SDCCH and PS Data Channels

Nokia Siemens Networks GSM/EDGE BSS, rel. RG20(BSS), operating documentation, issue 02

Feature description

BSS21161: SDCCH and PS data channels on DFCA TRX

DN70648156

Issue 2-0Approval Date 2010-07-28

Confidential

2 DN70648156Issue 2-0

BSS21161: SDCCH and PS data channels on DFCATRX

Id:0900d805807c2051Confidential

The information in this document is subject to change without notice and describes only the product defined in the introduction of this documentation. This documentation is intended for the use of Nokia Siemens Networks customers only for the purposes of the agreement under which the document is submitted, and no part of it may be used, reproduced, modified or transmitted in any form or means without the prior written permission of Nokia Siemens Networks. The documentation has been prepared to be used by professional and properly trained personnel, and the customer assumes full responsibility when using it. Nokia Siemens Networks welcomes customer comments as part of the process of continuous development and improvement of the documentation.

The information or statements given in this documentation concerning the suitability, capacity, or performance of the mentioned hardware or software products are given "as is" and all liability arising in connection with such hardware or software products shall be defined conclusively and finally in a separate agreement between Nokia Siemens Networks and the customer. However, Nokia Siemens Networks has made all reasonable efforts to ensure that the instructions contained in the document are adequate and free of material errors and omissions. Nokia Siemens Networks will, if deemed necessary by Nokia Siemens Networks, explain issues which may not be covered by the document.

Nokia Siemens Networks will correct errors in this documentation as soon as possible. IN NO EVENT WILL Nokia Siemens Networks BE LIABLE FOR ERRORS IN THIS DOCUMENTA-TION OR FOR ANY DAMAGES, INCLUDING BUT NOT LIMITED TO SPECIAL, DIRECT, INDI-RECT, INCIDENTAL OR CONSEQUENTIAL OR ANY LOSSES, SUCH AS BUT NOT LIMITED TO LOSS OF PROFIT, REVENUE, BUSINESS INTERRUPTION, BUSINESS OPPORTUNITY OR DATA,THAT MAY ARISE FROM THE USE OF THIS DOCUMENT OR THE INFORMATION IN IT.

This documentation and the product it describes are considered protected by copyrights and other intellectual property rights according to the applicable laws.

The wave logo is a trademark of Nokia Siemens Networks Oy. Nokia is a registered trademark of Nokia Corporation. Siemens is a registered trademark of Siemens AG.

Other product names mentioned in this document may be trademarks of their respective owners, and they are mentioned for identification purposes only.

Copyright © Nokia Siemens Networks 2010. All rights reserved

f Important Notice on Product Safety Elevated voltages are inevitably present at specific points in this electrical equipment. Some of the parts may also have elevated operating temperatures.

Non-observance of these conditions and the safety instructions can result in personal injury or in property damage.

Therefore, only trained and qualified personnel may install and maintain the system.

The system complies with the standard EN 60950 / IEC 60950. All equipment connected has to comply with the applicable safety standards.

The same text in German:

Wichtiger Hinweis zur Produktsicherheit

In elektrischen Anlagen stehen zwangsläufig bestimmte Teile der Geräte unter Span-nung. Einige Teile können auch eine hohe Betriebstemperatur aufweisen.

Eine Nichtbeachtung dieser Situation und der Warnungshinweise kann zu Körperverlet-zungen und Sachschäden führen.

Deshalb wird vorausgesetzt, dass nur geschultes und qualifiziertes Personal die Anlagen installiert und wartet.

Das System entspricht den Anforderungen der EN 60950 / IEC 60950. Angeschlossene Geräte müssen die zutreffenden Sicherheitsbestimmungen erfüllen.

DN70648156 Issue 2-0

3



Table of contentsThis document has 24 pages.

Reason for update . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71.1 In general. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71.2 Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82.1 Software requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82.2 Hardware requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

3 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93.1 Support of GPRS territories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93.1.1 PS DFCA radio resource managment . . . . . . . . . . . . . . . . . . . . . . . . . . 103.1.2 DFCA PS territory C/I estimation process . . . . . . . . . . . . . . . . . . . . . . . 103.1.3 Final selection of DFCA hopping parameters . . . . . . . . . . . . . . . . . . . . 133.1.4 Training sequence selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133.1.5 Resource preference between non-DFCA TRXs and DFCA TRXs . . . . 133.1.6 Hopping list handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133.1.7 Cell allocation list with PS DFCA functionality . . . . . . . . . . . . . . . . . . . . 143.1.8 Unsynchronized PS DFCA functionality. . . . . . . . . . . . . . . . . . . . . . . . . 143.1.9 PS DFCA management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143.1.9.1 Territory type planning with PS DFCA . . . . . . . . . . . . . . . . . . . . . . . . . . 143.1.9.2 DFCA MA list planning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153.2 SDCCH support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163.3 Pre-emption support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173.4 DTM support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

4 System impacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184.1 DFCA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184.2 GPRS, EGPRS and CS3&4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184.3 DTM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184.4 Dynamic SDCCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184.5 Increased dynamic SDCCH capacity. . . . . . . . . . . . . . . . . . . . . . . . . . . 184.6 Pre-emption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184.7 Enhancement on priority call and pre-emption in BSC . . . . . . . . . . . . . 194.8 Energy optimised TCH allocation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

5 User interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205.1 Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205.2 MML commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235.3 Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235.4 Measurements and counters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235.4.1 Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235.4.2 Counters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

4 DN70648156Issue 2-0



List of figuresFigure 1 Example of a DFCA configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Figure 2 DFCA C/I estimations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Figure 3 PS data throughput . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

DN70648156 Issue 2-0

5



List of tablesTable 1 Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Table 2 Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Table 3 Counter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

6 DN70648156Issue 2-0


Id:0900d805807c8cbaConfidential

Reason for update

Reason for update

Issue history

Details

Issue Number

Date of Issue Reason for Update

1-0 03/2009 First issue for new release

1-1 08/2009 Editorial changes

2-0 07/2010 Updated with impact of Energy optimised TCH alloca-tion feature.

DN70648156 Issue 2-0

7


Introduction

Id:0900d8058060cab6Confidential

1 Introduction

1.1 In generalThe “SDCCH and PS data channels on DFCA TRX” (BSS21161) feature is an enhance-ment of the “Dynamic frequency and channel allocation” (BSS11052) feature.

If DFCA is used without the “SDCCH and PS data channels on DFCA TRX” feature, then DFCA TRXs can only carry CS traffic, and the SDCCH and PS data channels use the BCCH TRX. In this case, if more capacity is required for the SDCCH or PS data chan-nels, additional regular TRXs need to be created. This requires additional frequency planning and more spectrum, which is taken either from BCCH frequencies or from DFCA frequencies. Typically, in the BCCH layer, frequency re-use is already tight, and the re-planning of the BCCH layer is difficult and time consuming. If frequencies are taken from the DFCA layer, then the spectral efficiency of the DFCA feature drops.

The “SDCCH and PS data channels on DFCA TRX” feature provides a superior solution, by enabling the use of SDCCH and PS data channels on DFCA TRXs. As this feature is an enhancement of the CS DFCA feature, it requires activation of the license keys of both features in order to be operational.

1.2 BenefitsThis feature is very important for DFCA rollouts where configuring the additional SDCCH and PS data channels to use extra regular TRXs is not a practical solution. In most cases, the BCCH TRX capacity is not enough for the CCCH, SDCCHs and PS data channels.

The feature improves the ease of operability in the BSS and reduces operating expenses by avoiding the need for separate frequency planning for additional non-DFCA TRXs. Whenever additional SDCCH and PS data channel capacity is required, the DFCA uses the already configured DFCA TRXs, selecting frequencies dynamically and automatically.

The operator also saves on capital expenses by exploiting DFCA to its full potential, thereby improving data and radio network performance, as well as the network’s readi-ness to cater for increased PS traffic. With the introduction of this feature, SDCCH capacity is no longer limited to regular TRXs.

8 DN70648156Issue 2-0


Id:0900d8058025ea09Confidential

Requirements

2 Requirements

2.1 Software requirementsThe “SDCCH and PS data channels on DFCA TRX” feature requires the following software releases: • BSC S14 • BTS UltraSite CX7.0 • BTS MetroSite CXM7.0 • BTS FlexiEDGE EP3.0 • NetAct OSS5.1 CD set 2

2.2 Hardware requirementsThis feature requires the following hardware: • MetroSite EDGE TRX • UltraSite EDGE baseband unit (BB2E or BB2F)

DN70648156 Issue 2-0

9


Functional description

Id:0900d805805ed967Confidential

3 Functional descriptionThe “SDCCH and PS data channels on DFCA TRX” feature extends DFCA functionality to support SDCCH and GPRS/EDGE traffic, in addition to CS traffic. An example DFCA configuration is shown in “Figure 1”. With the introduction of this feature, only the BCCH TRX remains out of the DFCA algorithm’s reach. PS (GPRS) territories can be upgraded and downgraded freely to and from DFCA TRXs. Similarly, both static and dynamic SDCCH channels can be used by the DFCA layer.

Support of this feature makes it possible to use both DTM and pre-emption on DFCA TRXs.

Figure 1 Example of a DFCA configuration

This section is divided into the following sub-sections: • “Support of GPRS territories” • “SDCCH support” • “Pre-emption support” • “DTM support”

For more information on activating this feature, refer to “Activating and testing BSS21161: SDCCH and PS data channels on DFCA TRX”.

3.1 Support of GPRS territoriesWhen a GPRS territory is upgraded to use a DFCA TRX, the DFCA algorithm selects appropriate DFCA hopping parameters for those TSLs upgraded to the GPRS territory. The same DFCA hopping parameters are used for the entire PS territory on the TRX. The DFCA hopping parameters are delivered to the BTS by means of a new Abis message, and to the PCU using the existing GPRS territory upgrade message. The PCU uses the DFCA TRX as if it were a regular TRX, and does not need to perform dynamic channel allocation calculations e.g. for frequency use. The PCU only saves the hopping

TS 0 TS 1 TS 2 TS 3 TS 4 TS 5 TS 6 TS 7

BCCH TRX

DFCA TRX 1

DFCA TRX 2

DFCA TRX 3

BCCH SDCCH

SDCCH SDCCH

SDCCH

CS

CS territory

GPRS/EDGE territory

GPRS/EDGE territory

CS territory

10 DN70648156Issue 2-0




parameters received from the DFCA algorithm, and uses these parameters for all packet-related communication with the TRX.

All GPRS territory types (dedicated, default and additional) are supported on the DFCA TRX. A GPRS territory upgrade to a new DFCA TRX is triggered either by a radio resource change in the cell or when the PCU requests more resources.

3.1.1 PS DFCA radio resource managmentThe main difference between DFCA channel allocation and regular channel allocation is that, when a DFCA radio channel is allocated, the frequency hopping parameters are also allocated. In the case of DFCA CS services, the radio frequency hopping parame-ters are allocated separately for each MS connection. Refer to the “Dynamic frequency and channel allocation” (BSS11052) feature description for more information.

In the case of PS services, the introduction of DFCA only affects the selection of hopping parameters. Radio resource management is done just like it is without DFCA. First the radio resources are divided between CS and PS services, TRX by TRX, in what is called the territory method. After this, the BSC allocates the best possible hopping parameters for the selected TRX in the PS territory. All the PS territory TSLs on the TRX use the same hopping parameters. The hopping parameters include: MA list, MAIO and TSC.

Once the BSC has selected the timeslots and DFCA hopping parameters for the PS ter-ritory, the PCU assigns these timeslots to individual mobile station connections, just like it does with a radio frequency hopping TRX. Refer to the “GPRS system feature descrip-tion” for more information.

3.1.2 DFCA PS territory C/I estimation processIn the C/I estimation process, the DFCA algorithm determines the co-channel and adjacent channel interference for every timeslot in the PS territory. The algorithm esti-mates how this interference would change for all available combinations of DFCA MA lists and MAIO.

The DFCA algorithm searches the neighboring cells listed in the incoming and outgoing BIM of each BTS. Out of these neighboring cells, instances of co-channel and adjacent channel interference are identified using the DFCA tables in the BSC, and the real level of interference caused by these instances is estimated. In cases of adjacent channel interface, an 18 dB offset is added to the C/I estimate to account for a lower interference relation when compared to co-channel interference.

For each channel (combination of TSL, MA list and MAIO), the DFCA algorithm repeats the C/I estimation process for the following types of interference (shown in “Figure 2”): • incoming downlink interference • incoming uplink interference • outgoing downlink interference • outgoing uplink interference

For each of these four cases, the algorithm calculates the minimum C/I difference between the estimated C/I and a target C/I value. This minimum value corresponds to the neighboring cell that experiences or causes the most restrictive interference. The lowest of these four minimum values therefore corresponds to the most restrictive inter-ference caused by this particular channel. This minimum value is used by the DFCA algorithm to compare various channel combinations, and to finally decide which is the best combination of frequency hopping parameters for all the PS timeslots.

DN70648156 Issue 2-0

11




Figure 2 DFCA C/I estimations

Step 1: assigning TSLs to the PS territoryWhen PS DFCA is used, the BTS can only have a BCCH TRX and DFCA TRXs, and therefore the territory method is used in the same way as it is done without DFCA (refer to the “GPRS system feature description” for more information). The “Prefer BCCH fre-quency GPRS (BFG)” parameter can be used to determine whether the BCCH TRX or DFCA TRXs are preferred in PS territory allocation. After selecting the TRX and the required TSLs, the DFCA algorithm checks whether the TSLs can be upgraded to the PS territory, based on the C/I estimation. If a TSL does not meet the threshold defined by the “Soft blocking C/I GPRS” parameter, this TSL is excluded from the upgrade, and only those TSLs that have a larger TSL number (that is, TSLs at the end of the TRX) are upgraded to the territory.

For the case that the TRX already has a PS territory, and this territory is extended, the DFCA algorithm always uses the same hopping parameters as used in the existing ter-ritory. In this case, only a soft blocking check is made to ensure appropriate quality of the upgraded TSLs. DFCA does not allow co-channel use within a cell. With PS DFCA, it may happen that, when a PS territory is extended on a TRX, another CS DFCA is already using the same DFCA hopping parameters on another TRX. In order to allow a GPRS upgrade, the DFCA algorithm starts an intracell handover to move the CS, so that the DFCA hopping parameters can now be changed.

Step 2: incoming downlink C/I estimationIn this step, interfering co-channel and adjacent channel connections in neighboring cells are identified, and the level of interface potentially caused by each interfering cell is estimated. The algorithm goes through the cells listed in the incoming interference BIM table and checks the DFCA radio resource (RR) table for ongoing co-channel and adjacent channel connections in these cells.

PSUL

PSDL

New PS channel Existing connectionin neighboring cell

Outgoing UL interference

Incoming DL interference

Incoming UL interference

Outgoing DL intererence

12 DN70648156Issue 2-0




When an interfering connection is found, the C/I value from the incoming interference BIM table is used. This statistical C/I value is adjusted by the actual downlink transmit power reduction of the interfering connection, which is available in the DFCA RR table.

Using the real C/I value estimates for each interfering connection, the most significant incoming downlink interference source is identified for each TSL in the PS territory.

The initial downlink transmit power for the PS territory is always the maximum power level.

Step 3: incoming uplink C/I estimationTo estimate the incoming uplink C/I, the outgoing interface BIM is used. This exploits the fact that the interference propagation path of the outgoing downlink is the same as that of the incoming uplink. The uplink incoming C/I estimate is derived by using the C/I values from the outgoing interference BIM, and adjusting these values by the uplink transmit power reductions of the possibly interfering connections, available in the DFCA RR table.

Using the real C/I value estimates for each interfering connection, the most significant uplink incoming interference source is identified for each TSL in the PS territory.

The inital uplink transmit power for the PS territory is always the maximum power level.

Step 4: outgoing downlink C/I estimationIn this step, the co-channel and adjacent channel connections in neighboring cells that may experience interference caused by the possible PS channels are identified, and the level of interference affecting each of these interfered channels is estimated. When con-sidering outgoing interface, it is assumed that the PS territory causes the same amount of interference, irrelevant of whether the PS territory is really used by PS connections or not.

The DFCA algorithm goes through the cells listed in the outgoing interference BIM table, and checks the DFCA RR table for ongoing co-channel and adjacent channel connec-tions in these cells. Whenever a channel is found that would experience interference, the DFCA RR table record of this channel is examined to see if a directly measured C/I value is available. If the directly measured C/I is not available, the C/I value from the outgoing interference BIM table is used. This value is scaled by the BIM scaling factor for the interfered connection under consideration, which is also listed in the DFCA RR table. In the case of PS territory TSLs, a directly measured C/I value is not available.

The maximum affected outgoing downlink interference is identified by calculating the minimum C/I difference for each interfered channel, that is, the difference between the C/I target of the interfered connection (taken from the DFCA RR table) and the C/I caused by the new potential PS territory channel.

Step 5: outgoing uplink C/I estimationIn this step, the uplink interference that could be caused in neighboring cells by a poten-tial PS territory timeslot is estimated. The outgoing uplink C/I estimation exploits the fact that the interference propagation path of the outgoing uplink interference is the same as that of the incoming downlink interference. This means that the incoming interference BIM table is used.

For the outgoing uplink C/I estimation, all the C/I values in the incoming interference BIM table are examined. Each C/I value is scaled using the BIM scaling factor corresponding to the channel under consideration, taken from the DFCA RR table.

DN70648156 Issue 2-0

13




The maximum affected outgoing uplink interference is identified by calculating the minimum C/I difference for each interfered connection, that is, the difference between the C/I target of the interfered connection (taken from the DFCA RR table) and the C/I caused by the new potential PS territory channel.

HR-specific considerations in C/I estimationsWhen a half-rate (HR) connection is causing interference on a PS territory TSL, the incoming C/I from each HR sub-channel is increased by 3 dB.

3.1.3 Final selection of DFCA hopping parametersThe following rules are used when deciding which is the best MA-MAIO combination for a PS territory TSL: • If an unused MA-MAIO combination is found among the incoming BIM neighbors for

all TSLs, then this combination is selected. • If an unused combination is not found, but the C/I values of all TSLs are above the

C/I target for GPRS (refer to the “C/I target GPRS” parameter description), then the combination with the highest C/I sum is selected. The value of 63 dB is used in the values for idle TSLs.

• If some TSLs have a C/I value below the C/I target, but all C/I values are above the C/I soft blocking limit for GPRS (refer to the “Soft blocking C/I GPRS” parameter description), the sum of those C/I values that are below the C/I target is calculated and the MA-MAIO combination with the lowest sum below the C/I target is selected.

• If the sum below the C/I target is equal for several combinations, then the sum of values above the C/I target is calculated and the MA-MAIO combination with the highest C/I sum above the target is selected.

3.1.4 Training sequence selectionWith PS DFCA, the same DFCA hopping parameters are used for all TSLs included in the PS territory on the TRX. When the PS territory is extended, the same TSC is selected for the upgraded TSLs as that used in the other TSLs on the same TRX.

In case of a totally new upgrade, the DFCA algorithm can select any TSC. In this case, the TSC is chosen according to the worst TSL that is included in the territory upgrade. The chosen TSC is therefore the best possible for the most critical TSL in the territory.

3.1.5 Resource preference between non-DFCA TRXs and DFCA TRXsWhen PS DFCA is used, all TRXs except the BCCH TRX have to be configured as DFCA TRXs. The “Prefer BCCH frequency GPRS (BFG)” parameter is therefore used to favor either the BCCH TRX or the other DFCA TRXs in GPRS channel allocation.

3.1.6 Hopping list handlingThe MS assignment procedure in the PS territory differs from that in the CS territory. For PS services, the MA list can be broadcast to be readily available in the MS, while for CS services the MA list is sent to the MS in the assignment.

For this efficent PS assignment procedure to be also used in the case of PS territories, only one MA list is allowed for PS services in the BCCH BTS. There are no limitations in other BTSs.

14 DN70648156Issue 2-0




3.1.7 Cell allocation list with PS DFCA functionalityThe “SDCCH and PS data channels on DFCA TRX” feature removes the need for having two different hopping layers in the DFCA BTS, as extra regular TRXs are not needed any more. This allows use of one common cell allocation list for both the SDCCH and TCH phases, facilitating an optimized call setup and handover procedure (refer to the “AMR signaling optimization (BSS20916)” feature description).

When this feature is in use, the cell allocation list includes only frequencies from DFCA hopping lists (DMALs) or from unsynchronized hopping lists (DUMALs), depending on whether the DFCA TRXs are working in synchronized or non-synchronized mode.

3.1.8 Unsynchronized PS DFCA functionalityFor the case that the DFCA loses interference control, refer to “Automatic configuration changes” in the “Dynamic frequency and channel allocation” (BSS11052) feature description. With PS DFCA the same unsynchronized DFCA MA list is used as for the CS service.

3.1.9 PS DFCA managementThis section is divided into: • “Territory type planning with PS DFCA” • “DFCA MA list planning”

3.1.9.1 Territory type planning with PS DFCAWith PS DFCA, a TSL is considered to be occupied irrespective of whether there really is a GPRS connection taking place or not. Downlink and uplink power use is also always considered to be at a maximum. This means that PS DFCA always requires more fre-quency spectral capacity in DFCA C/I estimation than it really uses. With PS DFCA, the same DFCA hopping parameters (MA, MAIO and TSC) are always used for all the TSLs in the PS territory on the TRX. These PS-specific DFCA rules should also be taken into account when planning the PS territory.

There are three different territory types possible: • “Additional territory” • “Default territory” • “Dedicated territory”

Additional territoryThe additional territory type is the most spectrally efficient, as it is only used when there really is an active MS in the territory. In the case that a totally new TRX is upgraded to PS territory, the DFCA algorithm can select any available DFCA hopping parameters for the upgraded territory. After the transfer of data is completed, the additional territory is downgraded and used DFCA resources are released. When additional resources are needed again, the DFCA algorithm can once again allocate the best possible hopping parameters for the TRX, without the need to keep the same parameters used by the previous territory on the TRX. This territory type maximizes PS quality and hence also PS data throughput on the DFCA TRX.

DN70648156 Issue 2-0

15




Default territoryWhen a default territory is defined for a DFCA TRX, the DFCA hopping parameters remain the same as long as the territory stays in the TRX. After the entire territory is downgraded from the DFCA TRX, e.g. due to a traffic peak, the DFCA algorithm can select new DFCA hopping parameters.

Dedicated territoryIn a dedicated territory, the TSLs are allocated to a PS territory for a very long time, even months. A TSL in a PS territory on a DFCA TRX is considered to be an occupied TSL irrespective of whether there really is any ongoing PS traffic or not. This results in a dedicated PS territory that is not as spectrally efficient as an additional PS territory. In normal DFCA functionality, hopping parameters, and hence spectral resources, are allo-cated only when these are really in use. This kind of limitation mean that special consid-erations need to be taken into account when a dedicated territory is to be used on a DFCA TRX. Refer to “DFCA MA list planning” for more information.

3.1.9.2 DFCA MA list planningWith PS DFCA, the MA list planning is simpler than with for non-PS DFCA only (refer to the “Dynamic frequency and channel allocation” (BSS11052) feature description), as there is no need to plan for an extra regular TRX layer. The frequency band is simply split between DFCA frequencies and the BCCH layer. Typically, all the DFCA BTSs in a band have the same frequency plan, and DFCA frequencies are divided between one or more DFCA MA lists. In the BSC, the PS data implementation is limited so that the BCCH BTS can only have one MA list. Refer to the “GPRS system feature description” for more information. This also limits the DFCA PS implementation so that only one DFCA MA list can be used for PS data. The operator needs to define all the DFCA fre-quencies in one list, and set that to be valid for both CS and PS services, or then select a DFCA MA list that is also valid for PS services, or just for PS services. The “DFCA MA list usage” parameter defines whether the DFCA MA list is used for CS services, for PS services, or both.

When both the CS and PS territories can use all the available hopping frequencies, the PS data throughput can be optimized. When DFCA is used, a C/I target parameter defines how many dBs are allocated for a PS territory and also how many for the differ-ent CS speech codecs. “Figure 3” shows how EGPRS performance is strongly affected by the C/I of the channel: • If the C/I for the PS territory is set to high, throughput is maximized, but CS perfor-

mance in busy hour situations may also be affected, and a soft blocking situation may arise

• If the C/I target is set to lower than the speech C/I target, maximal throughput is still offered in lower CS traffic situations, but the speech quality in busy hours is not affected that much.

16 DN70648156Issue 2-0




Figure 3 PS data throughput

This kind of C/I planning works especially for the case that DFCA TRXs use only addi-tional PS resources. In the additional PS territory type, the DFCA algorithm can dynam-ically control the quality of the PS territory by assigning resources only when these are needed and used.

In case of dedicated and default territories, the DFCA algorithm cannot control the used channels dynamically on DFCA TRXs. If PS traffic is only occasional and bursty, use of the default and dedicated territories on a DFCA TRX may waste some capacity, as it is reserved but not used. In this kind of situation, an alternative DFCA MA list plan for the PS may work better.

A frequency plan for DFCA could be as follows: • All hopping frequencies are used in the CS DFCA MA list • Some of the CS DFCA frequencies are also reused in a separate PS DFCA MA list,

which is assigned to a different MS group using the “DFCA MA list group id” param-eter

Using this kind of frequency plan, the performance of PS services is limited according to the number of PS frequencies. PS and CS services interfere with each other ran-domly, causing uncontrolled interference of the CS calls. This interference can be toler-ated by CS calls if there are enough controlled frequencies in the CS MA list.

3.2 SDCCH supportThis feature covers both static and dynamic SDCCHs for DFCA TRXs. SDCCH alloca-tion uses the same DFCA MA lists as those used for traffic channels.

The BSC allocates DFCA hopping parameters when the first sub-channel is reserved. Since one SDCCH TSL includes several sub-channels that are used by different MSs,

(E)GPRS throughput/TSL

0

10

20

30

40

50

60

70

0 4 8 12 16 20 24 28 32

C/I

Kbp

s EGPRS

GPRS CS1-2

(E)GPRS throughput per TSL

C/I

kbit/

s

0 4 8 12 16 20 24 28 320

10

20

30

40

50

60

70

EGPRS

GPRS CS1-2

DN70648156 Issue 2-0

17




any mobile-specific measurements are not used in the channel C/I estimation process. The allocation is done using the same algorithm as that used to allocate a TSL in PS territory. The BSC optimizes the SDCCH quality, allocating always the best available SDCCHs. If several SDCCHs have the same C/I, the BSC allocates the SDCCH TSLs that are already using the most SDCCH sub-channels. In this way, the BSC ensures that SDCCH TSLs are used as efficiently as possible. In the C/I estimation process, the SDCCH-specific C/I limits are used. If none of the available SDCCHs are able to meet the C/I soft blocking SDCCH requirement, the request is blocked from the DFCA layer. If TSL reconfiguration for dynamic SDCCH was blocked from the DFCA layer, the BSC checks the possibility of dynamic SDCCH on the BCCH TRX.

The parameters are delivered to the BTS using the channel activation message, as in the case of a TCH setup. The BSC automatically informs neighboring BSCs about allo-cated PS territory and static SDCCH channels on DFCA TRXs.

Within the SDCCH TSL, all sub-channels use the same hopping parameters, whereas different SDCCH TSLs on the TRX can have different DFCA hopping parameters. When all SDCCH channels are released from the SDCCH TSL, the BSC also releases the hopping parameters. In case of a dynamic SDCCH, the TSL is also reconfigured to a TSL. Whenever the first sub-channel is again allocated from the SDCCH TSL, the BSC can allocate any DFCA hopping parameters for the TSL, according to the current C/I sit-uation in the the network, in order to offer the best possible quality for SDCCH channels.

SDCCH allocation uses the following order of preference: • Static SDCCH from the BCCH TRX • Static SDCCH from a DFCA TRX • Dynamic SDCCH from a DFCA TRX • Dynamic SDCCH from the BCCH TRX

3.3 Pre-emption supportThe “SDCCH and PS data channels on DFCA TRX” feature also includes the pre-emption procedure for DFCA TRXs. In a temporary congestion situation, the priority levels and the pre-emption indicators may be used to determine whether an assignment or handover request has to be processed unconditionally and immediately. The pre-emption procedure is triggered, causing the forced release or forced handover of a lower-priority connection if no resource is available immediately. Refer to the “Radio resource pre-emption and queuing” feature description for more information.

If a forced handover is done for a call on a DFCA TRX, the BSC recalculates the C/I estimate for the channel. The C/I estimation is done in the same way for a normal call setup and for a handover procedure.

3.4 DTM supportThis feature also includes support for DTM calls. In DTM, CS and PS calls are allocated in consecutive timeslots. The DTM connection uses the DFCA hopping parameter defined for the GSM/EDGE territory for both CS and PS services.

18 DN70648156Issue 2-0



System impacts

4 System impactsThis chapter describes the dependencies or interactions of the “SDCCH and PS data channels on DFCA TRX” feature with other features and functionalities.

The chapter is divided into the following sections: • “DFCA” • “GPRS, EGPRS and CS3&4” • “DTM” • “Dynamic SDCCH” • “Increased dynamic SDCCH capacity” • “Pre-emption” • “Enhancement on priority call and pre-emption in BSC” • “Energy optimised TCH allocation”

4.1 DFCA“SDCCH and PS data channels on DFCA TRX” is an enhancement of the “Dynamic fre-quency and channel allocation” (BSS11052) feature, and requires this feature to be licensed, activated and configured.

4.2 GPRS, EGPRS and CS3&4The “GPRS”, “EGPRS” and “CS3&4” licensed features are supported on DFCA TRXs by means of “SDCCH and PS data channels on DFCA TRX”.

4.3 DTMThe “Dual transfer mode” (BSS20088) licensed feature is also supported on GPRS DFCA TRXs.

4.4 Dynamic SDCCH“Dynamic SDCCH” is supported on DFCA TRXs by means of “SDCCH and PS data channels on DFCA TRX”, as long as the DYNAMIC_SDCCH parameter is set to TRUE in the PRFILE parameter file.

Refer to the “PRFILE and FIFILE parameter list” for more information on the DYNAMIC_SDCCH parameter.

4.5 Increased dynamic SDCCH capacityThe “Increased dynamic SDCCH capacity” licensed feature is supported on DFCA TRXs, if “Dynamic SDCCH” is supported.

4.6 Pre-emptionPre-emption is used on DFCA TRXs by means of “SDCCH and PS data channels on DFCA TRX”, as long as the PREEMPT_USAGE parameter is set to TRUE in the PRFILE parameter file.

DN70648156 Issue 2-0

19


System impacts


Refer to the “PRFILE and FIFILE parameter list” for more information on the DYNAMIC_SDCCH parameter.

4.7 Enhancement on priority call and pre-emption in BSCThe “Enhancements on priority call and pre-emption in BSC” (BSS20869) feature is sup-ported on DFCA TRXs, if “Pre-emption” is supported.

4.8 Energy optimised TCH allocationWhen PS and SDCCH on DFCA TRX feature is in use with “Energy optimsed TCH allo-cation”, DL RX level based TRX selection is applied for DFCA TCH allocation which prefers BCCH TRX for TCH allocation if DL RX level is within DL RX level window.

20 DN70648156Issue 2-0


Id:0900d80580606d47Confidential

User interface

5 User interfaceThe impacts on the user interface due to the “SDCCH and PS Data Channels on DFCA TRX” feature are described in this chapter.

The chapter is divided into the following sections: • “Parameters” • “Alarms” • “Measurements and counters”

5.1 Parameters“Table 1” shows the parameters related to the “SDCCH and PS data channels on DFCA TRX” feature.

Name Level Description Range Default value

TRX priority in TCH allocation (TRP);

trxPriorityInTchAlloc

SEG The TRP parameter is used to determine whether the BCCH TRX or DFCA TRXs are pre-ferred in TCH allocation.

If the license key for this feature is not activated, then the TRP parameter is used to define whether the BCCH TRX or other TRXs of the regular fre-quency area are pre-ferred in TCH allocation. Refer to the “BSS radio network parameter dic-tionary” for more infor-mation.

0 - no prioritization between TRXs

1 - TCH is allocated primarily from the BCCH TRX

2 - TCH is allocated primarily from DFCA TRXs

3 - TCH is allocated primarily from DFCA TRXs for AMR users, and from the BCCH TRXs for non-AMR users.

0

Table 1 Parameters

DN70648156 Issue 2-0

21


User interface


Prefer BCCH fre-quency GPRS (BFG);

preferBCCHfreqGPRS2

SEG The BFG parameter is used to determine whether the BCCH TRX or DFCA TRXs are pre-ferred in GPRS channel allocation, when a DFCA TRX is configured for PS use in the BTS.

If the license key for this feature is not activated, then the BFG parameter is used to define whether the BCCH TRX or other TRXs of the regular fre-quency area are pre-ferred in GPRS channel allocation. Refer to the “BSS radio network parameter dictionary” for more information.

0 - no prioritization between TRXs

1 - GPRS channels are allocated primarily from the BCCH TRX

2 - GPRS channels are allocated primarily from a DFCA TRX

0

C/I target GPRS;

dfcaCiTargetGPRS

BSC This parameter defines the target C/I value for GPRS connections on the DFCA layer.

Its value should be equal to or greater than the value of the “Soft blocking C/I GPRS” parameter.

The parameter is only visible when the feature is activated.

0 .. 63 dB,

in steps of 1 dB

20 dB

C/I target SDCCH;

dfcaCiTargetSDCCH

BSC This parameter defines the target C/I value for SDCCH connections on the DFCA layer.

Its value should be equal to or greater than the value of the “Soft blocking C/I SDCCH” parameter.


0.. 63 dB,

in steps of 1 dB

14 dB


Table 1 Parameters (Cont.)

22 DN70648156Issue 2-0



User interface

Soft blocking C/I GPRS;

dfcaSoftBlockingCiGPRS

BSC This parameter defines the minimum acceptable (soft blocking) C/I value for GPRS connections on the DFCA layer.


-20 .. -43 dB,

in steps of 1 dB,

where -20 dB means that soft blocking is disabled

-20 dB

Soft blocking C/I SDCCH;

dfcaSoftBlockingCiSDCCH

BSC This parameter defines the minimum acceptable (soft blocking) C/I value for SDCCH connections on the DFCA layer.


-20.. 43 dB,

in steps of 1 dB,

where -20 dB means that soft blocking is disabled

-20 dB

DFCA MA list usage;

dfcaMAListUsage

BSC This parameter defines whether the DFCA MA frequency list is used for CS or PS channels, or both.

It is related to the MA list parameter “DFCA MA list state (MALS)”, which indicates if the list is ready for use, and to the BTS parameter “DFCA mobile frequency alloca-tion lists (DMAL)”, which indicates which DFCA MA lists are attached to the BTS in question.


CS, PS or CSPS (both) CSPS



DN70648156 Issue 2-0

23


User interface


5.2 MML commandsThe “SDCCH and PS data channels on DFCA TRX” solution has an impact on the fol-lowing MML commands: • EBE command for creating MA frequency lists • EBT command for modifying MA frequency lists • EBI command for the output of MA frequency lists • EEH command for modifying DFCA parameters • EEO command for the output of BSC parameters • EQO, EQA, EQC and EQE commands for handling BTS parameters

5.3 AlarmsThe “SDCCH and PS data channels on DFCA TRX” feature does not introduce any new alarms to the BSS.

However, the existing alarm with ID 3273 and message “GPRS/EDGE territory failure” is modified to reflect the new causes, related to DFCA parameters, that can result in GPRS territory upgrade failures.

These new causes take into account: • Conflicts in DFCA hopping parameters • Connection problems between the BSC and BTS • RNW configuration problems related to the BTS configuration

Refer to “Failure printouts (2000 - 3999)” for a detailed description of the modified alarm.

5.4 Measurements and counters

5.4.1 MeasurementsThe “SDCCH and PS data channels on DFCA TRX” feature modifies the measurements shown in “Table 2”.

DFCA MA list group ID;

dfcaMAListGroupId

BSC This parameter defines a group ID for the DFCA MA list. Frequencies can be reused on DFCA MA lists belonging to differ-ent groups.


0 .. 32,

in steps of 10



24 DN70648156Issue 2-0



User interface

5.4.2 CountersThe “SDCCH and PS data channels on DFCA TRX” feature introduces a new counter, shown in “Table 3”.

Name Changes

100 DFCA measure-ment

Connection types PS data and SDCCH are supported in addition to the existing connection types FR/EFR, 14.1 Data, HR, AMR and AMR HR.

108 DFCA SAIC mea-surement

Connection types PS data and SDCCH are supported in addition to the existing connection types FR/EFR, 14.1 Data, HR, AMR and AMR HR.

Table 2 Measurements

Name Type Description Triggered

DFCA HOP PARAMS NOT VALID

Integer number

Number of SDCCH channel releases caused by invalid DFCA hopping parameters.

When the SDCCH channel is released in the BSC due to invalid DFCA hopping parameters.

Table 3 Counter

Documents

SDCCH and PS Data Channels