Data Resources Management

8/23/2019 Data Resources Management

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All rights reserved 2005, Alcatel

Alcatel BSS B9 release

Data resources management / August 2005


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All rights reserved 2005, AlcatelData resources management /August 2005

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Agenda

Radio resources management

Best-effort TBF resources allocation / reallocation

CS pre-emption process

QoS counters and indicators


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Agenda






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Autonomous Packet Resource Allocation

Contrary to the previous BSS releases and thanks to theAutonomous Packet Resource Allocation feature (alsocalled RAE-4 for Resource Allocation Enhancements n4),

the MFS no longer needs to request additional SPDCHto the BSC, as all the usable PS capable radio timeslotsare explicitly allocated to the MFS through the RRAllocation Indication message


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Messages between BSC and MFS (1/3)

As in previous releases a coordination is performedbetween the MFS and the BSC to allocate radio timeslotsfor the PS traffic

The protocol between the MFS and the BSC to handle radioresources uses two BSCGP messages which are new in B9release

they replace the Radio Allocation Request/Confirm and RadioDeallocation Command/Complete used in B8 release by the MFS andthe BSC

moreover the Load Indication message used in B8 release is no moreused in B9 release


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RR Allocation Indication:

this message is sent from the BSC to the MFS to provide the MFSwith the location of the allocated SPDCH

this message is transmitted periodically every RR_ALLOC_PERIOD *TCH_INFO_PERIOD seconds = 2 * 5 seconds

a bitmap named SPDCHs_Allocation is defined within this messageand indicates whether available timeslots in the cell are allocated ornot to the MFS. The bitmap is present for all the available PS capableTRX of a cell, even if no SPDCH is allocated to the MFS for a given

TRX


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RR Usage Indication:

this message is sent from the MFS to the BSC periodically (everyTCH_INFO_PERIOD seconds) or in response to a Radio ResourceAllocation Indication message

it provides the BSC with the location of the SPDCH allocated to the MFS (inaccordance with the Radio Resource Allocation Indication messagesreceived from the BSC)

it also provides the BSC with the current usage of the allocated SPDCH, i.e.whether the SPDCH carries PS traffic or not, or whether its basic Abis nibbleis available or not

four bitmaps are defined within the RR Usage Indication message:

SPDCHs_Confirmation bitmap, SPDCHs_Usage bitmap and SPDCHs_RadioUsagebitmap. A fourth bitmap called DTM TCH bitmap indicates the DTM TCH usage of theSPDCH (this last bitmap is defined as a provision for further use, and all its bits arealways set to 0)

these four bitmaps are present for all the available PS capable TRX of a cell, even ifno SPDCH is allocated to the MFS for a given TRX


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MFS / BSC synchronisation (1/5)

With the Autonomous Packet Resource Allocation feature,the SPDCH resource management is based on bitmapexchanges between the MFS and the BSC

The BSC informs the MFS about the SPDCH allocations(which ones are allocated to the MFS and which ones areallocated to the BSC)

On receipt of a RR Allocation Indication message, theMFS sends a RR Usage Indication containing aSPDCHs_Confirmation bitmap and a SPDCHs_Usagebitmap


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Three SPDCH allocation states are defined in the MFS: not allocated: this state corresponds to a SPDCH that is currently not

allocated to the MFS (i.e. it is allocated to the BSC)

allocated: this state corresponds to a timeslot which is allocated to the

MFS. A timeslot in the allocated state can either be unused or used tosupport some TBF

de-allocating: this state corresponds to a radio timeslot for which theBSC has requested to the MFS a de-allocation (through a RR

Allocation Indication message) but the confirmation of the de-allocation has not yet been done (through a RR Usage Indication

message). That confirmation will be sent after the CS pre-emptionprocess is over (on TCH_INFO_PERIOD timer expiry), i.e. after all theimpacted TBF have been handled (e.g. through T1 reallocations) andafter the SPDCHs basic Abis nibbles have been fetched back


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The reception of a RR Allocation Indication message fromthe BSC allows the MFS to update itsSPDCHs_Confirmation bitmap. The role of this bitmap is toindicate the status of each SPDCH from the point of view ofthe MFS and also to acknowledge the allocation of SPDCHnewly granted by the BSC and the deallocation of SPDCHgiven back to the BSC. The value of each bit in theSPDCHs_Confirmation bitmap has the following meaning:

0: this SPDCH is not allocated to the MFS (SPDCH allocation state isnot allocated)

1: this SPDCH is allocated to the MFS (SPDCH allocation state isallocated or de-allocating)


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The MFS also takes a picture of the current SPDCH usageand updates the SPDCHs_Usage bitmap accordingly. Thevalue of each bit in the SPDCHs_Usage bitmap has thefollowing s meaning:

0: this SPDCH is either allocated to the MFS and unused (*), or isnot allocated to the MFS

1: this SPDCH is allocated to the MFS and used (*)

(*) a radio timeslot is said to be used if at least one TBF, RT PFC or

one UL block has some radio resources allocated on it, and/or if itsbasic Abis nibble is being used by a GCH channel or is still switchedto an Ater nibble in the BSC. Else the radio timeslot is said to beunused


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The MFS also updates the SPDCHs_RadioUsage bitmap.The bit value has the following meaning:

0: this SPDCH is either allocated to the MFS and there is no TBFallocated on it, or is not allocated to the MFS

1: this SPDCH is allocated to the MFS and there is at least one TBFallocated on it


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Non preemptable PS zone in a cell (1/2)

Among the radio TS usable for PS traffic (i.e. the radio TS which arecurrently in allocated MFS state), some of them cannot be preemptedby the BSC (due to CS traffic) if they have previously been reported asbeing used for PS traffic (in a RR Usage Indication message sent by

the MFS)

At MFS level, those radio TS are said to belong to the non preemptablePS zone of the cell

The limit of the non preemptable PS zone is given by theNon_Preemptable_PS_Zone_Limit value provided in the RR AllocationIndication message (it corresponds to the limit of theMAX_SPDCH_HIGH_LOAD zone of the BSC)


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Non preemptable PS zone in a cell (2/2)

At RR Allocation Indication message reception by theMFS, all the non preemptable radio TS are marked asbelonging to the non preemptable PS zone. This radio TSmarking shall only be reevaluated when receiving anotherRR Allocation Indication message

Remark : the non preemptable PS zone of a cell can bemodified, for example, in case of TRX addition in the cell, in

case of TRE failure in the cell, in case of change of theMAX_PDCH_HIGH_LOAD parameter value by theoperator, or in case of TRX ranking modification


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Load evaluation (1/5)

The BSC takes every TCH_INFO_PERIODs a sample of the currentusage on TCH, TCH/SDCCH and TCH/SPDCH TS

At the expiry of the TCH_INFO_PERIOD timer, the timer is re-startedand the following load samples 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)

TCH_INFO_PERIOD = 5s

NB_USED_CS_TS(k)

NB_USED_PS_TS(k)NB_USED_TS(k)

NB_UNUSED_TS(k)


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NB_USED_CS_TS(k): number of available timeslots handled by theBSC and carrying CS traffic in the cell at sampling instant tk

a TS is taken into account in the evaluation of NB_USED_CS_TS(k) if:

SPDCH allocation state = not allocated

Occupancy state = used (i.e. the TS is currently carrying CS traffic or isallocated as SDCCH)

NB_USED_PS_TS(k): number of available timeslots used for PStraffic in the cell at sampling instant tk

a TS is taken into account in the evaluation of NB_USED_PS_TS(k) if: SPDCH allocation state = allocated or de-allocating

Occupancy state = used


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NB_UNUSED_TS(k): at the expiry of TCH_INFO_PERIOD timer, theBSC computes the number of unused timeslots at sampling instant tk NB_UNUSED_TS(k) = NB_TS(k) NB_USED_CS_TS(k)

max(MIN_SPDCH(k), NB_USED_PS_TS(k))

NB_TS(k): total number of TCH, TCH/SDCCH or TCH/SPDCH timeslotsavailable in the cell. This parameter is re-computed everyRR_ALLOC_PERIOD * TCH_INFO_PERIOD to take into account possibleTRX failure

MIN_SPDCH(k): minimum number of SPDCHs that are always allocated tothe MFS. This parameter is re-computed every RR_ALLOC_PERIOD *

TCH_INFO_PERIOD to take into account possible TRX failure


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Load evaluation: for each cell, every RR_ALLOC_PERIOD * TCH_INFO_PERIOD, the

BSC computes three averaged values through a sliding window ofsize LOAD_EV_PERIOD_GPRS (default value = 3):

AV_USED_CS_TS(k) =

(1/LOAD_EV_PERIOD_GPRS)*i=0 to LOAD_EV_PERIOD_GPRS -1NB_USED_CS_TS(k-i)

AV_USED_PS_TS(k) =

(1/LOAD_EV_PERIOD_GPRS)*i=0 to LOAD_EV_PERIOD_GPRS -1NB_USED_PS_TS(k-i)

AV_UNUSED_TS(k) =

(1/LOAD_EV_PERIOD_GPRS)*i=0 to LOAD_EV_PERIOD_GPRS -1 NB_UNUSED_TS(k-i)


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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 = 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


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MAX_SPDCH_LIMIT calculation (1/7)

MAX_SPDCH_LIMIT calculation:

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/PS

Margin

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_CSMARGIN_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


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Calculation of MIN_SPDCH, MAX_SPDCH andMAX_SPDCH_HIGH_LOAD:

re-evaluated every RR_ALLOC_PERIOD * TCH_INFO_PERIOD totake into account TRX failures

introduction of a ratio named AVAILABILITY_TS_RATIO(k), evaluatedperiodically every RR_ALLOC_PERIOD * TCH_INFO_PERIOD atinstant tk:

= NB_TS(k) / NB_TS_DEFINED

NB_TS_DEFINED: total number of TCH, TCH/SDCCH or TCH/SPDCH

timeslots available in the cell if there is no TRX failure. This parameter isretrieved from the O&M configuration of the cell


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Calculation of MIN_SPDCH, MAX_SPDCH andMAX_SPDCH_HIGH_LOAD:

MAX_SPDCH(k) = RoundUp[ min(MAX_PDCH NB_TS_MPDCH,NB_TS_SPDCH) *AVAILABILITY_TS_RATIO(k) ]

NB_TS_SPDCH: total number of TCH/SPDCH timeslots available in the cellif there is no TRX failure. This parameter is retrieved from the O&Mconfiguration of the cell

MAX_SPDCH_HIGH_LOAD(k) = RoundUp[ min(MAX_PDCH_HIGH_LOAD NB_TS_MPDCH, NB_TS_SPDCH) *

AVAILABILITY_TS_RATIO(k) ]MIN_SPDCH(k) = RoundUp[ (MIN_PDCH NB_TS_MPDCH) *

AVAILABILITY_TS_RATIO(k) ]


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Margins for CS and PS traffics: two new margins, one for CS traffic and one for PS traffic are

introduced to guarantee that a certain number of timeslots are keptavailable for the arrival of new calls between two transmissions of the

RR Allocation Indication message: the first margin, named MARGIN_PRIORITY_CS, is dedicated to CS traffic

the second margin, named MARGIN_PRIORITY_PS, is dedicated to PStraffic

these two margins are re-evaluated every RR_ALLOC_PERIOD *TCH_INFO_PERIOD, before the computation of MAX_SPDCH_LIMIT

MARGIN_PRIORITY_CS(k) = (THR_MARGIN_PRIO_CS *(NB_TS(k) MAX_SPDCH_HIGH_LOAD(k)) / 100

MARGIN_PRIORITY_PS(k) = (THR_MARGIN_PRIO_PS *MAX_SPDCH_HIGH_LOAD(k)) / 100


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the basic idea to evaluate MAX_SPDCH_LIMIT is to estimate thenumber of unused TS and to share them between CS and PS traffic,taking into account both margins (for CS and PS traffics) defined to

guarantee a certain number of TS available to serve incoming calls

Computation of

MAX_SPDCH_LIMIT_CS

MARGIN_PRIORITY_CS

AV_USED_CS_TS(k)AV_UNUSED_TS(k)

MAX_SPDCH_LIMIT_CS(k)

Computation of

MAX_SPDCH_LIMIT_PSAV_USED_PS_TS(k)

MAX_SPDCH_LIMIT_PS(k)

MIN_SPDCHMARGIN_PRIORITY_PS

Computation of

MAX_SPDCH_LIMIT

MAX_SPDCHMAX_SPDCH_HIGH_LOAD

MAX_SPDCH_LIMIT(k)


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MAX_SPDCH_LIMIT_CS:

determines the maximum number of SPDCHs that can be allocated to the MFS inorder to ensure that a certain number of timeslots (margin) is kept in the BSC to servepossible incoming CS requests received between two sendings of the RR Allocation

Indication message MAX_SPDCH_LIMIT_CS(k) = RoundDown [ NB_TS(k) AV_USED_CS(k) -

MARGIN_CS(k) ]

MARGIN_CS(k) = max(MARGIN_PRIORITY_CS(k), AV_UNUSED_TS(k) / 2)

MAX_SPDCH_LIMIT_PS:

determines the minimum number of SPDCHs that should be allocated to the MFS inorder to ensure that a certain number of timeslots (margin) is kept in the MFS to

possibly serve incoming PS requests if AV_USED_PS_TS(k) is lower or equal than MIN_SPDCH then

MAX_SPDCH_LIMIT_PS(k) = MIN_SPDCH(k)

else MAX_SPDCH_LIMIT_PS(k) = RoundUp (AV_USED_PS_TS(k) +MARGIN_PRIORITY_PS(k))


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it can be in the range of [MIN_SPDCH, MAX_SPDCH]

its value can be either MAX_SPDCH_LIMIT_CS or

MAX_SPDCH_LIMIT_PS

Zone whereMAX_SPDCH_LIMIT = MIN( MAX_SPDCH,

MAX_SPDCH_LIMIT_CS)

Zone whereMAX_SPDCH_LIMIT = MIN(MAX_SPDCH_LIMIT_PS,

MAX_SPDCH_HIGH_LOAD)

0

MAX_SPDCH

MAX_SPDCH_HIGH_LOAD

MIN_SPDCH

MIN_SPDCH

MAX_SPDCH_LIMIT_CS

MAX_SPDCH_HIGH_LOAD MAX_SPDCH

MAX_SPDCH_LIMIT_PS


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TRX priority

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

PS_PREF_BCCH_TRXHW 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/DCS TRX)

TRX having the maximum number of consecutive SPDCHsTRX identity (low TRX id -> high TRX id)


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MAX_SPDCH_LIMIT TS selection (1/13)

PS TS and TRX ordering:

the first step consists in ordering the PS timeslots and the PS TRX soas to obtain an ordered list of TCH/SPDCH timeslots

the ordering of the timeslots is based on the following criteria: selection of the TRX: the TRX having the lowest rank in the TRX ranking

table (refer to the slide on TRX priority) is selected first

selection of the TS: once the TRX has been selected, the TCH/SPDCHtimeslots having the lowest timeslot index, i.e. located at the most left sideof the TRX, is selected first


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Different PS TS zones:MAX_SPDCH_HIGH_LOAD zone:

this zone corresponds to the MAX_SPDCH_HIGH_LOAD consecutive PScapable TS that are preferred for PS allocation

in this zone, allocated TBFs cannot be pre-emptedNon pre-emptable PS zone:

this zone is always inside the MAX_SPDCH_HIGH_LOAD zone

in this latter zone, we search for the rightest TS allocated to the MFS andused. Then, all the TS located at its left define the non pre-emptable PSzone

inside this zone, a TS: remains allocated to the MFS if already allocated to the MFS

is allocated to the MFS if previously allocated to the BSC and unused

remains allocated to the BSC if already allocated to the BSC and used


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Different PS TS zones:

MAX_SPDCH_LIMIT zone:

this zone corresponds to the MAX_SPDCH_LIMIT consecutive PS capableTS that are preferred for PS allocation

inside this zone, a TS:

remains allocated to the MFS if already allocated to the MFS

is allocated to the MFS if previously allocated to the BSC and unused

remains allocated to the BSC if already allocated to the BSC and used

PS traffic zone:

this zone corresponds to the larger zone between the non pre-emptable PSzone and the MAX_SPDCH_LIMIT zone


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Different PS TS zones:

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


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Selection of the TCH/SPDCH TS:

to be selected, the states of a TCH/SPDCH timeslot must have thefollowing values:

SPDCH allocation state = allocated: the timeslot is already allocated to theMFS

SPDCH allocation state = not allocated and occupancy state = unused:the timeslot is allocated to the BSC but there is no CS traffic on it


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Selection of the TCH/SPDCH TS:

the process begins with the non pre-emptable PS zone:

all the TS in this zone that can be or are allocated to the MFS are allocated to theMFS. The verification in terms of number of TS allocated to the MFS is done onlywhen all the TS inside this zone have been handled

if at the end of the non pre-emptable PS zone, the number of selected TS forthe MFS is strictly lower than MAX_SPDCH_LIMIT then the process ofselection continues in the MAX_SPDCH_LIMIT zone

if at the end of the MAX_SPDCH_LIMIT zone, the number of selected TS forthe MFS is still lower than MAX_SPDCH_LIMIT, the process continuesoutside this zone until this number reaches MAX_SPDCH_LIMIT

once MAX_SPDCH_LIMIT TS have been selected, all the remainingTCH/SPDCH TS are now allocated to the BSC, even if they were previouslyallocated to the MFS. This means that a TS with a SPDCH allocation state setto allocated that is no more allocated to the MFS, has its SPDCH allocationstate set to de-allocating


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Pre-reservation mechanism in the PS traffic zone:

in order to increase the PS capacity and limit the occurrence of holesin the SPDCHs_Allocation bitmap, each TCH/SPDCH capable TScarrying CS traffic and located inside the PS traffic zone, has its pre-

reservation state set to pre-reserved for PS. No new incoming CScall can be served on this TS, if it becomes unused once it is pre-reserved for PS. This is valid until the TS becomes not pre-reservedfor PS again and of course still handled by the BSC

the modification of the value of the pre-reservation state can onlyoccur when the SPDCHs_Allocation bitmap is built, everyTCH_INFO_PERIOD * RR_ALLOC_PERIOD seconds


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Pre-reservation mechanism in the PS traffic zone:

the following transition can be foreseen for a timeslot inside the PS trafficzone:

it goes from not pre-reserved for PS to pre-reserved for PS or remains in pre-reserved for PS if it is in one of the two following situations:

SPDCH allocation state = not allocated and occupancy state = used SPDCH allocation state = de-allocating

it goes from pre-reserved for PS to not pre-reserved for PS or remains in not pre-reserved for PS if it is in the following situation:

SPDCH allocation state = allocated

the following transition can be foreseen for a timeslot outside the PS trafficzone:

it goes from pre-reserved for PS to not pre-reserved for PS or remains in not pre-reserved for PS if it is in one of the following situations:

SPDCH allocation state = not allocated

SPDCH allocation state = allocated

SPDCH allocation state = de-allocating


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CS calls in the Non pre-emptable PS zone:

to speed up the release of a TS carrying a CS call inside both the non pre-emptable PS zone and the MAX_SPDCH_LIMIT zone, it is proposed toreallocate the concerned CS call in the CS zone using an intra-cell handover

if EN_RETURN_CS_ZONE_HO = enabled, each time MAX_SPDCH_LIMIT iscalculated, the BSC shall check whether TCHs are allocated in both theMAX_SPDCH_LIMIT zone and the non pre-emptable PS zone. In this case, itshall send a Start HO (cause 30) message to the HO Preparation entity, totrigger an intracell handover, to move these TCHs into the CS zone

if for any reason, the handover fails, the TCH will remain in the PS zone, untilthe next calculation of MAX_SPDCH_LIMIT, where a new HO could betriggered, if still needed

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 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

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

S C S ( / )


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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 theMAX_SPDCH_LIMIT zone

MAX_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

MAX SPDCH LIMIT TS l ti (12/13)


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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

MAX SPDCH LIMIT TS l ti (13/13)


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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

P t (1/4)


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Parameters (1/4)

RR_ALLOC_PERIOD:

new in B9 release

per BSC, no OMC-R access

range: 1 to 30

default: 2 definition: this parameter allows to tune the time between two sendings of the

BSCGP RR Allocation Indication message

TCH_INFO_PERIOD:

existing in B8 release

per BSS, displayed at the OMC-R

range: 2 to 25,5s

default: 5s

definition: periodicity of TCH usage information update in the BSC

P t (2/4)


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Parameters (2/4)

LOAD_EV_PERIOD_GPRS:

existing in B8 release

per cell, changeable at the OMC-R

range: 3 to 30 default: 3

definition: number of load samples (calculated everyTCH_INFO_PERIOD seconds) used to compute the maximumnumber of slave PDCHs that the BSC can allocate to the MFS

P t (3/4)


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Parameters (3/4)

THR_MARGIN_PRIO_PS:

new in B9 release

per BSC, no OMC-R access

range: 0 to 100% default: 10%

definition: margin of radio timeslots reserved for PS traffic betweentwo sendings of the BSCGP RR Allocation Indication message. Thethreshold is expressed in percentage of radio timeslots

P t (4/4)


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Parameters (4/4)

EN_RETURN_CS_ZONE_HO:

new in B9 release

per cell, changeable at the OMC-R

range: enable / disable default: disable

definition: flag enabling the intracell handovers allowing to move TCHfrom the PS zone to the CS zone of PDCH/TCH allocation

A d


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Agenda





PDCH t t (1/3)


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PDCH states (1/3)

Following states are defined for a PDCH:

Allocated:

new definition in B9: the PDCH is a SPDCH which has been indicated asusable for PS traffic by the BSC

B8 definition: radio resource allocated to the MFS, but associatedtransmission resources are not allocated

Active:

new definition in B9: an allocated PDCH is active if it supports at least oneradio resource allocated for a TBF or for a RT PFC

the B8 definition was considering the parameter N_TBF_PER_SPDCHwhich is removed in B9 release

PDCH t t (2/3)


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PDCH states (2/3)


Full:

new definition in B9: an allocated PDCH is full in a given XL (XL = UL or DL)direction if and only if:

for GPRS Best Effort TBF: Nb_RT_PFC_XL + Nb_BE_TBF_XL MAX_XL_TBF_SPDCH

for EGPRS Best Effort TBF: Nb_RT_PFC_XL + Nb_BE_EGPRS_TBF_XL MAX_XL_TBF_SPDCH

for RT resource allocation: Nb_RT_PFC_XL + Nb_BE_TBF_XL MAX_XL_TBF_SPDCH

this is the same definition as in B8 release except that the concepts of RTPFC and best effort TBF are introduced

PDCH states (3/3)


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PDCH states (3/3)


EGPRS:

an allocated PDCH is in the EGPRS state if some radio resources areallocated in the DL direction, for an EGPRS TBF or an EGPRS RT PFC.

This state is only used when running the radio resourceallocation/reallocation algorithm in GPRS mode and when considering theUL direction of the candidate TBF allocations

This is nearly the same definition as in B8 release except that the concept ofRT PFC is introduced

Remark:

the busy PDCH state (number of established TBF on the PDCH higherthan N_TBF_PER_SPDCH) is no more used by the allocation algorithm

Introduction (1/6)


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Introduction (1/6)

Candidate TS allocation

Best-effort TBF allocation/reallocation request(received from RRM-PCC or dequeued from a Li list)

TRX list

computing (2)

Best candidate allocation computation (4)

No candidate TS allocation

RADIO RESOURCE ALLOCATION/REALLOCATION

ALGORITHM

TBF ESTABLISHMENT PROCESS

(cf. Figure in section 3.2.2) (9)

Cell Transmission Equity (5)

Enough GCHs Not enough GCHs

ALLOC OK case ALLOC FAILED case

Test if enough GCHs (6)

Available_Nb_GCH_With_Equity

TRX list

Transmission Resource

Availability (1)

DSPcongestion state

TRX list sortedby the BSC

Available_Nb_GCH

Transmission resourcereservation (8)

n_MS_requested,n_MS_requested_concurrent

Multislot class,Bias,Traffic type

Numberof radio TSs

determination (3)

Type of the TBF request

PDCH capacity/TFI/TAI/USF

allocation (7)

- rejected request- or L4 queuing- or L5/L6 queuing

- or L7 queuing (10)

- or try to change TBF mode

(EGPRS case) (11)

Introduction (2/6)


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Introduction (2/6)

The algorithm presented in the previous slide is used to findthe radio and transmission resources: in the Evolium BTS case

for GPRS and EGPRS best-effort TBF

in case of TBF establishment or TBF resources reallocation

We can distinguish four different goals: find the best candidate timeslot allocation (steps 2, 3 and 4)

verify if there are enough transmission resources (steps 1, 5 and 6) allocate the radio resources (step 7)

reserve the transmission resources (step 8)

Introduction (3/6)


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Introduction (3/6)

Transmission resource availability (1): it determines the total number of new GCHs which can be established

in the cell with free Abis and Ater resources (i.e. nibbles notassociated to a GCH) and with inter-cell GCH pre-emptions. Thisnumber is called Available_Nb_GCH

this step is completely new in B9 release

TRX list computing (2): it determines the TRX list on which the TBF candidate allocations will

be searched

Number of RTSs determination (3): it is performed prior to the determination of the best candidate

allocation for the TBF (4) and determines the n_MS_requested andn_MS_requested_concurrent values

Introduction (4/6)


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Introduction (4/6)

Best candidate allocation computation (4):

it consists in searching which are the best PDCHs onto which to establish (orreallocate) the TBF, according to various radio related criteria

if no candidate TBF allocation is found in (4), the request has failed (ALLOC

FAILED case due to radio resource reasons). Depending on the type of therequest, the request is rejected or queued into a Li list (10)

Cell transmission equity (5):

if a candidate TBF allocation is found on a TRX, the number of new GCHswhich are possible to be established on that TRX according to intra-cell equityrules is computed. This number is called Available_Nb_GCH_With_Equity

and corresponds to a number of intra-cell GCH pre-emptions that are possibletowards that TRX


Introduction (5/6)


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Introduction (5/6)

Test if enough GCHs (6):

the total number of GCHs which are already (or about to be)established on the previously selected TRX (i.e. Current_Nb_GCH)and/or which will be possible to be established on that TRX in the

future (i.e. Available_Nb_GCH + Available_Nb_GCH_With_Equity) istested

if there are not enough GCHs, the request has failed (ALLOCFAILED case due to transmission resource reasons). Depending onthe type of the request, the request is rejected or queued into a Li list(10)


Introduction (6/6)


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Introduction (6/6)

PDCH capacity / TFI / TAI / USF allocation (7):

if there are enough GCHs (i.e. it is possible to reachNb_GCH_For_TBF_Estab GCHs in the M-EGCH link of the selected TRX),then the radio resources of the best candidate TBF allocation found in (4) areallocated

the radio resource allocation (7) consists in the allocation of some PDCHcapacity, TFI, TAI and USF resources. The concept of PDCH capacity is newin B9 release

Transmission resource reservation (8):

the necessary transmission resources (which are not yet established) arereserved and the TBF establishment process is undertaken (9)

the main interest of the transmission resources reservation step is toguarantee that the transmission resources will remain available during theGCH establishment process

the priority order to reserve the GCHs is as follows : free Abis and Aterresources then inter-cell GCH pre-emptions and finally intra-cell GCH pre-emptions

Allocation policies (1/4)


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The concept of allocation policy is introduced in B9 releaseand is linked to the establishment of the transmissionresources (GCH)

For an Evolium BTS there are two TBF allocation policies(ASAP, Optimal) which are used to serve best effort TBFestablishment / reallocation or One UL block requests



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The ASAP policy is used for best effort TBFestablishments, for T1 / T2 / T4 TBF best effort reallocationsand for one UL block allocations. The goal is to serve therequest as soon as possible, even if the TBF allocation or

throughput are not optimal: if it is possible, an ASAP request is served immediately on a TRX

having already Nb_GCH_For_TBF_Estab established GCHs.Otherwise, the establishment of Nb_GCH_For_TBF_Estab GCHs ona TRX of the cell will be necessary to serve the request

in the best candidate TBF allocation computation, the candidate TBFallocations located on the TRXs having alreadyNb_GCH_For_TBF_Estab established GCHs are favored



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The Optimal policy is used for T3 best effort TBFreallocations

The idea is to ensure that a significant bandwidth will be

offered to the MS upon T3 reallocation, even if it takessome time to establish all the necessary GCHs:

all the possible GCHs (Target_Nb_GCH) are systematically requestedto be established before serving the request, and an Optimalrequest will only be served if the total number of GCHs successfullyestablished on the TRX is greater than Nb_GCH_For_TBF_Estab

in the best candidate TBF allocation computation, the candidate TBFallocations located on the TRXs having already a high number ofGCHs are not favored



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The minimum number of GCHs which are required on the TRX to servethe request (Nb_GCH_For_TBF_Estab) is:

UL TBF establishment without concurrent TBF: 1

UL TBF establishment with concurrent TBF: 1 to 5 depending on the Max

allowed (M)CS of the existing concurrent DL TBF DL TBF establishment without concurrent TBF: 1

DL TBF establishment with concurrent TBF: 1 to 5 depending on the Maxallowed (M)CS of the existing concurrent UL TBF

T1 TBF reallocation: 1

One UL block allocation : 1 T4 TBF reallocation: 1 or 2 depending on the Max allowed CS of the TBF(s)

T3 TBF reallocation : 1 to 5 depending on the Max allowed (M)CS of theTBF(s)

TRX list computing (1/3)


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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 to

the 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 highestthroughput) 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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UL or DL TBF establishment without concurrent TBF:

the candidate TRXs list is defined with the following restrictions:

for GPRS MSs, no restriction on TRXs

for EGPRS MSs, only EGPRS capable TRXs are taken into account. If thereis no candidate allocation, then the radio resource allocation algorithm is runagain in GPRS mode on the full TRX list (i.e. on both EGPRS and nonEGPRS capable TRXs)

UL or DL TBF establishment with concurrent TBF:


in case of EGPRS concurrent TBF, the candidate TRXs have to be EGPRScapable



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T1 and T3 TBF reallocations:


if the current mode is EGPRS, then the candidate TRXs have to be EGPRScapable

T4 TBF reallocation:

there is no specific restriction to define the candidate TRXs list

Number of RTSs determination (1/7)


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The number of radio timeslots to be allocated to a TBF isdetermined according to the:

GPRS or EGPRS MS multislot class

bias traffic type (data / signalling)



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The number of radio timeslots has to be determined:

for the direction of the request, = n_MS_requested:

in case of TBF establishment without a concurrent TBF, the direction of therequest is the direction of the TBF to establish

in case of TBF establishment with a concurrent TBF (with T2 reallocationallowed), the direction of the request is the direction of the MS bias

in case of TBF establishment with a concurrent TBF (with T2 reallocationnot allowed), the direction of the request is the direction of the TBF toestablish

in case of DL or UL TBF reallocation (TBF without a concurrent TBF), thedirection of the request is the direction of the TBF to reallocate

in case of DL and UL TBF reallocation (the two TBFs are concurrent), thedirection of the request is the direction of the MS bias

and for the concurrent direction, = n_MS_requested_concurrent



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When allocating resources to a mobile, both n_MS_requested andn_MS_requested_concurrent are considered, even when only one TBFis established, to take into account a potential future concurrent TBF.Exception : in case of TBF establishment with a concurrent TBF and T2reallocation not allowed, n_MS_requested_concurrent shall not be used

For a mobile with (MAX (UL TS)+ MAX (DL TS) > MAX (UL TS + DLTS)) then the multislot class does not determine the number of slots ineach direction independently of the opposite direction:

the highest possible number of slots is requested in the directioncorresponding to the bias of the MS, i.e. in the direction on which the highest

volume of data is being transferred exception: in case of TBF establishment with a concurrent TBF and T2

reallocation not allowed, the direction of the bias is ignored to determinen_MS_requested



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Differences with B8 release :

the Ater usage (normal / high) is no more taken into account todetermine the number of PDCH to allocate to a TBF (the parameterMAX_PDCH_PER_TBF_High_Ater_Usage is removed in B9 release)

the immediate UL TBF establishment case is no more considered (ULTBF establishment without concurrent DL TBF where onlyn_MS_requested is taken into account to allocate resources to the ULTBF)



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UL TBF establishment without concurrent TBF:

Access type Bias Multislot class Traffic type for ULallocation

n_MS_requested andn_MS_requested_concurrent

RACH one phase DL Default Signalling 1

PRACH one phase DL GPRS Data According to GPRS MS multislotclass

EGPRS Packet Channel request one phaseon PRACH

DL EGPRS Data According to EGPRS MSmultislot class

EGPRS Packet Channel request one phaseon RACH

DL EGPRS Signalling 1

PRACH access (short access, page

response, cell update, MM procedure)DL Default Signalling 1

EGPRS Packet Channel request (shortaccess, signalling) DL Default Signalling 1

Packet Resource Request UL GPRS or EGPRS Data According to GPRS or EGPRSMS multislot class



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DL TBF establishment without concurrent TBF:

the number of radio timeslots is determined according to the traffic type:

traffic type = signalling: n_MS_requested = n_MS_requested_concurrent = 1

traffic type = data: n_MS_requested and n_MS_requested_concurrent are

determined by the MS multislot class (EGPRS multislot class for an EGPRS capableMS when En_EGPRS = enabled, GPRS multislot class otherwise)

UL or DL TBF establishment with concurrent TBF:



traffic type = data: n_MS_requested and n_MS_requested_concurrent are set

according to the MS multislot class (GPRS MS multislot class if the concurrent TBF isa GPRS TBF, EGPRS MS multislot class if the concurrent TBF is an EGPRS TBF)



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traffic type = data: n_MS_requested and n_MS_requested_concurrent are

determined by the MS multislot class (EGPRS multislot class for an EGPRS TBF,GPRS multislot class otherwise)


the traffic type is equal to data in case of T3 TBF reallocation


the number of radio timeslots is determined according to the traffic type: traffic type = signalling: n_MS_requested = n_MS_requested_concurrent = 1

traffic type = data: n_MS_requested and n_MS_requested_concurrent aredetermined by the GPRS MS multislot class

Best candidate allocation computation(1/11)


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(1/11)

Once all the usable PDCHs are determined, the differentcandidate timeslot allocations are sorted according totheir respective available throughput, in order tochoose the one offering the highest throughput to serve the

considered request. This is a complete change compared tothe previous BSS releases (B6, B7 and B8)



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(2/11)

Candidate timeslot allocation: a candidate timeslot allocation is a double list of contiguous PDCH in

a TRX (one list for the direction of the request, one list for theopposite direction), which verifies the concurrent constraints asdefined by the MS multislot class

to be included in a candidate timeslot allocation in order to serve abest effort TBF, a PDCH on a given TRX must verify the followingconditions:

the PDCH shall be allocated in the MFS (i.e. the PDCH is in the allocatedstate, but not in the not allocated or de-allocating state). This condition isnew in B9 release and comes from the fact that the MFS does not request

PDCH to the BSC the PDCH shall not be in the Full state in the considered direction

the PDCH shall not be locked due to a CS pre-emption process



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(3/11)

Candidate timeslot allocation:

specific cases:

when reallocating a TBF, whatever the trigger T1, T2, T3 or T4, the existingset of radio resources shall not be taken into account when computing the

best candidate TBF allocation. This rule impacts the PDCH stateevaluation (PDCH Full state), the computing of all the throughput basedcriteria (Nb_BE_TBF_XL, Nb_BE_EGPRS_TBF_XL,THROUGHPUT_RATIO, ) and the PDCH capacity allocation(USED_CAPACITY_BEST_EFFORT_XL)

T3 and T4 TBF reallocation: the PDCHs in the EGPRS state shall beexcluded in case of T3 or T4 reallocation of an UL GPRS TBF. Thisconstraint only applies to the UL direction



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(4/11)

Available throughput of a candidate timeslot allocation:

this is a completely new metric introduced in B9 release. In the pastreleases the idea was already to give the highest possible throughputto a TBF (allocating the highest number of TS, if possible not busy)

but there was no explicit metric evaluating the throughput provided bya candidate TS allocation

the available throughput of a given candidate timeslot allocation(available_throughput_candidate_XL) is the overall throughputprovided by its PDCHs. It depends both on the potential throughput ofits PDCHs (potential_throughput_PDCH) and on the availablecapacity on each of its PDCHs (available_capacity_PDCH_XL)



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(5/11)


Potential throughput of a given PDCH:

the potential throughput of a PDCH is calculated as follows according toO&M parameters for the Evolium BTS case:

GPRS best effort TBF: R_AVERAGE_GPRS

EGPRS best effort TBF: R_AVERAGE_EGPRS



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(6/11)


Available capacity on a given PDCH:

The available capacity on a given PDCH (available_capacity_PDCH_XL) is calculatedas follows for a GPRS best effort TBF (XL corresponds to either UL or DL) :

(1 USED_CAPACITY_GBR_XL * (1 + QOS_SAFETY_MARGIN/100)) /

(Nb_BE_TBF_HIGHER_PRIOR_XL*SCHEDULING_PRIORITY_FACTOR +Nb_BE_TBF_SAME_PRIOR_XL + 1)

QOS_SAFETY_MARGIN and SCHEDULING_PRIORITY_FACTOR are O&Mparameters. If the SCHEDULING_PRIORITY_FACTOR parameter value is strictlygreater than 1, this will tend to avoid piling up several TBFs with different priorities onthe same PDCHs, which would degrade the throughput of the low priority TBFs

USED_CAPACITY_GBR_XL is a variable indicating the total PDCH capacity that hasalready been allocated to RT PFCs (both GPRS and EGPRS) on the PDCH in the XLdirection

Nb_BE_TBF_HIGHER_PRIOR_XL (respectively Nb_BE_TBF_SAME_PRIOR_XL)indicates the total number of Best Effort TBFs (GPRS or EGPRS) which have someradio resources allocated on the considered PDCH in the XL direction, and whosepriority (combination of THP (Traffic Handling Priority; QoS parameter used for theinteractive traffic class) and of Precedence) is strictly higher than (respectively equalto) the priority of the TBF to establish / reallocate. In case some TBF reallocations arein progress for some MSs, the old sets of radio resources of the MSs shall not betaken into account when computing Nb_BE_TBF_HIGHER_PRIOR_XL andNb_BE_TBF_SAME_PRIOR_XL



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(7/11)


Available capacity on a given PDCH:

the available capacity on a given PDCH (available_capacity_PDCH_XL) is calculatedas follows for an EGPRS best effort TBF (XL corresponds to either UL or DL):

(1 USED_CAPACITY_GBR_XL * (1 + QOS_SAFETY_MARGIN/100)) /(Nb_BE_EGPRS_TBF_HIGHER_PRIOR_XL*SCHEDULING_PRIORITY_FACTOR +Nb_BE_EGPRS_ TBF_SAME_PRIOR_XL + 1)

Nb_BE_EGPRS_TBF_HIGHER_PRIOR_XL and Nb_BE_EGPRS_TBF_SAME_PRIOR_XL only take into account EGPRS TBF (the best effort GPRSTBF and the GPRS RT PFC are not taken into account)

the best effort TBFs having a priority strictly lower than the priority of the TBF toestablish / reallocate are not taken into account. Indeed, the T3 TBF reallocation will

enable to demultiplex those low priority TBFs in the future in the above formula the numerator gives the remaining capacity not used by RT

PFCs whereas the denominator counts the number of best effort TBF sharing thisremaining PDCH capacity. Therefore the ratio corresponds to an average availablePDCH capacity per best effort TBF



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Available capacity of a given candidate timeslot allocation:

for a given candidate timeslot allocation with n PDCHs (n 1), the availablecapacity is computed as follows, for each direction (XL corresponds to either

UL or DL): available_capacity_candidate_XL = i = 1 to n available_capacity_PDCHi_XL

Available throughput of a given candidate timeslot allocation:

finally, the available throughput of a candidate timeslot allocation iscomputed as follows, for each direction (XL corresponds to either UL or DL):

available_throughput_candidate_XL = potential_throughput_PDCH *available_capacity_candidate_XL



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Candidate time slot allocations sorting: the algorithm used in B9 release is completely modified

compared to the one used in B8 release as the key criterion isnow the provided throughput instead of the number of TS

only the candidate timeslot allocations for which some PDCHcapacity, TFI, TAI and USF resources can be allocated in thedirection(s) in which the TBF has to be established, are valid. If suchcandidate timeslot allocation is not found, the best effort TBFallocation / reallocation request has failed and the process is aborted

else, all the valid candidate timeslot allocations are sorted accordingto the following list of ordered criteria (from the highest priority to the

lowest). This list of criteria is valid in all cases: for GPRS or EGPRSservice (contrary to the B8 release case where two lists were used),and in a cell belonging to an Evolium BTS or to a DRFU BTS



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(10/11)

Candidate time slot allocations sorting:

ALPHA: if the policy is ASAP, then the candidate TS allocations which areon some TRXs for which Current_Nb_GCH - Min_Nb_GCH_GBR -Nb_MPDCH Nb_GCH_For_TBF_Estab are preferred

A: the candidate TS allocations which have the lowest number of PDCHs in

the EGPRS state are preferred B: the candidate TS allocations, which have the highest available throughput

in the direction of the bias (available_throughput_candidate_XL) are preferred

C: the candidate TS allocations, which have the highest available throughputin the direction opposite to the bias (available_throughput_candidate_XL) arepreferred

D: the candidate TS allocations, which are on the TRX with the highestpriority, are preferred

E: for EGPRS best effort TBF establishments only: the candidate TSallocations, which have the lowest number of GPRS TBFs in the direction ofthe bias, are preferred

F: combination with the PDCHs that have the lowest index are preferred



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(11/11)

Candidate time slot allocations sorting:

Remarks:

the A criterion is only relevant for an UL GPRS TBF establishment /reallocation (i.e. when considering the UL direction of a candidate TS

allocation in GPRS mode) when evaluating criterion F, the concurrent constraints imposed by the MS

multislot class (if it is known) or by the default multislot class (if the MSmultislot class is not known) shall be taken into account

PDCH capacity / TFI / TAI / USF allocation(1/4)


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(1/4)

Once a candidate TS allocation has been found (in thebest candidate allocation computation step), the followingradio resources are allocated to the MS in the directions inwhich a TBF has to be established:

PDCH capacity

TFI

PDTCH / PACCH

TAI

USF (only in the UL direction)



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(2/4)

PDCH capacity allocation:

this step is new in B9 release

the PDCH capacity allocation is performed on the best candidate TSallocation so as to guarantee a minimum bandwidth for the

corresponding TBF(s) (data throughput and throughput generated onPACCH channels in DL and in UL)

the PDCH capacity allocation shall only be performed in EvoliumBTSs (no PDCH capacity needs to be allocated in DRFU BTSs)

the PDCH capacity allocation should always succeed, because the

candidate TS allocations for which the PDCH capacity allocationcannot be performed have been excluded during the best candidateallocation computation step



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(3/4)


PDCH capacity needed for a best effort TBF:

in a given direction (UL or DL) and on a given PDCH, the minimum capacity (in termsof radio block scheduling in MAC layer) that is required for a best effort TBF is calledneeded_capacity_Best_Effort_XL (XL corresponds to either UL or DL)

this capacity corresponds to a minimum bandwidth that shall be guaranteed for thebest effort TBF

it is computed as follows:

needed_capacity_Best_Effort_XL = 20 / T_MAX_FOR_TBF_SCHEDULING

with T_MAX_FOR_TBF_SCHEDULING an O&M parameter in ms

this calculation of needed_capacity_Best_Effort_XL approximates the maximal load

which can be generated by the data traffic and the signalling traffic of the TBF(signalling traffic on the PACCH in the direction of the TBF). To simplify, it isconsidered that needed_capacity_Best_Effort_DL =needed_capacity_Best_Effort_UL



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algorithm to allocate the PDCH capacity needed for a best effort TBF:

in a given direction (XL corresponds to either UL or DL) and on a given PDCH, themaximum PDCH capacity which can be allocated is equal to:

1 - USED_CAPACITY_GBR_XL* (1 + QOS_SAFETY_MARGIN/100) -USED_CAPACITY_BEST_EFFORT_XL

USED_CAPACITY_GBR_XL indicates the total PDCH capacity that has already beenallocated to RT PFCs (both GPRS and EGPRS) on the PDCH in the XL direction

USED_CAPACITY_BEST_EFFORT_XL indicates the total PDCH capacity that hasalready been allocated to best effort TBFs (both GPRS and EGPRS) on the PDCH inthe XL direction in order to ensure a minimum bandwidth for those best effort TBFs

QOS_SAFETY_MARGIN is an O&M parameter

in the direction(s) in which a TBF has to be established, a PDCH capacity equal to

needed_capacity_Best_Effort_XL shall be allocated on each PDCH included in thebest candidate TS allocation

then on each PDCH, the value of USED_CAPACITY_BEST_EFFORT_XL shall beincreased accordingly (incrementation by needed_capacity_Best_Effort_XL)

TBF establishment process (1/6)


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( )

The aim of the TBF establishment process is to:

establish the GCHs which were previously reserved

determine the Maximum allowed (M)CS

GCH establishment

the process differs according to the TBF allocation policy: ASAP orOPTIMAL



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Maximum allowed (M)CS calculation:

triggers to assess the maximum allowed (M)CS of a best effort TBF in case ofEvolium BTS:

the nominal trigger to assess the maximum allowed (M)CS of a given best effort TBFis when that TBF is established or reallocated. In case of TBF reallocation, the

maximum allowed (M)CS of the TBF can be increased or decreased the maximum allowed (M)CS of a best effort TBF already established on a given TRX

shall also be reassessed when the Established_Nb_GCH value of the TRX isincreased. In such a case, all the best effort TBFs established on the TRX shallpotentially be warned of their new max allowed (M)CS value

at last, the maximum allowed (M)CS of a best effort TBF already established on aTRX shall be reassessed when a RT PFC is deleted or when an existing RT PFC is

modified (RT PFC modification request with AGBR decrease in a direction) on theTRX. Indeed, when a RT PFC is deleted or its AGBR decreased in a direction, theMin_Nb_GCH_GBR value of the TRX may become lower, which may allow toincrease the maximum allowed (M)CS of the best effort TBFs established on the TRX



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Maximum allowed (M)CS calculation:

triggers to assess the maximum allowed (M)CS of a best effort TBF incase of Evolium BTS:

no maximum allowed (M)CS decrease is managed in case the

Established_Nb_GCH value of a TRX is decreased on the other hand, the Min_Nb_GCH_GBR value of a TRX will never

increase so as to imply a maximum allowed (M)CS decrease for an existingbest effort TBF. So the creation of a RT PFC (or the modification of a RTPFC with AGBR increase in a direction) will have no influence on themaximum allowed (M)CS of the best effort TBFs already established on theTRX



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Maximum allowed (M)CS calculation: calculation of the maximum allowed (M)CS value of a best effort

GPRS (respectively EGPRS) TBF, Evolium BTS case:

the maximum allowed (M)CS is determined according to the number ofestablished GCHs in the M-EGCH link, the Min_Nb_GCH_GBR value of the

TRX, the GPRS (respectively EGPRS) capability of the TRX, the direction ofthe TBF (DL or UL) and the Max_GPRS_CS (respectivelyMax_EGPRS_MCS) parameter value

refer to the below tables for the calculation of Max allowed (M)CS accordingto the number of GCHs in the M-EGCH link

finally:

TBF_Max_allowed_CS = min(Max allowed CS according to the number ofGCHs of the M-EGCH link, GPRS capability of the TRX, Max_GPRS_CS)

TBF_Max_allowed_MCS = min(Max allowed MCS according to the numberof GCHs of the M-EGCH link, EGPRS capability of the TRX,Max_EGPRS_MCS)



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Number of established GCHs in the M-EGCH link

(Established_Nb_GCH - Min_Nb_GCH_GBR

- Nb_GCH_Impacted_By_CS_Preemption)

Max allowed CS of the TBF according to the number of

GCHs of the M-EGCH link

(TBF_Max_allowed_CS)

UL TBF DL TBF

1 CS2 CS1 (*)

2 CS4 CS4

(*) the maximum allowed (M)CS of a (E)GPRS DL TBF established on a TRX having an M-EGCH link containing 1 GCH is set to (M)CS1 (and not

(M)CS2). Indeed, it shall be guaranteed that the MFS-BTS signalling messages will always be possible to be sent in the M-EGCH link in DL. A

possible consequence of this is that the maximum allowed (M)CS of a (E)GPRS DL TBF may be (M)CS1 even if the MAX_(E)GPRS_(M)CS

parameter was set to (M)CS2 (Target_Nb_GCH = 1 if only one PDCH is active on the TRX). Those cases are deemed acceptable (no necessity

to optimise the throughput of the 1 RTS TBFs)



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Number of established GCHs in the M-EGCH link

(Established_Nb_GCH - Min_Nb_GCH_GBR

- Nb_GCH_Impacted_By_CS_Preemption)

Max allowed MCS of the TBF according to the number

of GCHs of the M-EGCH link

(TBF_Max_allowed_MCS)

UL TBF DL TBF

1 MCS2 MCS1 (*)

2 MCS5 MCS5

3 MCS6 MCS6

4 MCS7 MCS7

5 MCS9 MCS9

TBF establishment cases (1/3)


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UL TBF establishment without concurrent TBF:

Evolium BTS case:

the UL TBF is immediately established provided that one UL resource isavailable on a TRX already established

on receipt of the MS request, if no TRX is established or if all the PDCHs onthe already established TRXs are full in UL, the radio resources of the ULTBF are allocated on some RTS(s) of a non-established TRX. Thereafter,the corresponding PDCH group waits for Nb_GCH_For_TBF_Estab GCHsto be established in the M-EGCH link of that TRX to complete the TBFestablishment

contrary to the B8 release, there is no PDCH resource anticipation processfor the subsequent DL TBF



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UL (resp. DL) TBF establishment with concurrent TBF:

case where T2 reallocation is not allowed: the allocated radioresources in UL (resp. DL) shall comply with the constraints imposedby the concurrent DL (resp. UL) TBF and the candidate timeslot

allocations are reduced to the combinations which verify theconcurrent constraints with the already established DL (resp. UL) TBF

case where T2 reallocation is allowed and the existing TBF is notestablished in the direction of the bias: there is no specific condition



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UL (resp. DL) TBF establishment with concurrent TBF:

case where T2 reallocation is allowed and the existing DL (resp. UL) TBF isestablished in the direction of the bias:

first, the candidate allocations which verify all the following constraints are searched:

T3 TBF reallocation constraints: those constraints are exactly the same as for aclassical T3 TBF reallocation, applied to the existing concurrent TBF. Thoseconstraints guarantee that a T2 TBF reallocation will only be triggered if a significantthroughput gain can be offered to the MS in the direction of the bias

T4 TBF reallocation constraints: in case of GPRS mode, the PDCHs in EGPRSstate in the UL direction shall not be considered. That constraint makes T2 and T4TBF reallocations coherent with each other: following a T2 TBF reallocation, an MSwill not immediately become candidate for T4 reallocation if it is avoidable

the ALPHA criterion shall be mandatorily respected. That constraint makes the globalprocess coherent with the ASAP policy

in case of failure (i.e. no candidate allocation is found), the candidate allocationswhich do not require to reallocate the existing TBF are searched:

the allocated radio resources in UL (resp. DL) shall comply with the constraintsimposed by the concurrent DL (resp. UL) TBF

in case of failure (i.e. no candidate allocation is found in the two previous steps), theremaining candidate allocations are searched without any constraint

TBF reallocation cases (1/10)


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best candidate allocation computation:

the candidate timeslot allocations do not require to have the same numberof PDCHs than the current allocation. A candidate timeslot allocation of one

PDCH is sufficient, since the intention of the radio resource reallocation is tosave the TBF(s)

the PDCHs of the TRXs which are highly impacted by the CS pre-emptionhave been previously locked: this prevents to look for candidate TSallocations on those TRXs

the radio resource allocation algorithm is run with the ASAP policy. Thanks

to the allocation criterion ALPHA, the candidate TS allocations located onthe TRXs having already one established GCH are favored (Evolium BTS)



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goals of the T3 reallocation (Evolium BTS):

provide a higher throughput, if it is possible, to any TBF in the cell

establish a new M-EGCH link for one of the TRXs of the cell. This is

possible because the T3 TBF reallocation requests are played with theOptimal allocation policy

perform a radio defragmentation process to limit the risk that the TBFs areimpacted by a CS pre-emption. The goal is that the PDCHs supporting theTBFs in the cell are always the first or left-most allocated PDCHs of thecell (when considering the ordered TRXs list provided by the BSC and the

RTSs from RTS 0 to RTS 7 on a given TRX)



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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 anestablished TBF in the direction of the bias verifying the following

conditions: more than N_CANDIDATE_FOR_REALLOC bytes have been sent on the

DL TBF or received on the UL TBF since their establishment

T3192 is not running



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THROUGHPUT_RATIO:

for each MS which is candidate for a T3 TBF reallocation, a throughput ratio iscalculated

this throughput ratio is useful to:

validate the candidate TBF allocations when playing the radio resource reallocationalgorithm

sort the T3 TBF reallocation requests within the L5 and L6 lists: low value of thethroughput ratio means high priority of the request

THROUGHPUT_RATIO = ALLOCATED_THROUGHPUT /OPTIMAL_THROUGHPUT

ALLOCATED_THROUGHPUT is the throughput currently allocated to the TBF in thedirection of the bias and is equal to potential_throughput_PDCH *available_capacity_candidate_XL

OPTIMAL_THROUGHPUT is the optimal throughput that could be potentiallyallocated to the TBF in the direction of the bias by considering its multislot class and isequal to potential_throughput_PDCH * n_MS_requested



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a candidate TBF allocation shall fulfil the following condition:

NEW_THROUGHPUT_RATIO min(1, (1+MIN_THROUGHPUT_GAIN ) *

CURRENT_THROUGHPUT_RATIO) NEW_THROUGHPUT_RATIO is the throughput ratio of the candidate

TBF allocation

CURRENT_THROUGHPUT_RATIO is the throughput ratio of the currentTBF allocation

MIN_THROUGHPUT_GAIN is an O&M parameter



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the radio resource allocation algorithm is run with the Optimal policy. It isthe best candidate TBF allocation which is targeted, without any distinction

for the GCHs/PDCHs that are currently established. The candidate TBFallocations on already established TRXs (Evolium BTS) / establishedPDCHs (DRFU BTS) are not favored (no ALPHA criterion)



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reallocation attempts:

T3 reallocation attempts occur at each expiry of theT_CANDIDATE_TBF_REALLOC timer

up to N_MAX_PERIODIC_REALLOC_T3 T3 reallocation attempts can takeplace at each T_CANDIDATE_TBF_REALLOC timer expiry

in case of successful T3 reallocation attempt, no new attempt takes placeuntil the next T_CANDIDATE_TBF_REALLOC timer expiry even if less thanN_MAX_PERIODIC_REALLOC_T3 attempts have occurred

up to two T3 TBF reallocations can be successfully played at each

T_CANDIDATE_TBF_REALLOC timer expiry (one in L5 list and one in L6list)



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goal of the T4 reallocation:

avoid the UL GPRS - DL EGPRS TBF multiplexing situations

indeed, in those multiplexing situations, some dummy DL GPRS TBF(s)

may have to be managed by MAC in order to schedule the USFs of the ULGPRS TBF(s), which can induce a throughput reduction for the DL EGPRSTBFs

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. This means that a DL TBF can be T4 reallocatedeven if it has currently no UL concurrent TBF



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the candidate timeslot allocations do not require to have the same numberof PDCHs than the current allocation

in the UL direction, the candidate timeslot allocations cannot contain PDCHsin the EGPRS state. Therefore the criterion A is not relevant

the radio resource allocation algorithm is run with the ASAP policy. Thanksto the allocation criterion ALPHA, the candidate TS allocations located onthe TRXs having already Nb_GCH_For_TBF_Estab established GCHs arefavored



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reallocation attempts:

upon T_CANDIDATE_TBF_REALLOC timer expiry it shall be attempted toreallocate a maximum of N_MAX_PERIODIC_REALLOC_T4 candidate

MSs queued within the L7 list if a reallocation succeeds, the next request within the L7 list shall be played

(up to the N_MAX_PERIODIC_REALLOC_T4 limit)

Parameters (1/7)


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R_AVERAGE_GPRS

new in B9 release

per cell, OMC-R access: changeable

range: 0 to 20000 bit/s

default: 12000 bit/s definition: average bitrate per PDCH for non-Edge capable terminals in this

cell

R_AVERAGE_EGPRS

new in B9 release


range: 0 to 59200 bit/s default: 30000 bit/s

definition: average bitrate per PDCH for Edge capable terminals in this cell

Parameters (2/7)


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QOS_SAFETY_MARGIN

new in B9 release


range: 0 to 100%

default: 20%

definition: additional capacity (in terms of radio bandwidth and interms of transmission resources) which is reserved for a streamingTBF (RT PFC) to correctly fulfill its AGBR contract and to possiblyconvey other multiplexed NRT PFC(s) of the same TBF. The part of

this margin that is not used by the streaming TBF may be used byother TBF(s)

Parameters (3/7)


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SCHEDULING_PRIORITY_FACTOR

new in B9 release

per MFS, no OMC-R access

range: 1 to 10

default: 5

definition: when computing the best candidate timeslot allocation for aNRT TBF, this factor enables to give a higher weight (PDCH capacity)to the already established NRT TBFs having a higher schedulingpriority (combination of THP and of Precedence) than the TBF to be

established or reallocated

Parameters (4/7)


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T_MAX_FOR_TBF_SCHEDULING

new in B9 release


range: 0,12 to 0,3s (step size: 20 ms)

default: 0,3s (15 * 20ms)

definition: maximum time between two scheduling of a given NRTTBF (either between two DL block requests for a NRT DL TBF, orbetween two UL blocks received for a given NRT UL TBF)

Parameters (5/7)


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MIN_THROUGHPUT_GAIN

new in B9 release


range: 0,1 to 5

default: 0,4

definition: minimum throughput gain required to be provided to the MSwhen performing a T2 or T3 TBF reallocation

Parameters (6/7)


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N_MAX_PERIODIC_REALLOC_T3:

new in B9 release


range: 0 to 500

default: 20 definition: total number of (unsuccessful) T3 radio resource reallocation

attempts that are allowed to be performed upon expiry of theT_CANDIDATE_TBF_REALLOC timer. As soon as a T3 radio resourcereallocation attempt succeeds, no other attempt is performed (even if lessthan N_MAX_PERIODIC_REALLOC_T3 attempts have been performed so

far). The UL-biased MSs and the DL-biased MSs are considered regardlessof each other. As a result, in a given cell, up to 2 xN_MAX_PERIODIC_REALLOC_T3 T3 radio resource reallocation attemptswill be performed upon expiry of the T_CANDIDATE_TBF_REALLOC timer

Parameters (7/7)


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N_MAX_PERIODIC_REALLOC_T4:

new in B9 release


range: 0 to 500

default: 5

definition: defines the total number of T4 radio resource reallocationattempts (successful or not) that are performed upon expiry of theT_CANDIDATE_TBF_REALLOC timer

Removed parameters


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Following B8 parameters are removed in B9 release:

N_TBF_PER_SPDCH

EN_RES_REALLOCATION

MAX_PDCH_PER_TBF_High_Ater_Usage

N_MAX_PERIODIC_REALLOC

Agenda


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CS pre-emption (1/10)


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Principles:

the CS pre-emption process is triggered when a radio TS is reportedby the BSC as no longer allocated to the MFS. The PDCH p

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