN

Attempt to re-establish call

Successful within 20s *

call re-established

Not successful within 20s * call released

* MAX WAIT TIME OF RE-ESTAB REQ is a modifiable timer in MSC

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04 RN2010EN20GLN00 Radio Resource Management v1.0 [Compa