bsspar115 chapter 01 radio resource administration mo v3.2

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© NOKIA BSSPAR / 11.2006-V3

Radio Resource Administration

CHAPTER 1


http://slidepdf.com/reader/full/bsspar115-chapter-01-radio-resource-administration-mo-v32 2/33© NOKIA BSSPAR / 11.2006-V3

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 SequenceCode

• Explain the use of FDMA and frequency reuse

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



Basic TDMA StructureRadio

ResourceAdministration

TDMA frame

= 8 timeslots= 4.615 ms

01

34

5

76

01

23

45

76

01

23

45

200 kHz

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

frequency

TDMA frame 2

2 2 2



Multi, Super and Hyper FrameRadio


0 1 2 49 500 1 2 24 25

0 2047

0 1 2 48 49 500 1 24 25

0 7

2048 super frames = hyper frame

Super frame = 26 x 51 multi framesor 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/s

TCH 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/s

TCH 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

tT T

tt

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



RadioResource

AdministrationSignalling Channel Mapping

(BCCH + SDCCH/4 + SACCH/C4)

f s ff s f s

Downlink 51 TDMA frames = 235 ms

-

Uplink

BCCH CCCH

f s f s

CCCH CCCHSDCCH 0

SDCCH 1

SDCCH 2

SDCCH 3

SACCH

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



RadioResource


(BCCH +CCCH/9)

f s ff s f s

Downlink 51 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




RadioResource


(SDCCH/8 +SACCH/C4)

f

f

i = idle TDMA frame

f


iii

iii

SDCCH 0

SDCCH 1

SDCCH 2

SDCCH 3

SDCCH 4

SDCCH 5

SDCCH 6

SDCCH 7

SDCCH 1SDCCH 2

SDCCH 3SDCCH 4

SDCCH 5

SDCCH 6SDCCH 7

SDCCH 0

Downlink

Uplink

SACCH

0/4 SACCH1/5

SACCH

2/6 SACCH3/7

SACCH6/2 SACCH

7/3

SACCH4/0SACCH

5/1


1 51

1 51




RadioResource

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/C4

MBCCH = broadcast control channelMBCCHC = BCCH + SDCCH/4 + SACCH/C4MBCCB = BCCH + SDCCH/4 with CBCHSDCCB = SDCCH with CBCHMPBCCH = PBCCH + PCCCH + PTCCH packet control channels




RadioResource

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




Maximum SDCCH Capacity

• The upper limit for the number of SDCCHs in the BSC depends on the number of TRXs thatare connected to the BSC Signalling Units (BCSU) and the number of BCSUs that are working

in the BSC.• The maximum SDCCH capacity of the BCSU is calculated with the following formula:

• Max_ SDCCH _count_per_BCSU = 12 * Max_TRX_count_per_BCSU

• Max_ SDCCH _count_per_BCSU includes both the static SDCCHs, which you configure, andthe dynamic SDCCH resources

• The absolute limit is that the maximum SDCCH number in a TRX must not exceed 16

channels.• The maximum number of dynamic and static SDCCH channels together is limited to 12

subchannels (that is, SDCCH/4 and SDCCH/8) in the TRXs that use the 16 kbit/s link for theTelecom signalling. TRXs of higher capacity signalling link (32 kbit/s or 64 kbit/s) can beconfigured up to 16 SDCCHs.

• The above constraint is due to the fact that with 16kbps TRX signaling, only 18 RTSLs perTRX can be supported.

• This is a theoretical limitation, and higher configurations are possible but not advisable.




RadioResource

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(NECI) Y/N Enables feature is generalordinaryCallOnFacch (EOF) Y/N Enables ordinary call set up on FACCHemerCallOnFacch (EEF) Y/N Enables emergency call set up on FACCHreestablishOnFacch (ERF) Y/N Enables call reestablishment on FACCH

•Main difference between FACCH Call Set-Up and Dynamic SDCCH is that in the former, same TSLas used for SDCCH is used for TCH, done through “MODE MODIFY” command from MSC.

FACCH Call Set Up




RadioResource

Administration

Mobile terminating call -> MSC performs paging

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

BSC parameters

noOfMultiframesBetweenPaging (MFR) 2..9 multi frames Defines how often MSlistens 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




RadioResource

Administration

Mobile sends channel requests to BTS seperated by random time intervals in case of noanswer!

Parameters

maxNumberRetransmission 1,2,4,7 Defines maximum allowed(RET)

number of retransmissionsnumberOfSlotsSpreadTrans 3..12,14,16,20,25,32,50 Defines time interval between(SLO) consecutive retransmissions

RACH Parameters




RadioResource

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 combinedconfiguration0..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 besend

= 0 AGCH messages have higher priority than PCH ones

Number of paging groups

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

AGCH Parameters




RadioResource

AdministrationErlang 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 2 1 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 2 2 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 2 3 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 2 4 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 2 5 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 2 6 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 2 7 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 2 8 1 8 .6 0 2 0 . 2 0 2 1 .2 0 2 2 . 9 09 3 .7 8 4 . 3 4 4 .7 5 5 . 3 7 2 9 1 9 .5 0 2 1 . 0 0 2 2 .1 0 2 3 . 8 0

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

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

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

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

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

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

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

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

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

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

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




RadioResource

AdministrationPaging 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




RadioResource

Administration

Cell with 325 subscribers1 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




RadioResource

Administration

Same cell with 325 subscribersAdditional 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




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

f1f2

f3

f1

f1

bcc = 1bcc = 2

bcc = 3

R di




Training Sequence CodeRadio


Training Sequence Code TSC

tsc 0..7 Setting of TSC

Used to determine signal distortion and bit error rate

training

sequence 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*

R di




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


Radio




Frequency ReuseRadio


Frequency to be used by TRX

initialFrequency Setting of ARFCNs

f1f2

f3

f4

f5

f6

f7

f1f2

f3

f4

f5

f6

f7

f1f2

f3

f4

f5

f6

f7

Radio




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

Radio




Frequency

Time

F 1

F 2

F 3

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,N(HOP) BB = base band hopping

RF = RF hoppingN = no frequency hopping at all

Radio




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

RF HoppingRadio




TRX 1

TRX 2

TRX 3

0 1 72 Timeslot

TRX 4

BCCH

f1 – no hopping

f2,f3..fn –

hopping accordingmobile allocation listOne hopping sequencenumber only

RF Hopping(Standard Technique)

RadioResource

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 usedMobileAllocation0..255 0 = BTS detached from any list

1..255 = indicates list which shall be used

RF HoppingRadio




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 TCHTRX-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 thenext one

maioStep 0..62

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

ad oResource

Administration

RF HoppingRadio




BCCH

Band allocation:

MA listConsecutive ARFCN

Only 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 required

RF Hopping(Tight Frequency Reuse)


F Pl Ch iRadio




Frequency Plan ChangingResourceAdministration

BSIC / TSCFrequenciesFrequency hopping settingIntelligent underlay overlay TRX settings

bsspar115 chapter 01 radio resource administration mo v3.2

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