4 Downlink Dual Carrier

Downlink Dual CarrierLink adaptation
Feature interworking
New parameters
Dimensioning (PCU2-E)
Single carrier allocations in Downlink and Uplink
Up to 5 TSLs in DL - max MS Multislot Class capability supported by PCU2 (Class 40-45)
Up to 296 kbps (5TSLs @ MCS9) of theoretical peak RLC/MAC throughput
Up to BSS13
Dual Carrier in Downlink - part of 3GPP Rel.7 GERAN Evolution
BSS14
increased flexibility of TSL allocation
more efficient sharing of the system throughput
Higher number of TLSs allocated for DL TBFs
up to 10 TSLs in DL
Improved user data throughput and reduced user perceived delay
up to 592 kbps (10TSLs @ MCS9) of theoretical peak RLC/MAC throughput
c1
c1
c2
Introduction
With Downlink Dual Carrier (DLDC) resources of an EGPRS downlink TBF can be assigned to a mobile station on two TRXs.
DLDC introduces new (EGPRS) multislot capabilities, and a new MS hardware is required. A DLDC capable MS has one transmitter-receiver with two receivers (Rel. 7 terminal required).
DLDC enables higher data rates through usage of higher timeslot quantity, DLDC doubles the timeslot quantity. For example a multislot class 30 MS is capable up to 10 downlink timeslots, five on each carrier, that is 5+5 dual carrier configuration.
DLDC feature is licensed feature with TRX capacity license. DLDC is application software.
Maximum number of slots in DL
Maximum throughput at MSC9 [kbps]
Single carrier mode
Dual carrier mode
Single carrier mode
Dual carrier mode
6
12
355
710
MS has to indicate its Dual Carrier capability
Multislot Capability Reduction for Downlink Dual Carrier field in MS Radio Access Capability IE (3GPP TS 24.008)
the presence of this field means that MS supports DLDC while the absence means the opposite
this field determines the MS Multislot Capability for Dual Carrier mode
Particular signaling messages have been modified in order to support DLDC feature (3GPP TS 44.060), e.g.:
Packet Downlink Assignment and Packet Timeslot Reconfigure have been extended with new Information Elements describing the resources for both carriers, e.g.:
Assignment Type (dual or single carrier)
Frequency Parameters C1(C2) or Dual Carrier Frequency Parameters
Timeslot Allocation C1(C2)
EGPRS Packet Downlink ACK/NACK – two separate EGPRS Channel Quality Report IEs for both assigned carriers (EGPRS Channel Quality Report and Secondary Dual Carrier Channel Report)
Presentation / Author
If an MS erroneously indicates DLDC-capability but no EGPRS multislot class, PCU treats the MS as a non-DLDC-capable MS.
PCU ignores the 'Downlink Dual Carrier for DTM Capability' field of the MS Radio Capability IE, and it never allocates DLDC resources for an MS in dual transfer mode
* © Nokia Siemens Networks
Downlink Dual Carrier
MS Multislot Class (3GPP TS 45.002)
the maximum number of DL TSLs (Rx) is applicable to each carrier separately
the maximum aggregated (over both carriers) number of DL TSLs must not exceed 2*Rx
the sum of UL TSLs and TSLs on any DL carrier must not be greater than value of ‘Sum’
Multislot Capability Reduction for Downlink Dual Carrier
based on the indicated MSCR the maximum number of DL TSL is determined according to the following table
Table 1 Multislot capabilities for particular MS classes
Table 2 Maximum number of DL TSL for Dual Carrier allocations supported by PCU2
Multislot Class
Maximum number of DL TSL per one carrier
Maximum number of DL TSLs for Dual Carrier for different values of the ‘Multislot Capability Reduction for Downlink Dual Carrier’
0
1
2
3
4
5-7
5
10
9
8
7
6
6
4
8
8
8
7
6
6
5
10
10
10
9
8
7
The maximum number of DL slots supported by PCU /BSS20084/ differs from that defined for the multislot class in /45002/, the multislot capability reduction is subtracted from the maximum aggregate number of slots as given in the standard, and the reduction affects timeslot allocation only when the result is less than the maximum aggregate number defined in Table 1: e.g. in case of multislot class 35 — for which the standard allows five DL slots per carrier and an aggregate of ten over two carriers, while PCU supports four and eight slots, respectively — the multislot capability reduction is subtracted from the standardised ten aggregate slots, and therefore a reduction of less than three slots does not affect the maximum number of DL slots PCU may allocate.
‘Multislot Capability Reduction for Downlink Dual Carrier’ field value 7 is reserved for future use, but in case PCU erroneously receives value 7, it handles the MS as if the reduction indicated were 6.
Table 4 Exemplary DC MS configurations for Multislot Classes 30-33
Table 1 Multislot capabilities for exemplary MS classes
Table 2 Maximum number of DL TSL for Dual Carrier allocations supported by PCU2
MS indicating High Multislot Class 30 and MSCR=2 is to be assigned resources in DLDC mode
At max 8 DL TSLs in total (on both carriers) may be assigned and 1 TSL in UL
Multislot Class
Maximum number of DL TSL per one carrier
Maximum number of DL TSLs for Dual Carrier for different values of the ‘Multislot Capability Reduction for Downlink Dual Carrier’
0
1
2
3
4
5-7
5
10
9
8
7
6
6
4
8
8
8
7
6
6
5
10
10
10
9
8
7
TRX selection
Determination of the Rx/Tx-window size
the number of TSLs to be allocated to TBF(s)
Determination of DLDC allocation candidates
all configurations which could be assigned to MS considering current resources availability
Selection of the highest-capacity DLDC allocation
Selection of the highest-capacity SC allocation
Final allocation selection
the best one of the previously determined DLDC and SC allocations
ready
Single Carrier allocation selection (capacity criterion)
Final allocation selection (SC and DC comparison)
start
DLDC Channel Allocation – BTS selection
In BTS selection algorithm for a DLDC MS both the best SC and the best DLDC BTS capacities are calculated
DLDC BTS capacity is calculated as the maximum sum of capacities offered by a pair of TRXs which can be used for DLDC resource allocation
TRX capacity is calculated taking into account GPRS territory size, load resulting from ongoing TBFs and MS Multislot capabilities
BTS offering the highest capacity is selected whether this capacity is SC or DLDC
among BTSs providing the same capacity the one with lager GPRS territory is selected
If the highest capacity calculated for the selected BTS was DLDC, the pair of TRXs providing the best DLDC capacity is identified in the BTS selection output
additionally the TRX providing the best SC resources is identified - the TRX providing the best SC capacity may not be one of the DLDC TRXs
If the BTS has been chosen due to its higher SC capacity, only SC resources are looked for in channel allocation procedure – DLDC channel allocation is not proceeded
ready
start
BTS selection in a segment is done when a new TBF is created or the existing TBF is getting reallocated.
Calculation of the best DLDC BTS capacity is followed by the calculation of the best single carrier BTS capacity, which is carried out as required for S13. For DLDC activated BTSs, both the best DLDC and the best single carrier capacities are therefore calculated; for BTSs which are not DLDC activated, only the best single carrier capacity is calculated. When BTS is being selected for a non-concurrent TBF, the better of the calculated DLDC and single carrier capacities is kept for comparison with other BTSs; in concurrent cases, the best DL and UL capacities are first selected from the respective DLDC and single carrier configurations, and then the lower of these two capacities is kept for comparison with other BTSs.
When the highest capacity calculated for the selected BTS was single carrier, when BTS is selected for a non-concurrent UL TBF or when resources are being allocated from the extended or super extended coverage areas of an extended cell, no TRXs are identified in the BTS selection output
Furthermore, when a DL TBF is being created for a DLDC-capable MS, PCU carries out BTS selection also when it holds existing resources for the MS provided that these resources are only in UL and they are allocated from a BTS which is not DLDC activated.
DLDC Channel Allocation is proceeded only if the selected BTS was chosen on the basis of its max DLDC capacity
DLDC Channel Allocation – TRX selection
In case the resource (re)allocation does not involve BTS selection, the pair of TRXs providing the best DLDC capacity and the TRX offering the best SC capacity are selected within the current BTS
TRXs capacity is calculated as the sum of capacities offered by all TSLs which can be assigned to a TBF (GPRS territory size and MS Multislot capabilities)
TSL capacity is calculated taking into account load resulting from ongoing TBFs
Only a pair of TRXs with the best DLDC capacity and a TRX providing the best SC capacity are used in further phase of DLDC channel allocation procedure
ready
start
DLDC Channel Allocation – Rx/Tx-window
Rx/Tx-window is a set of DL/UL contiguous TSLs determined based on MS Multislot Capabilities
Either PS territory size or the MSCR do not affect the size of the Rx/Tx-window
these two factors are taken into account in the further phase of channel allocation procedure
In case of concurrent (UL+DL) TBFs the distribution of TSLs between the Rx- and Tx-windows is determined according to the CONC_UL_TBF_FAVOR_DIR and CONC_DL_TBF_FAVOR_DIR parameters (PRFILE) and the observed UL and DL data transfer intensities
For DLDC allocations the Rx-window size is the same and it comprises the same timeslots on both carriers
For DLDC concurrent allocations Tx-window is limited to 2 TSLs since Extended Dynamic Allocation (EDA) is not supported with DLDC
Example: MS of Multislot Class 33 indicating MSCR=0
for non-concurrent DLDC allocation the Rx-window equals 5 TSLs
for concurrent DL favored allocation Rx-window equals 5 TSLs while Tx-window comprises 1 TSLs
for concurrent UL favored non-EDA allocation Rx-window equals 4 TSLs while Tx-window comprises 2 TSLs
ready
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In case of non-EDA UL TBF the concurrent DLDC TBF establishment may trigger the re-allocation of the UL resources – the preference is given to DLDC configuration
DLDC Channel Allocation – DLDC allocation candidates (1)
Rx-window (together with Tx-window) is slid over the pair of the selected TRXs and for each position DLDC allocation candidate is determined
for each Rx-window position PCU allocates on both carriers the maximum possible number of TSLs within the Rx-window
all the available PS TSLs covered by the Rx-window are selected as a DLDC allocation candidate
Different amount of TSLs and different TSL numbers may be allocated on different TRXs
If MS indicates MSCR different than zero, the number of DL TSLs in Rx-window is limited according to table 2 or table 3
PCU excludes TSLs one-by-one selecting the TSL which is closest to the CS/PS territory border
PS TSLs of the DLDC allocation candidate which cannot serve more TBFs due to multiplexing limits (determined by two attributes pcuMaxNoULtbfInCH and pcuMaxNoDLtbfInCH) are excluded
ready
start
When DLDC resources are searched, the Rx window is of equal size on both carriers and it comprises the same timeslots on both carriers but during selection of TSLs configuration different number of TSLs and different TSL numbers on different TRXs are possible.
DLDC Channel Allocation – DLDC allocation candidates (2)
In case of concurrent allocation, if at either end of the Rx-window there are TSLs which cannot be allocated on either TRX (e.g. TSLs which are not part of the PS-territory), they may be shifted to the opposite direction
the number of TSLs shifted from the Rx-window to the Tx-window must not increase Tx-window to more than 2 TSLs (EDA is not supported with DLDC)
if TSLs cannot be shifted the Rx/Tx-windows are reduced
UL TSLs cannot overlap DL allocation even if allocated on different carriers
Multislot class physical restrictions defined in 3GPP TS 45.002 (TSLs required by an MS for switching between transmission, reception and measurements) must be respected
Allocation candidates having TSLs on only one DL carrier are just ignored
Exemplary DLDC allocation candidates for MS class 33: Rx-window=5 and Tx-window=1
if TSLs cannot be shifted the Rx/Tx-windows are reduced
this reduction is done only for the currently considered allocation candidate
after shifting to the next position the Rx- and Tx- windows are restored to the original sizes
DLDC Channel Allocation – DLDC allocation selection
Among all DLDC allocation candidates the one providing the highest capacity is selected
The capacity offered by the TSLs of a DLDC allocation candidate is calculated as a sum of the capacities of each timeslot included in the DLDC allocation candidate
In case of concurrent TBFs, both UL and DL capacity are considered
The allocation providing the best capacity is selected whether it comprises the most TSLs or not
If more than one configuration yields the same capacity, the configuration with the most TSLs is preferred
ready
start
DLDC Channel Allocation – Final allocation selection
Following DLDC allocation selection the best SC allocation is searched on the TRX providing the best SC capacity within the selected BTS
the highest-capacity SC allocation is then considered in the final resource selection
The best DLDC allocation is compared with the best SC one and the configuration providing higher capacity is finally chosen
if the capacity of DLDC and SC allocations is the same, the one with higher number of TSLs is chosen
if the capacity and number of TSLs of DLDC and SC allocations are the same, DLDC allocation is selected
in case of concurrent UL-favored EDA allocation the SC allocation is selected
In case of non-concurrent DLDC TBF the carrier farther from the PS/CS territory border is selected as carrier 1
In case of a concurrent TBFs, if UL resources are available on both DLDC carriers, the carrier providing higher UL capacity is selected as carrier 1
ready
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In case the number of allocated TSLs is lower than the number required in DLDC configuration a territory upgrade is triggered
PS territory upgrades
For DLDC-capable MS having SC allocation the standard (legacy) PS territory upgrade procedure is applied
the territory is extended so that the MS capability on one carrier can be fulfilled
PCU does not indicate whether territory upgrade is requested for DLDC-capable MS or non-DLDC-capable one
For DLDC TBF the PS territory upgrade may be requested if the following conditions are fulfilled (all legacy criteria must be met as well)
the number of allocated TSLs is less than the number of TSLs the MS could use in DL (considering the Rx-window size and indicated MSCR)
PS territory of the selected BTS includes TSLs on no more than 2 TRXs
the number of TSLs in the PS territory limited by the border between the PS and CS territories is lower than minimum of Rx-window and Max_MSCR – Rx-window
Max_MSCR is the maximum number of DL TSLs the MS could use on both TRXs according to its multislot class and MSCR (tables 1, 2 and 3)
Example: MS Class 33 with MSCR=2 -> Rx-window=5, Max_MSCR=8; number of TSLs on TRX-2 < Max_MSCR – Rx-window
In the downgrade procedure, BTS selection and Channel Allocation algorithm may lead reallocation of TBF from Dual Carrier to Single Carrier, Dual Carrier to Dual Carrier or Single Carrier to Dual Carrier
In case of PS territory upgrade for DLDC TBF the number of requested TSLs is the maximum of the following two numbers:
the number of TSLs needed to reduce the average number of TBFs per PDCH to the value defined by PRFILE parameter PR_NR_T_PSW_UPGRADE_TAR_TBF_NB
the number of TSLs necessary to increase the number of PS territory TSLs to the value of min(Rx-window, Max_MSCR – Rx-window)
Example: the PS/CS territory border limits the PS territory on TRX-2 to 2 TSLs
MS Class 33 with MSCR=0 -> Rx-window=5, Max_MSCR=10, Max_MSCR – Rx=5 -> upgrade of 3 TSLs is requested (not considering the average TBFs per TSL rule)
MS Class 33 with MSCR=2 -> Rx-window=5, Max_MSCR=8, Max_MSCR – Rx=3 -> upgrade of 1 TSLs is requested (not considering the average TBFs per TSL rule)
PS territory upgrades
These territory upgrade rules apply both for initial TBF creation and for TBF reallocations
PRFILE parameter PR_NR_T_PSW_UPGRADE_TAR_TBF_NB (default 1.0 TBFs per TSL)
Link Adaptation
With DLDC a single TBF is split on two independent carriers
there are no constraints on the two carriers paired in DC mode - they may have very different frequency reuses and different hopping laws (it is possible that only one of them performs FH)
One common Link Adaptation instance is applied to both carriers
LA provides TBF (not carrier) specific MCS variables (Commanded MCS, Initial MCS and Max MCS for Retransmissions)
MCS to be applied is determined using the Commanded MCS, Initial MCS and Max MCS for Retransmissions variables as in the current implementation
In case of higher asymmetry (e.g.: MCS-9 vs. MCS-5) MS would even experience throughput degradation after switching to DC mode; however, in case of lower asymmetry (e.g.: MCS-9 vs. MCS-7) MS would experience the throughput gain even with common LA
The EGPRS PACKET DOWNLINK ACK/NACK message may contain two channel quality reports, namely EGPRS Channel Quality Report IE and Secondary Dual Carrier Channel Report IE. The EGPRS PACKET DOWNLINK ACK/NACK message may contain only one channel quality report and it can be either EGPRS Channel Quality Report IE or Secondary Dual Carrier Channel Report IE. The EGPRS PACKET DOWNLINK ACK/NACK message may be received without any channel quality reports.
If the DL DC configuration (TRX-x and TRX-y) is reallocated to DL DC configuration (TRX-z and TRX-w) and if EPDAN message is received during the reallocation, then it may happen that BEP values measured on old resources (TRX-x and TRX-y) are fed into the LA algorithm and the resulting MCS is then used on the new resources (TRX-z and TRX-w). This is accepted.
If a DL DC configuration (TRX-x and TRX-y) is reallocated to single carrier mode (TRX-z) and if EPDAN message is received during the reallocation, then it may happen that the BEP measured on old carrier-1 (TRX-x) is fed into the LA algorithm (the BEP measured on old carrier-2 (TRX-y) is ignored) and the resulting MCS is then used on the new resources (TRX-z). This is accepted.
If a TBF operating in single carrier mode (TRX-x) is reallocated to dual carrier configuration (TRX-z and TRX-w) and if EPDAN message is received during the reallocation, then it may happen that the BEP measured on old resources (TRX-x) is fed into the LA algorithm and the resulting MCS is then used on the new resources (TRX-z and TRX-w). This is accepted.
When the channel quality measurements (C_VALUE, GMSK_MEAN_BEP and/or 8PSK_MEAN_BEP) are used in other than LA purposes, then the PCU shall aply the values received in the EGPRS Channel Quality Report IE as in the existing implementation. The channel quality measurements received in the Secondary Dual Carrier Channel Report IE are used only for LA purposes.
EGPRS
EGPRS must be enabled if DLDC feature is wanted to be used.
No support of simultaneous DLDC and DTM
DLDC mode cannot be established if DLDC capable MS is having a DTM connection
If for a (DLDC and DTM capable) MS being in DLDC mode a DTM request is received, PCU releases the DLDC TBF and initiates the SC TBF establishment
No support of simultaneous DLDC and Extended Dynamic Allocation
DLDC mode cannot be established if DLDC capable MS is having a EDA allocation
UL EDA TBF may be established only if DLDC-capable MS is not in DLDC mode
When an UL-favored concurrent TBF allocation leads to an UL EDA TBF allocation, an existing DLDC TBF needs to be reallocated as a SC TBF
No support of DLDC in Extended Area and Super Extended Area
DLDC is always disabled for E- and S-TRXs
No support of Flexi EDGE Dual TRX Automatic Power Down
if DLDC is used the territory is not moved to another TRX in order to be able to shut down TRXs
Possibility of activation cannot be guaranteed on PCU2-U/D, PCU2-E itself will not restrict the possibility of activation.
DL TBF operating in DLDC configuration can be either in RLC ack mode or in RLC unack mode
DLDC Enabled
object: BTS unit: - range: 0 (N) 1 (Y) step: 1 default: 0
This parameter determines the Downlink Dual Carrier feature status (enabled/disabled) in the BTS Note: Setting this parameter to its default value means that feature is disabled in the BTS. When enabling the DLDC, the following pre-requirements are checked by the system: DLDC license is in ON state and there is enough capacity EGPRS is enabled in the cell (egprsEnabled=1) BTS is served by PCU2 The following checking must be done by the operator: BTS has 2 normal area TRXs which are EGPRS enabled (gprsEnabledTrx=1) and belong to same EDAP and the same DSP Default GPRS Capacity (defaultgprsCapacity) is configured in such a way that the GPRS territory is split onto two TRXs; to fully exploit supported MS multislot capabilities, PS territory should comprise of at least 5 TSLs on each TRX. It is also recommended to enable the High Multislot Class feature. After enabling/disabling the DLDC the operator must trigger updating of the PCU (new MML command) in order to get the PCU DSP resources reallocated. O&M updates to RNW database the DLDC update info to value “update needed” in order to tell the user that PCU must be updated.
PCU up to date
object: BTS unit: - range: Update needed Update done step: - default: Update needed
DLDC update info for BTS object to tell operator whether DLDC information is updated to PCU or not after DLDC modification. Only system can modify this parameter. Note: This is not user adjustable attribute – it’s rather kind of system indicator whether the PCU update after DLDC feature activation should be done by the user or not.
PUTD
PCU up to date
object: PCU unit: - range: Update needed Update done step: - default: Update needed
DLDC update info for PCU object to tell operator whether DLDC information is updated to PCU or not after DLDC modification. Only system can modify this parameter. Note: This is not user adjustable attribute – it’s rather kind of system indicator whether the PCU update after DLDC feature activation should be done by the user or not.
DOP
object: BSC unit: - range: 0..80 step: 1 default: 0
With this parameter operator can change the behavior of the PCU selection algorithm in cases when DLDC is used and the pool contains both PCU2-E and PCU2-D/U type cards. Note: The higher value of this parameter the higher preference for PCU2-E (PCU2-E cards are allowed to get higher load than other PCU2 types).
DLDC OFFSET FOR PCU2-E – is taken into account in PCU load calculations. If the value for DLDC offset for PCU2-E selection(DOP) parameter is different than 0 (meaning that PCU2-E cards are then preferred for DLDC DAPs) it is allowed that PCU2-E cards gets higher load than other PCU2 types.
BTS: With this parameter system informs user whether or not DLDC information of the BTS is updated to PCU
PCU: With this parameter system informs user whether or not DLDC information of all BTSs using this PCU is updated to PCU
Operator gives the new PCU update command which causes following steps to be done by system:
Territories of the whole PCU are downgraded
EDAP table is updated
Territories of the whole PCU is upgraded so that DLDC enabled BTSs are handled first
DLDC update infos are updated to “update done” value
BTS DLDC TSL BALANCE THRESHOLD
PRFILE parameter object: BSC unit: % range: 0..100 step: 1 default: 100
This parameter determines the threshold for triggering an intra-BTS load reallocation for a DLDC-capable MS having single carrier DL TBF when DLDC resources are available within the BTS. Note: The DLDC intra-BTS reallocation may be triggered if three following conditions are met MS does not have a concurrent EDA UL TBF DLDC is activated in BTS average capacity of DL allocated TSLs ≤ average capacity of all BTS DL PS TSLs*BTS_DLDC_TSL_BALANCE_THRESHLD Rule: The lower the value of this attribute the more stringent condition for DLDC intra-BTS reallocation. Setting this parameter to e.g. 50% means that DLDC intra-BTS reallocation will be triggered if the average capacity of DL allocated TSLs is twice lower than average free capacity of all DL PDCHs in BTS.
REQ 9 TSL DL
This counter provides the number of requests for 9-TSL DL TBF allocation or reallocation Trigger event: request for 9 TSLs for DL TBF (re)allocation. Use case: calculations of the 9-TSL Allocations Requests Ratio (REQ 9 TSL DL/REQ x TSL DL; x=1-12)
REQ 10 TSL DL
REQ 11 TSL DL
This counter provides the number of requests for 11-TSL DL TBF allocation or reallocation Trigger event: request for 11 TSLs for DL TBF (re)allocation. Use case: calculations of the 11-TSL Allocations Requests Ratio (REQ11 TSL DL/REQ x TSL DL; x=1-12)
REQ 12 TSL DL
These counters are updated regardless of the status of DLDC feature. Counters for 1-8 TSL DL TBF allocations/reallocations have been introduced in previous BSS releases
Updated When nine TSLs are requested for a TBF in DL (re)allocation. The number of requested TSLs is determined based on MS multislot class.
ALLOC 9 TSL DL
This counter provides the number of 9-TSL DL TBF allocations or reallocations Trigger event: 9 TSLs for DL TBF has been (re)allocated. Use case: calculations of the 9-TSL Allocations Ratio (ALLOC 9 TSL DL/ALLOC x TSL DL; x=1-12) REMARK: counters for 1-8 TSL DL TBF allocations/reallocations have been introduced in previous BSS releases
ALLOC 10 TSL DL
This counter provides the number of 10-TSL DL TBF allocations or reallocations Trigger event: 10 TSLs for DL TBF has been (re)allocated. Use case: calculations of the 10-TSL Allocations Ratio (ALLOC 10 TSL DL/ALLOC x TSL DL; x=1-12) REMARK: counters for 1-8 TSL DL TBF allocations/reallocations have been introduced in previous BSS releases
DL TSL REQUEST FOR DLDC CAPABLE MS
This counter provides the number of TSL allocation requests (initial or reallocation) for DLDC Trigger event: updated regardless of DLDC feature activation status upon receiving of the DL TBF allocation request from DLDC capable MS Use case: calculations of the Potential DLDC Users Ratio (DL TSL REQUESTS FOR DLDC CAPABLE MS / REQ x TSL DL (x=1..12)) Note: This KPI may be monitored before DLDC feature activation
Updated When nine TSLs are requested for a TBF in DL (re)allocation
DLDC TSL REQUEST IN DLDC ENABLED CELL
This counter provides the number of TSL allocation requests (initial or reallocation) for DLDC. Trigger event: Incremented by one when allocation is requested by DLDC capable MS in a cell where DLDC enabled BTS is available. Use case: calculations of the DLDC TBF Allocation Success Ratio
DLDC TSL ALLOCATION CREATED
This counter provides the number of created DLDC TSL allocations Trigger event: TSL allocation contains TSLs from two TRXs. Amount of allocated TSLs may be equal or lower than amount of requested TSLs. Use case: calculations of DLDC Allocation Success Ratio (DLDC TSL ALLOCATION CREATED / DLDC TSL REQUEST IN DLDC ENABLED CELL)
DLDC ATTEMPT FAILED DUE TERRITORY
This counter provides the number of failed DLDC allocation requests due to lacking DLDC territory in DLDC enabled BTS Trigger event: two TRXs of the DLDC BTS are not in one EDAP or not handled by the same DSP in PCU or there are no free resources in PS territory, and as a result a single carrier allocation is performed. Use case: calculations of the Ratio of DLDC Allocation Failures due to No Territory (DLDC ATTEMPT FAILED DUE TERRITORY/ DLDC TSL REQUEST IN DLDC ENABLED CELL)
Updated When nine TSLs are requested for a TBF in DL (re)allocation
VOLUME WEIGHTED LLC THROUGHPUT FOR DLDC NUMERATOR
This counter provides the numerator for Volume Weighted (VW) LLC throughput for DLDC capable MSs with at least 4-TSL DL allocations. The unit of the counter is 100 bytes2/10 ms. Trigger event: this counter contains the sum of the throughputs weighted by the volume of each LLC transmission burst within the TBF. An LLC transmission burst is a transmission period between two transmission breaks. Updated at the TBF release or reception of FLUSH-LL, if the size of the TBF was 1560 bytes or more. Use case: calculations of the Average Volume Weighted LLC Throughput for DLDC (VOLUME WEIGHTED LLC THROUGHPUT FOR DLDC NUMERATOR/ VOLUME WEIGHTED LLC THROUGHPUT FOR DLDC DENOMINATOR)
VOLUME WEIGHTED LLC THROUGHPUT FOR DLDC DENOMINATOR
This counter provides the denominator for Volume Weighted (VW) LLC throughput for DLDC capable MSs with at least 4-TSL DL allocations. Trigger event: this counter contains all the bytes transmitted within the TBFs. Updated at the TBF release or reception of FLUSH-LL, if the size of the TBF was 1560 bytes or more Use case: calculations of the Average Volume Weighted LLC Throughput for DLDC (VOLUME WEIGHTED LLC THROUGHPUT FOR DLDC NUMERATOR/ VOLUME WEIGHTED LLC THROUGHPUT FOR DLDC DENOMINATOR)
Transmission burst – continuous data flow - the transmission period between two transmission breaks
Dimensioning
The DLDC dimensioning (planning) activities on top of (E)GPRS are listed below:
Operators’ business plan investigation
Good understanding of current and future business plans (traffic figures with service types) for creating the most suitable BSS plan with DLDC or supports the operator to investigate the possible business scenarios for PSW and DLDC services.
Operators’ BSS network structure audit
Current and future CS and PS BSS network structure investigation of the hardware usage, software usage and capacity figures / limits.
Deployment plan preparation
The proper (E)GPRS BSS deployment plan is needed to find the way how the highest (E)GPRS – DLDC data rate with as less quality decrease as possible on CSW traffic can be achieved.
Capacity calculations based on deployment plan
Available / required air interface capacity and network element connectivity calculations
Parameter setting
IP/MPLS/IPoATM
IP v.s. FR
SGSN
RLC/MAC TSL data rate
The aim behind the preparation of deployment plan:
Maximize the TSL data rate (RLC/MAC), multislot usage and dual carrier usage
Minimize the impact of PSW services on CSW services (and vice versa)
Take all the hardware and software considerations into account
Controlled investment
Cell / segment option creation
The options can cover most of the cell/segment configurations of the network
These options can be analyzed in details, so the time consuming cell/segment based analysis is not needed
All the options are examples and can have different channel configuration
Detailed analysis is based on layer, signaling, CS and PS traffic point of view
S13 -> S14 conversions are required.
A valid DLDC license is required. Also PCU2 license and EGPRS license are needed.
GPRS and EGPRS are enabled in segment and DLDC is enabled in BTS.
BTS has 2 normal area TRXs which are EGPRS enabled and they belongs to same DAP
The first GPRS territory TRX must be selected from such an EDAP that contains at least two GPRS TRXs.
When selecting the next GPRS territory TRX to be upgraded, TRX from same EDAP is selected, if possible.
Value of parameter Prefer BCCH frequency GPRS (BFG) is taken into account also in DLDC enabled BTS even if it would mean that EDAP selection is not optimal from DLDC point of view.
BTS parameter CDEF has that kind of value that the PS territory is split onto two TRXs
S
a
a
a
a
a
d
d
d
d
S
S
d
d
d
d
d
D
B
B = BCCH
S = SDCCH
Layer planning, signaling, CS and PS traffic
PCU type
In PCU2-D/U, the DLDC territory on the BCCH TRX gives higher connectivity capacity than one in non-BCCH TRX: the DSP channels are used more efficiently better user throughput in BCCH TRX
In PCU2-E, however, the non-BCCH TRX gives higher connectivity capacity (full usage of 16 RTSL) better site throughput in non-BCCH TRX
Recommended and minimum CDEF values for DLDC cells as number of RTSL
PCU2-E dimensioning – 90% table
PCU2-E Abis channel 90% utilization leaves 102 channels available for dynamic allocation (territory upgrades)
This is sufficient for most cases especially for large EGPRS site configurations
The table indicates the maximum number of DAPs (~(E)GPRS sites) or DAP groups per PCU2-E as a function of DAP [TSL] and CDEF sum [RTSL]

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4 Downlink Dual Carrier