Technical Support Note
TS-BSC-SW-0879-I2.0
Dynamic Abis
Configuration in PCU2-E
Radio Controllers
BSC S14
This document contains following
type of information
Informative
X
Corrective
Urgent
Security
Information is classified as
Internal
Public
X
Customer Specific
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Table of Contents
Validity............................................................................................................................................3
Compatibility / Dependencies to other products.............................................................................3
Keywords........................................................................................................................................3
Summary ........................................................................................................................................3
Detailed description........................................................................................................................3
5.1
PSW territory upgrade loops .............................................................3
5.2
PCUPCM resource allocation............................................................4
5.3
PCU2-E DSP resource allocation......................................................8
6. Solution / Instructions ...................................................................................................................12
6.1
Dimensioning resources of single PCU2-E .....................................12
6.2
Configurations which should be avoided.........................................15
6.3
Dynamic Abis pool in Abis ETPCM .................................................15
6.4
GPRS territory update guard time (GTUGT) ...................................16
7. Note..............................................................................................................................................16
8. References ...................................................................................................................................16
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Contact:
Contact your local Nokia Siemens Networks support
Summary of changes:
None
29-06-2009
06-10-2009
© Nokia Siemens Networks
1.0
2.0
First Version
Added clarification on BTS type specific EDAP
size limits
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Purpose
This document contains generic information about products. These can be instructions that
explain problem situations in the field, instructions on how to prevent or how to recover
from problem situations, announcements about changes or preliminary information as
requirements for new features or releases.
1. VALIDITY
Product
BSCi
BSC2i
BSC3i
Flexi BSC
TCSM2A/E
TCSM3i
S14
X
X
Only upgraded Flexi BSC model
2. COMPATIBILITY / DEPENDENCIES TO OTHER PRODUCTS
None.
3. KEYWORDS
Dynamic Abis, PCU2-E
4. SUMMARY
There are several limitations that should be considered when EDAPs are created to
PCU2-E and when EGPRS and GPRS channels are configured to PCU2-E. If the
limitations are surpassed the load of the BSC increases because of failed territory upgrade
trials and, it is possible that some default (E)GPRS channels can not be taken into use.
This Technical Note clarifies issues related to Dynamic Abis configuration when
PCU2-E PIU type is in use.
5. DETAILED DESCRIPTION
5.1 PSW territory upgrade loops
In PSW territory upgrade procedure BSC connects radio timeslots to EGPRS or GPRS
use. During this procedure the BSC allocates PCUPCM transmission resources and the
PCU2-E software allocates DSP channel resources from PCU2-E. If there are not
applicable PCUPCM or DSP resources available for all new radio timeslots, then PCU2-E
upgrades those radio timeslots, for which the applicable resources can be found (partial
territory upgrade) and upgrade procedure fails for the other radio timeslots. When the
territory upgrade procedure fails for default or dedicated channels, the PCU2-E keeps a
record of failed radio timeslots so that it can inform BSC, when the applicable resources
for failed radio timeslots are available. When the suitable resources are released from
PCU2-E by territory downgrade and there is still need for upgrading these failed radio
timeslots, the BSC can immediately start a new upgrade for those radio timeslots. In case
of additional channels the PCU2-E does not keep a record of failed radio timeslots, but the
BSC makes a new territory upgrade trial after a guard time (guard time is 60 seconds or
GTUGT, if GTUGT is longer than 60 s). If any resources have not been released between
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these two territory upgrade trials then also the next territory upgrade trial fails. These
consecutive territory upgrades increase the load of the BSC.
5.2 PCUPCM resource allocation
Every PCU2-E has 8 internal PCUPCMs available to Abis interface direction (to BTS
direction), see figure 1 below. There are 1024 PCUPCM channels (16 kbit/s) available in
these PCUPCMs for one PCU2-E. One PCUCPM line is divided to 32 PCUPCM timeslots
(PCUPCM TSL) and one PCUPCM TSL contains four PCUPCM channels (PCUPCM
subTSL). The numbering of the PCUPCM TSLs and subTSLs is started from zero, e.g.
first PCUPCM channel is in PCUPCM TSL0 and subTSL0. Transmission for EDAPs,
EGPRS channels and, GPRS channels are allocated from these PCUPCMs. However,
internal system limitations can cause lack of applicable resources before the 1024-channel
limit. These limitations should be considered when configuring EDAP, EGPRS and GPRS
channels to PCU2-E.
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PCUPCM Channels(16 Kbits/sec)
PCUPCM Channels(64 Kbits/sec)
Figure 1 PCU2-E has 8 internal PCUPCMs.
Connecting EDAP area to PCUPCM
When DAP (Dynamic Abis Pool) is connected to PCUPCM, it is called EDAP (EGPRS
Dynamic Abis Pool).
BSC connects EDAPs to PCU2-E starting from the end of the 8th PCUPCM. If there is not
enough room for all EDAPs in the 8th PCUPCM then the BSC continues connection from
the end of the 7th PCUPCM and so on. The whole EDAP has to be connected to one
PCUPCM. EDAP cannot be divided between 8 PCUPCMs.
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Connecting EDAP area to PCUPCM since from S12 onwards the PCU2-E can allocate
EDAP to the different place in PCUPCM than the BSC has requested. This functionally
should decrease PCUPCM fragmentation in EDAP area and thus there should be less
failed EDAP configuration modifications, which is caused by lack of free consecutive
PCUPCM TSLs.
Note: When changes are made to the EDAP configuration of PCU, it is recommended to
make BCSU switchover for the BCSU that controls the PCU. This optimizes PCUPCM
channel allocation for the PCU.
Figure 2 Example of EDAP connections
Ultrasite and Metrosite BTS SW limits maximum size of EDAP to 12 timeslots. For Flexi
BTS the limitation is 29 timeslots (22 timeslots, if T1 is in use). However, BSC limitation
for EDAP is always 24 timeslots.
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Maximum amount of EDAPs connected to PCU2-E is 60 because there are six DSP cores
in one PCU2-E and one DSP core can handle 10 EDAPs.
Every EDAP timeslot connected to PCUPCM reserves 64 kbit/s transmission from the
PCUPCM and reduces 4 PCUPCM channels (16 kbit/s) from the PCU2-E’s total capacity
that is 1024 PCUPCM channels.
Maximum amount of EDAP timeslots connected to one PCU2-E is 204 because then
PCU2-E needs 52 timeslots for 208 EGPRS, extended GPRS/EDGE cell or CS3&CS4
master channels that are able to use the EDAP timeslots.
Note: When a new DAP is created to PCU2-E, BSC connects the EDAP area to the
PCUPCM. The EDAP reserves PCUPCM resources even there does not exist any TRX
attached to it. (Check also Initial DSP allocation)
PCUPCM hunting order
There are two limitations which are considered when the PCUPCM channel is selected; 1)
the whole 64kbit/s timeslot must be handled by one DSP core and 2) the PCUPCM
channel selected for GPRS/EGPRS channel cannot overlap with EDAP area. The first
limitation presents that PCU selects the DSP before the PCUPCM channel for a radio
timeslot (see chapter PCU2-E DSP resource allocation) and the second limits how many
PCUPCM channels can be connected for the master channels.
The PCU2-E starts hunting the PCUPCM channel for a new radio timeslot (GPRS and
EGPRS) from the beginning of the first PCUPCM. When the DSP is selected for a new
radio timeslot, the PCU2-E searches from the beginning of the first PCUPCM whether
there are a 64kbit/s timeslot reserved for the selected DSP. If there is the reserved timeslot
for selected DSP and there is a free 16kbit/s subTSL, then it is preferred. Otherwise, the
new 64kbit/s timeslot is reserved for the selected DSP and the PCUPCM channel is
selected from that PCUPCM timeslot. This is continued until the first PCUPCM is full and
then the PCUPCM hunting is continued to 8th PCUPCM until it gets the 64kbits/s timeslot.
See figure 3 for a sample PCUPCM(only 1st two PCUPCM are being shown) channel
allocation.
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Figure 3 Example of PCUPCM channel allocation.
5.3 PCU2-E DSP resource allocation
There are six DSP cores available in PCU2-E. Each of these DSP cores can handle up to
212 channels (16 kbit/s) including active EGPRS slave channels, EGPRS channels and
GPRS channels. Although one DSP core can handle up to 212 channels, the maximum
amount of master channels (EGPRS and GPRS) that can be connected to one DPS core
is 172 and the rest 40 DSP channels in the DSP are reserved for slave usage. Total
amount of 16 kbit/s channels in one PCU2-E is 1024 because of available PCUPCM
transmission of PCU2-E. There can appear lack of applicable DSP resources before the
1024 -channel limitation because of internal system limitations. These limitations should be
considered when EDAP, EGPRS, and GPRS channels are configured to PCU2-E.
DSP allocation for TRX
In PCU2-E the radio timeslots of one TRX cannot be shared between DSPs This means
that when the first timeslot(s) of the TRX is/are upgraded to the packet switched territory,
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the DSP is selected for the TRX and after that all new radio timeslots, which are upgraded
from that TRX, are allocated to the same DSP.
When the DSP is selected for TRX, the DSPs having less than 21 TRX attached are
preferred. This reduces upgrade failures in configurations, where packet switched
territories do not fit in one TRX. DSP allocation for GPRS and EGPRS channels are more
precisely introduced in following chapters.
Initial DSP allocation
PCU2-E software allocates DSPs for EDAPs when a new dynamic Abis pool is created or
an existing pool is deleted or modified. DSPs are also allocated after BCSU restart or
BCSU switchover. In all cases mentioned above, the DSP allocation for EDAPs is similar
and the allocation algorithm is shortly described below in Solution / Instruction chapter.
EDAP specific DSP resources
Each EDAP needs EDAP specific DSP resources from the PCU2-E. One DSP can take
care of 10 EDAPs.
The amount of active 16 kbits/s channels in a single DSP varies during operation. The
meaning of active channel in this concept is that the DSP channel is connected to the
GPRS or EGPRS channel or there is EGPRS slave traffic at the time. Each EGPRS and
GPRS channel allocates one 16 kbit/s channel from the DSP. Rest of the DSP resources
can be allocated for EGPRS slave channels using the EDAP resources. PCU2-E software
allocates resources for these EGPRS slave channels dynamically according to EGPRS,
extended GPRS cell and CS3&4 traffic situations.
PCU2-E software allocates dynamically resources from the EDAP and from the DSP for
the EGPRS slave channels. There is not fixed allocation between EDAP resources, DSP
resources and EGPRS slave channels in PCU2-E.
It should be noticed that EGPRS master channels (including also GPRS CS3&4 and
extended GPRS/EDGE master channels) and their slave must be allocated from the same
DSP
Since EGPRS master channels and their slave channels are allocated from the same
DSP, the DSP might become full from active channels (i.e. sum of the GPRS channels,
EGPRS channels and active EGPRS slave channels connected to the DSP) although
there is only a part of DSP’s master channel connectivity in use (less than 172 master
channels connected to DSP). If DSP selection in territory upgrade is aimed to this kind of
full DSP, the PCU2-E reduces slave channels so that territory upgrade can be successfully
performed. The amount of reduced slave channels is proportional to amount of the new
radio timeslots that is requested in territory upgrade.
Note: Slave reduction reduces territory upgrade failures, which are caused by lack of free
DSP channels in PCU (counters 001220 GPRS TER UG FROM CSW PARTIAL and
001221 GPRS TER UG FROM CSW FAILED). However, it might also cause more EDAP
congestion, which can be seen from statistics (counters 76020
DL_MCS_LIMITED_BY_PCU and 76019 UL_MCS_LIMITED_BY_PCU).
EGPRS synchronization master channels
PCU2-E requires that every EDAP must have one EGPRS channel, one extended GPRS
cell channel or one CS3&CS4 channel used as a synchronization master channel for all
EGPRS/extended GPRS cell/CS3&CS4 channels of the EDGE-TRXs that are connected
to the same EDAP and same DSP. The EGPRS channel situating in greatest available
radio timeslot (RTSL7) of the first EDGE-TRX of the DSP handling the EDAP is usually
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used as a synchronization master channel. Dedicated EGPRS channels are preferred over
default channels in the selection of synchronization master channel. If necessary, default
EGPRS channels are preferred over additional channels. PCU2-E can reallocate
synchronization master channel dynamically if needed e.g. when synchronization master
channel becomes faulty.
EGPRS channels
EGPRS channels of EDGE capable TRX(s) have to be allocated from the DSP(s) that
is/are serving the EDAP. It should be noticed that the radio timeslots of one TRX cannot
be shared between DSPs. There can be maximum 172 EGPRS master channels in a
single DSP.
When selecting the DSP for a new EGPRS TRX (concept new TRX means that there are
no previous radio timelslots in PS territory), the following rules are applied in order
1. The DSP having less than 21 TRX attached.
2. The reduction of the EDAP handling capacity of the DSP is minimized. The DSP can
be selected in this phase if the following equation is satisfied
DSPchs − nch ( EGPRS ) − nch (GPRS ) ≥ 4 * MIN {EDAP size, nch ( EGPRS )}
where,
• DSPchs is the amount of channels in single DSP core (212 channels).
• nch(EGPRS) is number of EGPRS channels connected to the DSP. This number
contains also the new radio timeslots
• nch(GPRS) is number of GPRS channels connected to the DSP.
3. The DSP already serving the EGPRS-TRX attached to the same EDAP. All EGPRS
channels using the same EDAP pool are pack to the same DSP.
4. DSP having least GPRS channels connected.
Note: Since DSPs are allocated for EDAPs only in startup or when EDAP configuration is
modified, the PCU2-E software may face an EDAP load situation where upgrade of
EGPRS channels would exceed DSP resources available for the given EDAP. In this case
PCU2-E rejects the territory upgrade request (or performs partial territory upgrade). This
kind of temporary limitation is likely to happen with an upgrade of additional EGPRS
channels and under heavy EGPRS traffic.
GPRS channels
When CS3&4 or extended GPRS cell feature is not activated in cell, the DSP selection for
GPRS channels is depending on whether there are EDAPs configured in PCU or not. If
there are EDAPs created in PCU, the GPRS channels are distributed to EDAPs, so that
one EDAP does not suffer more than the others. If there are not any EDAPs created, then
the GPRS channels under the same segment are tried to pack in to same DSP. Otherwise,
if there are no other TRX upgraded from the same segment, the GPRS channels are tried
to distribute evenly to DSPs. It should be noticed that the radio timeslots of one TRX
cannot be shared between DSPs.
When selecting the DSP for a new GPRS TRX the following rules are applied in order
Case 1: Mixed GPRS/EGPRS configuration in PCU (at least one EDAP created in
PCU)
1. The DSP having less than 21 TRXs attached.
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2. GPRS channels are distributed to EDAPs, so that one EDAP does not suffer more than
the others. The distribution to EDAPs means that at first, the PCU2-E searches the EDAP
that is having least GPRS channels connected to it's DSPs (the sum of the GPRS
channels calculated over the DSPs of the EDAP). When the EDAP having least GPRS
channels in its DSPs is found, the DSP selection is done from these DSPs. From these
DSPs, the DSP having least EGPRS channels and most GPRS channels connected is
selected.
Case 2: Pure GPRS configuration in PCU (no EDAPs created in PCU)
1. The DSP having less than 21 TRX attached.
2. DSP having already some GPRS channels connected under the same segment
3. DSP having most free DSP channels available
When CS3&4 or extended GPRS cell feature is activated, the GPRS channels belonging
to the CS3&4 or extended GPRS cell territory are allocated as EGPRS channels, because
they use EDAP resources.
DSP allocation examples
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Figure 5. Example of DSP channel allocation where 4 (16 kbit/s) channels are allocated for
EGPRS master channels and 2 (16 kbit/s) channels are allocated for GPRS channels.
Remaining 206 channels can be used for EGPRS slave channels according to traffic. In
the picture there are 8 active EGPRS slave channels.
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Figure 6. Example of DSP channel allocation where 8 (16 kbit/s) channels are allocated for
EGPRS master channels and, 8 (16 kbit/s) channels are allocated for GPRS channels.
Remaining 196 channels can be used for EGPRS slave channels.
6. SOLUTION / INSTRUCTIONS
6.1 Dimensioning resources of single PCU2-E
This chapter gives a short introduction to the dimensioning of single PCU2-E.
EDAP resources
It should be estimated amount of GPRS channels that will not use the EDAP, amount of
EGPRS channels that will use the EDAP and the service level of these EGPRS channels,
when size of EDAP is configured.
1. Ultrasite and Metrosite BTS SW limits maximum size of EDAP to 12 timeslots.
For Flexi BTS the limitation is 29 timeslots (22 timeslots, if T1 is in use).
However, BSC limitation for EDAP is always 24 timeslots.
2. It is not recommended to configure more timeslots to EDAP than there are
EGPRS channels that use the EDAP. Note that in this case the amount of EGPRS
channels contains also the channels of the additional territories (default
channels + additional channels)
Since one DSP core in PCU2-E can handle 10 EDAPs, the amount of logical DSPs
needed for each EDAP is needed to know. This concept “logical DSP needed for EDAP”
means that how many halves of DSPs are needed to satisfy the DSP resource need of
single EDAP. The amount of logical DSPs needed for each EDAP can be calculated with
the next formula:
LogicalDSPneedForEDAP = (4*EDAP Size + EGPRS Channels)/21
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where
• EDAPsize is EDAP size presented in 64 kbit/s timeslots
• EGPRSchannels is amount of default and Dedicated EGPRS channels using the
EDAP
• 21 is the logical channel count per EDAP per DSP (one DSP has 212 channels
and one DSP can handle up to 10 EDAPs)
Note: There are no fixed allocations for EDAPs in one DSP core but the DSP resources
for the EGPRS master channels are given in order those are requested and slave channel
allocation is done according to traffic priorities.
The logical DSP core count is rounded up to nearest integer.
If the sum of the logical DSP core counts for all EDAPs in PCU2-E exceeds the available
logical DSP core count (60, then PCU2-E automatically reduces amount of DSP core
counts among EDAPs with more than 1 ideal DSP core. The algorithm uses the average
16 kbit/s channel load of single DSP as a basis for the reduction. The reduction is made
during initial DSP allocation.
3. When dimensioning EDAPs for a single PCU2-E, the using of PCUPCM
resources should be planned so that the automatic reduction algorithm is not
used in the PCU2-E. The sum of logical DSP cores used for EDAPs in PCU2-E
should not overstep 60 logical DSP cores.
4. When dimensioning EDAPs for a single PCU2-E, the using of PCUPCM
resources should be planned so that ideal DSP core counts for EDAPs can be
shared between the two DSP core groups both having 6 DSP cores without need
to reduce DSP core count from any EDAP.
There is 1024 PCUPCM channels (16kbit/s) transmission capacity available for a single
PCU2-E. So it is not possible to allocate 212 PCUPCM channels transmission capacity for
every DSP in PCU2-E.
When dimensioning PCUPCM resources for EDAP and EGPRS channels, PCUPCM
resources should be handled as PCUPCM timeslots (64 kbits/s). There are 256 PCUPCM
timeslots transmission capacity available for a single PCU2-E. These 256 PCUPCM
timeslots are shared between 6 DSPs of PCU2-E. One DSP can handle maximum 53
PCUPCM timeslots (43 PCUPCM timeslots for master channels +´10 PCUPCM timeslots
for slave channels) and minimum 0 PCUPCM timeslots.
5. The maximum total amount of EDAP timeslots connected to one PCU2-E is 204
PCUPCM timeslots.
Traffic channels
Each EDAP timeslot (64 kbit/s) reduces one PCUPCM timeslot from the total 256
PCUPCM timeslots capacity of the PCU2-E. The PCUPCM timeslots that can be used for
traffic channels in PCU2-E is counted with the next formula:
where
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•
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FreePCUPCMtimeslotsForTrafficChannels is the amount of free PCUPCM timeslot
that can be used for EGPRS channels and GPRS channels.
SizeOfEDAP is size of one EDAP connected to PCU2-E.
EGPRS channels
Each EGPRS channel needs one PCUPCM channel (16 kbits/s) from PCU2-E and one
channel from DSP. There is also a limitation that one 64 kbit/s timeslot in PCUPCM must
be handled by one DSP core. Because one DSP core has 212 channels and 40 channels
are reserved for slave usage from the DSPs that are serving some EDAP, it also means
that EDAP serving DSP core can handle only 43 64 kbit/s timeslots.
As we have estimated the amount of the EGPRS channels and we have calculated the
amount of the DSPs serving the EDAPs (LogicalDSPneedForEDAP), we can check does
one PCU2-E have enough resources to handle estimated amount of the EGPRS channels
with the following formulas.
First, the amount of needed PCUPCM timeslot (64kbit/s) for EGPRS is calculated with
next formula.
NeededPCUP CMtimeslot sForEDAPx =
EGPRSchann elsDAP
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where
• NeededPCUPCMtimeslotsForEDAPx is amount of PCUPCM timeslot needed by a
single DAP.
• EGPRSchannelsDAP is the size of EGPRS territory that is using the DAP (default
+ Dedicated EGPRS channels)
The result is rounded upwards.
Then the next formula can be used for checking if the DSPs serving the EDAP have
enough resources to handle all needed PCUPCM timeslots:
NeededPCUPCMtimeslotsForEDAPx ≤ 4 * LogicalDSPneedForEDAPx
where
• NeededPCUPCMtimeslotsForEDAPx is amount of PCUPCM timeslot needed by a
single DAP.
• LogicalDPSneedForEDAPx is amount of logical DSPs serving the EDAPx
If the previous clause is true, then we can proceed to next step. If the result is false, then
the EGPRS territories under the examined EDAP should be re-dimensioned i.e. territory
sizes should be decreased or some territories should be moved to another PCU.
Total amount of PCUPCM timeslots needed by EGPRS channels can be calculated with
the next formula:
where
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•
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NeededPCUPCMtimeslotsForEGPRSinPCU is total amount of PCUPCM timeslots
needed by the EGPRS territories in PCU2-E
NeededPCUPCMtimeslotsForEDAPx is amount of PCUPCM timeslot needed by a
single DAP.
Final step is to check that the amount free PCUPCM timeslot for traffic channels is equal
or greater than the needed PCUPCM timeslots for EGPRS. If the amount is less then the
re-dimensioning is needed.
6. When dimensioning EGPRS territories, the sum of EDAP timeslots and PCUPCM
timeslots needed for EGPRS in PCU2-E is not allowed to overstep 256 PCUPCM
timeslots.
GPRS channels
Maximum amount of PCUPCM channels (16 kbit/s) that can be used for GPRS channels
can be calculated with the next formula:
MaxAmountGPRSchannlesInPCU =
4 * ( FreePCUPCMtimeslotsF orTrafficC hannels − NeededPCUPCMtimeslot sForEGPRSi nPCU )
where
• MaxAmountGPRSchannelsInPCU is the maximum amount of default GPRS
channels configured to PCU2-E (+ PBCCH/PCCCH channels in TRXs not
attached to DAP).
• FreePCUPCMtimeslotsForTrafficChannels is the amount of free PCUPCM timeslot
that can be used for EGPRS channels and GPRS channels
• NeededPCUPCMtimeslotsForEGPRSinPCU is total amount of PCUPCM timeslots
needed by the EGPRS territories in PCU2-E
If some resources for dynamic expansion of the PSW territories are taken into account, the
formula is written
MaxAmountGPRSchannlesInPCU =
4 * ( FreePCUPCMtimeslotsF orTrafficC hannels − NeededPCUPCMtimeslot sForEGPRSi nPCU )
* Utilizatio nT arg et
where
• UtilizationTarget is the utilization factor (less than 1) of the PCUPCMs when the
Dedicated and Default channels are upgraded.
6.2 Configurations which should be avoided
Dummy EDAPs
It is not recommended to configure any dummy EDAPs (EDAPs, which have not anyTRXs
attached) to the PCU2-E. These dummy EDAPs cause unbalanced DSP allocation and
reduce PCUs performance.
6.3 Dynamic Abis pool in Abis ETPCM
Several Abis ETPCM connected to same BTS
It is possible to use several ETPCMs for Abis transmission in some BTS types. When
several Abis ETPCMs are used, it is possible to increase EDAP capacity of the BTS by
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creating own DAPs to each Abis ETPCM. In this case only the TRXs situating in the same
Abis ETPCM with the DAP can use the EDAP resources.
Note: EGPRS territory handling procedures do not share load equally between the
EDAPs.
Changing Dynamic Abis pool size in BSC and in BTS
The user has to be aware of Abis ETPCM mappings in BTS when he/she makes changes
to DAP configuration in BSC. It may be harmful if area reserved for the dynamic Abis pool
in BTS is overstepped in BSC.
The user has to be aware of DAP configuration in BSC when he/she makes changes to
Abis ETPCM mappings in BTS. Every time Abis ETPCM mappings are changed in BTS
these changes has to be take account also in BSC.
WARNING:
One EDAP resource cannot be shared between several BCF cabinets. It may
damage the TRX or DTRU HW if EDAP is tried to share between several cabinets.
6.4 GPRS territory update guard time (GTUGT)
The BSS Radio Network Parameter GPRS territory update guard time defines a guard
time between subsequent GPRS territory upgrade/downgrade procedures. This parameter
can be set to higher value if there appear load problems because of PSW territory
handling procedures. It is not recommended to set this parameter to lower value than the
default value.
7. NOTE
Information in this TN is valid for PCU2-E from S14 onwards.
TN version
1.0
Valid from
S14 CD
Valid to
8. REFERENCES
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