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SDCCH_Dimensioning

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									                SDCCH DIMENSIONING GUIDELINE

                  THE ERICSSON GSM SYSTEM R7




© Ericsson Radio Systems AB 1998


The contents of this product are subject to revision without notice due to
continued progress in methodology, design and manufacturing.
Ericsson assumes no legal responsibility for any error or damage
resulting from usage of this product.
This product is classified as Ericsson Wide Internal.




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                                 Contents

                                 1 Revision history................................................................ 5
                                 2 Introduction....................................................................... 5
                                 3 Events that require an SDCCH ........................................ 6
                                 3.1 Normal Location Updating.................................................................. 6
                                 3.2 IMSI attach/detach............................................................................. 6
                                 3.3 Periodic Registration.......................................................................... 7
                                 3.4 Call set-up ......................................................................................... 7
                                 3.5 Short Message Service point to point (SMS p-p)................................ 7
                                 3.6 Facsimile group 3 set-up.................................................................... 8
                                 3.7 False Accesses.................................................................................. 8
                                 4 Possible configurations and limitations ........................ 8
                                 4.1 SDCCH configurations....................................................................... 8
                                 4.2 SDCCH limitations............................................................................10
                                 5 Automatic SDCCH dimensioning .................................. 10
                                 5.1 Basic SDCCH configuration ..............................................................10
                                 6 Manual SDCCH dimensioning ....................................... 11
                                 6.1 SDCCH Grade of Service .................................................................11
                                 6.2 SDCCH Grade of Service with Immediate Assignment on TCH ........12
                                 6.3 SDCCH / TCH ratio...........................................................................14
                                 6.4 Half rate............................................................................................15
                                 6.5 Extended range ................................................................................17
                                 6.6 High Speed Circuit Switched Data ....................................................17
                                 6.7 SDCCH traffic estimations ................................................................17
                                 6.8 Recommended configurations...........................................................21
                                 7 Dimensioning based on STS-data ................................ 22
                                 7.1 Cells with no congestion ...................................................................22
                                 7.2 Cells with congestion ........................................................................22
                                 8 Summary ......................................................................... 23
                                 9 Parameters...................................................................... 23
                                 9.1 BSC parameters ...............................................................................23
                                 9.2 MSC parameters...............................................................................25
                                 10 References ...................................................................... 26




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            1                Revision history

                             Revision       Date             Description
                             A              1998-12-11       Created. Based on SDCCH Dimensioning
                                                             Guideline for R 6.1.
                                                             Event times have been updated.
                                                             Adaptive Configuration of Logical Channels
                                                             feature included.
                                                             Dimensioning for Half Rate included.
                                                             Dimensioning for extended range cells
                                                             included.
                                                             Dimensioning for HSCSD included.
                                                             SDCCH load calculations updated.
                                                             Summary included.
                                                             Recommended configurations updated.
                                                             New dimensioning tables for half rate.




            2                Introduction
                             On the Standalone Dedicated Control Channel (SDCCH), different signalling
                             and transmission activities take place. This document describes how to select a
                             suitable SDCCH configuration for both full rate and half rate traffic. The
                             different events that require an SDCCH are briefly described. The SDCCH
                             holding times for each event are also included. When having estimated the
                             SDCCH load, there are tables on how to choose a suitable SDCCH
                             configuration.
                             In the Ericsson GSM System R7, it is possible to let the system automatically
                             dimension/re-dimension the SDCCH configuration depending on the SDCCH
                             load. This is done with the feature Adaptive Configuration of Logical Channels.
                             By using this optional feature, the cumbersome task of manual dimensioning
                             will be avoided. The reader could then focus on section 5 and regard the rest of
                             this document as background information.
                             The SDCCH traffic estimations in this document are based on the ERA5 traffic
                             model used by Ericsson, see ref. 6. The need of SDCCHs can vary substantially
                             between networks due to e.g. subscriber behaviour, half rate mobiles and
                             parameter settings. The best way to use these estimations is to understand the




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                   calculations involved in the dimensioning of the SDCCH and re-make them for
                   the particular network with its unique input parameters.
                   An optimum manual SDCCH configuration, for every cell, can only be
                   achieved by looking at cell statistics, i.e. Statistics and Traffic measurement
                   Subsystem (STS) counters. Therefore, this document also describes how to
                   select an SDCCH configuration based on STS data. An SDCCH dimensioning
                   based on STS data follows the same principles as SDCCH dimensioning based
                   on traffic estimations.




        3          Events that require an SDCCH
                   The following procedures have an effect on the SDCCH load:

                   • Mobility Management procedures, i.e. Normal Location Updating, Periodic
                     Registration and IMSI attach/detach.

                   • Connection Management, i.e. Call set-up, Short Message Service point to
                     point (SMS p-p), Fax set-up and Supplementary Services.
                   The values for the Holding time of the SDCCH originates from time
                   measurements performed by Ericsson, although some assumptions have been
                   made.



        3.1        Normal Location Updating
                   Every time a Mobile Station (MS) passes an LA border, a Normal Location
                   Updating is performed. The approximate time that an SDCCH is occupied
                   during a Normal Location Updating is
                      Holding time:      3.5 seconds



        3.2        IMSI attach/detach
                   The IMSI detach procedure enables the MS to indicate to the network that it is
                   about to become inactive. The IMSI attach is performed when the MS is turned
                   on.
                   IMSI attach is a Location Updating which gives the same Holding time as
                   Normal Location Updating, i.e.
                        IMSI attach Holding time:        3.5 seconds
                   The IMSI detach procedure consist of the IMSI Detach Indication message sent
                   from the MS to the network. No authentication is performed and no
                   acknowledge message is sent to the MS. We have assumed
                        IMSI detach Holding time:        2.9 seconds




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                             which is the average time for Location Updating minus the average measured
                             time for authentication (0.6 seconds).



            3.3              Periodic Registration
                             To avoid unnecessary paging of an MS by updating the attach/detach registers
                             in case the Mobile services Switching Centre (MSC) never got the IMSI detach
                             message, there is a type of Location Updating called Periodic Registration.
                             Periodic Registration is a Location Updating, which gives the same Holding
                             time as Normal Location Updating, i.e.
                                   Holding time:    3.5 seconds.



            3.4              Call set-up
                             When a connection is to be established, a channel for signalling has to be
                             allocated. The authentication, ciphering mode initiation and set-up signalling are
                             performed on the SDCCH.
                             The estimated time that the SDCCH is occupied with the performance of a call
                             set-up differs slightly between MS originated and MS terminated calls.
                                   MS originated call Holding time: 2.7 seconds
                                   MS terminated call Holding time:2.9 seconds



            3.5              Short Message Service point to point (SMS p-p)
                             The SMS p-p is a text message service supported since the Ericsson GSM
                             System R5. This service provides the transmission of an SMS between a
                             message handling system (service centre) and a mobile station.
                             The transmission of an SMS p-p normally takes place on the SDCCH. If a
                             Traffic CHannel (TCH) already is allocated, when assigning a channel for the
                             SMS p-p, the SMS transmission takes place on the allocated TCH, using the
                             Slow Associated Control CHannel (SACCH).
                             The time that the transmission of an SMS p-p holds the SDCCH is the sum of
                             the set-up time for the SMS transmission, the time it takes to transfer the
                             message itself and the time to close the connection. The holding time for the set-
                             up is slightly shorter than the time for a normal call set-up since less signalling
                             is involved.
                             The holding time of the SDCCH is based on measurements, and accounts for
                             the time between the Channel Activation message and the RF Channel Release
                             message.
                                   Holding time:    6.2 seconds




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                   The measurements were performed for MS terminated SMS p-p, but is
                   considered to be valid also for MS originated SMS.
                   The SDCCH holding time will vary depending on the length of the SMS p-p.
                   The above SDCCH holding time is the average value based on measured MS
                   terminated SMS p-p.



        3.6        Facsimile group 3 set-up
                   The Facsimile group 3 service allows the connection (send and/or receive) of
                   CCITT group 3 fax apparatus to the MSs in a GSM Public Land Mobile
                   Network (PLMN).
                   The set-up for a fax transmission takes place on the SDCCH. It can be assumed
                   that the set-up of a fax transmission holds the SDCCH as long as the set-up for
                   a regular call.
                        MS originated call Holding time:2.7 seconds
                        MS terminated call Holding time:        2.9 seconds



        3.7        False Accesses
                   When a Channel Request message is received by the system, an SDCCH is
                   allocated by sending an Immediate Assignment message. If it happens that the
                   channel request was caused by radio disturbances, no more messages are
                   received from the non-existing MS and the system waits a certain time before
                   performing a disconnection.
                   The time that a False Access holds the SDCCH is estimated to
                        Holding time:    1.8 seconds




        4          Possible configurations and limitations
                   The SDCCHs are possible to configure in a limited set of ways and there are
                   some limitations on the number of SDCCHs that is possible to have in a cell.
                   These possible configurations and limitations apply both for manual and
                   automatic SDCCH dimensioning.



        4.1        SDCCH configurations

        4.1.1      SDCCH/8
                   8 subchannels for signalling are mapped on one time slot. Each assigned
                   SDCCH/8 results in one less TCH for that cell.




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            4.1.2            SDCCH/4 (combined SDCCH and BCCH)
                             There is a possibility to map 4 subchannels for signalling on the time slot used
                             for the BCCH. As a result of combining the SDCCH with the BCCH, the
                             paging capacity on the BCCH is reduced. The paging capacity is reduced to a
                             1/3 and therefore this configuration should not be used in areas with high
                             paging load, see Ref. 3.


            4.1.3            Cell Broadcast
                             The Cell Broadcast service provides the transmission of an SMS from a
                             message-handling centre to all MSs in the serving area of the BTS. If the Cell
                             Broadcast service is active in a cell, one signalling subchannel is replaced by
                             one Cell Broadcast Channel (CBCH).


            4.1.4            Possible configurations
                             The optional Cell Broadcast service and the possibility to have combined
                             SDCCH and BCCH result in four possible SDCCH-configurations. Each cell
                             can have one out of these SDCCH configurations defined:

                             • SDCCH/4: The SDCCH is combined with the CCCH in time slot 0 on the
                               BCCH carrier. This SDCCH configuration provides 4 subchannels for
                               signalling. Only one SDCCH/4 can be defined for each cell.

                             • SDCCH/8: This SDCCH configuration provides 8 subchannels for
                               signalling. Up to 16 SDCCH/8 can be defined for each cell.

                             • SDCCH/4 including CBCH: If one subchannel is replaced by a CBCH, the
                               SDCCH/4 configuration provides 3 subchannels for signalling.

                             • SDCCH/8 including CBCH: If one subchannel is replaced by a CBCH, the
                               SDCCH/8 configuration provides 7 subchannels for signalling.
                             If an SDCCH/4 is chosen it is automatically allocated at time slot 0 on the
                             BCCH carrier. For the SDCCH/8s the time slot number and channel group can
                             be specified. It is possible to place up to 7 of the SDCCH/8s on the BCCH-
                             carrier (3 in extended range cells).
                             The SDCCH/8s in a cell may be positioned as follows:

                             •    All SDCCH/8s are placed on the BCCH frequency.

                             •    All SDCCH/8s are placed on the same time slot number.

                             •    Some SDCCH/8s are placed on the BCCH frequency in channel group 0.
                                  The rest are placed on the other channel groups on the same time slot
                                  number.
                             Note that there are limitations on how many SDCCH/8 it is possible to have in
                             a cell, see section 4.2.




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         4.2       SDCCH limitations
                   The number of TRXs limits the possible number of SDCCH/8s in a cell; i.e. it
                   is not possible to have more SDCCH/8s in a cell than the number of TRXs.
                   However it is possible to add an SDCCH/4 even if the number of SDCCH/8
                   equals the number of TRXs in a cell.
                   The maximum number of SDCCH/8s is limited to 16 per cell. This number is
                   reduced by one if an SDCCH/4 is defined for the cell.




         5         Automatic SDCCH dimensioning
                   The SDCCH dimensioning in the Ericsson GSM System R7 can be done
                   automatically with the optional Adaptive Configuration of Logical Channel
                   feature, see Ref. 4. This feature will add extra SDCCH/8s by reconfiguring idle
                   TCHs when the SDCCH load is high. When the SDCCH load goes down, the
                   extra SDCCH/8s will be removed by reconfiguring them back to TCHs. This
                   means that the Base Station Controller (BSC) dynamically will reconfigure the
                   cells by adding and removing SDCCH/8s when needed. With this feature the
                   cumbersome task of manual dimensioning is avoided.
                   The feature is implemented in the BSC and is activated or deactivated per cell
                   basis by parameter setting.



         5.1       Basic SDCCH configuration
                   To benefit from the Adaptive Configuration of Logical Channel feature, the
                   basic SDCCH configuration should be under-dimensioned. The basic
                   configuration can be any combination of SDCCH/8s and SDCCH/4, even no
                   SDCCHs at all (which is preferably avoided due to congestion reasons).
                   It is recommended to choose:

                   •   One SDCCH/8 as the basic configuration for all cells,
                                                       ≈
                       if Location Area > 2100 Erlang (≈500 TRXs).

                   •   One SDCCH/4 as the basic configuration for all cells,
                                                       ≈
                       if Location Area < 2100 Erlang (≈500 TRXs).
                   It is possible for the operator to choose a different basic configuration for cells
                   where a lot of SDCCH signalling always take place, but this is not needed in
                   normal cases. The benefit of only using SDCCH/8s in a network is that the
                   operator simplifies considerations about paging load. Initial combined
                   SDCCH/4 configurations decreases the paging capacity and should only be
                   used in Location Areas with low paging load. For further information regarding
                   paging load and Location Area dimensioning, see Ref. 3.

                   Note: If there is an Overlaid/Underlaid (OL/UL) structure in the site with
                   combined normal and extended range cells, the Adaptive Configuration of
                   Logical Channel feature will place all additional SDCCH/8s in the UL subcell.


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                             This could cause TCH capacity problem in sites with only one TRX in the UL
                             subcell. Therefore, in these cases, reallocate the TRXs from OL to UL.




            6                Manual SDCCH dimensioning
                             Although it is recommended to make use of the Adaptive Configuration of
                             Logical Channel it is still possible to configure the SDCCH manually.
                             The generated SDCCH and TCH traffic in a cell are the inputs for the SDCCH
                             dimensioning. For a given number of TRXs and an estimated SDCCH / TCH
                             ratio, a suitable SDCCH configuration for that cell can be chosen.



            6.1              SDCCH Grade of Service
                             The Grade of Service (GOS) is defined as the probability that a newly arriving
                             call finds all channels busy and is denied service. The GOS is also sometimes
                             called blocking rate.
                             The SDCCH dimensioning is a compromise between SDCCH blocking rate and
                             TCH capacity. A connection for speech or data requires an SDCCH for the call
                             set-up signalling and a TCH for the remainder of the call. In order to have a
                             successful call set-up, there has to be an available SDCCH as well as an
                             available TCH. The SDCCH and the TCH are equally important for the
                             completion of a call, but since the SDCCHs use the physical channels more
                             effectively, the SDCCHs should be dimensioned for a better grade of service
                             compared to the TCHs.
                             A rule of thumb is that the SDCCH GOS should be dimensioned for no more
                             than 1/4 of the TCH GOS, i.e. if the SDCCH exceeds 1/4 of the TCH GOS, a
                             configuration with more SDCCHs should be used. However, when using the
                             configuration with only four signalling channels, i.e. the SDCCH/4
                             configuration, an SDCCH GOS of TCH GOS/2 should be allowed.




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                   The rule of thumb stated above is illustrated by an example:
                        Assume that a cell is dimensioned for a GOS of 2 % on the TCH.
                        If a configuration with 4 subchannels for signalling is used (only one
                        SDCCH/4), the SDCCH should not be dimensioned for a GOS in excess
                        of:
                        Max. SDCCH GOS = 1/2 * 2 % = 1 %.
                        For all other SDCCH configurations, the SDCCH should not be
                        dimensioned for a GOS in excess of:
                        Max. SDCCH GOS = 1/4 * 2 % = 0.5 %.



         6.2       SDCCH Grade of Service with Immediate
                   Assignment on TCH

         6.2.1     General
                   Since the Ericsson GSM System R6, it is possible to perform the initial
                   signalling (Immediate Assignment) on a TCH. In case of Immediate Assignment
                   on TCH, the Channel Administration Processing (see Ref. 1) assigns a TCH for
                   signalling instead of an SDCCH. Immediate Assignment is recommended when
                   the optional Adaptive Configuration of Logical Channels feature is used as well
                   as when it is not used.
                   The Channel Administration allows seven different channel allocation strategies
                   (CHAPs).
                   The TCH first strategy decreases the signalling load on SDCCH significantly,
                   thus enabling the possibility to use a combined SDCCH / BCCH in most
                   situations. However, the traffic load on TCH will in this case increase
                   substantially. Since SDCCH uses the physical channels more efficiently the
                   TCH first strategy is not recommended.
                   The SDCCH first strategy means that an SDCCH always is allocated if there is
                   an idle SDCCH and in case there is congestion on SDCCH, the signalling is
                   performed on a TCH instead. The SDCCH first is the recommended strategy,
                   since the resources are used more efficiently and the trunking loss is reduced to
                   a minimum. This strategy is described below.


         6.2.2     SDCCH dimensioning, SDCCH first strategy
                   When all SDCCHs are occupied, additional call set-ups are performed on
                   TCHs instead. This means that the traffic load on TCH increases, but it is
                   possible to use a configuration with more available TCHs. Thus, there is a
                   trade-off between the overflow traffic load on TCH, originating from Immediate
                   assignment on TCH, compared to the extra capacity that can be added on TCH
                   by reducing the number of time slots reserved for SDCCH. The trunking gain
                   for configurations with a small number of SDCCHs is substantial.



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                                      In this paper, the breakpoint when it is beneficial to add one SDCCH is defined
                                      as when 0.5 Erlang1 of the signalling traffic is carried by TCH. If the traffic
                                      load exceeds the breakpoint, one extra SDCCH has to be added. When the
                                      overflow traffic on TCH is equal or less than 0.5 Erlang, it is beneficial to use a
                                      TCH extra instead of adding an SDCCH, since the total TCH capacity
                                      increases with almost one Erlang.
                                      Recommendations for initial dimensioning of the SDCCH configuration when
                                      using Immediate Assignment on TCH are presented in appendix B, C & E.
                                      The GOS, or percentage of the time that all SDCCH channels are occupied at
                                      the breakpoint, is presented in Table 1. The values are found from simulations,
                                      see Ref. 5.
                                      Table 1. Percentage of time when all SDCCHs are occupied at the breakpoint
                                      for different configurations of SDCCH.

                                        SDCCH/4                                                                         18 %.

                                        SDCCH/8                                                                         11 %.

                                        SDCCH/4 + SDCCH/8                                                               9 %.

                                        2 * SDCCH/8                                                                     7 %.

                                        SDCCH/4 + 2 * SDCCH/8                                                           6 %.

                                        3 * SDCCH/8                                                                     5%



                                      The SDCCH should not be dimensioned for an SDCCH occupancy percentage
                                      in excess of these figures. If the GOS on SDCCH becomes higher, it is
                                      beneficial to add an SDCCH.
                                       Example:
                                              Suppose that the traffic on SDCCH is 4 Erlang in a cell, that combined
                                              BCCH is not used and that Immediate assignment on TCH is not used. In
                                              this case it is necessary to use two SDCCH/8 in order to meet the demand
                                              for a GOS less than 0,5 % (see section 6.1). The capacity on TCH is 14
                                              Erlang if there are three TRXs in the cell.
                                              If Immediate assignment on TCH, SDCCH first, is used, it is possible to
                                              use only one SDCCH/8. The GOS on SDCCH is in this case 3 %2 which
                                              yields that the overflow traffic on TCH is 3 % * 4 Erlang = 0.12 Erlang.
                                              The capacity of the TCHs in the cell is now 14.93 - 0.12 ≈ 14.7 Erlang,



1 The breakpoint is defined at 0.5 Erlang since the overflow traffic on TCH is more bursty and has higher variance than Erlang distributed traffic. This
  means that the overflow traffic on TCH decreases the total capacity on TCH with slightly more than 0.5 Erlang.

2 This value comes from an Erlang B table, 3 % corresponds to the blocking rate for 8 channels with 4 Erlang traffic.

3 14.9 Erlang is the capacity of 22 TCHs (3 TRXs * 8 time slots - one BCCH - one SDCCH/8 = 22 TCHs) with a 2 % blocking.




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                        which means that the TCH capacity in the cell is increased with 0.7
                        Erlang.

                   Note: When Immediate Assignment on TCH is used, there is no congestion at
                   Immediate Assignment at all. There could of course be congestion both on
                   SDCCH and TCH, but in this case, 100 % of the resources are used in the cell.



         6.3       SDCCH / TCH ratio
                   When dimensioning the SDCCH, the main factor is the SDCCH traffic and
                   TCH traffic ratio, i.e. SDCCH-load / TCH-load. For every combination of
                   SDCCH configuration and number of TRXs, there is a breakpoint in terms of
                   the SDCCH / TCH ratio where the SDCCH GOS exceeds the rule of thumb
                   stated in section 6.1 and 6.2.2.
                   A complete list of tables, including every (reasonable) combination of SDCCH
                   configuration, number of TRXs and their "breakpoint values" (given in
                   percentage) is included in appendix A and appendix B.
                   The selection of which SDCCH configuration to use is illustrated by an
                   example:
                      Assume a situation with the following data:
                      Number of TRXs in cell:               3
                      Cell Broadcast used:                  No
                      Estimated SDCCH load:                 5 mE/subscriber
                      Estimated TCH load                    20 mE/subscriber.
                      Immediate Assignment on TCH:          Not used
                      The SDCCH / TCH ratio = 5 / 20 = 25%
                      After having calculated the SDCCH / TCH ratio, find the correct table in
                      appendix A or B based on the number of TRXs in the cell (in this case table
                      A3). The values given in parentheses are for Cell Broadcast. The
                      configurations shaded grey are the recommended configurations for an
                      average cell, Cell Broadcast not used, according to the traffic estimations in
                      section 6.7.
                   Table 2. Table A3 from appendix A
                    3 TRXs

                                           Number of     Capacity,     Number of   Capacity,    Max.
                    SDCCH configuration    SDCCH         SDCCHs        TCHs        TCH          SDCCH/TCH-
                                           subchannels                                          ratio

                    SDCCH/4                4 (3)         0.87 (0.46)   23          15.8         5.5% (2.9%)

                    SDCCH/8                8 (7)         2.7 (2.2)     22          14.9         18% (15%)

                    SDCCH/8 + SDCCH/4      12 (11)       5.3 (4.6)     22          14.9         36% (31%)

                    2 * SDCCH/8            16 (15)       8.1 (7.4)     21          14.0         58% (53%)




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                                            The configuration SDCCH/4 + SDCCH/8 has a maximum
                                            SDCCH / TCH ratio of 36 %, which is sufficient. Note that this
                                            configuration has a combined SDCCH / BCCH. If a combined
                                            BCCH can not be used (e.g. due to excessive paging load), the 2 *
                                            SDCCH/8 configuration must be used.
                             The tables are calculated with the following GOS.
                             TCH:                                    2%
                             SDCCH/4:                                1% (1/2 of the TCH GOS)
                             all other SDCCH configurations:         0.5 % (1/4 of the TCH GOS)
                             Other values of the GOS will affect the capacity. However, the TCH GOS only
                             has a marginal effect on the maximum SDCCH / TCH ratio as long as the
                             relation between the SDCCH GOS and TCH GOS are kept the same. This
                             means that these tables also can be used for dimensioning cells with other
                             congestion levels than 2%.



            6.4              Half rate
                             The possibility to use different channel services was introduced in the Ericsson
                             GSM system R6.1. One of the services, half rate, enables two call connections
                             to be established on the same timeslot.
                             When half rate is used it will theoretically double the number of available traffic
                             channels. In practice, however, live networks will most likely consist of a
                             mixture between half rate mobiles and full rate mobiles.
                             Half rate will affect the SDCCH dimensioning since more signalling will be
                             required when the number of TCHs is increased. An important dimensioning
                             factor is therefore the half rate penetration, i.e. the percentage of half rate
                             mobiles in the network.
                             When half rate TCH capacity calculations are done it is assumed that the half
                             rate mobiles are evenly spread among the cells, i.e. all cells have the same half
                             rate penetration. The TCH capacity calculations made in this guideline are best
                             illustrated with an example:
                                            If for example a 2 TRX cell is used, it can accommodate 14 full
                                            rate TCHs, i.e. 14 subscribers if one SDCCH/8 is used for
                                            signalling. A half rate penetration of 10 % would mean that 10 %
                                            of the 14 subscribers would be using a half rate connection, i.e.
                                            1.4 subscribers (after been rounded up = 2 subscribers). This
                                            would result in 13 timeslots used for full rate and 1 timeslot used
                                            for half rate, resulting in 13 full rate TCHs and 2 half rate TCHs,
                                            i.e. 15 TCHs in total. The TCH capacity is then calculated for 15
                                            TCHs with an Erlang B table with appropriate blocking figure.
                             This guideline will present SDCCH dimensioning guidelines for a half rate
                             penetration up to 25 %. A list of tables is found in appendix D (without
                             Immediate Assignment on TCH) and E (with Immediate Assignment on TCH,
                             SDCCH first).


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                             The selection of which SDCCH configuration to use is illustrated by an
                             example:
                                  Assume a situation with the following data:
                                  Number of TRXs in a cell:4
                                  Cell Broadcast used:                          No
                                  Estimated SDCCH load:                         5 mE/subscriber
                                  Estimated TCH load:                           20 mE/subscriber
                                  Half rate penetration:                        10 %
                                  Immediate Assignment on TCH:                  Not used
                                  The SDCCH / TCH ratio = 5/20 = 25 %
                                  After having calculated the SDCCH / TCH ratio, find the correct table in
                                  appendix D or E based on the half rate penetration and if Cell Broadcast is
                                  used or not (in this case table D3).
                                  In the table find the column matching the number of TRXs used in the cell
                                  (in this case 4 TRXs). The values in the table show the maximum
                                  SDCCH / TCH ratios for different SDCCH configurations. The
                                  configurations shaded grey are the recommended configurations and alter
                                  depending on whether the cell is at the border of a Location Area or not.
                                  Three types of cells are considered in the tables, Average cells [AC], Inner
                                  cells [IC] and Border cells [BC] (see section 6.7.1). The configuration 2 *
                                  SDCCH/8 has a maximum SDCCH / TCH ratio of 37 %, which is
                                  sufficient in this case. Note that this configuration is recommended to use
                                  for 4 TRX cells at the border of a Location Area.
                             Table 3. Table D3 from appendix D.
                                                 Haf Rate Penetration: 10%
                                                       No Cell Broadcast
                                                                          Number of TRXs
  SDCCH configuration
                              1              2                3                  4               5              6              7
         SDCCH/4         30% [AC, IC]       9%               5%
         SDCCH/8          93% [BC]      30% [AC, IC]        17%                12%
  SDCCH/8 + SDCCH/4                      59% [BC]      33% [AC, IC, BC]     24% [AC, IC]       17%            14%            11%
      2 * SDCCH/8                          99%              54%              37% [BC]       27% [AC, IC]     22% [IC]        18%
 2 * SDCCH/8 + SDCCH/4                                                         51%           36% [BC]      30% [AC, BC]   24% [AC, IC]
      3 * SDCCH/8                                                                              49%            39%          32% [BC]




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            6.5              Extended range
                             In cells the available number of TCH is the input value of SDCCH
                             dimensioning. If a cell is changed to extended range, the number of TCHs is
                             reduced to half since each TCH consists of two time slots. Consequently the
                             SDCCH need is reduced to half and a change of the “input TRX value” for the
                             tables in appendix C is needed. Use the following formula for this new TRX
                             value:
                                    (Appendix C’s input TRX value) = (#TRXs / 2)
                             Use this value (round up) as the input value for appendix C.
                             If there is a UL/OL structure in a site with combined normal and extended
                             range cells, the SDCCH dimensioning is to be done by using the tables in
                             appendix C with a slight modification. A change of “input TRX value” for
                             appendix C is needed. This is due to the TCH capacity reduction extended
                             range gives the UL subcell. Use the following formula for this new TRX value:
                                    (Appendix C’s input TRX value) = (#TRXs in UL)/2 + (#TRXs in OL).
                             Use this value (round up) as the input TRX for appendix C. For example an OL
                             subcell with 3 TRXs and an UL extended range subcell with 3 TRXs gives an
                             input TRX value of 5.
                             The SDCCHs are to be placed in the UL (extended range) subcell.



            6.6              High Speed Circuit Switched Data
                             When there are High Speed Circuit Switched Data (HSCSD) mobiles in the
                             network, the network should be optimised for this use in the means of where to
                             allocate the SDCCHs. The SDCCHs should all be allocated on the same
                             channel, preferable the BCCH frequency. This is done to increase space for
                             HSCSD mobiles, which uses up to four consecutive timeslots.



            6.7              SDCCH traffic estimations
                             Most of the traffic estimations in this chapter come from the ERA5 Traffic
                             model used by Ericsson, see Ref. 6. ERA5 is based on Ericsson GSM System
                             R5 Main Requirements model. As being aimed for design and test, it is quite
                             demanding.
                             The figures differ substantially between different networks. Therefore, the
                             figures should be substituted with the values given by the operator, if available.
                             The figures also vary between cells. If possible, the SDCCH dimensioning
                             should be followed up by looking at STS-data (see section 7).
                             As a reference value SDCCH traffic figures for the so-called BAS1 Traffic
                             model (ref. 8) is presented as well (see section 6.7.9). The BAS1 Traffic model
                             is based on collected statistics for a large number of networks and represents in
                             some sense an average network. However, when being uncertain of what the



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                   SDCCH load will be like in a network it is recommended to use the SDCCH
                   load according to the ERA5 Traffic model.
                   Knowing the SDCCH holding times, with a given number of performances
                   during busy hour for every procedure, the generated SDCCH traffic per
                   subscriber can be calculated as follows:
                   For each type of procedure, multiply the number of performances per busy hour
                   and subscriber by the holding time of the channel. By dividing the result by 3.6,
                   the procedures contribution to the SDCCH load in mErlang/subscriber is
                   achieved.


         6.7.1     Normal Location Updating
                   The Location Updating contribution to SDCCH load differs very much between
                   an inner cell, and a cell at the border of a Location Area. Furthermore, if the
                   cell is at the border of a Location Area, the number of Location Updatings in
                   the cell depends on the traffic situation. For example, a highway crossing a
                   Location Area border results in a larger number of Location Updatings in those
                   Location Area border cells.
                   The figures given in the ERA5 Traffic model for Location Updating are
                   Number of Location Updatings:           1.0 per subscriber and busy hour
                   In these estimations, three types of cells have been considered:

                   • Average cell [AC]: This type of cell has the average number of Location
                     Updatings given in the ERA5 Traffic model.

                   • Inner cell [IC]: This type of cell is considered to have no Location Updatings
                     at all.

                   • Border cell [BC]: This type of cell is considered to have three times the
                     average number of Location Updatings.
                   The number of Location Updatings in the border cell comes from the
                   assumption that there are twice as many inner cells as border cells, were
                   virtually all the Location Updatings are performed.
                   3.5 seconds holding time =>

                   Average:      1.0 * 3.5 / 3.6 = 1.0 mE per subscriber
                   Inner:        0 mE per subscriber
                   Border:       3 * 0.5 = 3.0 mE per subscriber


         6.7.2     IMSI attach/detach
                   The attach and detach procedures are optional to the operator. If used, the
                   number of performances is highly dependent on the subscriber behaviour.
                   The figures given in the ERA5 Traffic model for IMSI attach/detach are


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                                           Number of IMSI attach/detach:                     2.0 per subscriber and busy hour
                                      3.5 and 2.9 seconds Holding time respectively =>

                                      2.0 * [(3.5 +2.9)/2] / 3.6 = 1.8 mE per subscriber


                6.7.3                 Periodic Registration
                                      The implementation of the Periodic Registration is optional. If used, the time
                                      between registrations is a choice of the operator. Consequently, the SDCCH
                                      load due to Periodic Registration varies substantially between operators.

                                      If the cell parameter T3212 (see Ref. 2) is set to 2 hours4, the number of Busy
                                      Hour Call Attempts (BHCA) for Periodic Registration is
                                              Number of Periodic Registrations:                          0.5 per subscriber and busy hour
                                      3.5 seconds Holding time =>

                                      0.5 * 3.5 / 3.6 = 0.5 mE per subscriber
                                      The rate of Periodic Updatings is actually over-estimated since no Periodic
                                      Registration is performed half an hour after a Normal Location Updating,
                                      Mobile Terminated or Originated call.


                6.7.4                 Call set-up
                                       Obviously, the number of call set-ups depends on the subscriber behaviour and
                                       differs considerably from one network to another.
                                       The figures given in the ERA5 Traffic model for call set-up are
                                              MS Originated traffic (including no B-answer): 0.8 BHCA
                                              MS Terminated traffic (including no B-answer): 0.4 BHCA.
                                      2.7 seconds and 2.9 seconds holding time for MS originated and MS terminated
                                      calls respectively =>
                                      (0.8 * 2.7 + 0.4 * 2.9) / 3.6 = 0.9 mE/subscriber


                6.7.5                 SMS p-p
                                      The number of SMS p-p transmissions is highly dependent on the subscriber
                                      behaviour, but also how the operator uses this service. As an example, SMS
                                      can be used for delivering internal network notices, e.g. voice-mail.
                                       The figures given in the ERA5 Traffic model for SMS p-p are
                                              Number of SMS p-p:                  1.0 per subscriber and busy hour



4 Note that the cell parameter T3212 usually is set to a longer time than half an hour (the default value for T3212 is 4 hours). A shorter time on
  T3212 is here used to be certain not to underestimate the SDCCH load.




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                   In this estimation, it is assumed that all SMS p-p traffic is sent on the SDCCH.
                   6.2 seconds Holding time =>

                   1.0 * 6.2 / 3.6 = 1.7 mE/subscriber


         6.7.6     Facsimile group 3 set-up
                   In the Ericsson traffic model, the number of fax transmissions is small and will
                   only have a marginal effect on the total SDCCH load. Therefore, Facsimile
                   group 3 set-up will not be taken in consideration in the SDCCH traffic
                   estimations in this document.


         6.7.7     False access
                   The number of false accesses is related to the number of SDCCHs in the cell
                   rather than being traffic dependent. The additional SDCCH load due to false
                   accesses is probably in most cases marginal, and will not be taken into
                   consideration in the SDCCH traffic estimations in this document.


         6.7.8     Margin for traffic peaks
                   It is not proper dimensioning to let the average busy hour fully utilise the
                   system. Instead, margins for traffic peaks are needed.
                   Peaks can be due to the random nature of traffic. Traffic peaks can also be due
                   to special events (such as football games or traffic accidents). How much
                   margin to pay for depends on operator. In this document, a margin for traffic
                   peaks of 20 % is added to the estimated SDCCH load.


         6.7.9     Total SDCCH load
                   For the three different types of cells stated in section 6.7.1 (i.e. Average-, Inner-
                   and Border cells), the total SDCCH load per subscriber can be achieved by
                   adding the contributions from each event.




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                             Table 4. SDCCH load calculations for ERA5 and BAS1 Traffic model.The
                             BAS1 model corresponds in some sense to an average network. When not
                             being familiar with the subscriber behaviour in a network it is recommended
                             to dimension according to the more demanding ERA5 Traffic model.

Event                             Average                 Inner                  Border

Traffic model                ERA5           BAS1   ERA5       BAS1       ERA5        BAS1

Location Updating:            1.0           0.5      0            0        3.0            1.5    mE/subscr.

IMSI attach/detach:           1.8           0.4     1.8           0.4      1.8            0.4    mE/subscr.

Periodic Registration:        0.5           0.2     0.5           0.2      0.5            0.2    mE/subscr.

Call set-up:                  0.9           0.8     0.9           0.8      0.9            0.8   mE/subscr.

SMS p-p:                      1.7           0.3     1.7           0.3      1.7            0.3   mE/subscr.

Total:                        5.9           2.2     4.9           1.7      7.9            3.2   mE/subscr.

20 % traffic margin           7.1           2.6     5.9           2.0      9.5            3.8   mE/subscr.
added:




            6.7.10           SDCCH / TCH ratio
                             The SDCCH / TCH ratio is the ratio between the estimated SDCCH load,
                             calculated in section 6.7.9, and the estimated TCH load, which is given in the
                             ERA5 Traffic model.
                                    TCH load:      29 mE / subscriber
                             SDCCH / TCH ratio =

                                    Average:       7.1 / 29 = 24 %
                                    Inner:         5.9 / 29 = 20 %
                                    Border:        9.5 / 29 = 33 %

                             Experience from live GSM networks shows that the SDCCH / TCH ratio
                             differs quite a lot between different networks and different time intervals in a
                             network. This depends, amongst others, on the parameter setting, the subscriber
                             behaviour, the size of the Location Areas and the services provided by the
                             network operator. The SDCCH / TCH ratio has shown to be, in most cases,
                             between 10 % and 40 %.



            6.8              Recommended configurations
                             In appendix C, Table C1 and C2 contain the recommended SDCCH
                             configurations, based on the SDCCH / TCH ratio calculated in section 6.7.10.




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                   Six different types of cells have been considered; Average, Inner and Border
                   cells, with and without Cell Broadcast.
                   Appendix D and E contain recommended SDCCH configurations for the
                   situation when half rate is used in a network. Recommended SDCCH
                   configurations for Average, Inner and Border cells are found here for half rate
                   penetrations ranging from 5 % up to 25 %, with and without Cell Broadcast.




         7         Dimensioning based on STS-data
                   An estimation of the SDCCH load, as described in section 5.7, is based on
                   assumptions regarding the subscriber behaviour. Furthermore, the SDCCH
                   need can differ considerably between different cells. Example of factors that
                   might differ between cells are generated traffic per subscriber, LA borders and
                   subscriber mobility.
                   A more accurate dimensioning is achieved by using cell statistics, i.e. Statistics
                   and Traffic measurement Subsystem (STS) counters. The STS counters provide
                   statistics regarding SDCCH load, SDCCH congestion, TCH load and TCH
                   congestion. When there is congestion on SDCCH or TCH, the availability of
                   the channels should also be checked. It is common that there are blocked
                   channels or hardware problems not discovered until there is congestion in the
                   cell, since in this case, this cell is more thoroughly evaluated.
                   Statistics of the traffic load and congestion should be collected during busy hour
                   when the traffic reaches the peak levels.
                   Information about useful STS counters can be found ref. 7.



         7.1       Cells with no congestion
                   As long as there is no congestion in neither the TCH nor the SDCCH, the
                   SDCCH configuration is not critical. However, the cell should still be
                   dimensioned for a future increase in traffic. With no statistics of the congestion
                   levels, the dimensioning has to be based on statistics regarding the SDCCH load
                   and TCH load.
                   It is reasonable to assume that the SDCCH / TCH ratio is not going to differ
                   that much when the overall traffic in the cell increases. The SDCCH / TCH
                   ratio can be calculated using the statistics from the STS counters. A suitable
                   SDCCH configuration can be selected using the tables in appendix A, as
                   described in section 6.3.



         7.2       Cells with congestion
                   The most accurate SDCCH dimensioning is achieved by looking at the
                   congestion level for the TCHs and the SDCCHs for the specific cell. The
                   optimum configuration is achieved by selecting a configuration with as many


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                             TCHs as possible, without letting the SDCCH GOS exceed 1/4 of the TCH
                             GOS (with only one SDCCH/4: 1/2 of the TCH GOS). This procedure can be
                             applied regardless of the TCH congestion level in the cell.
                             When using Immediate Assignment on TCH, the SDCCHs could be
                             dimensioned for a much higher utilisation compared to the case without using
                             Immediate Assignment on TCH. The trunking gain is in most cases substantial
                             and yields a higher capacity on TCH.
                             There are STS counters that provide the percentage of the time when all
                             channels are occupied. These counters should be monitored for SDCCH and
                             TCH and the SDCCH dimensioning should be performed according to the
                             figures for GOS in section 6.3.




            8                Summary
                             This section is a short summary of the most important things to remember
                             dimensioning SDCCHs. The main recommendations of the guideline are as
                             follows:

                             •    Use the optional Adaptive Configuration of Logical Channel feature when
                                  available.

                             •    Use Immediate Assignment on TCH, SDCCH first. Use it when Adaptive
                                  Configuration of Logical Channels is activated as well as when it is not.

                             •    For manual dimensioning, use cell statistics, i.e. STS counters, to find an
                                  optimum SDCCH configuration. If STS data is not available, use the
                                  recommended configurations in this guideline. The recommended
                                  configurations are found in the appendices.




            9                Parameters

            9.1              BSC parameters
                             In this section some of the most important BSC parameters for SDCCH
                             dimensioning are explained.

                             SDCCH sets the number of SDCCH/8 to be used in a cell. Up to 16 SDCCH/8
                             can be specified per cell. The number of SDCCH can not be more than the
                             number of TRXs within the cell.

                             CBCH sets if Cell Broadcast Channel is to be used or not.

                             MFRMS is the multiframe interval and is defined as the transmission interval
                             of paging messages to the same paging group.




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                   BCCHTYPE can be either:

                   •   COMB = Combined; The cell has combined BCCH and SDCCH/4.

                   •   COMBC = Combined with CBCH; The cell has a combined BCCH and
                       SDCCH/4 with a CBCH subchannel.

                   •   NCOMB = Not combined; The cell does not have a combined BCCH and
                       SDCCH/4.
                   If COMB is used the capacity of the CCCH will decrease with 2/3, compared to
                   the NCOMB case.

                   T3212 is the time between Periodic Registrations.

                   ATT sets if attach-detach is allowed.

                   CCHPOS defines if an SDCCH/8 shall be placed on the BCCH frequency or
                   according parameter TN. The following values of parameter CCHPOS exists:
                        BCCH             All SDCCH/8s in channel group zero will be placed on
                                         the BCCH frequency. This alternative is not valid for
                                         channel groups other than zero.
                        TN               All SDCCH/8 will be placed on the time slot number
                                         entered with parameter TN.
                   TN defines the timeslot number on which the SDCCH/8 will be placed. This
                   parameter does not have any effect for channel group 0 having CCHPOS =
                   BCCH.
                   ACCSTATE activates and deactivates the Adaptive Configuration of Logical
                   Channels feature per cell basis.
                   SLEVEL defines the level of remaining subchannels when an attempt to
                   reconfigure a TCH to an SDCCH/8 will take place.
                   STIME defines the minimum time interval before an SDCCH/8 added by the
                   Adaptive Configuration of Logical Channels feature can be reconfigured back
                   to a TCH.

                   CHAP is used for selecting the Channel Allocation Profile. The profile is set
                   per cell.




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                             Table 5. BSC parameter table

                                 Parameter       Default value      Recommended                Value range
                                   name              R7                 value

                               SDCCH                   1                   -                0 to 16 SDCCH/8

                               CBCH                   NO                   -                     YES, NO

                               MFRMS                   6                   4              2-9 CCCH multiframes

                               BCCHTYPE             NCOMB                  -           COMB, COMBC, NCOMB

                               T3212                   40                 40                 0-255 Deci hours

                               ATT                    YES                YES                     YES, NO

                               CCHPOS                 TN                   -                    BCCH, TN

                               TN                      2                   -                0 to 3 (normal cell)
                                                                                         0, 2 (extended range cell)

                               SLEVEL                  0                   -                  0 to 2, CONG

                               STIME                   20                  -                15 to 360 seconds

                               CHAP                    0                   1                       0 to 7




            9.2              MSC parameters
                             The following MSC parameters and exchange properties are relevant for
                             SDCCH dimensioning:
                             BTDM implicit detach supervision should be equal (or longer) than T3212 in
                             the BSC. If T3212 is increased, BTDM must also be increased.
                             Note that T3212 is set in decihours (periods of 6 minutes) and BTDM is set in
                             minutes.

                             GTDM is an extra guard time in minutes before the subscriber is set to detach.


                             Table 6. MSC parameter table

                               Parameter         Default value      Recommended                Value range
                               name                  R7                 value

                               BTDM                   OFF             T3212 * 6       6-1530 (steps of 6) minutes or
                                                                                                  OFF

                               GTDM                     -                  -                  0-255 minutes




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         10        References

                   Ref. 1.     User Description, Channel Administration, 4/1553-HSC 103 12
                               Uen A
                   Ref. 2.     Radio Network Parameters and Cell Design Data, 6/100 45-HSC
                               103 12 Uen A
                   Ref. 3.     Location Area Dimensioning Guideline, 11/100 56-HSC 103 12
                               Uen Rev A
                   Ref. 4.     User Description, Adaptive Configuration of Logical Channels,
                               20/1553-HCS 103 12 Uen A
                   Ref. 5.     SDCCH Dimensioning, simulation of GOS, ERA/LVR/D-98:0299
                   Ref. 6.     ERA5 Model, Hans Andersson, Z/EP-95:153
                   Ref. 7.     User Description and Engineering Guideline, Radio Network
                               Statistics, 7/100 45-HSC 103 12 Uen A
                   Ref. 8.     BAS1 Model, Hans Andersson, Z/EP-96:072




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                              Appendix A - Immediate assignment on
                              TCH not used
                              Table A1 - A7 are tables for selecting SDCCH configurations as described in
                              section 5.1. Immediate assignment on TCH is not used. The tables are
                              calculated with the following GOS.
                              TCH:                                      2%
                              SDCCH/4:                                  1 % (1/2 of the TCH GOS)
                              all other SDCCH configurations:           0.5 % (1/4 of the TCH GOS)
                              Note that SDCCH/4 should not be used in case of high paging load in the
                              Location Area.
                              The figures in parenthesis are for configurations where Cell Broadcast is used.
                              The configurations shaded grey are the recommended configurations for an
                              average cell according to the traffic estimations in section 5.7.
                              Table A1
                    1 TRX

                                            Number of     Capacity,     Number of   Capacity,   Max.
                    SDCCH configuration     SDCCH         SDCCHs        TCHs        TCH         SDCCH/TCH-
                                            subchannels                                         ratio

                    SDCCH/4                 4 (3)         0.87 (0.46)   7           2.9         30% (16%)

                    SDCCH/8                 8 (7)         2.7 (2.2)     6           2.3         120% (94%)




                              Table A2
                    2 TRXs

                                            Number of     Capacity,     Number of   Capacity,   Max.
                    SDCCH configuration     SDCCH         SDCCHs        TCHs        TCH         SDCCH/TCH-
                                            subchannels                                         ratio

                    SDCCH/4                 4 (3)         0.87 (0.46)   15          9.0         9.7% (5.1%)

                    SDCCH/8                 8 (7)         2.7 (2.2)     14          8.2         33% (27%)

                    SDCCH/4 + SDCCH/8       12 (11)       5.3 (4.6)     14          8.2         65% (56%)

                    2 * SDCCH/8             16 (15)       8.1 (7.4)     13          7.4         109% (100%)




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                       Table A3
             3 TRXs

                                     Number of     Capacity,     Number of    Capacity,   Max.
             SDCCH configuration     SDCCH         SDCCHs        TCHs         TCH         SDCCH/TCH-
                                     subchannels                                          ratio

             SDCCH/4                 4 (3)         0.87 (0.46)   23           15.8        5.5% (2.9%)

             SDCCH/8                 8 (7)         2.7 (2.2)     22           14.9        18% (15%)

             SDCCH/4 + SDCCH/8       12 (11)       5.3 (4.6)     22           14.9        36% (31%)

             2 * SDCCH/8             16 (15)       8.1 (7.4)     21           14.0        58% (53%)




                       Table A4
             4 TRXs

                                     Number of     Capacity,     Number of    Capacity,   Max.
             SDCCH configuration     SDCCH         SDCCHs        TCHs         TCH         SDCCH/TCH-
                                     subchannels                                          ratio

             SDCCH/8                 8 (7)         2.7 (2.2)     30           21.9        12% (10%)

             SDCCH/4 + SDCCH/8       12 (11)       5.3 (4.6)     30           21.9        24% (21%)

             2 * SDCCH/8             16 (15)       8.1 (7.4)     29           21.0        39% (35%)

             2 * SDCCH/8 + SDCCH/4   20 (19)       11.1 (10.3)   29           21.0        53% (49%)




                       Table A5
             5 TRXs

                                     Number of     Capacity,     Number of    Capacity,   Max.
             SDCCH configuration     SDCCH         SDCCHs        TCHs         TCH         SDCCH/TCH-
                                     subchannels                                          ratio

             SDCCH/4 + SDCCH/8       12 (11)       5.3 (4.6)     38           29.1        18% (16%)

             2 * SDCCH/8             16 (15)       8.1 (7.4)     37           28.3        29% (26%)

             2 * SDCCH/8 + SDCCH/4   20 (19)       11.1 (10.3)   37           28.3        39% (36%)

             3 * SDCCH/8             24 (23)       14.2 (13.4)   36           27.3        52% (49%)




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                             Table A6
                    6 TRXs

                                            Number of     Capacity,     Number of   Capacity,   Max.
                    SDCCH configuration     SDCCH         SDCCHs        TCHs        TCH         SDCCH/TCH-
                                            subchannels                                         ratio

                    SDCCH/4 + SDCCH/8       12 (11)       5.3 (4.6)     46          36.5        15% (13%)

                    2 * SDCCH/8             16 (15)       8.1 (7.4)     45          35.6        23% (21%)

                    2 * SDCCH/8 + SDCCH/4   20 (19)       11.1 (10.3)   45          35.6        31% (29%)

                    3 * SDCCH/8             24 (23)       14.2 (13.4)   44          34.7        41% (39%)




                             Table A7
                    7 TRXs

                                            Number of     Capacity,     Number of   Capacity,   Max.
                    SDCCH configuration     SDCCH         SDCCHs        TCHs        TCH         SDCCH/TCH-
                                            subchannels                                         ratio

                    SDCCH/4 + SDCCH/8       12 (11)       5.3 (4.6)     54          44.0        12% (10%)

                    2 * SDCCH/8             16 (15)       8.1 (7.4)     53          43.1        19% (17%)

                    2 * SDCCH/8 + SDCCH/4   20 (19)       11.1 (10.3)   53          43.1        26% (24%)

                    3 * SDCCH/8             24 (23)       14.2 (13.4)   52          42.1        34% (32%)

                    3 * SDCCH/8 + SDCCH/4   28 (27)       17.4 (16.6)   52          42.1        41% (39%)




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                              Appendix B - Immediate assignment on
                              TCH used
                              The dimensioning in this section is based on the case when Immediate
                              Assignment on TCH, SDCCH first, is used.
                              Table B1 - B7 are tables for selecting SDCCH configurations as described in
                              section 5.2. The tables are calculated with the assumption that the limit for the
                              capacity is reached on SDCCH when 0.5 Erlang of the signalling traffic is
                              served by TCH.
                              Max. SDCCH / TCH - ratio is calculated as:
                              (Signalling on SDCCH + TCH) / (Capacity on TCH - 0.5 Erlang)
                              Note that SDCCH/4 should not be used in case of high paging load in the
                              Location Area.
                              The figures in parenthesis are for configurations where Cell Broadcast is used.
                              The configurations shaded grey are the recommended configurations for an
                              average cell according to the traffic estimations in section 5.7.
                              Table B1
                    1 TRX

                                             Number of     Capacity,    Number of   Capacity,   Max.
                    SDCCH configuration      SDCCH         Signalling   TCHs        TCH         SDCCH/TCH-
                                             subchannels   SDCCH +                              ratio
                                                           TCH

                    SDCCH/4                  4 (3)         2.8 (2.0)    7           2.9         117% (83%)

                    SDCCH/8                  8 (7)         5.8 (5.0)    6           2.3         322% (278%)




                              Table B2
                    2 TRXs

                                             Number of     Capacity,    Number of   Capacity,   Max.
                    SDCCH configuration      SDCCH         Signalling   TCHs        TCH         SDCCH/TCH-
                                             subchannels   SDCCH +                              ratio
                                                           TCH

                    SDCCH/4                  4 (3)         2.8 (2.0)    15          9.0         33% (24%)

                    SDCCH/8                  8 (7)         5.8 (5.0)    14          8.2         75% (65%)




10/100 56-HSC 103 12 Uen Rev A 1998-12-11                                                                     31(45)
SDCCH DIMENSIONING GUIDELINE



                       Table B3
             3 TRXs

                                   Number of     Capacity,     Number of    Capacity,   Max.
             SDCCH configuration   SDCCH         Signalling    TCHs         TCH         SDCCH/TCH-
                                   subchannels   SDCCH +                                ratio
                                                 TCH

             SDCCH/4               4 (3)         2.8 (2.0)     23           15.8        18% (14%)

             SDCCH/8               8 (7)         5.8 (5.0)     22           14.9        40% (35%)

             SDCCH/4 + SDCCH/8     12 (11)       9.1 (8.3)     22           14.9        63% (58%)




                       Table B4
             4 TRXs

                                   Number of     Capacity,     Number of    Capacity,   Max.
             SDCCH configuration   SDCCH         Signalling    TCHs         TCH         SDCCH/TCH-
                                   subchannels   SDCCH +                                ratio
                                                 TCH

             SDCCH/4               4 (3)         2.8 (2.0)     31           22.8        13% (9%)

             SDCCH/8               8 (7)         5.8 (5.0)     30           21.9        27% (23%)

             SDCCH/4 + SDCCH/8     12 (11)       9.1 (8.3)     30           21.9        43% (39%)

             2 * SDCCH/8           16 (15)       12.4 (11.5)   29           21.0        60% (56%)




                       Table B5
             5 TRXs

                                   Number of     Capacity,     Number of    Capacity,   Max.
             SDCCH configuration   SDCCH         Signalling    TCHs         TCH         SDCCH/TCH-
                                   subchannels   SDCCH +                                ratio
                                                 TCH

             SDCCH/8               8 (7)         5.8 (5.0)     38           29.1        20% (17%)

             SDCCH/4 + SDCCH/8     12 (11)       9.1 (8.3)     38           29.1        32% (29%)

             2 * SDCCH/8           16 (15)       12.4 (11.5)   37           28.3        45% (42%)




32(45)                                                              10/100 56-HSC 103 12 Uen Rev A 1998-12-11
                                                                             THE ERICSSON GSM SYSTEM R7



                              Table B6
                    6 TRXs

                                            Number of     Capacity,     Number of   Capacity,   Max.
                    SDCCH configuration     SDCCH         Signalling    TCHs        TCH         SDCCH/TCH-
                                            subchannels   SDCCH +                               ratio
                                                          TCH

                    SDCCH/8                 8 (7)         5.8 (5.0)     46          36.5        16% (14%)

                    SDCCH/4 + SDCCH/8       12 (11)       9.1 (8.3)     46          36.5        25% (23%)

                    2 * SDCCH/8             16 (15)       12.4 (11.5)   45          35.6        35% (33%)

                    2 * SDCCH/8 + SDCCH/4   20 (19)       15.8 (15.0)   45          35.6        45% (43%)




                              Table B7
                    7 TRXs

                                            Number of     Capacity,     Number of   Capacity,   Max.
                    SDCCH configuration     SDCCH         Signalling    TCHs        TCH         SDCCH/TCH-
                                            subchannels   SDCCH +                               ratio
                                                          TCH

                    SDCCH/8                 8 (7)         5.8 (5.0)     54          44          13% (11%)

                    SDCCH/4 + SDCCH/8       12 (11)       9.1 (8.3)     54          44          20% (19%)

                    2 * SDCCH/8             16 (15)       12.4 (11.5)   53          43.1        29% (27%)

                    2 * SDCCH/8 + SDCCH/4   20 (19)       15.8 (15.0)   53          43.1        37% (35%)




10/100 56-HSC 103 12 Uen Rev A 1998-12-11                                                                    33(45)
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34(45)                         10/100 56-HSC 103 12 Uen Rev A 1998-12-11
                                                                              THE ERICSSON GSM SYSTEM R7




                                  Appendix C - Recommended SDCCH
                                  configurations
                                 Table C1 and Table C2 presents the recommended SDCCH configurations
                                 according to the traffic estimations in section 5.7.

                                 Note that SDCCH/4 should not be used in case of high paging load in the
                                 Location Area.
                                  Table C1
        No Cell Broadcast

        Number of TRXs        SDCCH configuration,    SDCCH configuration,    SDCCH configuration,    SDCCH configuration,
                              Average Cell            Inner Cell              Border Cell             Average cell,
                                                                                                      Immediate ass. on TCH

        1                     SDCCH/4                 SDCCH/4                 SDCCH/8                 SDCCH/4

        2                     SDCCH/8                 SDCCH/8                 SDCCH/8                 SDCCH/4

        3                     SDCCH/8 + SDCCH/4       SDCCH/8 + SDCCH/4       SDCCH/8 + SDCCH/4       SDCCH/8

        4                     SDCCH/8 + SDCCH/4       SDCCH/8 + SDCCH/4       2 * SDCCH/8             SDCCH/8

        5                     2 * SDCCH/8             2 * SDCCH/8             2 * SDCCH/8 + SDCCH/4   SDCCH/8 + SDCCH/4

        6                     2 * SDCCH/8 + SDCCH/4   2 * SDCCH/8             3 * SDCCH/8             2 * SDCCH/8

        7                     2 * SDCCH/8 + SDCCH/4   2 * SDCCH/8 + SDCCH/4   3 * SDCCH/8             2 * SDCCH/8




                                 Table C2
        Cell Broadcast used

        Number of TRXs        SDCCH configuration,    SDCCH configuration,    SDCCH configuration,    SDCCH configuration,
                              Average Cell            Inner Cell              Border Cell             Average Cell,
                                                                                                      Immediate ass. on TCH

        1                     SDCCH/8                 SDCCH/8                 SDCCH/8                 SDCCH/4

        2                     SDCCH/8                 SDCCH/8                 SDCCH/8 + SDCCH/4       SDCCH/4

        3                     SDCCH/8 + SDCCH/4       SDCCH/8 + SDCCH/4       2 * SDCCH/8             SDCCH/8

        4                     2 * SDCCH/8             SDCCH/8 + SDCCH/4       2 * SDCCH/8             SDCCH/8 + SDCCH/4

        5                     2 * SDCCH/8             2 * SDCCH/8             2 * SDCCH/8 + SDCCH/4   2 * SDCCH/8

        6                     2 * SDCCH/8 + SDCCH/4   2 * SDCCH/8             3 * SDCCH/8             2 * SDCCH/8

        7                     2 * SDCCH/8 + SDCCH/4   2 * SDCCH/8 + SDCCH/4   3 * SDCCH/8             2 * SDCCH/8




10/100 56-HSC 103 12 Uen Rev A 1998-12-11                                                                       35(45)
SDCCH DIMENSIONING GUIDELINE



                      Table C3 is a quick reference for estimating the capacity in a cell for different
                      number of TRXs. The table can be used for approximate estimations regarding
                      capacity when data to do a more accurate SDCCH dimensioning is not
                      provided. The capacity estimations can be used at an early stage in the cell
                      planning process, e.g. for estimating the capacity using a nominal cell plan.
                      The SDCCH configurations are based on the traffic estimations in section 5.7,
                      and correspond to the "average cell" in table C1 (no Cell Broadcast).


                      Table C3
                No Cell Broadcast

                Number of           SDCCH configuration,    Number of       Number of      TCH capacity
                TRXs                                        signalling      TCHs           (Erlang at
                                                            subchannels                    2% GOS)

                1                   SDCCH/4                 4               7              2.9

                2                   SDCCH/8                 8               14             8.2

                3                   SDCCH/8 + SDCCH/4       12              22             14.9

                4                   2 * SDCCH/8             16              29             21.0

                5                   2 * SDCCH/8             16              37             28.3

                6                   2 * SDCCH/8 + SDCCH/4   20              45             35.6

                7                   2 * SDCCH/8 + SDCCH/4   20              53             43.1




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                                                                                             THE ERICSSON GSM SYSTEM R7




                              Appendix D - Half rate, Immediate
                              assignment on TCH not used
                             The dimensioning tables should be used when half rate is used in a network.
                             The tables are made in a way that it is possible to see the influence on SDCCH
                             dimensioning when half rate mobiles are introduced in a network. Tables D1 –
                             D10 are tables for selecting SDCCH configurations when different grades of
                             half rate mobiles are present in a network, i.e. the percentage of half rate
                             mobiles in a network, and give the maximum SDCCH / TCH ratio in percent
                             for the different configurations.
                             The tables are calculated with the following GOS:
                             TCH:                              2%
                             SDCCH/4:                          1 % (1/2 of the TCH GOS)
                             SDCCH/8                           0.5 % (1/4 of the TCH GOS)
                             The configurations shaded greys are recommended configurations according to
                             the traffic estimations in section 5.7. The tables contain recommended SDCCH
                             configurations, which will depend on whether the cell is close to the border of a
                             Location Area, or not. The letters given in the square brackets indicates where
                             the recommended configurations should be used. The following abbreviation is
                             used:
                             [AC]:                Average Cell
                             [IC]:                Inner Cell
                             [BC]:                Border Cell
                             Note that SDCCH/4 should not be used in case of high paging load in the
                             Location Area.
                             The tables are made for the two cases, if Cell Broadcast is used / not used.


                             Table D1: Max SDCCH / TCH ratio
                                                       Half Rate Penetration: 5%
                                                              No Cell Broadcast
                                                                                 Number of TRXs
  SDCCH configuration
                                1                 2                  3                  4              5              6              7
        SDCCH/4           30%   [AC, IC]        10%                 5%
        SDCCH/8            93% [BC]        33% [AC, IC, BC]        17%                12%
   SDCCH/8 + SDCCH/4                            64%           33% [AC, IC, BC]     24% [AC, IC]      18%            14%            12%
      2 * SDCCH/8                              109%                54%              37% [BC]      28% [AC, IC]     22% [IC]        18%
 2 * SDCCH/8 + SDCCH/4                                                                51%          37% [BC]      30% [AC, BC]   25% [AC, IC]
      3 * SDCCH/8                                                                                    50%            40%          33% [BC]




10/100 56-HSC 103 12 Uen Rev A 1998-12-11                                                                                       37(45)
SDCCH DIMENSIONING GUIDELINE



                           Table D2: Max SDCCH / TCH ratio
                                                      Half Rate Penetration: 5%
                                                           Cell Broadcast used
                                                                              Number of TRXs
  SDCCH configuration
                                1                2                3                   4                5               6               7
         SDCCH/4              16%               5%               3%
         SDCCH/8         75% [AC, IC, BC]   27% [AC, IC]        14%                10%
  SDCCH/8 + SDCCH/4                          56% [BC]        29% [AC, IC]         21% [IC]          15%              14%             10%
      2 * SDCCH/8                              100%           50%     [BC]      34%   [AC, BC]   25%   [AC, IC]     20%    [IC]      17%
 2 * SDCCH/8 + SDCCH/4                                                             47%            34% [BC]        28% [AC, BC]      23% [IC]
      3 * SDCCH/8                                                                                   47%              38%          31% [AC, BC]




                               Table D3: Max SDCCH / TCH ratio
                                                      Haf Rate Penetration: 10%
                                                           No Cell Broadcast
                                                                              Number of TRXs
  SDCCH configuration
                                1                2                3                   4                5               6               7
         SDCCH/4           30% [AC, IC]         9%               5%
         SDCCH/8            93% [BC]        30% [AC, IC]        17%                12%
  SDCCH/8 + SDCCH/4                          59% [BC]      33% [AC, IC, BC]     24% [AC, IC]        17%              14%             11%
      2 * SDCCH/8                              99%              54%              37% [BC]        27% [AC, IC]       22% [IC]         18%
 2 * SDCCH/8 + SDCCH/4                                                             51%            36% [BC]        30% [AC, BC]    24% [AC, IC]
      3 * SDCCH/8                                                                                   49%              39%           32% [BC]




                               Table D4: Max SDCCH / TCH ratio
                                                      Half Rate Penetration: 10%
                                                           Cell Broadcast used
                                                                              Number of TRXs
  SDCCH configuration
                                1                2                3                   4                5               6               7
         SDCCH/4              16%               5%               3%
         SDCCH/8         75% [AC, IC, BC]   24% [AC, IC]        14%                10%
  SDCCH/8 + SDCCH/4                          51% [BC]        29% [AC, IC]         21% [IC]          15%              12%             10%
      2 * SDCCH/8                              90%            50% [BC]          34% [AC, BC]     25% [AC, IC]       20% [IC]         16%
 2 * SDCCH/8 + SDCCH/4                                                             47%            33% [BC]        28% [AC, BC]      22% [IC]
      3 * SDCCH/8                                                                                   46%              37%          30% [AC, BC]




38(45)                                                                                    10/100 56-HSC 103 12 Uen Rev A 1998-12-11
                                                                                            THE ERICSSON GSM SYSTEM R7



                               Table D5: Max SDCCH / TCH ratio
                                                     Half Rate Penetration: 15%
                                                           No Cell Broadcast
                                                                            Number of TRXs
  SDCCH configuration
                                1                2                3                 4               5                6                7
        SDCCH/4           24% [AC, IC]          9%               5%
        SDCCH/8             75% [BC]        30% [AC, IC]        16%               12%
   SDCCH/8 + SDCCH/4                         59% [BC]        32% [AC, IC]        23% [IC]         17%              13%              11%
      2 * SDCCH/8                              99%            51% [BC]        36% [AC, BC]     26% [AC, IC]        21%              17%
 2 * SDCCH/8 + SDCCH/4                                                            49%           35% [BC]      29% [AC, IC, BC]   24% [AC, IC]
      3 * SDCCH/8                                                                                 47%           38% [BC]          31% [BC]




                               Table D6: Max SDCCH / TCH ratio
                                                     Half Rate Penetration: 15%
                                                           Cell Broadcast used
                                                                            Number of TRXs
  SDCCH configuration
                                1                2                3                 4               5                6                7
        SDCCH/4               13%               5%               3%
        SDCCH/8          61% [AC, IC, BC]   24% [AC, IC]        13%               10%
   SDCCH/8 + SDCCH/4                         51% [BC]        28% [AC, IC]        20% [IC]         14%              12%              10%
      2 * SDCCH/8                              90%            47% [BC]        32% [AC, BC]     24% [AC, IC]        19%              16%
 2 * SDCCH/8 + SDCCH/4                                                            45%           32% [BC]       27% [AC, IC]        22% [IC]
      3 * SDCCH/8                                                                                 45%            36% [BC]        29% [AC, BC]




                               Table D7: Max SDCCH / TCH ratio
                                                     Half Rate Penetration: 20%
                                                           No Cell Broadcast
                                                                            Number of TRXs
  SDCCH configuration
                                1                2                3                 4               5                6                7
        SDCCH/4           24% [AC, IC]          9%               5%
        SDCCH/8             75% [BC]        30% [AC, IC]        16%               11%
   SDCCH/8 + SDCCH/4                         59% [BC]        32% [AC, IC]        22% [IC]         16%              13%              11%
      2 * SDCCH/8                              99%            51% [BC]        34% [AC, BC]     25% [AC, IC]        21%              17%
 2 * SDCCH/8 + SDCCH/4                                                            47%           34% [BC]       28% [AC, IC]        23% [IC]
      3 * SDCCH/8                                                                                 46%            37% [BC]        30% [AC, BC]




10/100 56-HSC 103 12 Uen Rev A 1998-12-11                                                                                        39(45)
SDCCH DIMENSIONING GUIDELINE



                               Table D8: Max SDCCH / TCH ratio
                                                     Half Rate Penetration: 20%
                                                           Cell Broadcast used
                                                                            Number of TRXs
  SDCCH configuration
                                1                2                3                 4               5              6               7
         SDCCH/4              13%               5%               3%
         SDCCH/8         61% [AC, IC, BC]   24% [AC, IC]        13%                9%
  SDCCH/8 + SDCCH/4                          51% [BC]        28% [AC, IC]         19%             14%            11%              9%
      2 * SDCCH/8                              90%            47% [BC]        31% [AC, IC]      23% [IC]         19%             15%
 2 * SDCCH/8 + SDCCH/4                                                         43% [BC]       31% [AC, BC]    26% [AC, IC]      22% [IC]
      3 * SDCCH/8                                                                                 43%          35% [BC]       29% [AC, BC]




                               Table D9: Max SDCCH / TCH ratio
                                                     Half Rate Penetration: 25%
                                                           No Cell Broadcast
                                                                            Number of TRXs
  SDCCH configuration
                                1                2                3                 4               5              6               7
         SDCCH/4          24% [AC, IC]          8%               5%
         SDCCH/8            75% [BC]        28% [AC, IC]        15%               11%
  SDCCH/8 + SDCCH/4                          54% [BC]        30% [AC, IC]        22% [IC]         16%            13%             10%
      2 * SDCCH/8                              90%            49% [BC]        33% [AC, BC]     25% [AC, IC]      20%             16%
 2 * SDCCH/8 + SDCCH/4                                                            45%           33% [BC]      27% [AC, IC]      22% [IC]
      3 * SDCCH/8                                                                                 46%          36% [BC]       30% [AC, BC]




                               Table D10: Max SDCCH / TCH ratio
                                                     Half Rate Penetration: 25%
                                                           Cell Broadcast used
                                                                            Number of TRXs
  SDCCH configuration
                                1                2                3                 4               5              6               7
         SDCCH/4              13%               4%               2%
         SDCCH/8         61% [AC, IC, BC]     22% [IC]          13%                9%
  SDCCH/8 + SDCCH/4                         47% [AC, BC]     26% [AC, IC]         19%             14%            11%              9%
      2 * SDCCH/8                              82%            45% [BC]        30% [AC, IC]      23% [IC]         18%             15%
 2 * SDCCH/8 + SDCCH/4                                                         42% [BC]       30% [AC, BC]    25% [AC, IC]      21% [IC]
      3 * SDCCH/8                                                                                 43%          34%     [BC]   28% [AC, BC]




40(45)                                                                                  10/100 56-HSC 103 12 Uen Rev A 1998-12-11
                                                                                             THE ERICSSON GSM SYSTEM R7




                                Appendix E - Half rate, immediate
                                assignment on TCH used
                               The dimensioning tables should be used when half rate is used in a network and
                               when Immediate Assignment on TCH, SDCCH first, is used. The tables are
                               made in a way that it is possible to see the influence on SDCCH dimensioning
                               when half rate mobiles are introduced in a network. Table E1 – E10 are tables
                               for selecting SDCCH configurations when different grades of half rate mobiles
                               are present in a network, i.e. the percentage of half rate mobiles in a network,
                               and give the maximum SDCCH / TCH ratio in percent for the different
                               configurations.
                               The tables are calculated with the assumption that the limit for the capacity is
                               reached on SDCCH when 0.5 Erlang of the signalling traffic is served by TCH.
                               Max. SDCCH / TCH – ratio is calculated as:
                               (Signalling on SDCCH + TCH) / (Capacity on TCH – 0.5 Erlang)
                               The configurations shaded greys are recommended configurations according to
                               the traffic estimations in section 5.7. The tables contain recommended SDCCH
                               configurations, which will depend on whether the cell is close to the border of a
                               Location Area or not. The letters given in the square brackets indicates where
                               the recommended configurations should be used. The following abbreviation is
                               used:
                               [AC]:               Average Cell
                               [IC]:               Inner Cell
                               [BC]:               Border Cell
                               Note that SDCCH/4 should not be used in case of high paging load in the
                               Location Area.
                               The tables are made for the two cases, if Cell Broadcast is used / not used.


                               Table E1: Max SDCCH / TCH ratio
                                                       Half Rate Penetration: 5%
                                                              No Cell Broadcast
                                                                                 Number of TRXs
  SDCCH configuration
                                1                 2                  3                  4              5              6              7
        SDCCH/4          117% [AC, IC, BC] 33% [AC, IC, BC]        17%                12%
        SDCCH/8               242%               75%          38% [AC, IC, BC]     27% [AC, IC]      20%            16%            13%
   SDCCH/8 + SDCCH/4                                               59%              43% [BC]      31% [AC, IC]   25% [AC, IC]      20%
      2 * SDCCH/8                                                                     58%          43% [BC]       34% [BC]      29% [AC, IC]
 2 * SDCCH/8 + SDCCH/4                                                                                              44%          36% [BC]
      3 * SDCCH/8                                                                                                   56%            45%




10/100 56-HSC 103 12 Uen Rev A 1998-12-11                                                                                       41(45)
SDCCH DIMENSIONING GUIDELINE



                               Table E2: Max SDCCH / TCH ratio
                                                       Half Rate Penetration: 5%
                                                            Cell Broadcast used
                                                                               Number of TRXs
  SDCCH configuration
                                1                 2                3                  4               5                6               7
         SDCCH/4         83% [AC, IC, BC]    24% [AC, IC]        12%                 9%
         SDCCH/8              208%            65% [BC]      33% [AC, IC, BC]       23% [IC]         17%             14%              11%
  SDCCH/8 + SDCCH/4                                              54%             39% [AC, BC]    28% [AC, IC]      22% [IC]          19%
      2 * SDCCH/8                                                                   54%           40%     [BC]   32%   [AC, BC]   26% [AC, IC]
 2 * SDCCH/8 + SDCCH/4                                                                                              42%            34% [BC]
      3 * SDCCH/8                                                                                                   54%              43%




                               Table E3: Max SDCCH / TCH ratio
                                                      Half Rate Penetration: 10%
                                                            No Cell Broadcast
                                                                               Number of TRXs
  SDCCH configuration
                                1                 2                3                  4               5                6               7
         SDCCH/4         117% [AC, IC, BC]   30% [AC, IC]        17%                12%
         SDCCH/8              242%            68% [BC]      38% [AC, IC, BC]     27% [AC, IC]       19%             15%              13%
  SDCCH/8 + SDCCH/4                                              59%              43% [BC]       30% [AC, IC]    24% [AC, IC]        20%
      2 * SDCCH/8                                                                   58%           42% [BC]        34% [BC]        27% [AC, IC]
 2 * SDCCH/8 + SDCCH/4                                                                                              43%            35% [BC]
      3 * SDCCH/8                                                                                                   55%              43%




                               Table E4: Max SDCCH / TCH ratio
                                                      Half Rate Penetration: 10%
                                                            Cell Broadcast used
                                                                               Number of TRXs
  SDCCH configuration
                                1                 2                3                  4               5                6               7
         SDCCH/4         83% [AC, IC, BC]      22% [IC]          12%                 8%
         SDCCH/8              208%           59% [AC, BC]   33% [AC, IC, BC]       23% [IC]         16%             13%              11%
  SDCCH/8 + SDCCH/4                                              54%             39% [AC, BC]    27% [AC, IC]      22% [IC]          18%
      2 * SDCCH/8                                                                   54%           39% [BC]       31% [AC, BC]     25% [AC, IC]
 2 * SDCCH/8 + SDCCH/4                                                                                              41%            33% [BC]
      3 * SDCCH/8                                                                                                   52%              41%




42(45)                                                                                    10/100 56-HSC 103 12 Uen Rev A 1998-12-11
                                                                                                 THE ERICSSON GSM SYSTEM R7



                               Table E5: Max SDCCH / TCH ratio
                                                       Half Rate Penetration: 15%
                                                               No Cell Broadcast
                                                                                  Number of TRXs
  SDCCH configuration
                                1                  2                  3                  4               5              6              7
        SDCCH/4          90% [AC, IC, BC]    30% [AC, IC]           16%                12%
        SDCCH/8              187%              68% [BC]        36% [AC, IC, BC]     26% [AC, IC]       18%            15%            12%
   SDCCH/8 + SDCCH/4                                                57%              41% [BC]       29% [AC, IC]     23% [IC]        19%
      2 * SDCCH/8                                                                      56%           41% [BC]      33% [AC, BC]   27% [AC, IC]
 2 * SDCCH/8 + SDCCH/4                                                                                                42%          34% [BC]
      3 * SDCCH/8                                                                                                     54%            43%




                               Table E6: Max SDCCH / TCH ratio
                                                       Half Rate Penetration: 15%
                                                               Cell Broadcast used
                                                                                  Number of TRXs
  SDCCH configuration
                                1                  2                  3                  4               5              6              7
        SDCCH/4          65% [AC, IC, BC]      22% [IC]             12%                 8%
        SDCCH/8              161%            59% [AC, BC]        31% [AC, IC]         22% [IC]         16%            13%            11%
   SDCCH/8 + SDCCH/4                                              52% [BC]          37% [AC, BC]    26% [AC, IC]     21% [IC]        18%
      2 * SDCCH/8                                                                      52%           38% [BC]      30% [AC, BC]   25% [AC, IC]
 2 * SDCCH/8 + SDCCH/4                                                                                                40%          32% [BC]
      3 * SDCCH/8                                                                                                     51%            41%




                               Table E7: Max SDCCH / TCH ratio
                                                       Half Rate Penetration: 20%
                                                               No Cell Broadcast
                                                                                  Number of TRXs
  SDCCH configuration
                                1                  2                  3                  4               5              6              7
        SDCCH/4          90% [AC, IC, BC]   30% [AC, IC, BC]        16%                11%
        SDCCH/8              187%                68%           36% [AC, IC, BC]     25% [AC, IC]       18%            14%            12%
   SDCCH/8 + SDCCH/4                                                57%              39% [BC]       28% [AC, IC]     22% [IC]        19%
      2 * SDCCH/8                                                                      53%           39% [BC]      32% [AC, BC]   26% [AC, IC]
 2 * SDCCH/8 + SDCCH/4                                                                                                41%          33% [BC]
      3 * SDCCH/8                                                                                                     52%            42%




10/100 56-HSC 103 12 Uen Rev A 1998-12-11                                                                                         43(45)
SDCCH DIMENSIONING GUIDELINE



                               Table E8: Max SDCCH / TCH ratio
                                                     Half Rate Penetration: 20%
                                                           Cell Broadcast used
                                                                              Number of TRXs
  SDCCH configuration
                                1                2                3                  4               5              6              7
         SDCCH/4         65% [AC, IC, BC]     22% [IC]          12%                 8%
         SDCCH/8             161%           59% [AC, BC]    31% [AC, BC]         22% [IC]          15%            12%            10%
  SDCCH/8 + SDCCH/4                                           52% [BC]          36% [AC, BC]    26% [AC, IC]     20% [IC]        17%
      2 * SDCCH/8                                                                  50%           37% [BC]      30% [AC, BC]     24% [IC]
 2 * SDCCH/8 + SDCCH/4                                                                                            39%         32% [AC, BC]
      3 * SDCCH/8                                                                                                 50%            40%




                               Table E9: Max SDCCH / TCH ratio
                                                     Half Rate Penetration: 25%
                                                           No Cell Broadcast
                                                                              Number of TRXs
  SDCCH configuration
                                1                2                3                  4               5              6              7
         SDCCH/4         90% [AC, IC, BC]   27% [AC, IC]        16%                11%
         SDCCH/8             187%            62% [BC]      34% [AC, IC, BC]     24% [AC, IC]       17%            14%            12%
  SDCCH/8 + SDCCH/4                                             54%              38% [BC]       27% [AC, IC]     22% [IC]        18%
      2 * SDCCH/8                                                                  51%           38% [BC]      30% [AC, BC]   25% [AC, IC]
 2 * SDCCH/8 + SDCCH/4                                                                                            39%          32% [BC]
      3 * SDCCH/8                                                                                                 51%            41%




                               Table E10: Max SDCCH / TCH ratio
                                                     Half Rate Penetration: 25%
                                                           Cell Broadcast used
                                                                              Number of TRXs
  SDCCH configuration
                                1                2                3                  4               5              6              7
         SDCCH/4         65% [AC, IC, BC]     20% [IC]          11%                 8%
         SDCCH/8             161%           54% [AC, BC]     29% [AC, IC]         21% [IC]         15%            12%            10%
  SDCCH/8 + SDCCH/4                                           49% [BC]          34% [AC, BC]    25% [AC, IC]      20%            17%
      2 * SDCCH/8                                                                  48%           36% [BC]      28% [AC, IC]     23% [IC]
 2 * SDCCH/8 + SDCCH/4                                                                                          37% [BC]      31% [AC, BC]
      3 * SDCCH/8                                                                                                 49%            39%




44(45)                                                                                   10/100 56-HSC 103 12 Uen Rev A 1998-12-11
                                            THE ERICSSON GSM SYSTEM R7




10/100 56-HSC 103 12 Uen Rev A 1998-12-11                        45(45)

								
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