01 Radio Resource Administration MO v3.1

© NOKIA BSSPAR / 11.2006-V3

Radio Resource Administration

CHAPTER 1


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Module Objectives• Give an overview about the TDMA frame structure

• Describe the logical channels, their mapping to TDMA frames and their parameters

• Demonstrate, how the signalling capacity effect the mapping of the logical channels

• Give an overview about the use of extended cells

• Describe the purpose of the Base Station Identity Code and the Training Sequence Code

• Explain the use of FDMA and frequency reuse

• Discuss the parameter settings required for base band and RF frequency hopping


Basic TDMA StructureRadio

Resource Administration

TDMA frame= 8 timeslots = 4.615 ms

01

34

5

76

01

23

45

76

01

23

45

200 kHz

physical channel e.g. allocated to onesubscriber with FR voiceand no frequency hopping

frequency

time

TDMA frame2

2 2 2


Multi, Super and Hyper FrameRadio


0 1 2 49 500 1 2 24 25

0 2047

0 1 2 4849500 1 24 25

0 7

2048 super frames = hyper frame

Super frame = 26 x 51 multi frames or 51 x 26 multi frames

26 multi frame = 120 ms 51 multi frame = 235 ms

TDMA frame = 4.615 ms

TDMA frame numbering

0 1 2 49 50


GSM Channel OrganisationRadio


Base StationSubsystem

Logical Channelsfor transport of specific content

Physical Channelstransport medium

MS

mapping

Physical channel parametersARFCNTime slot numberFrequency hopping algorithm


Logical ChannelsRadio


SCH

FCCH

PCH

BCCH

AGCH

RACH

SDCCH

NCH

SACCH

...

FACCH

Stand alone Dedicated Control Channel

Frequency Correction Channel

Synchronisation Channel

Broadcast Control Channel

Paging Channel

Slow Associated Control Channel

Fast Associated Control Channel

Paging Channel

Random Access Channel

Access Grant Channel

Notification Channel

BCH

CCCH

DCCH

TCH

DL

DL

DL

DL

UL

CommonChannels

DedicatedChannels

UL/DL

UL/DL

CBCH Cell Broadcast Channel


Traffic ChannelsRadio


TCH

TCH/EFR

TCH/FR TCH for Full Rate speech

TCH for Enhanced Full Rate speech

TCH/F9.6

TCH/HR TCH for Half rate Speech

TCH for full rate data transmission with 9.6 kbit/s

TCH/H4.8

TCH/F4.8 TCH for full rate data transmission with 4.8 kbit/sTCH for half rate data transmission with 4.8 kbit/s

TCH/H.2.4

TCH/F2.4 TCH for full rate data transmission with 2.4 kbit/sTCH for half rate data transmission with 2.4 kbit/s

...


Traffic Channel MappingRadio


...

26 TDMA frames = 120 ms

1 26

t t tt t t t ft tt t t tt t t tt ft t t ttts i

Full Rate Traffic Channel Configuration (UL & DL)

Half Rate Traffic Channel Configuration (UL & DL)


1 26

t

T T

t t

T

tf

t t

T T T T

t t

T

t

Tf

T

t

T

tt

T

s

S

t = full rate TCH, s = SACCH/T, i = idle TDMA frame

t = half rate TCH, s = SACCH/T (first user)T = half rate TCH, S = SACCH/T (second user) TDMA frame


Radio Resource

AdministrationSignalling Channel Mapping

(BCCH + SDCCH/4 + SACCH/C4)

f s ff s f s

Downlink51 TDMA frames = 235 ms

-

Uplink

BCCH CCCH

f s f s

CCCH CCCHSDCCH 0

SDCCH 1SDCCH 2

SDCCH 3SACCH

0/2 SACCH1/3

r r f r r rr r r r fr r r r r rr r r r fr r r r rr f r r

1 51

SACCH2/0 SACCH

3/1

SDCCH 0SDCCH 1SDCCH 3

SDCCH 3

f = FCCH, s = SCH, r = RACH TDMA frame- = dummy burst


1 51


Radio Resource


(BCCH +CCCH/9)

f s ff s f s

Downlink51 TDMA frames = 235 ms

-

Uplink

BCCH CCCH

f s f s

CCCH CCCH

r r f r r rr r r r fr r r r r rr r r r fr r r r rr f r r

1 51

CCCH CCCH CCCH CCCH CCCH CCCH

r rr r rr r r r r r r rr r r r r rr rr r r

f = FCCH, s = SCH, r = RACH TDMA frame- = dummy burst


1 51


Radio Resource


(SDCCH/8 +SACCH/C4)

f

f

i = idle TDMA frame

f


iii

iii

SDCCH 0SDCCH 1

SDCCH 2SDCCH 3

SDCCH 4SDCCH 5

SDCCH 6SDCCH 7

SDCCH 1SDCCH 2

SDCCH 3SDCCH 4

SDCCH 5SDCCH 6

SDCCH 7SDCCH 0

Downlink

Uplink

SACCH0/4 SACCH

1/5

SACCH2/6 SACCH

3/7

SACCH6/2 SACCH

7/3

SACCH4/0SACCH

5/1


1 51

1 51


Radio Resource

AdministrationChannel Mapping

(Parameter Setting)

Channel configuration defined by parameter channelType

TCHF = full rate traffic channelTCHH = half rate traffic channelTCHD = dual rate traffic channelERACH = random access channel of extended areaNOTUSED = timeslot has no radio definition or Abis allocationSDCCH = SDCCH/8 +SACCH/C4MBCCH = broadcast control channelMBCCHC = BCCH + SDCCH/4 + SACCH/C4MBCCB = BCCH + SDCCH/4 with CBCHSDCCB = SDCCH with CBCHMPBCCH = PBCCH + PCCCH + PTCCH packet control channels


Radio Resource

Administration

Static SDCCHs overbooked-> Free TCHs used for SDCCH traffic

Rules for dynamic SDCCH allocation:

• SDCCH is configured to TRX with least number of SDCCHs or no SDCCHs yet at all• SDCCH is configured to TRX with least number of occupied channels• If between different types of TCHs must be selected, the preference order is: HR, FR, DR TCH• Intelligent underlay overlay network: dynamic SDCCHs supported by regular TRXs only

Dynamic SDCCH allocation + FACCH call set up enabled simultaneously-> dynamic SDCCH allocation has higher priority

Exceptions:

• Configuration of any dynamic SDCCH resource in the BTS not possible• Only one TCH of the BTS is available

Dynamic SDCCH Allocation


Radio Resource

Administration

Alternative to dynamic SDCCH allocation

• Assignment of TCH to MS from CCCH instead of SDCCH• Call set up on FACCH instead on SDCCH

Parameters

newEstabCausesSupport Y/N Enables feature is generalordinaryCallOnFacch Y/N Enables ordinary call set up on FACCHemerCallOnFacch Y/N Enables emergency call set up on FACCHreestablishOnFacch Y/N Enables call reestablishment on FACCH

FACCH Call Set Up


Radio Resource

Administration

Mobile terminating call -> MSC performs paging

MS identifies paging message with the IMSI/TMSIMS listens to own paging group only

BSC parameters

noOfMultiframesBetweenPaging 2..9 multi frames Defines how often MS listens to

paging

MSC parameters

Repaging Interval 50..100 ms Time between consecutive pagingattempts

Repaging Attempts 0..5 Number of paging repetitions

Buffering

BTS stores up to 8 paging messages of the MSC in page group bufferBTS sends paging messages to MS according noOfMultiframesBetweenPaging

PCH Parameters


Radio Resource

Administration

Mobile sends channel requests to BTS seperated by random time intervals in case of no answer!

Parameters

maxNumberRetransmission 1,2,4,7 Defines maximum allowednumber of retransmissions

numberOfSlotsSpreadTrans 3..12,14,16,20,25,32,50 Defines time interval between

consecutive retransmissions

Random time interval between consecutive retransmissions

t = S + random [0,.. numberOfSlotsSpreadTrans – 1] RACH slots

S depends on numberOfSlotsSpreadTranssignalling channel mapping (CCCH + SDCCH combined or not in one multi

frame)

RACH Parameters

numberOfSlotsSpreadTrans = 10 signalling channel mapping = not combined -> S = 58 -> t = 58..67 time channel

requests


Radio Resource

Administration

Network gives the MS dedicated resources

Downlink CCCH blocks

PCH can be used for AGCH messagesAGCH cannot be used for PCH messages

Reservation of CCCH blocks for AGCH

noOfBlocksForAccessGrant 0..7 possible number, if CCCH and SDCCH are not combined1..7 possible number, if CBCH is used in non combined

configuration0..2 possible number, if CCCH and SDCCH are combined

Preference of AGCH messages on PCH

noOfBlocksForAccessGrant 0 PCH can be used only, if no paging messages have to be send

= 0 AGCH messages have higher priority than PCH ones

Number of paging groups

N = (number of CCCH blocks – noOfBlocksForAccessGrant) * noOfMultiframesBetweenPaging

AGCH Parameters


Radio Resource

Administration Erlang B Table

Chs 1% 2% 3% 5% Chs 1% 2% 3% 5%

1 0 .0 1 0 .0 2 0 .0 3 0 .0 5 21 1 2 .8 0 1 4 .0 0 1 4 .9 0 1 6 .2 0

2 0 .1 5 0 .2 2 0 .2 8 0 .3 8 22 1 3 .7 0 1 4 .9 0 1 5 .8 0 1 7 .1 0

3 0 .4 6 0 .6 0 0 .7 2 0 .9 0 23 1 4 .5 0 1 5 .8 0 1 6 .7 0 1 8 .1 0

4 0 .8 7 1 .0 9 1 .2 6 1 .5 2 24 1 5 .3 0 1 6 .6 0 1 7 .6 0 1 9 .0 0

5 1 .3 6 1 .6 6 1 .8 8 2 .2 2 25 1 6 .1 0 1 7 .5 0 1 8 .5 0 2 0 .0 0

6 1 .9 1 2 .2 8 2 .5 4 2 .9 6 26 1 7 .0 0 1 8 .4 0 1 9 .4 0 2 0 .9 0

7 2 .5 0 2 .9 4 3 .2 5 3 .7 5 27 1 7 .8 0 1 9 .3 0 2 0 .3 0 2 1 .9 0

8 3 .1 3 3 .6 3 3 .9 9 4 .5 4 28 1 8 .6 0 2 0 .2 0 2 1 .2 0 2 2 .9 0

9 3 .7 8 4 .3 4 4 .7 5 5 .3 7 29 1 9 .5 0 2 1 .0 0 2 2 .1 0 2 3 .8 0

10 4 .4 6 5 .0 8 5 .5 3 6 .2 2 30 2 0 .3 0 2 1 .9 0 2 3 .1 0 2 4 .8 0

11 5 .1 6 5 .8 4 6 .3 3 7 .0 8 31 2 1 .2 0 2 2 .8 0 2 4 .0 0 2 5 .8 0

12 5 .8 8 6 .6 1 7 .1 4 7 .9 5 32 2 2 .0 0 2 3 .7 0 2 4 .9 0 2 6 .7 0

13 6 .6 1 7 .4 0 7 .9 7 8 .8 3 33 2 2 .9 0 2 4 .6 0 2 5 .8 0 2 7 .7 0

14 7 .3 5 8 .2 0 8 .8 0 9 .7 3 34 2 3 .8 0 2 5 .5 0 2 6 .8 0 2 8 .7 0

15 8 .11 9 .0 1 9 .6 5 1 0 .6 0 35 2 4 .6 0 2 6 .4 0 2 7 .7 0 2 9 .7 0

16 8 .8 8 9 .8 3 1 0 .5 0 11 .5 0 36 2 5 .5 0 2 7 .3 0 2 8 .6 0 3 0 .7 0

17 9 .6 5 1 0 .7 0 11 .4 0 1 2 .5 0 37 2 6 .4 0 2 8 .3 0 2 9 .6 0 3 1 .6 0

18 1 0 .4 0 11 .5 0 1 2 .2 0 1 3 .4 0 38 2 7 .3 0 2 9 .2 0 3 0 .5 0 3 2 .6 0

19 11 .2 0 1 2 .3 0 1 3 .1 0 1 4 .3 0 39 2 8 .1 0 3 0 .1 0 3 1 .5 0 3 3 .6 0

20 1 2 .0 0 1 3 .2 0 1 4 .0 0 1 5 .2 0 40 2 9 .0 0 3 1 .0 0 3 2 .4 0 3 4 .6 0


Radio Resource

Administration Paging Example

Combined CCCH / SDCCH configuration

noOfBlocksForAccessGrant = 1 -> 2 CCCH blocks for PCH

3 MSs paged per paging message -> 3 pages per block

2 blocks per multi frame -> 3 * 2 = 6 pages per multi frame

Number of pages per hour -> 3600 s / 0.235 s * 6 = 91915

2 pages required per MS -> 91915 / 2 = 45957 MSs per hour

BTS 3 MS

Paging_Request

BTS 3 MS

Paging_Request


Radio Resource

Administration

Cell with 325 subscribers

1 call per subscriber once in a hour

1 location update (LU) per subscriber once in 2 hours

Duration of call assignment = 7 s -> 7 s / 3600 s = 1.94 mErl on SDCCH per subscriber

325 subscribers -> 325 * 1.94 mErl = 0.6305 Erl on SDCCH

Reservation time for LU = 7s -> 7 s / 7200 s = 0.97 mErl on SDCCH per subscriber

325 subscribers -> 0.3153 Erl on SDCCH

Total SDCCH traffic -> 0.6305 Erl + 0.3153 Erl = 0.9458 Erl

Blocking probability = 1% -> 5 SDCCHs required -> not combined with CCCH

Call Establishment &Location Update Example


Radio Resource

Administration

Same cell with 325 subscribers

Additional SMS traffic of 1 mErl per subscriber

325 subscribers -> 325 * 1 mErl = 0.325 Erl on SDCCH

Total SDCCH traffic -> 0.6305 Erl + 0.3153 Erl + 0.325 Erl = 1.2708

Blocking probability = 1% -> 5 SDCCHs required -> not combined with CCCH

Example Including SMS


Radio Resource

AdministrationExtended Cell

(Implementation)Normal region (frequency f1)N-TRX (Parameter eTrxInd = N)

Extended region (frequency f2 except timeslot 0)E-TRX (Parameter eTrxInd = E)

E-TRX

0 1 2 3 4 5 6 7

N-TRX

0 1 2 3 4 5 6 7

f1 f1 f1 f1 f1 f1 f1 f1

BCCH/SDCCH

NotUsed

TCH TCH TCH TCH TCH TCH

TCH TCH TCH TCH TCH TCHRACHSDCCH

f1 f2 f2 f2 f2 f2 f2 f2

Extended cell sizeParameter radiusExtensionValue = 1..67 radius of extended cellValue = 0 ordinary cell


Radio Resource

AdministrationExtended Cell

(Cell Selection, Handover)

Cell Selection

MS can camp on normal or extended cell, independently on the distance to the BTS

Failure of RACH burst -> Wrong cell selectedReselection on the basis of the path loss criterion C1

Handover to due Distance

maxMSDistanceHOThreshold 0..63 63 = maximum allowed distancethreshold exceeded -> handover triggered

toextended cell

minMSDistanceHOThreshold 0..63 63 = maximum allowed distancethreshold exceeded -> handover triggered

tonormal cell

Handover due to other Reason

hoTargetArea 0..3 indicates type of target cell (normal or extended)

indicates type of transceiver from which the BSC tries to allocate a channel (normal or extended)


Base Station Identity CodeRadio


Base Station Identity Code BSIC = Network Colour Code NCC + Base Station Colour Code BCC

bsIdentityCode Setting of BSIC

NCC 0..7, distinguishes between PLMNsBCC 0..7, distinguishes between clusters

BSIC + frequency channel -> unique identity of adjacent cell

f1f2f3

f1

f1

bcc = 1bcc = 2

bcc = 3


Training Sequence CodeRadio


Training Sequence Code TSC

tsc 0..7 Setting of TSC

Used to determine signal distortion and bit error rate

trainingsequence

encrypted bitsencrypted bits3 31

stealing flag stealing flag

57 bits 57 bits26 bits

1

tail bits tail bits

Burst on TCH

data± difference =difference

expected bursttraining sequence ??

received burst

correlation

data* data*training sequence*

data*


200 kHz

890 915 935 960

1 2 3 4 124123 1 2 3 4 124123

duplex distance

Absolute radio frequency carrier number ARFCN

uplink direction downlink direction

Example: GSM 900

Frequency Division Multiple AccessRadio



Frequency ReuseRadio


Frequency to be used by TRX

initialFrequency Setting of ARFCNs

f1f2

f3f4

f5f6

f7

f1f2

f3f4

f5f6

f7

f1f2

f3f4

f5f6

f7


Frequency Information for MSRadio


Idle mode -> MS listens on BCCH

idleStateBCCHAllocation 0..255 0 = MS gets frequency information frominitialFrequency lists of adjacent cells1..255 = MS gets frequency information fromdouble BCCH allocation list

bCCHAllocationList Indicates ARFCN values given by double BCCHallocation list

Dedicated mode -> MS listens on SACCH

measurementBCCHAllocation ADJ,IDLE ADJ = MS gets frequency information frominitialFrequency lists of adjacent cellsIDLE = MS uses same double BCCH allocation list as in idle mode


Frequency

Time

F1

F2

F3

Call is transmitted through several frequencies to• average the interference (interference diversity)• minimise the impact of fading (frequency diversity)

Principle of Frequency HoppingRadio


Frequency hopping techniques

btsIsHopping BB,RF,NBB = base band hoppingRF = RF hoppingN = no frequency hopping at all


Baseband Hopping

TRX 1

TRX 2

TRX 3

0 1 72 Timeslot

TRX 4

BCCH

f 1

f 2

f 3

f 4

HSN1Timeslot 0 hops over TRXs 2-4 onlyBCCH does not hop

HSN2Timeslots 1-7 hop over all TRXs

Base Band HoppingRadio


TRXs do not hopPhysical channels moved from one TRX to another

Hopping sequencehoppingSequenceNumber 0..63

0 = cyclic hopping1..63 = pseudorandom hopping


TRX 1

TRX 2

TRX 3

0 1 72 Timeslot

TRX 4

BCCH f1 – no hopping

f2,f3..fn – hopping accordingmobile allocation list One hopping sequencenumber only

RF Hopping(Standard Technique)

Radio Resource

Administration

TRXs do hop except TRX1 (provides BCCH)Up to 63 frequencies available defined by mobile allocation list -> better hopping gain

mobileAllocationList Setting of ARFCN values usedMobileAllocation 0..255 0 = BTS detached from any list

1..255 = indicates list which shall be used


MAI

-

0

1

2

-

3

4

5

-

6

7

8

MAIO

0

3

6

TRX-1 BCCH

TRX-2 TCH

TRX-3 TCH

TRX-4 TCH

TRX-5 BCCH

TRX-6 TCH

TRX-7 TCH

TRX-8 TCH

TRX-9 BCCH

TRX-10 TCH

TRX-11 TCH

TRX-12 TCH

RF Hopping(Freeform Hopping)

Sector 1

Sector 2

Sector 3

Standard technique

9 hopping hopping frequencies MAI = 0..8But 3 frequencies available for every TRX only

Freeform hopping

For every sector samemobile allocation listhopping sequence numberframe number (frame synchronization)

For every sector differentstarting points for hopping sequencepossible by mobile allocation index offset

maioOffset 0..62setting of MAIO

9 hopping hopping frequencies MAI = 0..89 frequencies available for every TRX

Radio Resource

Administration


MAIO

0

2

4

6

8

10

12

14

16

TRX-1 BCCH

TRX-2 TCH

TRX-3 TCH

TRX-4 TCH

TRX-5 BCCH

TRX-6 TCH

TRX-7 TCH

TRX-8 TCH

TRX-9 BCCH

TRX-10 TCH

TRX-11 TCH

TRX-12 TCH

RF Hopping(Flexible MAIO Management)

Sector 1

Sector 2

Sector 3

Freeform hopping

Not adequate for MA list with consecutive ARFCN valuesAvoids co-channel interferenceBut not adjacent channel interference

Flexible MAIO management

MAIO increases with constant step size from one TRX to the next one

maioStep 0..62

maioOffset = 0, 6, 12 for sector 1, 2, 3maioStep = 218 frequencies required (2 * number of hopping TRXs)

Radio Resource

Administration


BCCH

Band allocation:

MA listConsecutive ARFCN

Only BCCH frequency planning requiredOnly BCCH frequency planning required

Flexible MAIO managementMAIO Offset + MAIO Step

BCCH

Band allocation:

MA listDiscrete ARFCN

Freeform hoppingMAIO Offset

MA list and BCCH frequency planning requiredMA list and BCCH frequency planning required

RF Hopping(Tight Frequency Reuse)

Radio Resource

Administration


Frequency Plan ChangingRadio


BSIC / TSCFrequenciesFrequency hopping settingIntelligent underlay overlay TRX settings

01 Radio Resource Administration MO v3.1

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