training4 nortel feature evolution v15.1.1 to v17

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BUSINESS MADE SIMPLE

GSM Cookbook - Features description from V15.1.1 to V17

KONE BrunoGSM Access RF & System Performance CTF/18-07-08

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GSM Cookbook Topics (1/2)

• Training 1: GSM RF Seminar

• Network Architecture

• GSM Channel

• GSM Process (MOC, MTC, idle Process…)

• Network Capacity

• Network Implementation (Design, link budget)

• Frequency Planning definition

• Training 2: Nortel GSM Implementation & Parameters • Generalities

• Cell Selection and Reselection

• RACH and PCH Channel Control

• Radio Measurements in communication mode (L1M V2)

• Communication Supervision

• Power Control

• Handover

• DTX

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GSM Cookbook Topics (2/2)

• Training 3: AMR Implementation

• Training 4: Features description from V15.1.1 to V17 • AMR Evolution> AMR based on Traffic (AboT)> AMR HR on pre empted PDTCH> FACCH Repetition and Tx Power

Offset• Network Synchronization• Multi Paging UI• Handover 2G -3G• EMR• Multi zone Enhancement• Smart Power Management• A5/3 Encryption Algo

• Training 4: GSM Monitoring and Trouble-Shooting

• Trouble-Shooting feature & tools presentation (CDA, RMD, IM, CT/CPT)

• Counters Description from V15.1.1 to V17

• Introduction to Network Optimization and Performance

• GSM High level Metrics description

• BSS Alarms and Notifications

• Trouble-Shooting Work Flow

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AMR Evolution since V15.1.1

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Benefits• Extra flexibility for the AMR adaptation table selection

• Reduce the need for updating “customized” adaptation table in BSC Data Config which require Build On Line

Feature• Provide parameters to select any of the 4 adaptation tables (optimistic, typical,

pessimistic and customized) independently for FR and HR mode and for DL and UL

• amrAdapatationSet replaced by 4 new parameters

AMR improvement V15.1.1

• HW support :

BSC3000/TCU3000 with

S8K/S12K/BTS18K/eCell/ S2000 L&H

Extra flexibility for AMR tuning

downlinkslow MS -

no FHfast MS -

no FH 4FHideal FH

(>=8)SFH 900

TU3

5,9 -> 4,75 8 2,5 3,5 2,5 46,7 -> 5,9 10 4 5 4 5,510,2 -> 6,7 12,5 6,5 7,5 6,5 7,512,2 -> 10,2 17,5 12,5 12,5 12,5 13,5FR hysteresis 2,5 1,5 2 1,5 25,9 -> 4,75 12,5 10 10,5 10 116,7 -> 5,9 14 12 12,5 12 12,57,4 -> 6,7 19 17 17,5 17 16,5HR hysteresis 3,5 2 2 2 3

FR

th

resh

old

S

HR

th

resh

old

s

uplink

Parameters

Parameter Object Range Recommended Value Class

amrDlFrAdaptationSet bts [0 to3]0: typical radio condition1: optimistic radio condition2: pessimistic radio condition3: personalize with the BSC data configuration table

3 3

amrDlHrAdaptationSet bts [0 to3] 3 3

amrUlFrAdaptationSet bts [0 to3] 3 3

amrUlHrAdaptationSet bts [0 to3] 3 3

AMR improvement V15.1.1

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Feature• AMR-HR is activated on a TDMA basis according to the cell load

• When AMR-HR is activated on a new TDMA, existing calls in FR in good radio conditions are repacked in HR to free Traffic channels for new calls

• Risky calls in poor radio conditions are kept in FR to maintain the voice quality

• Cell load evaluated on busy TCH ratio (filtered)

• N+1 Cell LoadState for a N TDMA cell

• Cell Load State evaluated every 10 sec with 2 parameters AMR_HR_Begin and AMR_HR_End

AMR HR Based on Traffic V15.1.1

FR capacity

HR capacity

HR

FR

Traffic (Erl)

Time

9

AbOT Algo

1____ __*)1(*__ nTSTCHavailableTSTCHbusy

n RatioTCHFilteredratioTCHFiltered

The HR cell load state is evaluated by the BSC every 10 seconds, based on a

filtered busy TCH ratio and a set of thresholds, based on following principles

PDTCH is not taken into account in the algo.

Example: Cell with 3 TRX: 1BCCH, 1SDCCH 4 PDTCH => 18 TCH available

HRCellLoadStart = 80% => 14 TS busy, HR is activatedHRCellLaodEnd = 60% => Roughtly 10 TS busy, HR is deactivated

directHRRxlevOMC-R

-110-48 dBm

dBm

Cell load state

S0

S1

S2

S3

S4

Smax

RxLev distribution

RxLev1RxLev2RxLev3RxLev4

RxLev parameters, which manage SDCCH to HR direct TCH allocation for new calls, are changed based on load at cell level.

(n,p) voting parameters, which manage FR->HR handovers, are (de-)activated on a DRX basis acording to the cell load.


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HRCellLoadStart

HRCellLoadEnd

Parameter Object Range Recommended Value

Class

HRCellLoadStart bts Integer 0…100 80 3

HRCellLoadEnd bts Integer 0…100 60 3

filteredTrafficCoefficient bts Integer 0…1 step 0.001 0.5 3


AboT Parameters

11 Nortel Confidential Information

AMR signaling evolutions – V16Drivers

>Problem formulation : • AMR signaling channels are not optimized to work in the radio conditions, where low codec in full rate are used:

1.E-03

1.E-02

1.E-01

1.E+00

0 1 2 3 4 5 6 7 8 9 10 11 12Eb/No (dB)

FE

R

AMR 12.2

AMR 5.9

FACCH

SACCH

In a given environment (Eb/No), the error rates for AMR signalingchannels are significantly higher than for traffic channels

AMR signaling “robustness gap”


AMR signaling evolutions –V16 DL FACCH Repetition> Mechanism The Repeated Downlink FACCH functionality is applicable when sending

LAPDm command frames on the TCH/F channel. The BSS uses the Repeated Downlink FACCH functionality when AMR FR codec used is less than enableRepeatedFacchFr, each time the AMNU entity needs to re-transmit an I-frame on FACCH due to T200 expiry, it sends this frame again to the SPU entity (with a flag related to the retransmission). The SPU entity sends first the I-frame on FACCH in TDMA frame M as it does when the feature is disabled. And if the selected CODEC is lower than the threshold set to activate the feature, it

stores the LAPDm frame to be repeated in TDMA frame M+ 8 or M+ 9


AMR signaling evolutions - V16 Signaling Tx Offset > Mechanism

In order to increase the signaling channels (FACCH and SACCH) robustness in downlink, BTS may use a power offset (above the Tx power applicable for speech) to transmit the signaling bursts.

The Tx Power Offset for Signaling Channels is applicable to:

The first transmission of HO COMMAND and ASSIGNMENT COMMAND for all AMR calls in order to maximize the likelihood of decoding these messages from the first instance,

Every re-transmission of I-frame on FACCH for all AMR calls (HR and FR) in order to maximise the likelihood of decoding these messages.

Every RR and REJect frame on FACCH corresponding to an uplink retransmission for all AMR calls (HR and FR) in order to improve the two-ways robustness.

Every UA (respectively DM) frame on FACCH corresponding to an uplink re-transmission of SABM (respectively DISC) frames for all AMR calls (HR and FR) in order to improve the two-ways robustness.

The transmission of all SACCH frames for AMR FR 4.75 kbps, 5.9 kbps and 6.7 kbps calls (tunable with an OMC-R parameter sacchPowerOffsetSelection ) in order to avoid radio link time-out (that leads to drop calls.


AMR signaling evolutions - V16 Signaling Tx Offset > Mechanism

When applying the power offset,

> First case:

IF PWR + facchPowerOffset ≤ Pnominal

THEN

SPU modifies the dynamic power control in accordance with

PWR + facchPowerOffset

> Second case:

IF PWR + facchPowerOffset > Pnominal

THEN

SPU set the dynamic power control to: 0 BTS transmits the frame at Pnominal

Same algo for SACCH transmission but the parameter sacchPowerOffset is used


AMR signaling evolutions – V16

> DL FACCH repetition• increase FACCH DL robustness in bad radio conditions by proactively

retransmitting the LAPDM frame after 40 ms instead of waiting for T200 expiry (~180ms)

• Benefits both legacy mobiles (~2 dB) and Release 6 mobiles performing soft combining (~4 dB)

• Feature restricted to eDRX (on S8000/12000) & RM (BTS18000)

> Signaling Tx Offset• Apply a Transmit power offset to SACCH (up to 6 dB) and FACCH (up to 10 dB)

messages, compared with traffic channels• Allow setting of aggressive AMR target mode power controls• Feature restricted to eDRX (on S8000/12000) & RM (S18000)

Parameters


enableRepeatedFacchFr bts Disable / FR 4.75 / FR 5.9 and lower / FR 6.7 and lower

FR 6.7 and lower 2

facchPowerOffset bts [0 to 10] dB (with 2 dB step) 6 2

sacchPowerOffset bts [0 to 6] dB (with 2 dB step) 2 2

sacchPowerOffsetSelection bts Disable / FR 4.75 / FR 5.9 and lower / FR 6.7 and lower

FR 6.7 and lower 2

AMR signaling evolutions – V16


Other AMR evolutions – V16

> ENHANCEMENT OF AMR POWER CONTROL MECHANISM

Since this feature improves the downlink robustness, new parameters are

introduced to define dedicated target for uplink and downlink AMR CODEC. The

existing parameters (hrPowerControlTargetMode and frPowerControlTargetMode)

still apply on uplink and two new parameters are introduced for downlink targets: hrPowerControlTargetModeDl: downlink AMR codec target to define the

downlink power control threshold for HR AMR calls, frPowerControlTargetModeDl: downlink AMR codec target to define the

downlink power control threshold for FR AMR calls,

With setting a lower codec as a Downlink Power control target: A more protected AMR speech codec is used in downlink, Overall BS attenuation is higher and the overall interference level is decreased

accordingly.



> RATSCCH activation

amrReserved1 This parameters is now available at MMI which allows the activation of

RATSCCH procedure for AMR FR calls

In v16, an improvement of the L1M has been implemented which consists in the BTS

repeating the RATSCCH command until it receives an acknowledgment from the

mobile.

In v17, a further improvement has been implemented. It consists in improving the

robustness of the detection of the acknowledgement message received from the

mobile : this increases the probability of correctly decoding this message when it is first

received.

Thanks to these 2 improvements, amrReserved1 should be set to "0" in V16 and V17.

Warning: pessimistic Codec Set 10,2 / 6,7 / 5,9 /4,75 (amRreserved1 = 2) must not be

chosen because it would inhibit capacity HO i.e. handover from AMR FR to AMR HR

(as 12.2 cannot be used).

Parameters


hrPowerControlTargetModeDl bts [4k75, 5k9, 6k7, 7k4] 7k4 3

frPowerControlTargetModeDl bts [4k75, 5k9, 6k7, 10k2, 12k2] 12k2 23

amrReserved1 bts [0 to 2]0: RATSCCH procedure enabled (default value)1: RATSCCH procedure disabled - initial Full Rate ACS if optimistic therefore; ACS is [12.2k, 10.2k, 6.7k, and 5.9k]2: RATSCCH procedure disabled - initial Full Rate ACS if pessimistic therefore; ACS is [10.2k, 6.7k, 5.9k and 4.75]

0 3



> GSM/GPRS TS Dynamic sharing (introduced in V12.4) increases the efficiency of the Air interface

> 3 types of TS are defined:• fixed GPRS radio TS : used in order to guarantee a minimal number of

radio TS allocated to GPRS in this option, settable at OMC-R• fixed GSM radio TS : used only in GSM mode.• radio TS shared between GSM and GPRS : by default used in GPRS• mode, preempted by GSM in case of lack of fixed GSM radio TS.

> Feature benefit: radio interface efficiency (TS usage rate) increased by up to 20% vs GSM only TDMA

> Restriction:• HR voice calls

cannot be allocated on preempted PDTCH.

• call is forced in FR if a PDTCH must be preempted, even if radio conditions would have led to an HR allocation on a “normal” TCH.

PDTCH preemption for voice HR channel – V17Introduction: GSM/GPRS TS dynamic sharing


> Restriction of GSM/GPRS TS dynamic sharing removed: PDTCH can be preempted by HR channel

> In case of voice congestion and high HR penetration, more PDTCH will be preempted, up to the maximum number of preemptable PDTCH

> Feature also helps reducing call queuing as queued calls can be directly allocated to HR channel (RFF 32278)

FR channel orHR channel

PDTCH preemption for voice HR channel –V17Technical overview

> Feature activation through a new parameter: gprsPreemptionForHR on bsc object. Values: disabled (default) / enabled

> HR channel allocation upon TCH assignment or HO as per the following priority:• free HR channel of a TCH with the other HR already allocated• free HR channel• free HR channel of a preempted PDTCH with the other HR already allocated• HR channel of a new preempted PDTCH: in this case, PDTCH preemption

procedure is the same as for a FR PDTCH


Benefits

> Increase cell voice capacity for more than 50% HR usage

> Preserve GPRS/EDGE throughput during voice busy hours

> Performance:• Significant increase in Erlang

capacity, especially for high HR penetration rate

• simulations show gain up to 36% (14TCH, 6 pre-emptable PDTCH, 2% blocking rate)

Terminals & BSS HW dependencies

> DRX Egal I, DRX Egal II, DRX ND3, eDRX, RM

> Not supported on S2000/S4000

PDTCH preemption for voice HR channel - V17

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Enhanced Measurement Report (EMR)


> MS measurement (DL):• downlink RXLEV (RXLEV_DL)• downlink RXQUAL (RXQUAL_DL)• received level from 6 best neighbour cells (RXLEV_NCELL(n)) + cell identifiers

(frequency + BSIC)• MS_TXPWR_CONF: current MS transmission power (UL)

> BTS measurements (UL):• uplink RXLEV (RXLEV_UL)• uplink RXQUAL (RXQUAL_UL)• current BTS TX power (BS_TXPWR)• MS_BS_distance

NeighbourBTS

NeighbourBTS

NeighbourBTS

ServingBTS

MeasurementReport (SACCH)

RXLEV_DLRXQUAL_DL

RXLEV_NCELL(n)

Enhanced Measurement Report (EMR)Introduction: legacy measurement report (phase 1)


> RXLEV• Measurement of the MS received signal level: C+I+N• 6-bit coding, 64 levels from 0 to 63• Received power = -110 + RXLEV dBM• Sample logarithmic averaging during 0.5s, corresponding to the transmission

period (480 ms = 1 every 4 26-frame)• Measured on the serving cell and the list of neighbour cells

> RXQUAL• Measurement of the MS received signal quality: BER• 3-bit coding, 8 levels• averaging during 0.5s• Measurement before channel decoding

> 2 types of measurements:• Full measurement: performed on all slots of the reporting period (possibly

including unused slots in case of DTX)• Sub measurements: performed only on mandatory sent blocks (12TS instead of

100 TS)• L1M decides on the measurement type to be used depending on DTX use

indication

Enhanced Measurement Report (EMR)Introduction: legacy measurement report


> EMR is more accurate than legacy measurement report:• Current cell RXLEV is computed on all valid blocks, instead of either full

values or sub values ( RXLEV_VAL)• MS reports Mean_BEP and CV_BEP instead of synthetic indicator RXQUAL• Neighboring cell identification: neighboring cells are identified through cell

identifier instead of ARFCN+BSIC• 15 neighbour cells can be reported in the EMR message, instead of 6 in

legacy MR

> EMR includes a new counters at TDMA level:• Total number of DL transmitted frames• Estimated number of DL bad frames• Measurement made:

• per period of 480 ms• for each codec type: AMR-FR (4 counters), AMR-HR (3 counters), EFR/FR (1

counter)

> EMR includes measurements on 3G neighbour cell:• RSCP (Received Signal Code Power), equivalent to RXLEV_NCELL• 15 neighbour cells max. can be reported (GSM & UMTS)

Enhanced Measurement Report (EMR)Improvements vs legacy measurement report

ParametersParameter Object Range Recommended Value Class

reportTypeMeasurement bts 0 : Measurement report1 : Enhanced Measurement Report

1 3

servingBandReporting bts 0 : “no inband cell is favoured”1: “1 strongest inband cell is favoured”2: “2 strongest inband cells are favoured”3: “3 strongest inband cells are favoured”

3 3

servingBandReportingOffset bts 0, 1, ... 7, 0xFF : 0 dB, 6 dB, …, 42 dB, “not significant”

0 3

Terminals & BSS HW dependencies• Dual mode MS & GSM Rel-4 MS• BSC3000. Not supported on S4000, S2000E, S2000, S8000-BCF

Enhanced Measurement Report (EMR)


> Evolution of Radio Measurement Distribution (V15.1.1) includes UL FER counter

> New DL counters included in Enhanced Measurement Report allow to compute FER DL and provide DL FER distribution per TDMA:

• FER DL = number of bad frames / total number of speech frames

> Distribution based on same parameters as FER UL, settable at OMC-R:

• 4 thresholds (FERThreshold) defining FER ranges

• number of frames used to compute FER (250 to 3000)

• FER monitoring for EFR/FR, AMR/HR, AMR/FR

> DVQI (DL voice quality indicator):• Equivalent to UL TEPMOS• distribution for DL based on weighted FER with

codec usage

EMRDL transmitted frames

DL bad frames

FER = number of DL bad frames/ total number of DL transmitted frames

DL voice quality indicatorDVQI

Enhanced Measurement Report (EMR) Downlink voice quality monitoring


Handover 2G 3G

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2G – 3G service continuityCS HO GSM-UTRANFDD technologie: Introduction

> Objective: allow 3G capable handsets that are connected on 2G layer to move to 3G layer when necessary

> UE performs radio measurements on UMTS neighboring thanks to EMR.

> The network controls what the UE shall measure and sends the system information data concerning the neighboring cell.

GSM System

UMTS System

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2G – 3G service continuityCS HO GSM-UTRANFDD technologie: UMTS Adjacent cells


Class

MobileCountryCode AdjacentcellUtran String N/A 3

MobileNetworkCode AdjacentcellUtran String N/A 3

locationAreaCodeUTRAN AdjacentcellUtran String N/A 3

Rnc-id AdjacentcellUtran Integer (dB) [0 … 4095] N/A 3

Cid AdjacentcellUtran Integer [0 … 16383] N/A 3

FDD_ARFCN AdjacentcellUtran Integer [0 … 16383] N/A 3

scramblingCode AdjacentcellUtran Integer [0 … 511] N/A 3

Diversity AdjacentcellUtran 0~ No diversity1~Diversity

N/A 3

32 UMTS neighbours additional to the 32 GSM neighbours

32

>

Rxlev > qsearchC

CPICH_Ec/No fDDReportingThreshold2

2G – 3G service continuityCS HO GSM-UTRANFDD technologie: Measurement process(1/2)


Class

earlyClassmarkSendingUTRAN bts Integer disabled/enabled enabled 3

qsearchC handovercontrol Integer 0…15 7 3

fDDReportingThreshold2 handovercontrol Integer 0…63 28 (Ec/N0 =10) 3

fDDReportingThreshold handovercontrol Integer 0…6 (step of 6) 3 (RSCP =-97) 3

fDDMultiratReporting handovercontrol Integer 0…3 2 3

MS gives information on neighboring cells in EMR or legacy MR if: earlyClassmarkSendingUTRAN is

enabled

CPICH_RSCP > fDDReportingThreshold + fDDMultiratReporting

MS reports 3G bestcells

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2G – 3G service continuityCS HO GSM-UTRANFDD technologie: Measurement process (2/2)

Dual Mode MS measures:•on the serving cell: RXLEV & RXQUAL•on neighbour GSM cells: RXLEV (n) (measured on BCCH, BSIC)+ CPICH_RSCP of the best 3G cells

Serving Cell

Nei 2GNei 2G

Nei 3 G

MS sent in an EnhancedMeasurement report to

BTS

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2G – 3G service continuityCS HO GSM-UTRANFDD technologie: Handover service

“service handover” value

Handover to UMTS impact

Shall not No UMTS neighbouring cell shall be present

in the candidate cells list. Should not UMTS neighbouring cells can be present

present in the candidate cells list only if

handover cause is traffic or alarm reason.

For PBGT, no UMTS neighbouring cell

shall be present in the candidate cells list.

Should UMTS neighbouring cells can always be

present in the candidate cells list.

For dual mode MS, the BSC sends the service handover value tothe BTS on beginning of communication


Class

gsmToUMTSServiceHO bsc 0:Should; 1:Should not; 2:shall not;3: gsmToUMTSDisabled

0 3

The impact of this Parameter is

Core Network dependent

35

2G – 3G service continuityCS HO GSM-UTRANFDD technologie: Handover Algo

EXP1(n) = RxLevNCell(n) ave - [ rxLevMinCell(n) + Max(0, msTxPwrMaxCell(n) - msTxPwrCapability(n) ) ]

2G expression

PBGT(n) = Min [msTxPwrCapability(Band0), msTxPwrMax] – Min [msTxPwrCapabilityCell(n), msTxPwrMaxCell(n)] + (RxLevNCell(n)ave - RxLevDLave))

3G expression

EXP1(n) = CPICH_RSCP(n) – rxLevMinCellUTRAN(n)

PBGT(n) = (CPICH_RSCP(n) - RxLevDLave)

Maximum transmission power level the MS is allowed to use in traffic channel is not taken into account in EXP1 and PBGT for 2G -3G HO decision

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Cell ID

Cell ACell B

…

Neighboring cell

2G – 3G service continuity CS HO GSM-UTRANFDD technologie: Handover Algo

2G layer

3G layer: Cell A

CPICH_RSCP(A) < rxLevMinCellUTRAN(A) or

CPICH_RSCP < rxLevDLPbgtUTRAN(A)

3G layer: Cell B

CPICH_RSCP(B) – rxLevMinCellUTRAN(B)>0and

(CPICH_RSCP(B) - RxLevDLave) – hoMarginXX >0

L1M algorithms can be reused for HO to a UMTS cell, except capture HO and directed retry

37

2G – 3G service continuityCS HO GSM-UTRANFDD technologie: Handover Parameters

Parameter Object Range Recommended Value (W/0 ETP)

Class

hoMarginUTRAN adjacentCellUTRAN -63 to 63 -12 3

hoMarginAMRUTRAN adjacentCellUTRAN -63 to 63 63 3

hoMarginRxLevTRAN adjacentCellUTRAN -63 to 63 63 3

hoMarginRxQualTRAN adjacentCellUTRAN -63 to 63 63 3

hoMarginDistTRAN adjacentCellUTRAN -63 to 63 63 3

rxLevDLPbgtUTRAN adjacentCellUTRAN -63 to 63 - 48db 3

hoMarginTrafficOffsetUTRAN adjacentCellUTRAN -63 to 63 63 3

hoPingPongCombinationUTRAN adjacentCellUTRAN List of cause GSM to UMTS

See eng 3

hoPingPongTimeRejectionUTRAN adjacentCellUTRAN 0…60s 30 3

offsetPriorityUTRAN adjacentCellUTRAN 1…5 1 3

rxLevMinCellUTRAN adjacentCellUTRAN -63 to 63 -97 3

T3121 bts 2 to 255s 12 3

38

RR: Intersystem to UTRANHandover command(handover to UTRAN command

RANAP: Relocation request Ack

RRC: Handover to UTRAN Complete

MAP / Prepare

RNC3G-MSC2G-MSCBSCBTSUE

RANAP: Relocation request (Source RNC to target RNC Transparent container)

Handover

Indication

BSSMAP: HandoverRequired

T7 Started

MAP: PrepareHandover

Q.2630.1 ERQ

Q.2630.1 ECF

(RRC: handover to UTRAN command)Handover ack

BSSMAP: Handovercommand

T7 Stopped T8 +T3121 Started

Handover command(Handover to UTRAN Command)

RANAP: Relocation detectMAP: Process accesssignalling(relocation detect)

RANAP: Relocation complete

MAP: send endsignal

BSSMAP: Clear complete

T8 +T3121 Stopped

RF Chan rel

RF Chan rel ack

BSSMAP: Clear command

2G – 3G service continuity 2G to 3G Handover Execution (CS)

39

2G – 3G service continuityCS HO GSM-UTRANFDD technologie: Traffic distribution Strategy

2G layer

3G layer: Cell A

PBGT pseudo capture by using negative HoMarginUtran & tuning RxlevMincellUtran

3G layer: Cell B

2G layer is favor for accessibility Tuning of uMTSAccessMinLevel…

2G layer

eligible

Tunning HO traffic parameters

HO 2G -3G tuning will be applied according to several strategy scenario

eligible

40

Multi Zone

41

Multi Zone Single BCCH Description

>The main principle is to define two zones in a cell: inner zone (band1) and outer zone (band0).

>The outer zone contains the TRXs that cover the whole cell area.

>The inner zone TRXs may or may not match the outer zone coverage area.

>Outer Zone manages BCCH, Signaling (SDCCH), and traffic (TCH) channels, while Inner Zone only manages the traffic (TCH) channels.

Band0 layer carries BCCH, SDCCH and TCH

Band1 layer carries only TCH

42

Multi Zone Single BCCH: Direct TCH Allocation (Call Set Up)

OuterzoneOuterzoneInnerzoneInnerzone concentAlgoExtRxLevconcentAlgoExtRxLev

RxlevDL > ConcentAlgoExtRxLev or for AMR HR direct allocation in small zone

RxlevDL > AMRDirectAllocIntRxLevDL&

RxlevUL > AMRDirectAllocIntRxLevUL

+ hoMarginBeg

+ hoMarginBeg

+ hoMarginBeg

The time spent on SDCCH is not long enough to compute a weighted average on downlink Rxlev measurement before reception of the Abis connection state request.

Therefore in V17, L1M compensates by adding hoMarginBeg

43concentAlgoIntRxLevconcentAlgoIntRxLev

Ms call is allocated in Innerzone :if

RxlevDL < ConcentAlgoIntRxLevOr

RxQualDL < lRxQualDLOr

RxQualUL < lRxQualUL

Then MS moves to Outerzone

Multi Zone Single BCCH: Interzone Handover principle

OuterzoneOuterzoneInnerzoneInnerzone concentAlgoExtRxLevconcentAlgoExtRxLev

Ms call is allocated in Outerzone :if

RxlevDL > ConcentAlgoExtRxLevThen

MS moves to Innerzone

44

MutiZone HO Types

•Intercell intraband HO: band0 --> band0:

•Intercell interband HO: band1 --> band0

•Intracell intraband HO: band0 --> band0 OR band1--> band1

•Intercell interband HO: band0 --> band1

•Intercell intraband HO: band1 --> band1

•Interzone (Intracell Interband) HO: band1 --> band0

•Interzone (Intracell Interband) HO: band0 --> band1 :

45

In V17.0, the enhancement is to compensate the difference of propagation between the 2 zones thanks to power control

RxLev DL

BS Pwr Att

biZonePowerOffset

Band 0 Band 1

interZone handover

SACCH

SACCH

2

2

RxLev DL

BS Pwr Att

biZonePowerOffset

Band 0 Band 1

interZone handover

SACCH

SACCH

2

2

V17- Multi Zone EnhancementInterzone Handover: BS & MS Power compensation (1/2)

There is no power compensation during the handover: the initial power after a handover doesn’t take into account the difference of radio propagation between the two bands=> There is signal drop leading to problem of assignment or bad voice quality

46

V17- Multi Zone EnhancementInterzone Handover: BS & MS Power compensation (2/2)

When initiating an inter-zone handover, the BSC shall adapt the BS and the MS power control attenuations depending either on the difference of radio propagation according to the frequency band or on the difference of nominal output TX power between both zones.

Delta_RxLev_DL_oz_to_iz= ZoneTxPwrMaxReduction [oz] - ZoneTxPwrMaxReduction [iz] - biZonePowerOffset

Delta_RxLev_UL_oz_to_iz= - biZonePowerOffset

biZonePowerOffset = 0 in case of concentric cell & dual coupling system

Of course, on a handover from the inner to the outer zone, we have: Delta_RxLev_DL_iz_to_oz = - Delta_RxLev_DL_oz_to_iz

Delta_RxLev_UL_iz_to_oz = - Delta_RxLev_UL_oz_to_iz

47

V17- Multi Zone Enhancement Interzone Handover: Power adapatation (1/2)

MS power management:No power adaptation is required on the uplink for a Concentric cell or a Dual-coupling cell.For dual band:

If (Delta_RxLev_UL_xz_to_yz < 0)

then

new_MS_power (dBm) = Min(old_MS_power (dBm) - Delta_RxLev_UL_xz_to_yz ; MsTxPwrMaxCnx_new_band )

Else

new_MS_power (dBm)= old_MS_power (dBm)

MS power control shall be enabled

48

V17- Multi Zone Enhancement Interzone Handover: Power adapatation (2/2)

BS power management:if Delta_RxLev_DL_xz_to_yz is less than zero, a power loss shall be compensated thanks to a power increase (i.e. BS attenuation decrease) else the latter MS power is kept unchanged.

If (Delta_RxLev_UL_xz_to_yz < 0)

then

new_BS_power (attenuation in dB) =

Max(0, old_BS_power (attenuation in dB) + Delta_RxLev_DL_xz_to_yz )

Else

new_BS_power (attenuation in power level) = old_BS_power (attenuation in power level)

If the BS power control is disabled or on BCCH TDMA, there is no real power adaptation as the BTS shall emit at the maximum power allowed in the zone

49

Multi Zone Single BCCH: parameters Overview

biZonePowerOffset

zoneTxPowerMaxreduction

50

Early ClassMark Sending (class 3) (bts)

• It indicates if a multiband MS is authorized to send the early Classmark change message to the BSC via the BTS.

• The Classmark change indicates the frequency bands supported by the MS and MS power classes to perform HO procedures in the best conditions• If Enabled, this allows the MSC to receive the multiband information from MS and to

pass it on to the target BSC. It will speed up call set-ups, Handovers and Directed retries.

• Currently all Dual band cells are set to Allowed. However, all the cells that have a Dual Band neighbor should have this parameter set to allowed to access direct inner zone handovers in dual band cells (Used in EXP3 discussed later)

• Recommended value – [Allowed] for multi band networks

Multi Zone: Parameters involved (1/3)

51

> Following parameters are used in the Dual band Mono-BCCH implementation:

- concentAlgoIntRxLev : minimum signal strength below which a HO is triggered from band1 (inner zone) to band0 (outer zone).

- concentAlgoExtRxLev : maximum signal strength beyond which a HO is triggered from band0 (outer zone) to band1 (inner zone).

- biZonePowerOffset (in HandOverControl): an offset in the serving cell which is used to estimate the virtual RxLev of band0 (outer zone). Only used when the MS leaves the current bizone cell out of its band1 (inner zone).

(rxLev_band0 = rxLev_band1+ biZonePowerOffset); it is actually the difference in the signal strength between GSM and DCS bands (typically 8-12 db). It has to be calculated because all handover thresholds are defined according to the outerzone/band0 signal level.

- biZonePowerOffset (n) (in adjacentCellHandover): an offset in neighboring cell which is used to estimate the virtual RxLev of band1 signal to determine if the MS can directly access the inner band in the neighboring cell.

biZonePowerOffset(n) >= concentAlgoExtRxLev – rxLevMinCell (n)


52

> Following parameters are used in the Dual band Mono-BCCH implementation:

- ZoneTxPowerMaxReduction Class 2 (transceiverZone) : Attenuation with respect to bsTxPowerMax, which defines the maximum TRX transmission power in the zone (Used in creating two different coverage areas for two zones in monozone Concentric Cells). Dual band Concentric cell recommended value: large zone = [0] dB, small zone = [0] dB

- TransceiverEquipmentClass (class 2) (transceiverEquipment)When dual band (concentric cell) is used, the class of a TRX/DRX enables to distinguish

which DRX and which TDMA are used in the outer or inner zone. Class 1 corresponds to a TDMA in 900 band carrying BCCH so belonging to

transceiverZone = 0 (large/outer zone).Class 2 corresponds to a TDMA in 1800 band not carrying BCCH so belonging to

transceiverZone = 1 (small/inner zone)

- TransceiverEquipmentClass (class 2) (transceiverZone)Class of the TRX/DRXs partnered with the TDMA frames of the zone. The class of a

TRX/DRX sets its maximum transmission power.Class 1 corresponds to a TDMA in 900 band carrying BCCH so belonging to

transceiverZone = 0 (large/outer zone).Class 2 corresponds to a TDMA in 1800 band not carrying BCCH so belonging to

transceiverZone = 1 (small/inner zone).


53

Multi Zone Enhancement

Interzone Handover: Parameters(1/2)


concentricCell bts 0:monozone; 1:concentric2:dualband; 3:dualcoupling

TBD 2

ConcentAlgoExtRxLev handovercontrol -63 to 63 TBD 3

ConcentAlgoIntRxLev handovercontrol -63 to 63 TBD 3

ConcentAlgoExtMsRange handovercontrol -63 to 63 TBD 3

ConcentAlgoIntMsRange handovercontrol -63 to 63 TBD 3

biZonePowerOffset handovercontrol -63 to 63 TBD 3

biZonePowerOffset AdjacentCellHandover -63 to 63 TBD 3

rxLevMinCell AdjacentCellHandover -110 to 48 TBD 3

zoneFrequencyHopping TransceiverZone 0: hopping 1:not hopping

TBD 2

zoneTxPowerMaxreduction TransceiverZone Large zone [0]Small zone[1…55] dB

TBD 2

Transceiver equipment class

TransceiverEquipment 0…3 TBD 2

54

Multi Zone EnhancementInterzone Handover: Parameters(2/2)


Transceiver equipment class

TransceiverZone 1 or 2 TBD 2

TransceiverZone TransceiverZone 0: large; 1small TBD 2

StandardIndicator bts 0…9 TBD 2

msTxPwrMax2ndBand bts According to GSM band TBD 2

Early callsmark sending bts Not allowedAllowed

Allowed 3

btsTxPowerMax bts 0..47 43 3

55

Paging Process Evolution

Multi paging PrincipleThe multipaging command message is a Nortel Specificity. The principle of this implementation is to form group of paging on the Abis interface. Before BSS V14.3.1, for each paging message receives from the MSC; one paging message is sent on Abis interface to a target

cell.

UI Multi paging

Paging MS4

BTSBSCMSC

Paging MS1

Multi paging command

T_Paging_group Paging MS2

MS1, MS2, MS3

Paging MS3

T_Paging_group

Multi paging commandMS4

The aim of this feature is to reduce the congestion and overload messages on Abis interface. In order to achieve this goal, a new BSC timer Called T_Paging_Group was introduced, to define the minimum of time between two occurrences of multi paging command messages on Abis interface.

UI Multipaging PrincipleEach time a data request message (I frame on LapD) is used to convey a multipagingmessage to the BTS, the BSC has to wait for an acknowledgement before sending the next Multipaging message. Therefore, the paging process is RTD dependent. Using the Unit DataRequest message (UI frame on the LapD), no acknowledgement is required before sendingthe next frame, which decreases the lapd bandwidth associated to the BCCH TRX for paging

messages. .

UI Multi paging

BTS BSCI frame number N

(paging)Ack frame number N

I frame number N+1 (paging)

RTD dependency

Using a Data Request Message (I frame on LapD)

to send paging message to the BTS follows this principle (the lapd window is 1):

BTS BSCUI frame number N

(paging)

UI frame number N+1 (paging)

No need to wait for the acknowledgement of the frame number N

Line throughput dependency

Feature Activation

The feature is deactivated by default and can be activated thanks to a build on line.

Recommended upgrade steps are the following:

Upgrade of the BSC without activation of the UI MultiPaging feature (type 4)

Upgrade of the BTS supported by the BSC

Activation of the UI Multipaging feature in the BSC (via a build on line).

UI Multi paging

Extended CCCH

B C C C C C C C C CF S F S F S F S F S -

BCCH + CCCH downlink

8 TDMA

TS0 TS1 TS2 TS3 TS4 TS5 TS6 TS7

Extended CCCH downlink

Beaconfrequency

Extended CCCH is mandatory from:- 7 TRXs in mono-layer- 5 TRXs in multi-layer (micro or dual-band)

SDCCH

B C C C C C C C C C- - - - - - - - - - -

This feature consists of allowing the configuration of extended CCCH on TS 2, 4 and 6 of the BCCH TDMA. This feature allows to increase the rate of Paging and Immediate Assignment messages related to the cell

60

Paging Capacity Evolution

61LAC RAC

LAC RACA i/ffilter BSC

filter

A

Agprs

V14.3.²0/1, V15.0 V14.3.2, V15.1 V15.1.1AbisCS paging mode mult²ipaging I (RSL) multipaging I (RSL) multipaging UI (RSL)PS paging mode single paging I (GSL) single paging I (GSL) multipaging UI (GSL)

Grouping capacityCS paging 10 pages/group 12 pages/group 12 pages/groupSend method wait until timer expiry wait until timer expiry do not wait for timer expirySend periodicity 200ms (fixed) 200ms (fixed) 200 ms (max)Send rate max 50 paging/s/LAC max 60 paging/s/LAC > 60 paging/s/LACPS paging 1 page/message 1 page/message combined with CSSend rate limited by limited by combined with CS

Abis RTD Abis RTD

A i/f filterCS paging 45 paging/s/BSC 120 paging/s/BSC 105 paging/s/BSC

(12 msg / 100 ms)BSC filter N/A N/A 105 paging/s/BSC

(CS + PS)Network Engineering limitsCS paging 31 paging/s/BSC 64 paging/s/BSC 100 paging/s/BSC

31 paging/s/LAC 32 paging/s/LAC 100 paging/s/LAC PS paging (config A) 22-24 paging/s/RAC 35 paging/s/RAC * combined with CSPS paging (config B) 10 paging/s/RAC 14 paging/s/RAC * 30 paging/s/RAC

Radio limit 15-80 paging/s/cell 15-80 paging/s/cell 15-80 paging/s/cell(function of BTS parameters)

V15.1.1 FN 29479 (Paging capacity increase – UI)

V14.3.0 FN 25604 (multipaging command)

V15.1 FN 26257 (Paging load distribution on Agprs LAPD)

V15.1 FN 26306 (RTD LAPD)

Config A = 2-phase access and CCCH@BTSConfig B = 1-phase access (only after V15.0) or No CCCH@BTS

Lapd

Abis

* V15.1 only

1234

1

2

3

4

62

Security


> Authentication:• A3 provides SRES from RAND and Ki, A8 provides Kc from the same

arguments• Triplets (RAND, SRES, Kc) allow the network to authenticate end-users

> Encryption:• A5 allows data encryption/decryption from Kc• Encryption prevents intercept and decoding of user’s data and signalling

transiting on the air interface, in particular IMSI, IMEI, and calling/called numbers

• A5 embedded in the MS and BTS

A3

A5

A8

SRESRAND Kc

KiRAND

Authentication

A5/3Introduction


> Several attacks published on A5/2 since 1997 led GSM Association to prohibit the use of A5/2 from all GSM networks from end 2006

> A5/1 security more and more challenged as it uses the same ciphering key as A5/2

> GSMA may impose A5/3 in case of increasing risk on A5/1

A5/3Risks on A5/1 & A5/2


> Principle• Converts 64-bit blocks under the control of a 128-bit key (Kc)• Based on KASUMI algorithm specified in 3GPP TS 35.202

> DRX• Due to the hardware constraints, A5/3 algorithm designed only on DRX ND3,

eDRX and RM; older DRX do not support A5/3• New algorithm available by software upgrade from the BSC via Abis interface

> OMC / BSC• Normally supports all encryption algorithms• Enabled through parameter “encryptionAlgoSupported” settable at OMC

level; class-3 parameter, can be modified on line• BSC applies A5/3 to a communication provided that it is activated, supported

by DRX type and MS; otherwise, fallback to A5/1 or no encryption

> MS• All MS launched currently support A5/3 but penetration still low as first A5/3

capable MS launched 4Q05

A5/3Technical description


> Technical overview> Based on KASUMI algorithm specified in 3GPP TS 35.202

> Converts 64-bit blocks under the control of a 128-bit key (Kc)

> Dependencies> BTS: DRX ND3, eDRX, RM. Not supported on ND & old design DRX

> BSC 3000. Not supported on BSC12000

> MS: A5/3 capable

> MSC: must support phase II OAM parameters (cypherModeReject, encryptAlgoAssComp…)

A5/3Feature summary


This feature permits to reduce BTS power consumption by automatically switching

the PA off when no communication is in progress on the TRX for some time. PA is

automatically switched on as a communication establishment begins.

The PA can be switched OFF or ON thanks to an electronic switch. This switch can

be set to ON or OFF by software, thanks to a dedicated new TX firmware function.

Smart power managementFeatures description


SmartPowerManagement btsSiteManager Enable/disable the smart power management feature

Enable 2


• Market drivers & Benefits• Dynamically adjust BTS

power consumption to the actual cell traffic

• TDMA are switched off if still inactive after a certain timer period, settable at OMC-R

• HW dependencies• BTS 18000/6000/9000• S8000/S12000 V18 PoI

Smart power managementField results

Power consumption (dual band site)

0

200

400

600

800

1000

1200

1400

1600

1800

TimeW

atts

DC

900

1800

900 1800 900+1800W/o SPM (Watt DC) 1468 791 2259W/ SPM (Watt DC) 1370 642 2013Saving (%) 7% 19% 11%Saving (Watt DC) 97 149 246

- 2155 kWh/year - 172 €/year

Based on VO field results in EMEA Tier 1 customer

Environmentally friendly

BTS power bill reduction

69

RF Feature

70

Interferer cancellationOverview

f1 f1

f1 interferer

XWANTED WANTED

DSPDSPf1 wanted

(useful signal)Signal received=f1 wanted + f1 interferer + noise

INPUT

OUTPUTnoise

f1 interferer

noise

71

Interferer cancellation Principle 1/2

• Combination of signal processing and space diversity techniques to cancel interference according to propagation conditions• Signal processing:

On each antenna, at reception level, the training sequence is used to estimate the impulse response, so deduce usefull signal and noise and interferencesNot accurate when there are no interferers

• space diversity technique (Maximum Ratio Combining algorithm) find a linear combination of the antenna signals so that the interferer signal is nulled (=antenna diagram with a zero value on the interferer direction)

72

Interferer cancellation Principle (2/2)

• The Maximum Ratio Combining algorithm points the main lobe on the useful signal

• Interferer cancellation acts as if an antenna null was pointed on the strongest interfering mobile.

• Without interferer the algorithm acts as a pure diversity algorithm (MRC)

• Parameter set at OMC-R: parameter: trade-off the pure noise performances against the dominant interferer case

73

Interferer cancellationAntenna radiation patterns

No Interferer

One Interferer

74

Interferer cancellation Parameter


interferer cancel algo usage bts [0 to100]%- 0%: Maximum Ratio Combining (best pure thermal noisesensitivity): no interference cancellation, minimum speedcorrection. - 50%: MRC when no interferers (same pure thermal noisesensitivity as 0%): interference cancellation, medium speedcorrection. - 100%: Approximate MRC when no interferers: interferencecancellation, best speed correction.

50% 2

• signification : weight of the interferer in the network

• Values : • 0% : no interference; input signal = useful signal + white noise• 50% : half interference, half white noise; input signal = useful signal + white

noise + interfering signal• 100% : no white noise; input signal = useful signal + interfering signal

75

Interference cancellationParameter settings

= 50% is a good compromise between interference cancellation and pure thermal noise sensitivity:• does not degrade the sensitivity• gives almost the same interference cancellation performance as = 100%

0.5 dB cancellation loss in the range I/N = 0 t o 20dB (compared to 100%)

• medium trafic area (where isolated interferers will be removed with no coverage degradation)

= 100%achieves best interference cancellation, when pure thermal noise sensitivity is not an issue (not coverage, but interference limited)

76

Interferer cancellation Synchronous interferer - Simulations

-30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 (dB)-7.0

-6.0

-5.0

-4.0

-3.0

-2.0

-1.0

0

1.0

(dB)

C/(n

.I+N

)

n.I/N

Interference Cancellation - Several Synchronous InterferersS8000 - Typical Urban Environment - Rxqual 6 (ber=9.05 percent)

Legend 1 Interferer2 Interferers3 Interferers4 Interferers5 Interferers feature OFFfeature ON

loss of 1.5 dB du to the non white noise

no degradation of sensitivity

8dB Gain

Interference dominantThermal noise dominant

77

Interferer cancellation Asynchronous interferer

• The determination of the main lobe and the nulls of the antenna is computed during the training sequence at the center of the useful burst (26 bits)

• The accuracy of the computations depends on the time frame when interferences occur:• Interferer during the training sequence time frame • Interferer outside the training sequence time frame.

Useful signal

interfererWhite noise

Training sequence

78

Interferer cancellation Asynchronous interferer : simulations

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 (bit Period)

1e-3

1e-2

1e-1

BE

R

time shift

Influence of Interferer Delay - 1 Interferer-Noise

- S8000 - TU50 - C and I independent - C/N=10dB - I/N=15dB

Training Seq.(useful burst)

Information Bits (useful burst)

Information Bits(useful burst)

Legend1 ant.2 ant. feature OFF2 ant. feature ON

Interferer outside the window :same performances as MRC

Interferer in the window: it is eliminated

79

• Ass.: during the useful signal burst, there are 2*n asynchronous interferers from same energy

• interferer ’s synchronisation have been randomly picked up

• results have been averaged over all synchronisation values

Useful burstTSC

time

interf. 1 interf. 2 TSC

interf. 3 interf. 4TSC

Interferer cancellation Asynchronous interferer : Assumptions

80

-30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 (dB)-3.0

-2.0

-1.0

0

1.0

2.0

(dB)

C/(n

.I+N

)

n.I/N

Interference Cancellation - Several Asynchronous InterferersS8000 - Typical Urban Environment - Rxqual 6 (ber=9.05 percent)

Legend 2x1 Consecutive Interferers2x2 Consecutive Interferers3x2 Consecutive Interferers feature OFFfeature ON

Interferer cancellation Asynchronous interferer : Simulations

What is NW synchronisation ?Principles of the feature with an engineering view.

82

Network synchronisation general overviewNon synchronised NW

TSC : centre of the burst

Cell x1

TDMA y1

FN z1

Cell x2

TDMA y2

FN z2

z1 z1 + 1 …

z2 z2 + 1 …

Cells time base = from PCM time. Only the cells of the same site (on the same PCM) can be aligned.

All FN in the network are random

83

Network synchronisation general overviewSynchronised NW


Cell x1

TDMA y1

FN z

Cell x2

TDMA y2

FN z + offset

z z + 1 …

z+o z+o + 1 …

Bursts are alignedFNs can be determined

84

Network synchronisation general overviewBurst synchronisation and time synchronisation


Burst synchronisation

Cell x1

TDMA y1

FN z1

Cell x2

TDMA y2

FN z2

Time synchronisation

z1 z1 + 1 …

z2 z2 + 1 …

Burst synchronisation : for PCM clock differencesTime synchronisation : for FN differences

85

Network synchronisation new parametersNortel’s implementation of NW synchronisation

Nortel parameter name Definition Range Default value Recommended value

0: normal1: master2: slave3: gpsBurstSync4: gpsTimeSync5: masterGpsBurstSync6: masterGpsTimeSync

masterBtsSmId Identity of the master BTS Master BTS id or empty empty Depends on context

Allows to specify and control FN difference between BTS.

FNOffset parameter is on a per site basis.

tnOffsetAllows to specify and control TN difference between BTS

0 … 7 0 Set by NW planning

fnOffset 0 … 84863 0 Set by NW planning

btsSMSynchroMode Activation of the Synchronization feature 0: normal Depends on context

Apparently, only few parameters

86

Network synchronisation other parametersBesides the specific NW synchronisation parameters

> Direct interaction• BSIC (BCC/TSC + NCC)• FN Offsets (SACCH, SCH)

> Hopping law• HSN• Nb. And list of Frequencies (MA list)• MAIO

> Others• May require HO tuning, PW control tuning … • May require specific planning solutions

Besides the feature specific parameters, numerous engineering planning actions must be taken

87

What is NW synchronisation ?Synthesis

> From random to deterministic situation• Bursts are synchronised (position in the burst is no longer random)• FN are no longer random• Pseudo-random aspects remains (RNTABLE)

> Requires engineering• New parameters planning• Planning has to be rethought (BSIC plan, SACCH plan …)• Further tuning actions compare to synchronised situation

The reduction of random aspects allow more precise planning, on another hand, synchronizing a NW is a different story and previous

knowledge (rules) have to be updated accordingly (studies).

What is expected with NW synchronisation ?

89

Overview of the areas of change Clarify advantage vs. considerations

A potential for improvement if engineered with care.

+ - Collision probability : FNs are deterministic. Optimal

solution improving performances ?

Non recoverable collisions probability : Is collision

probability the best ?

Variability, range and number of the parameters :

feasibility of the best solution.

Gain limitations : tends to 1/Nb. Frequencies

Maybe already optimalLess interferences Not that easy to achieve

Interferers are "burst synchronized"

Features of interference and noise cancellation work

better.

TSCs collisions are worse, TSC range is only 8, TSC (BSIC)

planning : precision of IM, feasibility

Areas needing improvement may not be the ones with

benefits

SAIC mobiles performances incertitude

Less interferences impactRequires a careful TSC planning

More pertinent in some areas Optimal scheduling of SACCH : optimal DTX

Optimal BSIC (SCH) reading by MS : optimal HO

procedure

FN planning in 3 dimensions (SACCH, SCH, Pb Collision)

Evaluation (measurements) of impact on HO and on DTX

Evenly spread channels could induce better performances Feasibility, real quantity of impact ?

Interferences

quantity

Interferences

impact

Others

90

Detailed areas of change: Quantity of interferencesQuestions

> Planning : Could some associations (MA lists, HSN, MAIO, FN, TN) be better than others ?

> Variability : Does the complexity of planning limit the feasibility of the solutions ?

> Limitations : What is the range of impact on interferences quantity ?

We try here to answer the question “can a deterministic planning reduce the interferences quantity better than the pseudo-random one of

non synchronised NW ?”

91

F24

Cell x1, HSN1= 9MAIO1= 0FN1 = 150MA list = 38 Freq

F30 F4 F33 F25 F26 F26 F19

F22 F16 F22 F5 F2 F26 F37 F36

Cell x2, HSN2= 10MAIO2= 26FN2 = 1450MA list = 38 Freq

collision

Duration : d

Depends on 9 parameters

Detailed areas of change: Quantity of interferencesQuantity of interferences = Collisions probability.

92

Detailed areas of change: Quantity of interferencesCollision probability : depends on 9 parameters

> Example of calculation times for fractional reuse (only 7 parameters) :• With 31, 37 and 40 frequencies• Even after algorithm optimizations (84864 vs. 2715648 frames …)

sec days years84864 63 31 84864 82869696 60391324,65 698,973665 1,9184864 63 37 84864 98908992 66446276,29 769,0541238 2,1184864 63 40 84864 106928640 71439219,03 826,8428129 2,27

nb of calculations

nb Delta FN

nb MAIOnb HSNdurationCalculation duration

Processing systematic calculations

Calculation time The limiting factor

93

NbFreq Min Pb Max Pb Avg Pb StD Pb

31 0,20% 44,94% 3,23% 0,57%

Distribution of Co-channel probability of collisions for 38 frequencies

0

2000

40006000

8000

10000

0,00

%0,

90%

1,20

%1,

40%

1,60

%1,

80%

2,00

%2,

20%

2,40

%2,

60%

2,80

%3,

00%

3,20

%3,

40%

3,60

%3,

80%

4,00

%4,

30%

4,80

%

100,

00%

Collision Pb (%)

Nb

of c

ombi

natio

ns (

HS

N1,

H

SN

2, M

AIO

1, M

AIO

2, F

N1,

F

N2)

Detailed areas of change: Quantity of interferencesGains limitations : fractional reuse

Potential of gain within the limit of 1/ Nb. Freq (here 3.23%)

1/31

1/38

Planning has to find the right MAIO combinations

94

Detailed areas of change: Quantity of interferences

Can a deterministic planning reduce the interferences quantity better than the pseudo-random one of non synchronised NW ?

> High variability. Complexity vs. feasibility : calculation times, despite optimizations.

> Magic combinations : low collisions probabilities mostly go with high ones.

> Non recoverable collisions probability : a better potential than Collisions probability.

> With ad hoc, collisions probabilities are constant, and reduces complexity.

95

Detailed areas of change: Impact of interferencesVarious levels of impact > Uplink : some features interaction with synchronisation

• Nortel feature of interference cancellation• Noise cancellation feature• From V16 : Adaptative receiver feature

> Downlink : SAIC MS interactions with synchronisation• Blind vs. not blind architecture : mostly blind (sensitive to TSC)• 3GPP : gain, with 1 interferer, shall be at least 8 dB.• Penetration and performances

Both : Gain sensitive to nb. of interferers and TSC collisions.Downlink : Penetration, performances of SAIC mobiles to be assessed.

Uplink : features (ICA, noise cancellation) already active, only the additional gain of synchronisation

96

Detailed areas of change: Impact of interferencesUplink and downlink : Sensitivity to TSC collisions

2 (center of) bursts : red one = main signal, interfered, blue one = interferer.

Before NW synchronisation With NW synchronisation, different TSCs

With NW synchronisation, same TSCs

Cumulation

Critical interferers should not be allocated the same TSC.

97

Detailed areas of change: Impact of interferencesUplink and downlink : Impact of TSC

TSC collisions impact vary according to the various TSC couples (TSC1, TSC2) :

Impact of TSC in synchronised situation, without interference cancellation

98

TSC collisions impact vary according to the various TSC couples (TSC1, TSC2) :

Impact of TSC in synchronised situation, with interference cancellation

Detailed areas of change: Impact of interferencesUplink and downlink : Impact of TSC

99

Detailed areas of change: Impact of interferencesUplink (and downlink ?) : sensitivity to number of interferers

-30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 (dB)-3.0

-2.0

-1.0

0

1.0

2.0

(dB)

C/(

n.I+

N)

n .I/N

Interference Cancellation - Several Asynchronous InterferersS 8 00 0 - Typ ica l U rb an E nv iron m en t - R xqu al 6 (b er=9.0 5 p erce n t)

Legend 2x1 Consecutive In terferers2x2 Consecutive In terferers3x2 Consecutive In terferers fea ture OFFfeature ON

4.5dB Gain

-30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 (dB)-3.0

-2.0

-1.0

0

1.0

2.0

(dB)

C/(

n.I+

N)

n .I/N

Interference Cancellation - Several Asynchronous InterferersS 8 00 0 - Typ ica l U rb an E nv iron m en t - R xqu al 6 (b er=9.0 5 p erce n t)

Legend 2x1 Consecutive In terferers2x2 Consecutive In terferers3x2 Consecutive In terferers fea ture OFFfeature ON

4.5dB Gain

-30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 (dB )-7.0

-6.0

-5.0

-4.0

-3.0

-2.0

-1.0

0

1.0

(dB )

C/(

n.I

+N

)

n .I/N

Interference Cancella tion - Severa l Synchronous InterferersS8000 - Typical U rban Environm ent - R xqual 6 (ber=9.05 percent)

Legend 1 Inte rferer2 Inte rferers3 Inte rferers4 Inte rferers5 Inte rferers feature O FFfeature O N

loss of 1.5 dB duto the non white noise


8dB Gain


-30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 (dB )-7.0

-6.0

-5.0

-4.0

-3.0

-2.0

-1.0

0

1.0

(dB )

C/(

n.I

+N

)

n .I/N

Interference Cancella tion - Severa l Synchronous InterferersS8000 - Typical U rban Environm ent - R xqual 6 (ber=9.05 percent)

Legend 1 Inte rferer2 Inte rferers3 Inte rferers4 Inte rferers5 Inte rferers feature O FFfeature O N

loss of 1.5 dB duto the non white noise


8dB Gain


Higher gain when interferers are synchronized and fewer (reducing overlapping).

Uplink : gain is the «remaining» part

100

> Gain expected :• DL : SAIC mobiles (penetration, Architecture)• UL : ICA/Noise cancellation features.

> Maximum gain implies :• Optimal TSC planning• As less overlap between cells as possible

Detailed areas of change: Impact of interferencesConclusions

101

Detailed areas of change: OthersOther impacts of network synchronisation

> What is the FN offset impact on SACCH transmission ?

> What is the FN offset impact on BSIC reading and HO efficiency (SCH transmission) ?

And, “should FN offset be modified and how ?”

102

Detailed areas of change: OthersSACCH

> Non synchronised NW : FN offsets between cells are random :• SACCH transmission random : ~ spread.• No way to control it, anyway.

> Synchronised NW : • FN offset between 2 cells = 0 : the coincidence of the various

SACCH channels, could lead to additional RLT expiries.• Need to plan FN Offset to avoid, as much as possible, collisions

of SACCH.

Multiples of 26 (FR) or 13 (HR) are to be avoided

103

Detailed areas of change: OthersBSIC reading : MS has a limited time (10 sec) to identify and synchronize with neighbor cells

> Non synchronised NW : FN offsets between cells are random :• SCH transmission random : ~ spread.• No way to control it, anyway.

> Synchronised NW : • FN offsets between 2 cells could be set for each neighbor cell to

improve the efficiency of the mobiles to identify and synchronize with neighbor cells.

• Need to plan FN Offset to allow, as much as possible, spreading of SCH of the 6 strongest neighbors of each cell.

Planning of FN offset concerns the neighboring

104

What is expected with NW synchronisation ?Synthesis

> Quantity of interferences• Fractional reuse : Complex planning, involving many parameters. • With ad hoc, collisions probabilities are constant, and reduces complexity.

> Impact of interferences• Gains according to limitation of the NW (UL, DL)• Requires tight TSC planning (and abacus of gains). Reduced effects in

highly overlapped areas.

> Others• FN Offset have also to be planned according to SACCH and SCH

Planning solutions will be the key to improvement.Will require background information and preparation : abacus

(TSC), IM …

What has to be done to implement NW synchronisation ?

106

Overview of the planning steps

Planning of SACCH color Planning of SCH color

Global color

Use existing Frequency plan

Global color = FN

Ad hoc

Calculation of HSNs, MA lists, MAIOs and FN

Global color = mod(FN, 26*51)

Others

TSC (BCC) planF(IM*PbColl*Traffic, abacus)

NCC plan (BSIC)

(*)

(*) For ad hoc, as PbColl=constant, TSC plan can be done in parallel with previous steps

General steps of planning and their schedule

107

DRIVERS /BENEFITS

Capacity Increase (Erl)/MHz spectrum

Voice quality / Data throughput FER/BLER reduced in DL

thanks to interferer cancellation

TECHNICAL OVERVIEW

New Classmark 3 information element is used to inform the BSS about the MS capability

Several dB rejection on the strongest interferer in DL for DARP capable MS

Specific allocation rules : One TDMA priority field for SAIC MS : high, low, forbidden Increase frequency reuse on SAIC

dedicated TDMA

TERMINAL DEPENDENCIES

Maximum gain is obtained with Release 99 Terminals (1Q2005) supporting DARP capability Optional Feature : Single Antenna

Interference Cancellation or Downlink Advanced Receiver Performance (GERAN R6)

HW dependencies

Capacity gain is obtained with Network Synchronization

SAIC capable MS management

108

SAIC capable MS management

> Capacity gain can evaluated to 50% (better downlink performance in GMSK)1. Allocator enhancement allows defining specific TDMA pool with high

priority allocation rles for SAIC capable MS allowing increasing frequency reuse according to SAIC MS penetration : • 30% SAIC penetration allows for 15 % capacity gain

2. When no specific allocation rules are used, SAIC MS will require less BTS transmitted power (Itf reduction) and will use more often HR channel (BTS capacity increase). Moreover DL signalling blocks will be better received decreasing the call drop ratio.• Require high handset penetration to have capacity benefit

Site traffic gain with SAIC capable handset

0

50

100

150

200

250

Baseline With net Sync With SAIC 100%

Tra

ffic

in

erl

ang

Baseline With net Sync With SAIC 100%

16% gain

46 % gain

training4 nortel feature evolution v15.1.1 to v17

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