3-claro b9 rrm algorithms

7/29/2019 3-Claro B9 RRM Algorithms

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All rights reserved 2005, Alcatel

Radio Resource Management

Algorithms in B9

B9 Claro Workshop - February 14th 2006


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All rights reserved 2005, AlcatelB9 Claro Workshop / February 14th 06

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Agenda

Autonomous Packet Resource allocation

Computation of MAX_SPDCH_LIMIT

Selection of allocated PDCH

Impacts on CS Preemption algorithm

TBF allocation/re-allocation strategy

Transmission resources usage

Best candidate allocation of radio TS

Modifications of TBF reallocations algorithms

Parameters & Quality of Service indicators


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Modification of the PDCH allocation strategy

Autonomous Packet Resource Allocation

In B8:The BSC evaluates the number of timeslots that the MFS could use

to carry PS traffic (Max_SPDCH_Dyn),

The MFS does not know which timeslots are usable for PS traffic,

To serve a new TBF, the MFS needs to request new timeslots to theBSC.

Event-triggered mechanism

Max_SPDCH_Dyn = 8

TS allocated to BSC

TS allocated to

MFS


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Autonomous Packet Resource Allocation (RAE4)

In B9, the following new needs have appeared:

Need to know the list of basic Abis nibbles which are currentlyavailable to establish GCHs,

Need to know which basic Abis nibbles are preemptable / not-preemptable for CS traffic by the BSC. This information is useful:

For the QoS feature (in order to be able to ensure a given GBR foran RT PFC).

To define some priorities in the Abis nibble selection (preference isgiven to the non-preemptable basic Abis nibbles in order to limit theinteraction of CS over PS traffic).

Need to accelerate TBF establishment times (the B8 round trip delaybetween MFS and BSC to allocate some PDCHs can be avoided).

To meet all those needs, a process called AutonomousPacket Resource Allocation has been introduced in B9.


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In B9: The BSC evaluates a number of timeslots that the MFS can use to

carry PS traffic (Max_SPDCH_Limit),

Periodical exchange of messages between the BSC and the MFS:

BSC to MFS: list of RTS that the MFS can use,

MFS to BSC: acknowledgement of allocated / de-allocated RTS.

The MFS knows which timeslots can be used to serve a new TBF.

Periodical mechanism

Max_SPDCH_Limit = 8

TS allocated to BSC

TS allocated to

MFS


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CS/PS sharing is based on the evaluation of Max_SPDCH_Limit. The Max_SPDCH_Limit value:

Corresponds to a number of timeslots allocated to the MFS,

Evaluated at the BSC level,

Periodically, every TCH_INFO_PERIOD * RR_ALLOC_PERIOD,

Transmitted to the MFS using the RR Allocation Indication message,

Comprised between Min_SPDCH and Max_SPDCH.

The evaluation of Max_SPDCH_Limit is based on:

O&M parameters (Max_PDCH, Min_PDCH, Max_PDCH_HIGH_LOAD,HIGH_TRAFFIC_LOAD_GPRS, THR_MARGIN_PRIO_PS),

CS and PS load, averaged using a sliding window of sizeLoad_EV_Period_GPRS,

PS load: provided to the BSC by the RR Usage Indication message.

Sharing of unused TSs between CS and PS traffic.


7/64All rights reserved 2005, AlcatelB9 Claro Workshop / February 14th 06

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At the expiry of the TCH_INFO_PERIOD timer, the following loadsamples are calculated: NB_USED_CS_TS(k) & NB_USED_PS_TS(k)

NB_USED_TS(k) = NB_USED_CS_TS(k) + NB_USED_PS_TS(k)

NB_UNUSED_TS(k)

for each cell, every RR_ALLOC_PERIOD * TCH_INFO_PERIOD, the BSCcomputes three averaged values through a sliding window of sizeLOAD_EV_PERIOD_GPRS (default value = 3):

TCH_INFO_PERIOD = 5s

AV_USED_CS_TS(k)

AV_USED_PS_TS(k)

AV_UNUSED_TS(k)

NB_USED_CS_TS(k)

NB_USED_PS_TS(k)

NB_USED_TS(k)

NB_UNUSED_TS(k)

kk-1k-2

LOAD_EV_PERIOD_GPRS = 3

k+1 k+2

AV_USED_CS_TS(k+2)

AV_USED_PS_TS(k+2)

AV_UNUSED_TS(k+2)

RR_ALLOC_PERIOD * TCH_INFO_PERIOD


RAE4 : Load evaluation


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the BSC periodically (every RR_ALLOC_PERIOD *TCH_INFO_PERIOD) computes the number of Slave PDCHs that itcan provide to the MFS: MAX_SPDCH_LIMIT

MAX_SPDCH_HIGH_LOAD

Computation of CS/PSMargin

AV_USED_CS_TSAV_USED_PS_TSAV_UNUSED_TS

NB_TS_DEFINEDNB_TS_SPDCH

Computation of

Thresholds

THR_MARGIN_PRIORITY_CSTHR_MARGIN_PRIORITY_PS

NB_TS

MARGIN_PRIORITY_CS

MARGIN_PRIORITY_PS

Computation of

MAX_SPDCH_LIMIT

MAX_PDCH_HIGH_LOADMAX_PDCHMIN_PDCH

NB_TS_MPDCH

MAX_SPDCH_LIMIT

MIN_SPDCHMAX_SPDCH

O&M parameters

O&M parameter

= 100 HIGH_TRAFFIC_LOAD_GPRS


RAE4 : MAX_SPDCH_LIMIT Calculation


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Two new margins are introduced, to guarantee that acertain number of timeslots are kept available for thearrival of new calls between two transmissions of the RR

Allocation Indication message

CS Margin TS that should be kept at BSC for possibly incoming CS calls

Computation based on HIGH_TRAFFIC_LOAD_GPRS

PS Margin TS that should be allocated to the MFS for possibly incoming TBF

Computation based on THR_MARGIN_PRIO_PS andMAX_PDCH_HIGH_LOAD




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MAX_SPDCH_LIMIT Calculation : It can be in the range of [MIN_SPDCH, MAX_SPDCH]

Unused TS are shared equally between BSC and MFS

If the number of unused TS is too low (e-g high CS/PS traffic), then

Margins are used

Higher priority is given to CS over PS, except when used PDCH arebelow Max_PDCH_High_Load



MIN_SPDCH

MAX_SPDCH_HIGH_LOAD

MAX_SPDCH

reserved for PS priority for PS priority for CS reserved for CS

MAX_SPDCH_Limit


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Agenda











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Radio Resource AllocationIndication message:

Periodically, everyTCH_INFO_PERIOD *RR_ALLOC_PERIOD,

SPDCHs_Allocationbitmap: containsinformation whether a timeslot isallocated to the MFS or not.

Radio Resource UsageIndication message:

Periodically, everyTCH_INFO_PERIOD or in responseto a RR Allocation Indication,

SPDCHs_Confirmation bitmap:indicates or confirms whether atimeslot is allocated or not to the MFS,

SPDCHs_Usage bitmap: providesoccupancy states of timeslotsallocated to the MFS.


MAX_SPDCH_LIMIT TS selection

BSC MFS

Radio Resource AllocationSPDCHs_Allocation

Radio Resource UsageSPDCHs_Confirmation

SPDCHs_Usage


SPDCHs_Usage



SPDCHs_Usage

TCH_

INFO_

PERIOD

TCH_

INFO_

PERIOD

TCH_

INFO_

PERIOD

xRR_

ALLOC_

PERIOD


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The way to set the priority of the PS capable TRX (TRX_PREF_MARK= 0) is slightly modified in B9 release with the introduction of afrequency band criterion:

PS_PREF_BCCH_TRX

HW TRE capability (G4 HP -> G4 MP -> G3)

DR TRE capability (FR TRX -> DR TRX)

E-GSM TRX preference (new in B9, E-GSM TRX -> P-GSM/GSM850/DCSTRX)

TRX having the maximum number of consecutive SPDCHs

TRX identity (low TRX id -> high TRX id)

PS TS and TRX ordering:

First step : the TRX with lowest rank (see above) is selected first

Second step: once the TRX has been selected, the TCH/SPDCH timeslotshaving the lowest timeslot index, e-g. located at the most left side is selectedfirst


MAX_SPDCH_LIMIT TS selection : ordering

o ca on o e a oca on s ra egy


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o ca on o e a oca on s ra egy

MAX_SPDCH_LIMIT TS selection : PS TSzones

example: MAX_SPDCH_HIGH_LOAD = 8,MAX_SPDCH_LIMIT = 10

example: MAX_SPDCH_HIGH_LOAD = 8,MAX_SPDCH_LIMIT = 3

TRX2 TRX1

1 3 42 5 6 7 8 9 10 1211 13 14 15 16

MAX_SPDCH_LIMIT zone

PS CSPS CS CSCS CS

MAX_SPDCH_HIGH_LOAD zone

PS PS PS PS

Non pre-emptable PS zone

PS traffic zone

TRX2 TRX1

1 3 42 5 6 7 8 9 10 1211 13 14 15 16


PS CSPS CS CSCS CS


PS CS CS


PS traffic zone

CS

MAX_SPDCH_HIGH_LOAD zone:

the MAX_SPDCH_HIGH_LOADconsecutive PS capable TS that arepreferred for PS allocation

Non pre-emptable PS zone:

always insideMAX_SPDCH_HIGH_LOAD zone

in this latter zone, we search for therightest TS allocated to the MFS andused. Then, all the TS located at its leftdefine the non pre-emptable PS zone

MAX_SPDCH_LIMIT zone:

the MAX_SPDCH_LIMIT consecutivePS capable TS preferred for PSallocation

PS traffic zone:

the larger zone between the 2 above


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Impact on SPDCH capable TS carrying CS traffic: If located inside the PS traffic zone, they are pre-reserved for PS.

No new incoming CS call can be served on this TS, if it becomes unusedonce it is pre-reserved for PS.

Valid until the TS becomes not pre-reserved for PS again and of coursestill handled by the BSC

If located inside the Non pre-emptable PS zone and theMAX_SPDCH_LIMIT zone, an intracell Handover can be triggered

if EN_RETURN_CS_ZONE_HO = enabled, the BSC shall check whether

TCHs are allocated in both the MAX_SPDCH_LIMIT zone and the non pre-emptable PS zone, and trigger the HO (cause 30)

the TS will be considered as unused only once the handover will have beensuccessfully performed. As the pre-reservation state of such a TS is set topre-reserved for PS, no new incoming CS call can be allocated on it


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CS calls in the Non pre-emptable PS zone:

TRX2 TRX1

1 3 42 5 6 7 8 9 10 1211 13 14 15 16


PS CSPS CS CSCS CS


PS PS PS PS


PS traffic zone

TRX2 TRX11 3 42 5 6 7 8 9 10 1211 13 14 15 16


PS CSPS CS CSCS CS


PS CS CS


PS traffic zone

CS

PS CSused by PS used by CS CS used by CS, candidatefor HO cause 30


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PS PS CS CS CS CS CSCS CSPS PS CS CS CS CS CSCSCSPS PS CS CS CS CS CSCS CS

Examples of SPDCHs_Allocation_bitmap building:

2 TRXs in the cell

initial situation: TS1 and TS2 on TRX2 allocated to the MFS

the non pre-emptable PS zone is always included in the

MAX_SPDCH_LIMIT zoneMAX_SPDCH_LIMIT = 5

TRX 2 TRX 1

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

MAX_SPDCH_LIMIT_ZONE

PS traffic zone

1 1 0 1 0 0 1 0 1 0 0 0 0 0 0 0




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PS PS CS CS CS CS CSCSPS PS CS CS CS CS CSCSPS PS CS CS CS CS CSCS


MAX_SPDCH_LIMIT = 7

TRX 2 TRX 1

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16


PS traffic zone

1 1 1 1 0 0 1 0 1 1 0 0 0 0 0 0




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MAX_SPDCH_LIMIT = 4

PS PS CS CS CS CS CSCS

TRX 2 TRX 1

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16


PS traffic zone

1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0

PS PS CS CS CS CS CSCS




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Agenda











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CS Preemption (1/2)

BSC MFS



SPDCHs_Usage


SPDCHs_Usage

T_

PDCH_

PREEMPTION

=TCH

_INFO_

PERIOD

-1sec

TCH_I

NFO_

PERIOD

1) MFS knows which SPDCHs shall begiven back to the BSC

2) Impacted SPDCHs not used areimmediately given back to the BSCNote : SPDCHs considered not used ifno TBF resources are allocated onthese SPDCHs and their basic Abis

nibbles are free)3) Remaining impacted SPDCHs, which

are in use (at least one TBF isestablished on those SPDCHs or thebasic Abis nibbles of those SPDCHsare used by a GCH channel), aremarked as de-allocating

4) the CS pre-emption process shall becompleted beforeT_PDCH_Preemption timer (set toTCH_INFO_PERIOD - 1s)

5) When T_PDCH_Preemption expires,the fast preemption is launched.


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TBFs candidate for T1 reallocation:PACCH impacted by the pre-emption (as in B8)

TBFs for which the M-EGCH link size becomes too low to serve the

Max_Allowed_(M)CS of the TBF (new in B9).

Reallocated with a decrease of MaxMCS

DL

0 1 2 3 4 5 6 7

UL

0 1 2 3 4 5 6 7

No T1 candidate

T1 candidate

M-EGCHEGPRS TBF

TRX

2 preempted GCHsMax_EGPRS_MCS = MCS9 5 GCHs needed

4 GCHs


CS Preemption (2/2)

f f C


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Related Parameters

HMI name Definition Sub-system

Instance

OMC-Raccess

Type Defvalue

Range Unit

NEW :RR_ALLOC_PERIOD

This parameter allows to tune the time betweentwo sendings of the BSCGP RR AllocationIndication message

BSC BSC None(DLS)

Number

2 [1,30] None

NEW :

THR_MARGIN_PRIO_PS

Margin of radio timeslots reserved for PS trafficbetween two sendings of the BSCGP RRAllocation Indication message. The threshold isexpressed in percentage of radio timeslots

BSC BSC None(DLS)

Percentage

10 [0,100] %

NEW :EN_RETURN_CS_ZONE_HO

Flag enabling the intracell handovers allowing to

move TCH from the PS zone to the CS zone of

PDCH/TCH allocation

BSC cell Changeable

flag 1 [0,1] None

Removed parameters :

T_PDCH_PREEMPTION


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Agenda










M difi ti f th PDCH ll ti t t


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TRX capabilities for GPRS (maximum CS) and for EGPRS (EGPRSpossible or not, maximum MCS) are defined at MFS side using:

HW PS capability for each TRX,

Max_GPRS_CS O&M parameter,

En_EGPRS O&M parameter,

Max_EGPRS_MCS O&M parameter.

TRE generation HW PS capability of the TRX

G2 (TRE in a DRFU BTS) CS-1/2

G3 (TRE in an Evolium BTS) CS-1/4

G4 (TRE in an Evolium BTS) CS-1/4 + MCS-1/9


Definitions



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TRX is said established if there is an M-EGCH link associated tothis TRX with GCHs.

For each TRX, the following variables are defined:

Established_Nb_GCH:

Number of GCHs that are activated in the M-EGCH link

Non CS Preemptable GCH:

GCH, whose Abis nibble is not CS preemptable (Extra Abis nibble,Bonus Abis nibble,Basic Abis nibble mapped on a RTS inside theMax_SPDCH_High_Load zone.

CS Preemptable GCH:

GCH, whose Abis nibble is CS preemptable (Basic Abis nibblemapped on a RTS outside the Max_SPDCH_High_Load zone)


Definitions



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Target_Nb_GCH:

Estimation of the GCHs necessary in a given M-EGCH link to carry thetraffic

It may of course not be reached in case of congestion situations at

transmission level (Abis and/or Ater).It is a function of:

-Number of PDCHs on the TRX, on which radio resources have been allocated forBE TBFs,

-Max_GPRS_CS and Max_EGPRS_MCS O&M parameter values,

-Number of GCH needed per PDCH forMax_GPRS_CS / Max_EGPRS_MCS

-Whether Ater Usage in the GPU is high or not. If it is high, the value ofTarget_Nb_GCH is reduced so as to decrease the global Ater resourceconsumption in the GPU.


M-EGCH link size : Target_Nb_GCH



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Target_Nb_GCH is updated:At TBF allocation / reallocation,

At TBF release.

Example of Target_Nb_GCH evaluation:

Target_Nb_GCH =4 * 4.49 = 18GCHs for the MEGCH link of a TRX supportingone 4-TS EGPRS TBF (Max_EGPRS_MCS = MCS-9),

Target_Nb_GCH = 4 * 1.64 = 7GCHs for the M-EGCH link of a TRX supportingone 4-TS GPRS TBF (Max_GPRS_CS = CS-4).

(In this example, it is supposed that the Ater usage of the GPU is nothigh)


M-EGCH link size : Target_Nb_GCH

Max_GPRS_CS Nb_GCH(Max_GPRS_CS)

CS-1 0,73

CS-2 1,00

CS-3 1,25

CS-4 1,64

Max_EGPRS_MCS

Nb_GCH(Max_EGPRS_MCS)

MCS-1 0,89

MCS-2 1,00

MCS-3 1,33

MCS-4 1,50

MCS-5 1,86

MCS-6 2,36

MCS-7 3,49MCS-8 4,14

MCS-9 4,49



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When establishing new GCHs in the M-EGCH link of a given TRX, the freeAbis nibbles are selected with the following priorities:

1)Free basic Abis nibbles mapped to RTSs currently available for PS traffic

and within the Max_SPDCH_High_Load zone of the cell,

2)Free extra Abis nibblesandfree bonus Abis nibbles,

3)Free basic Abis nibbles mapped to RTSs currently available for PS traffic

and out of the Max_SPDCH_High_Load zone of the cell.

If not enough free Abis nibbles, or free Ater nibbles, use of GCH preemption:

4)Inter-cell GCH preemption,5)Intra-cell GCH preemption.


Abis selection in M-EGCH link



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Triggers for M-EGCH link establishment or capacity increase:New TBF allocated on the TRX

And Target_Nb_GCH becomes strictly higher than

Established_Nb_GCH.

Periodical GCH establishment process

Periodical attempt to increase the M-EGCH link size of TRXs, if its

size is lower than Target_Nb_GCH.

Addition of GCHs to the TRX of the cell (target TRX), whose

deficit in terms of number of GCHs is the highest.

Fast Initial PS Access feature O&M parameter at cell-level :

EN_FAST_INITIAL_GPRS_ACCESS.

Ensures that one M-EGCH link is always established on the the

most PS-prioritary TRX of the cell


M-EGCH link establishment or increase



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When a TBF is released and Target_Nb_GCH becomes strictlylower than Established_Nb_GCHunused GCHs: Triggers an inactivity timer (T_GCH_Inactivity)

Anticipates new TBF arrival,

GCH preemption.

At timer expiry, if Target_Nb_GCH is still strictly lower thanEstablished_Nb_GCH, the unused GCHs are released:

Choice of GCHs to release is the reverse order than the one used forGCH establishment.

If there is no TBF traffic in the cell and the TRX is the last established TRXof the cell:

Not all the GCHs are released (keep N_GCH_Fast_PS_Access GCHs),

Triggers T_GCH_Inactivity_Last timer.

Only valid if Fast Initial PS Access is disabled.


Handling of unused GCHs



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M-EGCH link

7 used GCHs

GCH1 B HL

GCH2 B HL

GCH3 B HL

GCH5 Extra

GCH4 Extra

GCH7 B > HL

GCH6 B > HL

Established_Nb_GCH = 10

3 unused GCHsGCH9 B > HL

GCH8 B > HL

GCH10 B > HL

B > HL: GCH uses a basic Abisnibble mapped on a RTS out of the

Max_SPDCH_High_Load zone of

the cell.

Extra: GCH uses an extra Abis

nibble or a bonus basic Abis nibble.

B HL: GCH uses a basic Abisnibble mapped on a RTS within the

Max_SPDCH_High_Load zone of

the cell.

At T_GCH_Inactivity timer

expiry

Established_Nb_GCH = 7

Target_Nb_GCH = 7


Handling of unused GCHs



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M-EGCH link capacity decrease:

GCHs are removed from an M-EGCH link of a TRX:

When a TBF is released and Target_Nb_GCH becomes

strictly lower than Established_Nb_GCH (unused GCHs andinactivity timer mechanism),

GCH preemption: inter-cell and intra-cell,

CS preemption: a basic Abis nibble used in the M-EGCH

link is mapped on a RTS that must be given back to theBSC (CS preempted RTS).


M-EGCH link capacity decrease

Modification of the TBF allocation/re-allocation strategy


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TBF Resource establishment process

The TBF resource establishment process operates in two steps:

Radio Resource Allocation

Algorithm

Find best candidate timeslot allocation

Verify if enough transmission resource

GCH reservation

GCH establishment

Maximum allowed (M)CS

Two policies are defined

ASAP,

Optimal

TBF Establishment

If Allocation = OK



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Two TBF allocation policies are defined: ASAP: used for BE TBF establishment, T1, T2 and T4 reallocation. Its goal is to

serve the request as soon as possible.

OPTIMAL: used for T3 reallocation. Its goal is to ensure that a significant bandwidthwill be offered to the MS upon T3 reallocation, even if it takes some time to establishall the necessary GCHs

Nb_GCH_For_TBF_Estab:

Minimum number of GCHs, which are required on the TRX to serve the request.

Type of request Policy Nb_GCH_For_Estab

TBF establishment (without concurrent) ASAP 1

TBF establishment (with concurrent) ASAP 1 to 5 (depending on the Max_Allowed_(M)CS ofthe concurrent TBF)

T1 TBF reallocation ASAP 1

T4 TBF reallocation ASAP 1 to 2 (depending on the Max_Allowed_CS ofconcurrent TBF)

T3 TBF reallocation Optimal 1 to 5 (depending on the Max_Allowed_(M)CS ofconcurrent TBF)





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Determination of the Max_Allowed_(M)CS of a TBF: Depends on the type of TBF (GPRS / EGPRS) and of the direction of the

TBF (UL / DL)

Is based on the number of established GCHs

Is limited by:

GPRS / EGPRS TRX capability, Max_GPRS_CS and Max_EGPRS_MCS (O&M parameters).

Nb_GCH Max_Allowed_CS

1 CS-2 (UL) / CS-1

(DL) 2 CS-4

Nb_GCH Max_Allowed_MCS

1 MCS-2 (UL) / MCS-1 (DL)

2 MCS-5

3 MCS-6

4 MCS-7

5 MCS-9

Modification of the TBF allocation/re allocation strategy




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3 cells @ 2 TRX: Max_PDCH_High_Load = 4 a maximum of 4 non CS preemptable basic Abis nibbles

can be established in the cell,

Max_PDCH = 8,

Max_EGPRS_MCS = MCS-9, Max_GPRS_CS = CS-4,

Max_SPDCH_Limit = 6 a maximum of 6 basic Abis nibbles can be established in thecell.

C

S

radio

Cell A

Cell B

Cell C

Abis

Basic

nibbles

6x4 extra

nibbles


Transmission resources establishment



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First EDGE MS (MS1), class 8 in cell A -> Target_Nb_GCH = 18 GCH Allocation for MS1

4 basic Abis nibble in the Max_PDCH_High_Load zone,

14 extra Abis nibbles,

Total = 18 GCHs.

Cell A

Cell B

Cell C

basic

extra

C

SMS1C

SCell A





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Second EDGE MS (MS2), class 8 in cell B -> Target_Nb_GCH = 18 GCH Allocation for MS2 4 basic Abis nibbles in the Max_PDCH_High_Load zone,

10 free extra Abis nibbles,

2 basic Abis nibbles outside the Max_PDCH_High_Load zone,

Inter GCH preemption between Cell A and Cell B: 14 extra Abis in cell A, 10 extra Abis in cell B,

2 extras Abis nibbles are pre-empted from Cell A to Cell B

Total = 18 GCHs. basic

extra

Cell A

Cell B

Cell C

C

SMS1MS2

C

SCell ACell B





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After GCH allocation of MS2 in cell B:

In Cell A: Established_Nb_GCH = 16

Next Periodical GCH process in Cell A:

2 basic Abis nibbles outside the Max_PDCH_High_Load zone,

Total = 16 + 2 = 18 GCHs.

basic

extra

C

SMS1MS2

C

SCell ACell B

Cell A

Cell B

Cell C

od cat o o t e a ocat o / e a ocat o st ategy


A d


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Agenda












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gy

TRX List computing

The goal of the TRX list computing step is to determine the TRX list onwhich the TBF or one UL block candidate allocations will be searched

The conditions for a TRX to be inserted into the TRX list are:

the TRX shall be PS capable

if the TRX is not already mapped to a DSP, and no DSP can be associated tothe TRX, then the TRX shall not be considered

Difference with B8 release:

there are no longer some restricted EGPRS capable TRX lists (i.e. selectionof the EGPRS TRX of highest class (that is which offer the highest

throughput) as long as the maximum number of EGPRS TBF per PDCH onthese TRX is not higher than a threshold). Indeed, all the EGPRS capableTRXs can offer the same potential throughput: they are all mapped on G4TRE, and the B8 concept of TRX pool type has disappeared



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gy

Best candidate allocation computation

Once all the usable PDCHs are determined, the different

candidate timeslot allocations are sorted according to

their respective available throughput, in order to

choose the one offering the highest throughput to serve theconsidered request. This is a complete change compared to

the previous BSS releases (B6, B7 and B8)



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gy

Definition : PDCH states

Allocated:

new in B9: the PDCH is a SPDCH indicated as usable for PS traffic by theBSC

B8 definition: radio resource allocated to the MFS, but associated transmissionresources are not allocated

Active:

new definition in B9: an allocated PDCH is active if it supports at least one

radio resource allocated for a TBF the B8 definition was considering the parameterN_TBF_PER_SPDCH which

is removed in B9 release

Full : as in B8 release

EGPRS: an allocated PDCH is in the EGPRS state if some radio resources areallocated in DL, for an EGPRS TBF. Only used when running the radioresource (re)allocation algorithm in GPRS mode and when considering the ULdirection of the candidate TBF allocations

Remark: the busy PDCH state (number of established TBF on the PDCHhigher than N_TBF_PER_SPDCH) is no more used by the allocation algorithm



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Available throughput of a candidate timeslot allocation

New metric introduced in B9 release.

It is the overall throughput provided by its PDCHs.

Depends on two variables: the potential throughput of its PDCHs

the available capacity on each of its PDCHs

Note : in the past releases the idea was already to give the highest

possible throughput to a TBF (allocating the highest number of TS, ifpossible not busy) but there was no explicit metric evaluating thethroughput provided by a candidate TS allocation



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Potential throughput of a given PDCH The potential throughput of a PDCH is calculated as follows according to O&M

parameters for the Evolium BTS case:

GPRS best effort TBF: R_AVERAGE_GPRS (default = 12kbit/s)

EGPRS best effort TBF: R_AVERAGE_EGPRS (default = 30kbit/s)

This potential throughput and its associated parameters are only used in thecomputation of the best allocation. No impact at all on the effective throughput !

Available capacity on a given PDCH

For a Best effort GPRS TBF, it takes into account all other BE GPRS TBF or EGPRSTBF on the same TS ( = 1 / Nb_BE_TBF_SAME_PRIOR_XL)

For a Best effort EGPRS TBF, it takes into account only the other BE EGPRS TBF on thesame TS ( = 1 / Nb_BE_EGPRS_ TBF_SAME_PRIOR_XL)

Available throughput of a given candidate timeslot allocation

Computed using available capacity and throughput for all PDCH of the allocation



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Candidate time slot allocations sorting : throughput-based: [ALPHA]: For ASAP policy only: the candidate timeslot allocations, which

are on some TRXs for which Established_Nb_GCH is greater thanNb_GCH_For_TBF_Estab are preferred.

[A]: For UL GPRS TBF establishment / reallocation only: the candidatetimeslot allocations, which have the lowest number of PDCHs in the EGPRSstate are preferred.

[B]: the candidate timeslot allocations, which have the highest availablethroughput in the direction of the bias are preferred.

[C]: the candidate timeslot allocations, which have the highest availablethroughput in the direction opposite to the bias are preferred.

[D]: the candidate timeslot allocations, which are on the TRX with the highest

priority, are preferred. [E]: for EGPRS TBFs establishments only: the candidate timeslot allocations,

which have the lowest number of GPRS TBFs in the direction of the bias, arepreferred.

[F]: combinations with the PDCHs that have the lowest index are preferred.

Agenda


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Agenda











TBF ll i


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TBF reallocation cases

T1: reallocation to maintain a TBF alive despite the CS preemption ofsome RTSs or of some GCHs in the cell.

T2: reallocation of an on-going TBF when establishing a concurrentTBF.

T3: reallocation useful to

Provide a higher throughput, if it is possible, to a TBF,

Establish a new M-EGCH link for one of the TRXs of the cell,

Perform a radio de-fragmentation process.

T4: reallocation to move an UL GPRS TBF sharing one PDCH with aDL EGPRS TBF onto PDCHs which do not support a DL EGPRS TBF.It concerns only GPRS TBFs.


T3 TBF ll ti


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Conditions for a MS to be candidate for T3 reallocation: the BSS systematically requests a T3 reallocation for any MS which has an

established TBF in the direction of the bias verifying the followingconditions:

more than N_CANDIDATE_FOR_REALLOC bytes have been sent on the DL TBFor received on the UL TBF since their establishment

T3192 is not running

Principles of T3 TBF reallocation:

Computing of a THROUGHPUT_RATIO (= Allocated_Throughput /

Optimal_Throughput)to know how sub-optimal a TBF allocation is.

A T3 TBF reallocation will only be allowed if a significant

THROUGHPUT_RATIO gain is reached. The minimal gain is set by the

system parameter: MIN_THROUGHPUT_GAIN (= 40%).

T3 TBF reallocation cases


T3 TBF ll ti l


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Initial situation: 3 MSs (MSa, MSb, and MSc), all GPRS and (4+1),

MSc is the most impacted by the multiplexing in terms of throughput.

In B8:

MSc is not candidate for T3 reallocation because its allocation is optimal (4 TS in DL),

In B9:

MSc is candidate for T3 reallocation,

A new TRX will be established (cf. Optimal policy) and MSc will then be reallocated on this new

TRX.

0 1 2 3 4 5 6 7

D

L

U

L

MSaMSaMSaMSa MSbMSbMSbMSb

MScMScMScMSc

MSc MSbMSa

0 1 2 3 4 5 6 7

D

L

U

L

0 1 2 3 4 5 6 7

D

L

U

L

MSaMSaMSaMSa MSbMSbMSbMSb

MSbMSa

0 1 2 3 4 5 6 7

D

L

U

L

MScMScMScMSc

MSc

T3 TBF reallocation cases : example


T3 TBF ll ti


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A T3 TBF reallocation can also be played for a radio defragmentation purpose:

TBF1

TBF2

Initial situation Final situation



T4 TBF ll ti


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T4 TBF reallocation:to avoid the UL GPRS - DL EGPRS TBF

multiplexing situations

triggering conditions

a GPRS MS becomes candidate for a T4 reallocation as soon as its ULGPRS TBF shares at least one PDCH with a DL EGPRS TBF

the MS remains candidate for a T4 reallocation, after an UL TBF release, ifa DL TBF is still ongoing => a DL TBF can be T4 reallocated even with noUL concurrent TBF

best candidate allocation computation

No need to have the same number of PDCHs than the current allocation

in UL direction, the candidate TS allocations cannot contain PDCHs inEGPRS state.

ASAP policy (favouring TRX with Nb_GCH_For_TBF_Estab alreadyestablished GCHs)

Agenda


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Agenda











R l t d P t


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Related Parameters

HMI name Definition Sub-system

Instance

OMC-Raccess

Type Defvalue

Range Unit

NEW :R_AVERAGE_GPRS

average bitrate per PDCH for non-Edge capableterminals in this cell

MFS cell Changeable

Throughput

12000 [0,20000]

Bit/s

NEW :

R_AVERAGE_EGPRS

average bitrate per PDCH for Edge capable terminalsin this cell

MFS cell Changeable

Throughput

30000 [0,59000]

Bit/s

NEW :T_MAX_FOR_TBF_SCHEDULING

maximum time between two scheduling of a given NRTTBF (either between two DL block requests for a NRT

DL TBF, or between two UL blocks received for a

given NRT UL TBF)

MFS MFS None(DLS)

Time 0.3 [0.12,0.3]

s

NEW :MIN_THROUGHPUT_G

AIN

minimum throughput gain required to be provided tothe MS when performing a T2 or T3 TBF reallocation

MFS MFS None(DLS)

Number

0.4 [0.1,5] None

NEW :N_MAX_PERIODIC_RE

ALLOC_T3

total number of (unsuccessful) T3 radio resourcereallocation attempts that are allowed to be performedupon expiry of the T_CANDIDATE_TBF_REALLOCtimer. As soon as a T3 radio resource reallocationattempt succeeds, no other attempt is performed (evenif less than N_MAX_PERIODIC_REALLOC_T3attempts have been performed so far). The UL-biasedMSs and the DL-biased MSs are considered

regardless of each other. As a result, in a given cell, upto 2 x N_MAX_PERIODIC_REALLOC_T3 T3 radioresource reallocation attempts will be performed uponexpiry of the T_CANDIDATE_TBF_REALLOC timer

MFS MFS None(DLS)

Number

20 [0,500] None

NEW :N_MAX_PERIODIC_RE

ALLOC_T4

defines the total number of T4 radio resourcereallocation attempts (successful or not) that areperformed upon expiry of theT_CANDIDATE_TBF_REALLOC timer

MFS MFS None(DLS)

Number

5 [0,500] None


R l t d P t


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Related Parameters

Following B8 parameters are removed in B9 release:

N_TBF_PER_SPDCH

EN_RES_REALLOCATION

N_MAX_PERIODIC_REALLOC

B9 Channel allocation strategy for PS transfers

New BSC Counters


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Counternumber

Name Definition

MC480 NB_TCH_HO_REQ_30_ReturnCSZone

Number of TCH intracell HO cause 30 requests

MC481 NB_TCH_HO_ATPT_30_ReturnCSZone

Number of TCH intracell HO cause 30 attempts.

MC924a TIME_SPDCH_LIMIT_HIGH_LOAD Time during which the cell is in high load situation for PStraffic. This situation impacts the number of slave PDCHs that

can be allocated to the MFS.

New BSC Counters


Removed MFS Counters


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Counter

number

Name Definition

P1 TIME_HIGH_LOAD_GPRS Time during which the cell is in a high load situation for PS traffic. Thissituation impacts the number of slave PDCHs that can be allocated to theMFS.

P414 CUMULATED_MAX_PDCH_DYN_SECONDS This counter integrates over time the value of MAX_SPDCH_DYN duringthe whole granularity period.

P415 MAX_MAX_PDCH_DYN This counter gives the maximum value of MAX_SPDCH_DYN during thewhole granularity period.

P416 MIN_OF_MAX_PDCH_DYN This counter indicates the minimum value of MAX_SPDCH_DYN that hasbeen observed over the whole granularity period.

P418 NB_SOFT_PREEMPTION Number of times the MFS receives a BSCGP LOAD INDICATION messagerequesting the MFS to de-allocate at least one slave PDCH that is currentlyallocated to the MFS.

P54 NB_PDCH_DYN_ALLOC_REQ Number of PDCH dynamic allocation requests.

P19 NB_PDCH_DYN_ALLOC_SUCC Number of PDCH dynamic allocation success.

P166 NB_DL_TBF_2_3_partial_succ Number of downlink TBF establishment requests requesting 2 or 3 slots,which are only partially satisfied by the initial allocation.

P167 NB_UL_TBF_2_3_partial_succ Number of uplink TBF establishment requests requesting 2 or 3 slots whichare only partially satisfied by the initial allocation.

P168 NB_DL_TBF_4_5_partial_succ Number of downlink TBF establishment requests requesting 4 or 5 slotswhich are only partially satisfied by the initial allocation.

P169 NB_UL_TBF_4_5_partial_succ Number of uplink TBF establishment requests requesting 4 or 5 slots whichare only partially satisfied by the initial allocation.

Removed MFS Counters


New MFS Counters


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Counter

number

Name Definition

P414bis CUMULATED_TIME_ALLOCATED_SPDCH

This counter integrates over time the values of the allocatedSPDCH during the whole granularity period.

P415bis MAX_OF_ALLOCATED_SPDCH This counter gives the maximum value of allocated SPDCHduring the whole granularity period.

P416bis MIN_OF_ALLOCATED_SPDCH This counter gives the minimum value of allocated SPDCHduring the whole granularity period.

P451a CUMULATED_TIME_PDCH_UL_TBF_CELL Cumulated time during which an UL TBF uses one PDCH,for all PDCHs of the TBF, and for all TBFs of the cell (inGPRS or EGPRS mode).

P451b CUMULATED_TIME_PDCH_DL_TBF_CELL

Cumulated time during which an DL TBF uses one PDCH,for all PDCHs of the TBF, and for all TBFs of the cell (inGPRS or EGPRS mode).

P452 CUMULATED_TIME_PDCH_DL_TBF_GMM_SIG_CELL

Cumulated time during which a DL TBF established forGMM signalling purposes uses a PDCH (in GPRS orEGPRS mode), for all TBFs of the cell.

P38e CUMULATED_TIME_PDCH_USED_DL_CELL

Cumulated time during which a PDCH is used by at leastone DL TBF (in GPRS or EGPRS mode), cumulated over allthe PDCHs of the cell.

P38f CUMULATED_TIME_PDCH_USED_UL_CELL

Cumulated time during which a PDCH is used by at leastone UL TBF (in GPRS or EGPRS mode), cumulated over allthe PDCHs of the cell.

New MFS Counters


RNO Indicators


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Ref. name Name Formula Unit

HCRCARRN HO_Cell_Return_CS_Zone_request MC480 number

HCRCARAN HO_Cell_Return_CS_Zone_allocated MC481 number

HCRCARFN HO_Cell_Return_CS_Zone_prep_fail MC480 - MC481 number

HCRCARFR HO_Cell_Return_CS_Zone_prep_fail_rate

(MC480-MC481) / MC480 %

HCRCARRR HO_Cell_Return_CS_Zone_rate HO_Cell_Return_Cs_Zone_allocated / CHO_all

%

QRPALCGT GPRS_BSC_high_load_time MC924a seconds

QRPALCGP GPRS_BSC_high_load_percent MC924a / GPRS_obs_period %

QRPALSAT GPRS_MAX_PDCH_Dyn_cumulated_over_time

P414bis seconds

QRPALSAN GPRS_MAX_PDCH_Dyn_avg P414bis / GPRS_obs_period %

QRPALSAR GPRS_MAX_PDCH_Dyn_reduction_rate ((P415bis *GPRS_obs_period ) -P414bis) / (P415bis *GPRS_obs_period)

%

QRPALSAM_MA

GPRS_MAX_PDCH_Dyn_max P415bis number

QRPALSAI_NA GPRS_MAX_PDCH_Dyn_min P416bis number

RNO Indicators


RNO Indicators


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ARPDCTUBUT GPRS_PDCH_used_UL_TBF_overall_time P451a seconds

ARPDCTUBUR GPRS_UL_TBF_occupancy_on_used_PDCH P451a / GPRS_obs_period number

ARPDCUUBUT GPRS_PDCH_UL_traffic_time P38f seconds

TRPDCUUN GPRS_PDCH_active_UL_avg P38f / GPRS_obs_period number

ARPDCUUO GPRS_PDCH_UL_traffic_time_ratio P38f / P38b %

TRPDUPDA GPRS_UL_useful_throughput_radio_PDCH_avg

GPRS_UL_useful_throughput_bits_ack / GPRS_PDCH_UL_traffic_time*

1000

kbits/s

ARPDCTUPIN GPRS_UL_TBF_Pilled_avg P451a/P38f number

: MS1

: MS2

: MS3

: MS5

: MS4

After 10 seconds in the same configuration :

GPRS_PDCH_used_UL_TBF_overall_time =

4 * 20 s (MS1 -> MS4) + 10 s (MS5) = 90s.GPRS_UL_TBF_occupancy_on_used_PDCH = 90 /10 = 9

GPRS_PDCH_UL_traffic_time = 6 * 10 s = 60 s

GPRS_PDCH_active_UL_avg = 60 / 10 = 6

GPRS_UL_TBF_Pilled_avg = 90 / 60 = 1,5

Example of UL TBF configuration :

RNO Indicators


RNO Indicators


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ARPDCTDBUT GPRS_PDCH_used_DL_TBF_overall_time P451b seconds

ARPDCTDBUR GPRS_DL_TBF_occupancy_on_used_PDCH P451b / GPRS_obs_period number

ARPDCUDBUT GPRS_PDCH_DL_traffic_time P38e seconds

TRPDCUDN GPRS_PDCH_active_DL_avg P38e / GPRS_obs_period number

ARPDCUDO GPRS_PDCH_DL_traffic_time_ratio P38e / P38b %

TRPDDPDA GPRS_DL_useful_throughput_radio_PDCH_avg

GPRS_DL_useful_throughput_bits_ack / GPRS_PDCH_DL_traffic_time*

1000

kbits/s

ARPDCTUPIN GPRS_UL_TBF_Pilled_avg P451b/P38e number

ARPDCTDSGT GPRS_PDCH_used_DL_TBF_GMM_signalling

_overall_time

P452 seconds

ARPDCTDSGO GPRS_PDCH_used_DL_TBF_GMM_signalling_time_ratio

P452/P451b %

RNO Indicators


RNO Indicators


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TRXDTPRN GPRS_PDCH_soft_preemption_request P418 number

QRPALPRR GPRS_PDCH_soft_preempted_per_softpreemption P417/P418 %

TRPALRQN GPRS_PDCH_dynamic_allocation_request P54 number

QRPALSUN GPRS_PDCH_dynamic_allocation_success P19 number

TRPALSUR GPRS_PDCH_dynamic_allocation_success_rate P19/P54 %

QRPALUNN GPRS_PDCH_dynamic_allocation_unsuccess P54-P19 number

QRPALUNR GPRS_PDCH_dynamic_allocation_unsuccess_rate (P54-P19)/P54 %

QRDTEP3N GPRS_DL_TBF_2_OR_3_TS_partial_success P166 number

QRDTEP3R GPRS_DL_TBF_2_OR_3_TS_partial_success_rate P166 / (P166 + P162 ) %

QRUTEP3N GPRS_UL_TBF_2_OR_3_TS_partial_success P167 number

QRUTEP3R GPRS_UL_TBF_2_OR_3_TS_partial_success_rate P167 / (P167 + P163) %

QRDTEP5N GPRS_DL_TBF_4_OR_5_partial_success P168 number

QRDTEP5R GPRS_DL_TBF_4_OR_5_partial_success_rate P168 / (P168 + 164) %

QRUTEP5N GPRS_UL_TBF_4_OR_5_TS_partial_success P169 number

QRUTEP5R GPRS_UL_TBF_4_OR_5_partial_success_rate P169 / (P169 +165) %

RNO Indicators


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