Dual Band Network Operation

Nokia Siemens Networks GSM/EDGE BSS, rel. RG20(BSS), operating documentation, issue 03

Feature description

BSS5050, BSS10118, BSS11116 and BSS8085: Dual Band Network Operation

DN9814105

Issue 11-1

Confidential

2 DN9814105Issue 11-1

BSS5050, BSS10118, BSS11116 and BSS8085: DualBand Network Operation

Id:0900d8058058fb79Confidential

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.

DN9814105Issue 11-1

3



Table of contentsThis document has 63 pages.

Summary of changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

1 Overview of Dual Band Network Operation . . . . . . . . . . . . . . . . . . . . . . . 8

2 System impact of Dual Band . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102.1 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102.2 Restrictions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112.3 Impact on transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112.4 Impact on BSS performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112.5 User interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112.6 Impact on Network Switching Subsystem (NSS) . . . . . . . . . . . . . . . . . . 122.7 Impact on NetAct products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122.8 Impact on interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132.9 Interworking with other features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132.10 Impact on mobile terminals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

3 Functionality of Dual Band Network. . . . . . . . . . . . . . . . . . . . . . . . . . . . 163.1 Handover and power control algorithm with Dual Band Network Operation

163.2 Cells allocated from the other frequency band in Dual Band Network Oper-

ation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213.3 Abnormal cases in channel assignment and handover in Dual Band Net-

work Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213.4 MS power optimisation and Dual Band Network Operation. . . . . . . . . . 22

4 System information messages in Dual Band Network . . . . . . . . . . . . . . 234.1 Idle mode Mobile Station and system information messages . . . . . . . . 234.2 Active mode mobile station and system information messages . . . . . . 254.3 System information messages during radio network reset . . . . . . . . . . 314.4 Remarks on system information messages. . . . . . . . . . . . . . . . . . . . . . 32

5 Planning Dual Band . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335.1 Planning a Dual Band network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335.1.1 Coverage planning strategies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 345.1.2 Different network strategies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375.1.3 Dual Band optimisation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395.2 Planning parameters in a Dual Band network . . . . . . . . . . . . . . . . . . . . 405.3 Dual Band site solutions and antenna configurations . . . . . . . . . . . . . . 415.4 Traffic management in a Dual Band network. . . . . . . . . . . . . . . . . . . . . 465.4.1 Traffic management features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 465.4.1.1 Features used in idle mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 465.4.1.2 Features used during call set-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 495.4.1.3 Features used during call . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 505.4.2 Traffic management between network layers . . . . . . . . . . . . . . . . . . . . 535.4.2.1 Two-layer dual band network. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 535.4.2.2 Three-layer network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 545.4.2.3 Traffic management in multivendor environment. . . . . . . . . . . . . . . . . . 59

4 DN9814105Issue 11-1



6 Implementing Dual Band. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 616.1 Performing Dual Band functionality tests . . . . . . . . . . . . . . . . . . . . . . . . 616.1.1 Basic functionality tests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 616.1.2 Monitoring and troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 616.2 Implementing Dual Band overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

DN9814105Issue 11-1

5



List of figuresFigure 1 Single band and dual band MS operation in a dual band network. . . . . . 9Figure 2 System information on BCCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Figure 3 Classmark updating to the MSC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Figure 4 First activation for MS access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28Figure 5 First activation, EGSM MS accessing PGSM cell . . . . . . . . . . . . . . . . . 30Figure 6 Second activation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30Figure 7 Dual band network planning and optimisation procedure . . . . . . . . . . . 34Figure 8 Use of GSM 1800 pico cells and microcells. . . . . . . . . . . . . . . . . . . . . . 35Figure 9 Co-located sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36Figure 10 Co-located sites and GSM 900/800 microcells/pico cells . . . . . . . . . . . 36Figure 11 GSM 900 and GSM 1800 cells under the same MSC . . . . . . . . . . . . . . 37Figure 12 GSM 900 and GSM 1800 cells under different BSCs but the same MSC .

38Figure 13 GSM 900 and GSM 1800 cells under different MSCs . . . . . . . . . . . . . . 38Figure 14 Site configuration 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41Figure 15 Site configuration 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42Figure 16 Site configuration 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43Figure 17 Site configuration 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44Figure 18 Site configuration 5: MetroSite BTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . 45Figure 19 Traffic management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46Figure 20 Handover candidates for GSM 900 macrocell . . . . . . . . . . . . . . . . . . . . 52Figure 21 Two-layer network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54Figure 22 Three-layer network strategy No. 1, priority to microcell layer. . . . . . . . 55Figure 23 Strategy No. 1, priority to microcell layer, main parameter values. . . . . 56Figure 24 Parameter change at coverage border . . . . . . . . . . . . . . . . . . . . . . . . . 57Figure 25 Three-layer network strategy No. 2, priority to 1800 layer . . . . . . . . . . . 58Figure 26 Strategy No. 2, main parameter values . . . . . . . . . . . . . . . . . . . . . . . . . 59

6 DN9814105Issue 11-1



List of tablesTable 1 Required additional or alternative hardware or firmware . . . . . . . . . . . . 10Table 2 Required software by network elements . . . . . . . . . . . . . . . . . . . . . . . . 10Table 3 Impact on BSC units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Table 4 BA range and the maximum numbers of ARFCNs . . . . . . . . . . . . . . . . 16Table 5 Idle mode mobile station and system information messages in single band

23Table 6 Idle mode mobile station and system information messages in dual band

23Table 7 Active mode Mobile Station and system information messages in single

band . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Table 8 Active mode Mobile Station and system information messages in dual

band . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27Table 9 Example values for RXLEV_ACCESS_MIN . . . . . . . . . . . . . . . . . . . . . 48Table 10 Example of the C2 parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49Table 11 HO priority and load factor parameters . . . . . . . . . . . . . . . . . . . . . . . . . 52Table 12 Example of handover priority and load factors . . . . . . . . . . . . . . . . . . . . 52

DN9814105Issue 11-1

7


Summary of changes


Summary of changesChanges between document issues are cumulative. Therefore, the latest document issue contains all changes made to previous issues.

Changes made between issues 11-1 and 11Information on InSite BTS has been removed.

Changes made between issues 11 and 10The NetAct Radio Access Configurator (RAC) changed to NetAct Configurator.

Changes made between issues 10 and 9The following chapters were added:

• System impact of Dual Band • Planning a Dual Band network • Planning parameters in a Dual Band network • Dual Band site solutions and antenna configurations • Traffic management in a Dual Band network • Performing Dual Band functionality tests • Implementing Dual Band overview

Chapter Technical description of Dual Band Network operation was removed and infor-mation included in the System impact of Dual Band chapter.

Chapter User interface of Dual Band Network was removed and information included in the System impact of Dual Band chapter.

All references to PBCCH/PCCCH removed.

Updated the (E)GPRS references to GPRS/EDGE to correspond the feature name change.

In Overview of Dual Band Network, the Operation was removed from the title and more information on single band and dual band MS operation was added.

Changes made between issues 9 and 8In Overview of Dual Band Network Operation, a list of related topics has been added.

In Technical description of Dual Band Network Operation, Flexi EDGE BTS has been added to the list BTSs that support GSM 800.

In Functionality of Dual Band Network Operation, more information on the combined umbrella and power budget handover has been added. In addition, a new graphic, Two-layer network, has been added.

Most of the Advanced Multilayer Handling related information has been removed to the new Advanced Multilayer Handling document.

Changes made between issues 8 and 7–1Handover and power control algorithm with Dual Band Network Operation: parameters updated in section Power control.

In addition, the document has been revised throughout to comply with the latest docu-mentation standards.

8 DN9814105Issue 11-1



Overview of Dual Band Network Operation

1 Overview of Dual Band Network OperationIn the Nokia solution, the ETSI item multiband operation is called Dual Band Network Operation, because the Nokia multiband operation solution supports the use of two fre-quency bands at a time in the BSC. For more information on the ETSI item multiband operation, see ETR 366.1997.

The supported variants of the Nokia Dual Band Network Operation are:

• BSS05050 Dual Band GSM 900/1800 • BSS30050 Dual Band GSM 800/1900 • BSS30040 Dual Band GSM 800/1800

It is possible to build capacity by using microcells or the Dual Band solution. If you have licences in more than one of the frequency bands specified in the GSM specifications, it is possible to support the use of multiband mobile stations (MSS) in both bands of the Dual Band solution with Dual Band Network Operation. This operation allows you to handle the growth of traffic. It is required particularly when the frequencies of one single band are limited.

The Dual Band GSM 900/1800, Dual Band GSM 800/1900, and Dual Band GSM 800/1800 Network Operation software provide handover support between GSM 900 and GSM 1800, GSM 800 and GSM 1900, and GSM 800 and GSM 1800 frequency bands respectively. One BSC is able to handle both GSM 900 and GSM 1800, or GSM 800 and GSM 1900, or GSM 800 and GSM 1800 cells, which can be set as neighbour cells.

There is no common broadcast channel (BCCH) and cell identity, therefore there is no need to have a single cell serving the different frequencies. There is no need for specific support for intra-cell handover between the bands, either. Frequency hopping between bands is not supported. For more information on Common BCCH, see Overview of Common BCCH Control in BSC.

The BSC supports the extension of the GSM 900 frequencies as a generic capability. The primary GSM 900 (PGSM 900) and extended GSM 900 (EGSM 900) frequencies are considered as GSM 900 frequencies and it is possible to configure and use both PGSM 900 and EGSM 900 frequencies in a single BTS object. A handover between PGSM 900 and EGSM 900 frequency band cells is a generic capability. For more infor-mation, see PGSM 900 - EGSM 900 BTS in BSC.

The support of EGSM 900 band is a generic capability.

Only one of the Dual Band variants can be in use in the BSC and therefore only one of them is included in the software package.

DN9814105Issue 11-1

9


Overview of Dual Band Network Operation


Figure 1 Single band and dual band MS operation in a dual band network

Other related topics in BSC/TCSM documentation

• Activate • Radio Network Performance

• Activating and testing BSS5050, BSS10118, BSS11116 and BSS8085: Dual Band Network Operation

• Reference • Commands

• MML Commands • Adjacent Cell Handling – EA • Frequency List and GPRS Objects Handling – EB • GSM Measurement Handling – TP

• Counters/Performance Indicators • Call Control Measurements (CS)

• 59 Dual Band Measurement • 71 MS Capability Indication Measurement

• Parameters • BSS Radio Network Parameter Dictionary

• Functional Area Descriptions • Radio Network Performance

• RF Power Control and Handover Algorithm • Feature Descriptions

• Existing Features • Radio Network Performance

• Advanced Multilayer Handling • Direct Access to Desired Layer/Band • Intelligent Underlay-Overlay • PGSM 900 - EGSM 900 BTS in BSC

• Packet Switched Data • GPRS/EDGE System Feature Description

GSM1900

GSM800

GSM1900

GSM800

GSM1900

GSM1900GSM800

GSM800

Single band MS Dual band MS

GSM800

GSM800

GSM1900

GSM800

GSM1900

GSM1900GSM800

GSM800

10 DN9814105Issue 11-1


Id:0900d8058058fb5aConfidential

System impact of Dual Band

2 System impact of Dual Band

2.1 RequirementsHardware requirements

Software requirements

Table Required software shows the earliest version that supports Dual Band.

Frequency band supportThe BSC supports Dual Band on the following frequency bands:

• GSM 800 • GSM 900 • GSM 1800 • GSM 1900

Network element HW/FW required

BSC No requirements

BTS Additional HW/FW required

TCSM No requirements

SGSN No requirements

Table 1 Required additional or alternative hardware or firmware

Network element Software release required

BSC S14

Flexi EDGE BTSs EP2

Possible in single BTS site.

UltraSite EDGE BTSs CX6


MetroSite EDGE BTSs CXM6


Talk-family BTSs DF7


MSC/HLR Not applicable

SGSN Not applicable

NetAct Not applicable

Table 2 Required software by network elements

DN9814105Issue 11-1

11




2.2 Restrictions • Neighbour cell changes during a call are not fully supported when the cells allocated

from another frequency band than the serving cell are concerned. For more informa-tion, see Neighbour cell changes and updating to active calls.

• The BSC does not support frequency redefinition. • If there are one or more network elements that do not support the Dual Band

Network Operation, the MS may not be able to use the dual band features. There-fore, all network elements should support the Dual Band Network Operation.

2.3 Impact on transmissionNo impact.

2.4 Impact on BSS performanceOMU signallingNo impact.

TRX signallingNo impact.

Impact on BSC

Impact on BTS unitsNo impact.

2.5 User interfaceBSC MMIThe following command group and commands are used for handling Dual Band:

• Base Station Controller Parameter Handling: EQF, EQM

BTS MMIDual Band cannot be managed with BTS MMI.

BSC parametersSEG-specific BTS radio network object parameters

• multiband cell reporting (MBR)

BSC unit Impact

OMU No impact

MCMU No impact

BCSU No impact

PCU No impact

Table 3 Impact on BSC units

12 DN9814105Issue 11-1




• early sending indication (ESI) • adjacency on other band (DBC)

BCCH allocation frequency list (BA) radio network object parameters

• frequency • BCCH frequency (FREQ)

• type of BCCH frequency list

There are also other parameters that are used in Dual Band network operation. Such parameters are, for example, handover and power control parameters. For more infor-mation, see RF Power Control and Handover Algorithm.

There are no special BSC-level parameters that you can use to control the activa-tion/deactivation of Dual Band.

For more information on the command groups and MML commands, see MML com-mands.

AlarmsThe following alarm is used by Dual Band:

• 7755 PHASE 1 BTS IS TRIED TO BE DEFINED AS DUAL BAND CELL

MeasurementsFollowing measurements are meant for collecting the distribution of single band and dual band mobiles (calls) in the network. You can start these measurements from both NetAct and the MMI including all BTSs in one BSC. The measurement results are provided in NetAct.

• 59 Dual Band Measurement • 71 MS Capability Indication Measurement

For more information on the measurements, see 59 Dual Band Measurement and 71 MS Capability Indication Measurement.

2.6 Impact on Network Switching Subsystem (NSS)No impact.

2.7 Impact on NetAct productsNetAct AdministratorNo impact.

NetAct MonitorNo impact.

NetAct ConfiguratorRadio network parameters related to Dual Band can be managed with the NetAct Con-figurator application.

NetAct ReporterNo impact.

DN9814105Issue 11-1

13




NetAct TracingNo impact.

2.8 Impact on interfacesImpact on A interfaceDual Band operation has impact on Mobile Station Classmark 3 Information Element (MS CM3 IE) to and from MSC.

Impact on Abis interfaceDual Band operation has impact on system information messages and MS CM3 Infor-mation Element.

2.9 Interworking with other featuresDirect Access to Desired Layer/BandDirect Access to Desired Layer/Band (DADL/B) can be used in the dual band environ-ment to direct calls from a stand-alone dedicated control channel (SDCCH) of the accessed cell to a traffic channel (TCH) of another cell which is allocated from the other frequency band than the accessed cell. This is possible if Dual Band is activated.

DADL/B is separate software and does not affect the operation of Dual Band.

For more information, see Direct Access to Desired Layer/Band.

Advanced Multilayer HandlingMany operators build capacity by using microcells or a dual band solution. As the number of network layers increases, the number of handovers between the layers also increases. When the traffic is low, that is, at night, extra capacity is not needed and the underlay capacity is not necessarily needed either. Therefore, adequate capacity can be achieved by using only the overlay network.

On the other hand, at night most of the mobile traffic takes place outdoors, particularly in fast moving vehicles. Furthermore, fast moving mobile stations (FMMS) in the micro-cell network generate many handovers with a relatively high speed. Therefore, it is more reasonable to keep the traffic in the overlay network instead of the underlay network to provide better quality to end users.

Advanced Multilayer Handling (AMH) can be used to prevent the use of the micro-cell/GSM 1800 or GSM 1900 layer during low traffic. Consequently, it is also used to keep the MSS either in the macro/GSM 900 or GSM 800 network once they have camped on it.

If the traffic load of the serving cell decreases under the predefined threshold, the fast moving MS (FMMS), MS Speed Detection and Umbrella handovers are not allowed to the lower layer cells.

For more information, see Advanced Multilayer Handling and RF Power Control and Handover Algorithm.

14 DN9814105Issue 11-1




Intelligent Underlay Overlay, Frequency Hopping and Intelligent Frequency HoppingFor maximum capacity, Intelligent Underlay Overlay (IUO), Frequency Hopping (FH), and Intelligent Frequency Hopping (IFH) can be used together with Dual Band (in both layers of a dual band network, if necessary). Note, that there are some limitations in using Dual Band together with IUO.

As IUO is a single-band system, it can be disturbed by the following dual band function-ality. IUO relies on the same band interference measurements. The more measure-ments are sent to the BSC, the more accurately the C/I calculation ensures a reliable handover between the regular and the super layers. As a dual band MS measures neighbours in both bands, less interference is analysed, and the IUO efficiency could then be affected.

You can use two parameters to overcome the measurement problem:

• The parameter dual band MS access to IUO layer, which indicates whether dual band MSS are allowed to use the super reuse TCHs. By preventing the dual band MS from accessing the super layer, the IUO performance is not affected. For instructions on how to change the value of the parameter, contact your Nokia Siemens Networks representative.

• The multiband cell reporting parameter has an effect on another band reporting of a dual band MS. This can be set to 1 in the IUO layer cells to allow the dual band MS to report only 1 measurement from the non-IUO layer. Thus, the IUO efficiency is not greatly affected.

If dual band MSS cause interference in the IUO super layer, it is advisable to use restric-tions. Frequency Hopping does not bring any special limitations when used together with Dual Band.

For more information, see Intelligent Underlay-Overlay.

GPRSThe neighbour cell frequencies are delivered to the MSS as a GPRS-specific list or as the same list as for the circuit switched services. The BCCH allocation (BA) list for GPRS is equal to the BA list from the SI2/SI2bis/SI2ter messages. In the Dual Band GSM 800/GSM 1800, GSM 900/GSM 1800 and GSM 800/GSM 1900 environments, these messages will include neighbours from the two frequency combinations.

For more information, see GPRS/EDGE System Feature Description.

HSCSD, GPRS and EDGEHigh Speed Circuit Switched Data (HSCSD), GPRS and EDGE do not bring any special limitations to Dual Band itself. When considering the higher C/I requirement for data services (if high data throughput is wanted), Dual Band can bring a flexible solution to meet the tighter quality requirements. If a wider bandwidth and less interference are expected in the GSM 1800/1900 layer, more data services should be allocated for that band. The MSS should naturally support a dual band or single band GSM 1800/1900 functionality.

For more information, see Overview of HSCSD and 14.4 kbit/s Data Services in BSC HSCSD and 14.4 kbit/s Data Services in BSC.

DN9814105Issue 11-1

15




2.10 Impact on mobile terminalsMobile terminals must support Dual Band functionality.

16 DN9814105Issue 11-1


Id:0900d8058058fb5dConfidential

Functionality of Dual Band Network

3 Functionality of Dual Band Network

3.1 Handover and power control algorithm with Dual Band Network OperationIndication of dual band MSThe BSC receives mobile station (MS) frequency band/dual band capability as well as power capability in MS CM3 IE. In call setup the MS CM3 IE comes in Classmark Change message from the MS and in inter-BSS handover it comes in Handover Request message from the MSC. In intra-BSS handovers the BSC maintains the infor-mation.

The BSC uses the classmark information in handovers for candidate cell selection, and for setting the power control limits and range for the MS in question.

Cell band indicationThe definition of the band of the serving cell (source cell) is made according to the BTS parameter frequency band in use (BAND) (values GSM, GSM 1800, GSM 800, GSM 1900, and MULTI for dual band operation). The definition of the band of the adjacent cell is made according to the adjacent cell parameter BCCH frequency (FREQ).

EGSM 900 band is supported as separate cell both in the single band and the dual band network. The extension of GSM 900 band consists of the ARFCN channel numbers from 975 to 1023. The ARFCN 0 is also included in the extended frequencies. The total number of the additional radio channels is 50.

Adjacent cells and measurement reportsThe adjacent cell list that the BSC delivers to the MS can include cells from both bands of the dual band variant used. Also the BA list can include frequencies of the two bands. The BSC fills adjacent cells ARFCN numbers or alternatively the BA list ARFCN numbers into SI2 / SI5 messages as BCCH channel sublists. ARFCN numbers in each sublist are placed in an ascending order, except that if ARFCN 0 is included in the set, it is put in the last position in the sublist. SI2 and SI2bis include the sublist of serving band frequencies and SI2ter includes the sublist of the other band frequencies for the MS idle state operation. SI5 and SI5bis include the sublist of serving band frequencies and SI5ter includes the sublist of the other band frequencies for the MS dedicated state operation.

The table below describes the maximum numbers of adjacent cells from the other band than the serving cell that can be fit in the Sys_Info_2ter / Sys_Info_5ter messages. The maximum number of adjacent cells depends on the used range. The BSC selects the range according to the used frequencies.

Range Lowest ARFCN Max. ARFCN range Max. number of frequen-cies

1024 range 0 1024 16 (17 if ARFCN 0 is included)

512 range selectable 512 18

Table 4 BA range and the maximum numbers of ARFCNs

DN9814105Issue 11-1

17




The MS reports the neighbour cells allocated from the other frequency band than the serving cell according to the multiband reporting parameter, which is indicated to the MS in the Sys_Info_2ter and Sys_Info_5ter messages.

For more information on the SI messages, see

• Idle mode Mobile Station and system information messages • Mobile Station in call and system information messages

The BCCH channel list that the MS composes is of one or two BCCH channel sublists. First, a sublist of serving band frequencies, received in SI2 and SI2bis for the idle state or in SI5 and SI5bis for the dedicated state, is put in the BCCH channel list. After serving band frequencies, the BCCH channel list is filled with the sublist of other band frequen-cies, if it is received in SI2ter for the idle state or in SI5ter for the dedicated state.

If the set of ARFCNs defined by the sublist includes frequencies that the MS does not support, these ARFCNs are not included in the BCCH channel list.

Power control

• BTSThe power control of the BTS is based on the power control parameters defined for the serving cell. The parameters are: • BS TX pwr max (PMAX1) • BS TX pwr max1x00 (PMAX2)

• BS TX pwr min (PMIN)

• power incr step size (INC)

• power red step size (RED)The parameter BS TX pwr max (PMAX1) is for frequency bands GSM 800 and GSM 900, and the range is the same for both bands.The parameter BS TX pwr max1x00 (PMAX2) is for frequency bands GSM 1800 and GSM 1900, and the range is the same for both bands.

• MSThe power control of the MS is based on the serving cell-specific parameters. The parameters are: • MS txpwr max gsm (PMAX1)

• MS txpwr max gsm1x00 (PMAX2) • MS txpwr min (PMIN)

• power incr step size (INC)

256 range selectable 256 22

variable bit map selectable 112 112

bit map 0 0 124 124

Range Lowest ARFCN Max. ARFCN range Max. number of frequen-cies

Table 4 BA range and the maximum numbers of ARFCNs (Cont.)

18 DN9814105Issue 11-1




• power red step size (RED)The parameter MS txpwr max gsm (PMAX1) is for GSM 800/900 bands and MS txpwr max gsm1x00 (PMAX2) is for GSM 1800/1900 bands. The parameters define the maximum power level that an MS may use.The range of parameter MS txpwr min (PMIN) depends on the serving cell allo-cation from GSM 900, GSM 1800, GSM 800, and GSM 1900 band.The MS power capability that the BSC receives in MS CM3 IE also affects the MS power control. It is used with MS txpwr max gsm (PMAX1) or with MS txpwr max gsm1x00 (PMAX2) for defining the maximum transmission power that the MS can use in serving cell.

Handover casesThe target cell selection in Dual Band Network Operation remains the same in handover cases where the source and target cells are allocated from the same band. When the source and target cell are allocated from different bands, the equations remain the same but you have to consider the handover margins between cells of different bands.

When the target cells for a handover are selected, the following handover criteria are used:

EQU1. AV_RXLEV_NCELL (n) > RXLEV_MIN (n) + MAX (0, Pa)

where

Pa = ( MS_TXPWR_MAX (n) - P )

EQU2. PBGT (n) > HO_MARGIN_PBGT (n)

where

PBGT (n) = ( MS_TXPWR_MAX - AV_RXLEV_DL_HO -(BS_TXPWR_MAX - BS_TXPWR) ) -( MS_TXPWR_MAX (n) - AV_RXLEV_NCELL (n) )

EQU2'. AV_RXLEV_NCELL (n) > AV_RXLEV_DL_HO + HO_MARGIN_LEVEL/QUAL (n)

For more information on the handover criteria and the situation in which each criteria is used, see RF Power Control and Handover Algorithm.

• MS_TXPWR_MAX is the maximum transmission power that an MS may use in the serving cell. It is defined by the parameter MS txpwr max gsm (PMAX1) which is set for the serving cell in the GSM 800 and 900 bands, and MS txpwr max gsm1x00 (PMAX2) which is set for the serving cell in the GSM 1800 and 1900 bands.

• AV_RXLEV_DL_HO is the measured and averaged downlink RX level for handover purposes.

• BS_TXPWR_MAX is the BTS's maximum transmission power. The parameters BS TX pwr max (PMAX1) and BS TX pwr max1x00 (PMAX2) are set for the serving cell.

• BS_TXPWR is the actual transmitting power used by the BTS. • MS_TXPWR_MAX(n) is the maximum RF power level that an MS is permitted to use

on a traffic channel in the adjacent cell n. It is defined by the parameter MS txpwr max gsm which is set for each adjacent cell in GSM 800 and 900 bands, and MS txpwr max gsm1x00 (PMAX2) which is set for each adjacent cell in GSM 1800 and 1900 bands.

DN9814105Issue 11-1

19




• AV_RXLEV_NCELL(n) is the measured and averaged BCCH RX level of adjacent cell n.

• RXLEV_MIN(n) is the level which the signal level in the adjacent cell (n) must exceed in order for the handover to become possible. The parameter RX lev min cell (SL) is set for each adjacent cell.

• P is the maximum power of the MS (MS Power Capability). • HO_MARGIN_PBGT(n) is the margin which the power budget of the adjacent cell

(n) must exceed for the handover to become possible. The parameter HO margin pbgt (PMRG) is set for each adjacent cell.

• HO_MARGIN_LEVEL(n) is used as a threshold for adjacent cell n in the handover caused by signal strength. It is defined by the parameter HO margin lev (LMRG) which is set for each adjacent cell.

• HO_MARGIN_QUAL(n) is used as a threshold for adjacent cell n in the handover caused by signal quality. It is defined by the parameter HO margin qual (QMRG) which is set for each adjacent cell.

When the source and target cell are allocated from different bands, the above-men-tioned equations remain the same but you have to consider the handover margins between cells of different bands as follows:

PBGT The MS_TXPWR_MAX is defined for the serving cell and the MS_TXPWR_MAX(n) is defined for the adjacent cell n. If the serving cell and the adjacent cell are allocated from a different band, you must take that into account when setting the HO_MARGIN_PBGT(n).

EQU1 In the handover equation and the related margin setting the P (MS Power Capability) is defined according to the target cell frequency band indicated in the CM3.

EQU2 Handover equation and the related margin setting remain as they are.

EQU2' Handover equation and the related margin setting remain as they are.

Umbrella handoverThe macrocell and microcell thresholds defined as BSC parameters are selected according to the serving cell band from the actual parameters:

• GSM macrocell threshold (GMAC)

• GSM microcell threshold (GMIC) • DCS macrocell threshold (DMAC)

• DCS microcell threshold (DMIC)

In an umbrella handover, the used macrocell and microcell thresholds are selected according to the inspected adjacent cell. This means that the following parameters are used for the adjacent GSM 800 and GSM 900 cell:

• GSM macrocell threshold (GMAC) • GSM microcell threshold (GMIC)

For the adjacent GSM 1800 and GSM 1900, the following parameters are used:

• DCS macrocell threshold (DMAC) • DCS microcell threshold (DMIC)

The MS Power Capability is defined according to the target cell frequency band indi-cated in the CM3. Note that all parameters in the umbrella handover equation concern the target cell.

20 DN9814105Issue 11-1




The umbrella handover criteria are as follows:

When the MS_TXPWR_MAX(n) is used:

av_rxlev_ncell(n) > HO_LEVEL_UMBRELLA(n)

and one of the following

1. (ms_power_capability >= macrocell_threshold)AND

(MS_TXPWR_MAX(n) >= macrocell_threshold)2. (ms_power_capability <= microcell_threshold)

AND(MS_TXPWR_MAX(n) <= microcell_threshold)

3. (ms_power_capability < macrocell_threshold)AND

(MS_TXPWR_MAX(n) < macrocell_threshold)AND

(ms_power_capability > microcell_threshold)AND

(MS_TXPWR_MAX(n) > microcell_threshold)

For more information, see RF Power Control and Handover Algorithm.

Power budget handoverIn the power budget (PBGT) handovers, the BSC uses the criteria described above.

Combined umbrella and power budget handoverIf combined umbrella and power budget handovers are used, the power budget handover takes into account not only the radio link properties but also the size/layer of the adjacent cell. When the umbrella handover is employed, the BSC performs power budget handovers only between cells of the same size/layer and therefore the size/layer of the adjacent cell must be equal to the size/layer of the serving cell for the handover to be allowed.

The BSC is able to determine the size/layer of a cell by two alternative methods. The method is selected with the parameter adjacent cell layer (ACL). The BSC determines the size/layer of a cell as follows:

• If the layer of the adjacent cell has not been defined, that is, if the use of the param-eter adjacent cell layer is disabled, the micro/macro thresholds are used instead of the layer definitions.

• If the cell layer has been defined for the adjacent cell with the parameter adjacent cell layer, the layer definitions are used instead of micro/macro thresholds.

Note that the microcell and macrocell thresholds must be defined separately for the GSM 900/800 and GSM 1800/1900 bands. For more information on microcell and mac-rocell thresholds, see RF Power Control and Handover Algorithm.

Other handover cases

• Radio reason handover Lev/Qual:Equations EQU1, EQU2 and EQU2' are used.

• Intra-cell handover:No adjacent target cells are selected, therefore none of the equations mentioned above are used.

DN9814105Issue 11-1

21




• Traffic reason handover:EQU1 and also a TRHO equation similar to EQU1 are used:

av_rxlev_ncell(n) > TRHO_TARGET_LEVEL(n) +Max(0,(MS_TXPWR_MAX(n) - P))

In the handover equation and the related margin setting, the P (MS Power Capabil-ity) is defined according to the target cell frequency band indicated in the CM3.

• Chained cells in rapid field drop:EQU1 is used.

• Fast moving MS handling in macrocell:EQU1 is used. A FMMS equation similar to EQU1 is also used:

av_rxlev_ncell(n) > HO_LEVEL_UMBRELLA(n) +Max(0,(MS_TXPWR_MAX(n) - P))

In the handover equation and the related margin setting, the P (MS Power Capabil-ity) is defined according to the target cell frequency band indicated in the CM3.For more information, see RF Power Control and Handover Algorithm.

• Forced handover:EQU1 is used.

• Distance based handover:EQU1 is used.

3.2 Cells allocated from the other frequency band in Dual Band Network OperationThe adjacency information stored in the network configuration database can contain cells allocated from the other frequency band even if the adjacency on other band (DBC) parameter indicates that Dual Band is deactivated in the serving cell. This is possible if you have activated Dual Band in one cell and then defined dual band adja-cencies for that cell. After that you have deactivated Dual Band on a cell basis by setting the adjacency on other band (DBC) to indicate a single band cell.

Due to the situation described above, the BSC verifies the use of Dual Band on a cell basis. This means that if Dual Band is deactivated in a certain cell, the adjacencies allo-cated from the other frequency band are excluded from the actual adjacent cell list that is delivered to the MS.

3.3 Abnormal cases in channel assignment and handover in Dual Band Network OperationWhen the network gives the RR commands, the (multiband) MS should obey the commands according to the following statements, which are either rejected or ignored. The actions described on this list are MSS in assignment completion, in handover com-pletion, and in frequency redifinition:

• If the mobile allocation IE indexes frequencies in more than one frequency band, an RR connection establishment failure has occurred.If an IMMEDIATE ASSIGNMENT message indicates (a) channel(s) in a different fre-quency band than to which the channel request message was sent, and if the MS supports the frequency band, the MS accesses the indicated channel(s) with the same power control level as the one used for the channel request message.If an IMMEDIATE ASSIGNMENT message indicates a channel in a non-supported frequency band, an RR connection establishment failure has occurred.

22 DN9814105Issue 11-1




• If the MS receives an ASSIGNMENT COMMAND message with a frequency list IE which indicates frequencies that are not all in one band, the MS stays on current channel(s) and sends an ASSIGNMENT FAILURE message with a cause 'frequency not implemented'.If the MS receives an ASSIGNMENT COMMAND message with a mobile allocation IE which indexes frequencies that are not all in one band, the MS stays on current channel(s) and sends an assignment failure message with a cause 'frequency not implemented'.An ASSIGNMENT COMMAND message sent to a multiband MS is not considered invalid because it indicates frequencies that are all in a different frequency band to that of the current channel.

• If the MS receives a HANDOVER COMMAND message with a frequency list IE or a fre-quency short list IE which indicates frequencies that are not all in one band, the MS stays on current channel(s) and sends a HANDOVER FAILURE message with the cause 'frequency not implemented'.If the MS receives a HANDOVER COMMAND message with a Mobile Allocation IE which indexes frequencies that are not all in one band, the MS stays on current channel(s) and sends a HANDOVER FAILURE message with the cause 'frequency not implemented'.A HANDOVER COMMAND message sent to a multiband MS is not considered invalid, because it indicates target cell frequencies that are all in one different frequency band than the absolute radio frequency channel number (ARFCN) in the Cell Description IE.

• If the MS receives a FREQUENCY REDEFINITION message with a Mobile Allocation IE which indexes frequencies that are not all in one band and a starting time IE which indicates a time that has not elapsed, the MS stays on the current channel(s) and sends an RR Status message with a cause 'frequency not implemented'.If the MS receives a FREQUENCY REDEFINITION message with a Mobile Allocation IE which indexes frequencies that are not all in one band and a Starting Time IE which indicates a time that has elapsed, the MS will abort the radio connection locally and attempt call re-establishment, if permitted.A FREQUENCY REDEFINITION message sent to a multiband MS is not considered invalid, because it indicates new frequencies that are all in a different frequency band than the ARFCN of the serving cell.Note also that the BSC does not support the frequency redefinition.

3.4 MS power optimisation and Dual Band Network OperationThe MS power optimisation can be made in three operations:

• call setup • intra-cell handover • inter-cell handover

In all these cases the MS power optimisation is independent of the target cell frequency band.

For more information on MS power optimisation, see RF Power Control and Handover Algorithm.

DN9814105Issue 11-1

23


System information messages in Dual Band Network


4 System information messages in Dual Band Network

4.1 Idle mode Mobile Station and system information messagesThe BSS sends the system information messages Sys_Info_2 and Sys_Info_2bis on a BCCH to single band mobile stations (MSS). These messages include the informa-tion about the BCCH allocation in the neighbour cells of one band (the same band as the BSS cell). The BSS also sends a Sys_Info_2ter message to dual band MSS. That message includes information about the other band's cells if the cell is defined as a dual band cell in the BSC. The Sys_Info_2ter message is meant only for dual band MSS and therefore the single band MSS ignore this message.

The extended GSM 900 (EGSM) frequencies are sent in the Sys_Info_2ter message, when the BSS cell is in the primary GSM 900 frequency band.

The MSS receive and handle the following messages concerning the idle mode opera-tion:

SINGLE BAND MS

PGSM 900 BSS Cell SI_2 (PGSM band)

SI_2ter (EGSM band)

EGSM 900 BSS Cell SI_2 (GSM 900 band)

SI_2bis (GSM 900 band)

GSM 1800 BSS Cell SI_2 (GSM 1800 band)






Table 5 Idle mode mobile station and system information messages in single band

DUAL BAND MS

PGSM 900 BSS Cell SI_2 (PGSM band)

SI_2ter (EGSM/GSM 1800)

EGSM 900 BSS Cell SI_2 (GSM 900 band)


SI_2ter (GSM 1800 band)

GSM 1800 BSS Cell in GSM 900/1800 network SI_2 (GSM 1800 band)



Table 6 Idle mode mobile station and system information messages in dual band

24 DN9814105Issue 11-1




System information on BCCH

Figure 2 System information on BCCH

The BSS sends the system information messages on the BCCH. The messages are:

• Sys_Info_2 • Sys_Info_2bis

• Sys_Info_2ter

The Sys_Info_2ter message is meant only for the dual band MSS and it is sent on a BCCH of a cell that is defined as a dual band cell. The execption to this principle concerns the extended GSM 900 frequencies. The EGSM 900 neighbour cell frequen-cies of the PGSM 900 mobile stations are sent in the Sys_Info_2ter message.

The Sys_Info_2bis is sent only if the EXT-IND (Extension Indication) bit in the neigh-bour cell description Information Element (IE) in both Sys_Info_2 and Sys_Info_2bis messages indicates that each IE carries only part of the BCCH Allo-cation. Sys_Info_2ter message is sent if:

• and only if this is indicated in the Sys_Info_3 message • the BSS cell is indicated as a dual band cell or EGSM 900 frequencies are used

The indication in Sys_Info_3 is included in the Sys_Info_3 Rest Octets IE.













DUAL BAND MS

Table 6 Idle mode mobile station and system information messages in dual band (Cont.)

MS BTS BSC MSC

System Information on BCCH

BCCH_Information

Sys_Info_2

Sys_Info_2bis

Sys_Info_2ter

DN9814105Issue 11-1

25




4.2 Active mode mobile station and system information messagesMobile station classmark codingThe Mobile Station Classmark 3 Information Element (MS CM3 IE) provides the network with information about the MS. The contents of MS CM3 affect the manner in which the BSS handles the operation of the MS.

The MS CM3 IE is included in the classmark change message that the MS sends. When the MS CM3 is included and the MS supports more than one frequency band, it includes all the frequency bands supported by the MS and the MS power capabilities in each sup-ported frequency band.

The CM2 information in the classmark change, paging response, classmark re-estab-lishment request, and in the classmark service request messages include the corre-sponding frequency band in use for a multiband MS. The CM1 information in the international mobile station identity (IMSI) detect indication and in the location updating request messages will also include the corresponding frequency band in use for the mul-tiband MS.

Controlled early classmark sendingIn early classmark sending, the MS sends a classmark change message to the network as early as possible after access to provide the additional classmark information. An MS that carries out the controlled early classmark sending option performs the early class-mark sending if and only if the network explicitly accepts it, as indicated in the last recep-tion in the accessed cell of the Sys_Info_3 message.

An MS that carries out one of the multiple band support options also carries out the con-trolled early classmark sending option. An MS that carries out the controlled early class-mark sending option indicates it in the classmark (ES IND = Establishment Indication bit). When this option is carried out, it is indicated in Classmark 2 (ES IND bit) and the MS sends the classmark change message containing the CM2 and CM3 information elements on the first occasion if the network accepts it.

The early sending of the classmark change message is defined as follows: if the last time slot of the block containing a Layer 2 UA frame occurs at time T during a contention resolution procedure, the MS is ready to transmit the classmark change message before T+40 ms, if applicable.

Classmark updating to the MSCThe DX MSC (MSC) must be able to store the information of a dual band MS. The BSS sends a CLASSMARK UPDATE message containing the information to the MSC. The information of a dual band MS is indicated in a Classmark Information 3 element of the message. The CM3 is provided to the target BSS in case of an external handover in a HANDOVER REQUEST message. The MSC must also provide the CM3 information to the target MSC in MSC-MSC handover case.

26 DN9814105Issue 11-1




Figure 3 Classmark updating to the MSC

When a signalling connection control part (SCCP) connection has been established for BSSAP messages and a CLASSMARK CHANGE message has been received from the MS, the BSS sends a CLASSMARK UPDATE message to the MSC at any point. The BSC informs the MSC of a dual band MS in the CLASSMARK UPDATE message. The CLASSMARK UPDATE is sent via the relevant SCCP connection associated with that MS transaction.

The CM3 is included in the HANDOVER REQUEST message (send from the MSC to the BSC) in external handovers. The MSC is aware of the CM3 received in CLASSMARK UPDATE message.

In a MSC-MSC handover case, the source MSC sends the HANDOVER REQUEST message with CM3 to the target MSC.

Mobile Station in call and system information messagesThe BSS sends the system information messages on a call-by-call basis. These messages include information on the BCCH allocation in the neighbour cells. The system information messages Sys_Info_5 and Sys_Info_5bis are meant for all single band and dual band MSS. In addition to these messages, a Sys_Info_5ter message is sent to a dual MS after the network has detected the dual band MS. The detection in the BSS is based on the Classmark Information 3 in the CLASSMARK CHANGE message sent by the MS.

The extended GSM 900 (EGSM) frequencies are sent in Sys_Info_5ter, when the serving cell is in the primary GSM 900 frequency band.

The MSS receive and handle the following messages concerning the call-by-call slow associated control channel (SACCH) filling:

MS BTS BSC MSC

SACCH information on call-by-call basis

Classmark_Change(CM3)


CM3 information on Handover_Request

Handover_Request(CM3)

Classmark_Update(CM3)

SINGLE BAND MS

PGSM 900 serv. cell SI_5 (PGSM band)

SI_5ter (EGSM band)

EGSM 900 serv. cell SI_5 (GSM 900 band)


Table 7 Active mode Mobile Station and system information messages in single band

DN9814105Issue 11-1

27




First activation for MS accessThe signalling sequence describes how a channel is activated for the first time for an MS accessing the network. The sequence describes both how a channel is activated and how SACCH SI is sent call-by-call.

GSM 1800 serv. cell SI_5 (GSM 1800 band)






SINGLE BAND MS

Table 7 Active mode Mobile Station and system information messages in single band (Cont.)

DUAL BAND MS

PGSM 900 serv. cell SI_5 (PGSM band)

SI_5ter (EGSM 1800)

EGSM 900 serv. cell SI_5 (GSM 900 band)



GSM 1800 serv. cell in GSM 900/1800 network SI_5 (GSM 1800 band)















Table 8 Active mode Mobile Station and system information messages in dual band

28 DN9814105Issue 11-1




Figure 4 First activation for MS access

The CHANNEL ACTIVATION message sent from the BSC to the BTS activates a radio channel. This message includes an optional information element SACCH Information IE. The SACCH Information IE includes the Sys_Info_5, Sys_Info_6, and if needed, Sys_Info_5bis messages. If the optional information element SACCH Infor-mation IE is present, the SACCH filling information is used for this channel until the channel is released or the information is changed by a SACCH INFO MODIFY message. This replaces any SACCH filling information given by the SACCH FILLING message(s). If this element is not present, the SACCH filling information given by the SACCH FILLING message(s) is used.

The SACCH Information IE is included in the channel activation only in the case of dual band cell.

The SACCH scheduling of Sys_Info_5, Sys_Info_6, Sys_Info_5bis, and Sys_Info_5ter in the BTS is as follows: 5, 6, 5bis, 6, 5ter, 6, 5, 6, and so on. In case of a missing Sys_Info_5bis / Sys_Info_5ter, it is replaced with Sys_Info_5 in the SACCH scheduling.

A dual band MS sends a CLASSMARK CHANGE message to the BSS. The message includes Classmark Information 3 (CM3) that is similar to MS Classmark 3 defined in ETR 366.1997. The CM3 includes information of a dual band MS.

After the BSC has received the CLASSMARK CHANGE message, the BSC sends SACCH information on a call-by-call basis to the MS by using an SACCH INFO MODIFY message which includes the Sys_Info_5ter message. The exception to this principle

MS BTS BSC MSC

Channel_Activation_Ack

sabm

Establishment_Indication

ua

Sys_Info_5

Sys_Info_6

Sys_Info_5bis



Sys_Info_5

Sys_Info_6

Sys_Info_5bis

Sys_Info_5ter

Immediate_Assignment

Channel_Activation(5,5bis,6)

Immediate_Assign_Command

CM_Service_Request

SACCH_Info_Modify(5ter)


DN9814105Issue 11-1

29




concerns the extended GSM 900 frequencies. The EGSM 900 neighbour cell frequen-cies are also sent in the Sys_Info_5ter message, when the serving cell is in the primary GSM 900 band.

The Sys_Info messages in channel activation and in SACCH INFO MODIFY messages are connection-specific and they are only valid when the MS is in a call in the specified cell.

The BSC makes the decision of the channels included in the Sys_Info_5ter based on the cell frequency numbers. These numbers are described in section Handover and power control algorithm with Dual Band Network Operation.

If the BTS (cell) is not defined as a dual band cell, the channel activation does not have to include the SACCH information IE.

Support for the EGSM 900 frequency band contains an exception to the first channel activation previously described. When an EGSM supporting MS is accessing a PGSM cell, Sys_Info_5ter information is sent to the BTS in the SACCH INFO MODIFY message immediately after an ESTABLISHMENT INDICATION message is received. With the help of the classmark information included in the ESTABLISHMENT INDICATION message, the EGSM band support in the mobile station can be detected and it is possible to send the Sys_Info_5ter information message.

After receiving the CLASSMARK CHANGE (CM3) message, the BSC does not send the SACCH INFO MODIFY message again. The signalling in this case is described in the following figure.

30 DN9814105Issue 11-1




Figure 5 First activation, EGSM MS accessing PGSM cell

Second activation for MS accessThe signalling sequence describes how a second channel is activated (TCH or SDCCH). The sequence describes how a channel is activated and how the SACCH SI is sent call-by-call. This also applies to handover cases.

Figure 6 Second activation

The CHANNEL ACTIVATION message sent from the BSC to the BTS activates a radio channel. This message includes an optional information element SACCH Information IE. The SACCH Information IE includes the Sys_Info_5, Sys_Info_6, and if

MS BTS BSC MSC


sabm

Establishment_Indication

ua

Sys_Info_5

Sys_Info_6

Sys_Info_5bis

Sys_Info_5ter



Sys_Info_5

Sys_Info_6

Sys_Info_5bis

Sys_Info_5ter


CM_Service_Request

Immediate_Assignment

Sacch_Info_Modify(5ter)

Immediate_Assign_Command

Channel_Activation(5,5bis,6)

MS BTS BSC MSC

Sys_Info_5

Sys_Info_6

Sys_Info_5bis

Sys_Info_5ter


Channel_Activation(SACCH Information 5,5bis,5ter,6)

DN9814105Issue 11-1

31




needed, Sys_Info_5bis and Sys_Info_5ter messages. No specific order is required between the Sys_Info_5, Sys_Info_5bis, Sys_Info_5ter, and Sys_Info_6 messages. If the optional information element SACCH Information IE is present, the SACCH filling information is used for this channel until the channel is released or the information is changed by a SACCH INFO MODIFY message. This replaces any SACCH filling information given by the SACCH FILLING message(s). If this IE is not present, the SACCH filling information given by the SACCH FILLING mes-sage(s) will be used.

The SACCH Information IE is included in the channel activation only in the case that the dual band cell is determined by the BSC.

The Sys_Info_5bis message is sent if the EXT-IND bit in the neighbour cell descrip-tion IE in both Sys_Info_5 and Sys_Info_5bis messages indicates that each IE only carries part of the BCCH allocation (BA).

If the BTS (cell) is not defined as a dual band cell, the channel activation does not have to include the SACCH Information IE.

Neighbour cell changes and updating to active callsThe following describes the neighbour cell list modification and the updating to active calls.

• The TRX-specific SI messages 5, 5bis, and 6 are sent to the BTS in the SACCH FILLING message and stored in the BTS. If these SI messages (5, 5bis, 6) are changed, the changes affect all TCHs including active TCHs.

• The Sys_Info_5ter message concerning the currently active calls is not sent to the BTS in case of a neighbour cell list modification but the earlier received call-specific Sys_Info_5ter is used and included in the BTS scheduling. After the neighbour definition change, the Sys_Info_5ter, which is made according to the new neighbour cell definitions, is available for new dual band calls.

• No SI deactivations and no SI re-scheduling are made in the BTS, that is, the Sys_Info_5ter, if available, remains in the BTS scheduling.

☞ The neighbour cell changes for active calls in a dual band environment may cause problems.

To avoid these problems, the neighbour cell changes during a call must be performed as follows:

• If there are changes to the neighbour cells allocated from the frequency band as the serving cell, the Sys_Info_5 (and Sys_Info_5bis if available) is handled in the SACCH Filling message as in the current implementation.

• If there are changes to the neighbour cells allocated from the other frequency band than the serving cell, the Sys_Info_5ter is not resent to the BTS due to link access procedure on the D-channel (LAPD) link load restrictions. You may consider blocking the cell with calls first-handed over from the cell or calls to be ended before neighbour cell changes (that is, the cell is blocked and empty of calls).

4.3 System information messages during radio network resetIn case of a radio network reset in BTS initialisation, the system information messages are sent to the BTSs as follows:

• SIs 1-6 to BTS /BCCH TRX

32 DN9814105Issue 11-1




• SIs 5-6 to non-BCCH TRX

The system information messages are always sent from the BSC to the BTS in the fol-lowing order: 1, 2, (2bis), (2ter), 3, 4, 5, (5bis), 6. The Sys_Info_2ter message is included in case of a dual band BSS cell and a phase 2 BTS.

4.4 Remarks on system information messages • The TRX-specific system information messages passed from the BSC to the BTS

replaces the existing system information messages. This also concerns the system information messages sent for the active calls in the channel activation messages.☞ The Sys_Info_5ter message is not sent in the SACCH FILLING message

and the Sys_Info_5ter remains in the BTS scheduling if earlier received on a call-by-call basis.

• The channel activation message including system information messages can enter the BTS in the middle of SACCH filling messages. The last system information messages received are sent to the MS. This means that the system information messages that are to be sent to the MS can consist of system information messages received in both channel activation messages and SACCH filling messages.

• When the system information messages are changed, the BTS must receive all of them from the BSC to keep them in scheduling (excluding Sys_Info_5ter). The system information message order must be the following: 1, 2, 2bis, (2ter), 3, 4, 5, 5bis, 6.

• If a channel activation message does not include the call-by-call-specific system information messages, the system information messages received in the BTS initial-isation are to be used.

DN9814105Issue 11-1

33


Planning Dual Band

Id:0900d8058058fb6fConfidential

5 Planning Dual Band

5.1 Planning a Dual Band networkThe dual band network planning does not differ much from the normal network planning procedure. The planning procedure starts from choosing the right capacity evolution plan for long-term use, including the use of Common BCCH and Dual Band. The capacity evolution plan and the dual band network implementation greatly depend on the facts described below. For more information on Common BCCH, see Overview of Common BCCH Control in BSC.

The current network situation:

• Number of subscribers / amount of traffic • Available bandwidth • Other capacity features used

• microcells • Separate indoor coverage • IUO / IFH

• Space in the current site places • Single band MS penetration • Locations of the existing sites

The coming dual band network:

• Single / multivendor • Available bandwidth for different bands • Expected traffic growth • Dual Band MS penetration • Importance of the data services (HSCSD, GPRS, EDGE) • Cost of the network

There are two basic capacity evolution approaches to implement Dual Band:

• Complete coverage provided with the GSM 1800/1900 band • Additional capacity provided with the GSM 1800/1900 band where needed, like in

traffic hot spots, microcells, or indoors.

The difference is relevant in terms of costs. The second solution is more cost-effective if no constraints are given in the licence. GSM 1800/1900 implies a more cost-effective network in the regions of a high traffic density, but a higher cost when providing a basic coverage. The GSM 900/800 network provides the wide area coverage, while GSM 1800/1900 is seen as an efficient capacity extension, where it is required. If the original GSM 900/800 network is highly interference limited, the new GSM 1800/1900 network might have a wider coverage as far as interference is concerned than the GSM 900/800 network.

It is not sufficient to only consider the dual band network growth. It is more important to compose a complete capacity evolution package, including other capacity features, new data services, expected traffic growth, and so on.

After choosing the right capacity evolution plan, including the most suitable Dual Band scenario (hot spot coverage, continuous coverage, microcells, and so on), the correct traffic management strategy must be chosen. This depends on the following facts:

34 DN9814105Issue 11-1



Planning Dual Band

• Single / dual band MS penetration • Network structure: GSM 900/1800 / GSM 800/1900 / GSM 800/1800 macrocells,

GSM 900/1800 / GSM 800/1900 / GSM 800/1800 microcells, IUO/IFH, indoor cells • Expected data traffic (HSCSD, GPRS, EDGE) • Single / multivendor network (available traffic management features).

The traffic management strategy can also be chosen during the parameterisation process.

When the normal planning procedure has been completed, we proceed with capacity planning (number of TRXs and sites), frequency planning, parameter planning, and opti-misation.

Figure 7 Dual band network planning and optimisation procedure

5.1.1 Coverage planning strategies Depending on the requirements, there is a wide variety of structures of Dual Band network that may be implemented. As Dual Band can be used with other features such as microcells, separate indoor cells, IUO, FH and IFH (in both 800 and 1900 bands, in both 900 and 1800 bands, or in both 800 and 1800 bands) and so on, there are numerous possible network structures. The different coverage types can be classified into mainly two types: continuous or non-continuous coverage.

The coverage can be constructed by using macrocells, microcells, pico cells, or indoor cells.

Non-continuous GSM 1800 coverageTypically, the operator with a dual band licence starts to build the GSM 1800 network on top of the GSM 900 network. The actual strategy on how to build the coverage depends greatly on subscriber behaviour, available bandwidth, and site availability.

GSM 1800/1900 pico cells and microcellsOne strategy to implement GSM 1800 network is to implement it where it is really needed for hot spot capacity improvement. A GSM 1800 micro/pico cellular layer imple-mented with a GSM 900 macro layer (a GSM 900 micro layer could also already be implemented).

Capacity Planning Monitoring

Frequency Planning Parameter Planning

NetAct Planner

NMS/2000

NetworkDoctor Traffica

NDW

PlanEditCDW

NetAct PlannerNetdim

DN9814105Issue 11-1

35


Planning Dual Band


In this case, the GSM 1800 layer would provide, for example, in-building coverage and an increased capacity in small high-density areas (this is ideal, for example, for wireless office type of solutions). The advantages here are that the 1800 cells can be planned largely independently of the 900 layer. Consequently, the in-building coverage can be optimised, rather than being limited by the problems of leakage interfering with the external GSM network. This kind of deployment can also be done where the capacity is really needed, making it a cost-efficient solution to start the dual band deployment.

Figure 8 Use of GSM 1800 pico cells and microcells

The disadvantage of this type of solution is that only dual band users benefit from the increased coverage. This is fine where the mobile population is static and can easily be identified for migration, for example in the mentioned office environment. Where the mobile population is transitory, for example at a railway station, it may be less beneficial (unless dual band is specifically marketed as an improved coverage service). Other dis-advantages of this solution are that this strategy causes a larger number of inter-band handovers, and the actual capacity increase in the network is more difficult to estimate.

To sum up, the advantages of the solution are:

• Fast and cost-efficient roll-out (according to the real capacity needs) • Optimised interference and coverage

The disadvantages of the solution are:

• Only Dual Band (DB) users benefit from the additional coverage and capacity • Large number of inter-band handovers

Co-located sitesOperators often want to use the existing GSM 900 sites particularly if the sites are large enough to accommodate additional hardware. The co-location of GSM 900/1800 equip-ment minimises the site acquisition costs and usually enables a fast roll-out of the GSM 1800 service due to the obvious benefits of having a ready site with transmission con-nections.

GSM1800 Micro/Pico cells

GSM900 Macro

GSM900 Macrocellsplus GSM1800 Micro/Pico cells

36 DN9814105Issue 11-1



Planning Dual Band

Figure 9 Co-located sites

This kind of strategy is often used in city centre areas where new site availability is more limited (and where the additional capacity is usually needed). Nokia’s integrated dual band BTS is ideally suited for this kind of solutions, enabling the fastest possible roll-out because of the possibility of also using the same BTS cabinet for both GSM 900 and GSM 1800 TRXs.

In this solution, the following points need to be considered:

• Fast roll-out • Saving in site costs and acquisition time • Infrastructure and site support systems are shared and can be used for GSM 900

and GSM 1800 BTSs (depending on their capacity) • Saving on periodic maintenance visits • Saving in transmission costs • Continuous GSM 1800 coverage may not be achieved, particularly if the GSM 900

coverage is only adequate. (If the site density is high enough, continuous coverage can be achieved.)

• If the coverage is not continuous, other disadvantages mentioned in the previous case are also valid (for example, an increased number of inter-band handovers).

• Indoor coverage usually requires additional GSM 1800/1900 sites due to penetra-tion difference, as compared to GSM 900/800.

Co-located sites and GSM 900/800 microcells/pico cellsIn this case, the GSM 1800/1900 hardware is co-sited with existing macro sites at capacity hot spots, with GSM 900/800 microcells/pico cells used to provide enhanced in-building coverage where needed.

From the capacity point of view, the aim of this strategy is to reduce the number of micro-cells/pico cells needed in the capacity enhancement in such a way that they are only used where the improved in-building coverage is needed - rather than for capacity.

Figure 10 Co-located sites and GSM 900/800 microcells/pico cells

DN9814105Issue 11-1

37


Planning Dual Band


The disadvantage of this approach is a more complicated traffic management and parameterisation.

Continuous GSM 1800/1900 coverageTo get the maximum benefit from the dual band system and to avoid unnecessary inter-band handovers, operators usually sooner or later improve the GSM 1800/1900 coverage so that it is seamless in those areas where it is needed.

This can be done, for example, by starting the GSM 1800/1900 roll-out by co-locating the GSM 1800/1900 macro BTSs with GSM 900/800 macro BTSs and using the GSM 1800/1900 microcellular solution to cover the holes in the coverage.

This solution avoids most of the problems mentioned in the previous examples and is also a preferred solution in a multivendor dual band network if the geographical separa-tion of the two dual band networks is not possible.

Having a seamless GSM 1800/1900 coverage enables you to fully use the additional band by keeping the dual band subscribers continuously in the 1800/1900 band in the areas where additional capacity is needed, therefore reducing the traffic load in the GSM 900/800 cells. In this case you can also provide an adequate service for roaming GSM 1800/1900 subscribers.

5.1.2 Different network strategies

GSM 900/800 and 1800/1900 cells under the same BSC

Figure 11 GSM 900 and GSM 1800 cells under the same MSC

This network strategy is the most recommended when regarding the costs of building the network, support of the BSS features, and management and optimisation of the network.

• Common transmission link • Inter-band handover causes intra-BSC handover; shorter and more reliable

handover • Fully uses the advanced BSS features and traffic management • Easy network management

MSC BSCOMC

NetAct

GSM900

GSM1800

38 DN9814105Issue 11-1



Planning Dual Band

GSM 900/800 and 1800/1900 cells under different BSCs

Figure 12 GSM 900 and GSM 1800 cells under different BSCs but the same MSC

This approach is normally used if the GSM 900/800 BSC capacity is not adequate to add GSM 1800/1900 cells. The following facts must be considered in this approach:

• Feasible network management • High BSC capacity • Requires extra MUX to use common Abis links • Inter-band handover causes inter-BSC handover; increase in A-interface signalling

load • Some advanced BSS features in traffic management and monitoring cannot be used

GSM 900/800 and 1800/1900 cells under different MSCs

Figure 13 GSM 900 and GSM 1800 cells under different MSCs

This approach is normally used in a multivendor environment where different vendors provide BSSs for different bands. Lack of MSC capacity can also lead to this kind of solution. The following facts must be considered in this approach:

• High BSC and MSC capacity • Extra transmission capacity needed

MSC

BSC(GSM)

OMC

NetAct

GSM900

GSM1800

BSC(DCS)

MSC BSC

GSM900

GSM1800

BSCMSC

DN9814105Issue 11-1

39


Planning Dual Band


• Inter-band handover causes inter-MSC handover; an increase in A-interface and MSC-MSC signalling load

• Some advanced BSS features in traffic management and monitoring cannot be used • Planning co-ordination more challenging • CDW / NDW is needed to manage both vendors' network in a centralised manner

PlanEdit can be used for an adjacency database in multivendor cases. It can get the neighbouring cell parameters of the other vendor's border areas automatically from the NetAct database. This might be the easiest solution for planning the border area neigh-bouring cells and for gathering the data.

5.1.3 Dual Band optimisationThe normal procedures used for network optimisation in single band networks are also valid in Dual Band networks. In addition, the network structure can cause some new details that need to be considered.

Common or separate quality, traffic, and alarm statistics from different bands can be constructed when NetAct is used and the cells of different bands are located under the same MSC. If the different bands are located under different MSCs (for example in multi-vendor cases), the common statistics cannot be gathered automatically. By using Nokia CDW/NDW, a limited set of the network statistics can be gathered from different vendors at the same time.

Network Doctor or NDW can be used to collect the quality statistics from the network. Some special dual band counters have been added (HO reasons, HO success) to support the Dual Band function. Other statistics, like TCH drop rate, RXQual, and so on, can be used as well.

The outdoor measurement tools, like TOM and TEMS, also support Dual Band function-ality. The coverage within the band, the MS idle mode operation, the handover param-eters, traffic management between the layers, and so on can be tested.

40 DN9814105Issue 11-1



5.2 Planning parameters in a Dual Band network The challenges in the actual parameter planning of a multi-vendor network are largely dependent on the complexity of the network configuration and structure. When simpler and uniform structures like continuous GSM 1800/1900 coverage is used, these chal-lenges are greatly reduced. The main Dual Band specific parameters to be defined are the following:

• Neighbour cell definitions • Parameters for traffic management between the layers (idle and dedicated mode)

You should take into account the management of the parameters of the neighbouring cells implemented with different equipment and of different vendors. The cell adjacen-cies in both cells need to be matched to each other. Without a proper network manage-ment solution this is not possible, hence the potential for mismatch and errors exist, particularly when re-tuning the network.

Defining neighbour cellsThere are basically four ways how the neighbour cell definition can be done:

• Manually (most practical in the simple network structure) • Neighbour generation in the planning tool (NetAct Planner, automatic transfer to the

network) • Neighbour generation by using a network measurement tool (TIM, TOM) • Fully integrated network configuration management using the Nokia Configuration

Data Warehouse.

DN9814105Issue 11-1

41



5.3 Dual Band site solutions and antenna configurations The BTS Site Package program defines and documents the macrocellular BTS site packages to be used in the BSS roll-out. A complete BTS Site Solution consists of:

• BTS • Antennas and feeders • Diplexers • Cellular transmission • Other site solution material and equipment.

By using a specific BTS Site Configurator program, it is easy to select the right compo-nents to compose the site, to order the components, and to calculate the price. The DB antenna/diplexer solutions are available and presented in the Configurator as well.

The following dual band site configurations are currently recommended.

Dual band site configuration 1

Figure 14 Site configuration 1

This site configuration can now be realised with the current antenna solutions. It has the following properties:

• Single band antennas (current accepted models) • Dual polarisation possible • MHA possible • Small risk for intermodulation • Reliable antenna measurement

GSM 900/800 GSM 1800/1900 GSM 900/800 GSM 1800/1900

Single banddualpolarisationantenna

Singlebandantenna

MHAsoptional

Main

MHAsoptional

DB BTS orseparate BTSs

Div.Div.Main

42 DN9814105Issue 11-1



• Usable now • Extra feeders needed • Extra antennas for the other band

The maximum configurations with the amount of antennas and feeders described above are the following:

• Wideband Combiner; (4+4) x n • RTC; (6+6) x n



• Single band antennas (current models) • Dual polarisation possible • Fewer feeders, fewer antennas • Requires GSM900/1800 or GSM800/1900 diplexers • High risk for intermodulation • MHA not currently possible (separate DC needed) • Antenna measurement not reliable • Extra antenna still needed for the other band

This site configuration has the following properties:

Maximum configurations:

• Wideband Combiner; (4+4) x n

GSM 900/800 GSM 1800/1900

Dual banddiplexers

DB BTS orseparate BTSs

Div.Main

Dual banddiplexers

DN9814105Issue 11-1

43



• RTC; (6+6) x n




• No extra antennas; dual band dual polarisation antennas used (Kathrein) • No diplexers, therefore small risk for intermodulation • Small losses • MHA possible • Reliable antenna measurement • Requires many feeders • Antennas still under testing


• Wideband Combiner; (4+4) x n • RTC; (6+6) x n

Dual band dualpolarisation antenna

MHAsoptional

44 DN9814105Issue 11-1






• No extra antennas • Fast roll-out • Dual band dual polarisation antennas (Kathrein), internal diplexers • Fewer feeders • Requires diplexers • High risk for intermodulation • MHA not currently possible • Maximum input power of the antenna may be too low for big TRX configurations

(8+8)


• Wideband Combiner; (4+4) x n; (8+8) x n • RTC; (6+6) x n

Dual band dualpolarisation antenna

Div.Main

Dual banddiplexersGSM 900/800

GSM 1800/1900

DN9814105Issue 11-1

45



Dual band site configuration 5: MetroSite BTS

Figure 18 Site configuration 5: MetroSite BTS

The MetroSite BTS configuration has the following properties:

• Fast roll-out • Dual band 2 port antennas (directional and omni)

• GSM 900 / GSM 900 • GSM 900 / GSM 1800 • GSM 1800 / GSM 1800

• No internal combiners needed • Short and light feeders • RX diversity • Antenna gain

• 5 dBi / directional antennas • 2 dBi / omni antennas

• 1 feeder per TRX

Related topics

• Overview of Common BCCH Control

46 DN9814105Issue 11-1


Id:0900d8058058fb6cConfidential

5.4 Traffic management in a Dual Band network

5.4.1 Traffic management featuresA dual band network requires a functionality that enables the management of different subscriber types.

In order to make the maximum use of the additional capacity provided by a dual band network, dual band users must be carefully managed between the bands. The strategy must be to optimise the availability and call quality of all users. This is achieved by managing the dual band mobiles between the GSM 900/800 and GSM1800/1900 cells (micro/macro). This can be done in the idle mode, during a call set up (on SDCCH), or during a call.

Figure 19 Traffic management

You must also be able to manage different kinds of subscriber type and mobile type profiles in billing and charging, so that you can create different service packages with different tariffs based on the used service and mobile type (Subscriber Segmentation in Dual Band).

5.4.1.1 Features used in idle modeThe C1 and C2 criteria can be used to force a dual band mobile station (MS) to camp on a specific cell when the mobile is in the idle mode. The C2 parameter can be used, for example, to force the dual band MSS to favour the GSM 1800/1900 cells in idle mode, even though they may have a lower signal level than the GSM 900/800 cells. This simply gives a fixed signal level offset to the GSM 1800/1900 signal level received by the mobile when it decides on which cell to camp.

The problem with using C2 is that the offset is fixed. This may result in the mobile camping on a barely acceptable GSM 1800/1900 carrier even though a far better, and possibly empty, GSM 900/800 carrier exists. This results in less than optimum call quality. This kind of problem can be partly avoided by setting a high enough value for the minimum access level for the cell.

The C1 and C2 equations are presented in ETSI TS 05.08 and the use is explained in ETSI TS 03.22.

IdleMode

Call Setup In Call

C2 ParameterDirect Access to

Desired Layer/Band

DB MS not allowedto access IUO

Super Layer or MBR

FMMS DetectUmbrella orPBGT HO

Advanced MultilayerHandling

Adjacent CellPriorities

& Load Factors

DN9814105Issue 11-1

47



It is important to remember that the C2 use requires a PHASE 2 mobile support, which all dual band MSS have.

C1 and C2 equations

where

A= Average received LEVEL - RXLEV_ACCESS_MIN

B= MS_TXPWR_MAX_CCH - P

and

RXLEVEL_ACCESS_MIN is the minimum downlink received level required to access the cell (BTS parameter).

MS_TXPWR_MAX_CCH is the maximum TX power level the MS may have in the cell (BTS parameter).

P is the maximum RF output power of the MS (fixed for each MS).

All values are expressed in dBm. The path loss value criterion is satisfied when C1 > 0 (GSM 03.22).

where

H(x) = 0 for x < 0, that is, Penalty_Time <T

H(x) = 1 for x ≥ 0, that is, Penalty_Time ≥ T

T is a timer started from 0 when the cell appears on the list of the 6 strongest BCCH frequencies of the MS.

How to use C1 and C2 in Dual Band environmentAll the parameters involved in these equations are cell-specific and they are sent within the System Information messages on the BCCH.The MS uses the C1 criterion in order to camp on the cells according to the received power levels and minimum access levels of the cells. By using the C2 criterion, the MS camps again in another cell set, where it starts a call set-up.

The method proposed here to set the C2 parameter is based on the difference in a cell of the following values:

• GSM parameter RXLEV_ACCESS_MIN • Propagation behaviour • EIRPThe parameter cell reselect offset is used to give a higher priority to the chosen cell (GSM 1800/1900, micro, and so on). To ensure the camping to the “right” cell, the cell reselect offset value should be set higher than the difference in RxLev_Access_Min, Propagation, and EIRP between the cells ("delta" offset) to camp on.

Equation 1 . C1 = (A - MAX(B,0))

Equation 2. C2 = C1 + CELL_RESELECT_OFFSET - TEMPORARY_OFFSET*H(Penalty_Time - T) for Penalty_Time 11111

Equation 3. C2 = C1 - CELL_RESELECT_OFFSETfor Penalty_Time = 11111

48 DN9814105Issue 11-1



The "delta" offset is calculated as follows:

where

Propagation is normally set to 10 dB in favour of 900/800 MHz cells. Another value can be used on the propagation difference measurements.

The parameter penalty time is used when the microcells are present to ensure that only slow moving mobiles would camp in the micro layer. It means that, during the penalty time, the microcell has a lower priority to be selected to get enough measure-ment results (to see if the MS is moving slow or fast). After the penalty time, the microcell is selected if the MS is slow moving. The proposed value is 20 seconds.

The parameter temporary offset is used to change the priority of the cell selection for the penalty time (for example, microcell).

Example of C2 strategy

The following assumptions have been made:

• Three-layer network; macro 900, micro 900, macro 1800 • The highest priority for slow moving mobiles to the microcell • The second priority to the 1800 cells (fast moving mobiles).

The following values have been selected for the sake of understanding, although they may be extreme and require fine-tuning on an existing network.

Depending on the priority set for each layer, cell reselect offset can be calcu-lated. To ensure the camping to the chosen cell, cell reselect offset should be set bigger than the "delta" offset between the candidate cells. The C2 parameter planning could proceed according to the following steps:

1. In this example, the 2nd priority is given to the M1800 cell. The M1800 cell should be set to look at least 27 dB stronger than the M1900 cell that has the lowest priority. The parameter cell reselect offset can be set to 30 dB.

2. The 1st priority was set to the π 900 cell. The π 900 cell should be set to look at least 18 dB stronger than the 2nd priority cell M1800 and 35 dB stronger than the

RXLEV_ACCESS_MIN

M900 -110 dBm

M1800 -98 dBm

π 900 -95 dBm

Table 9 Example values for RXLEV_ACCESS_MIN

Equation 4. (Celltype 1 Celltype 2) = Celltype = RxLev_Access_Min + Propagation + EIRP

(M900 - M1800) = 12 + 10 + 5 = 27 dB(M900 - 900) = 15 + 0 + 20 = 35 dB(M1800 - 900) = 3 10 + 15 = 18 dB

wherePropagation M900 M1800 = + 10 dB,Propagation M1800 - 900 = -10 dB.

DN9814105Issue 11-1

49



M900 cell (MAX (30dB + 18dB), 35dB). cell reselect offset can be set to 60 dB.

3. Because fast moving MSS are not to be camped in the π 900 cell, the penalty time and temporary offset parameters must be used. The penalty time can be set to 20 seconds and temporary offset to 60 dB to cancel the effect of the cell reselect offset parameter of the π 900 cell during the penalty time.

During the penalty time, the highest priority is given to the M1800 and the 2nd priority to the M900 layer. The microcell layer is not selected because of the high temporary offset value to ensure that the fast moving MS stays in the macrocell layer.

After the penalty time, the microcell layer has the highest priority for slow moving mobiles. The second priority is given to the M1800 layer (fast moving mobiles).

5.4.1.2 Features used during call set-upIf the call can be transferred from a GSM 900/800 cell to a GSM 1800/1900 cell during the call set-up (that is, on SDCCH), less of the GSM 900/800 capacity is wasted, as compared to a case where the call is first set up on the GSM 900/800 layer and then transferred to a GSM 1800/1900 cell. The mechanisms for initiating the SDCCH handover are Direct Access to the Desired Layer/Band or the normal Directed Retry.

Direct Access to the Desired Layer/BandThe existing priority and load factor concept can be used together with Direct Access to the Desired Layer/Band (DADL/B). The call can be directed during the call set-up to the layer having the highest priority, for example, the 1800/1900 layer. By using the load factors, it is possible to prevent the layer with the highest priority from being blocked. If the load increases over the predefined threshold, new priorities are calculated to favour the less occupied layer.

The following parameters are related to Direct Access to the Desired Layer/Band:

• min time limit directed retryThis parameter determines the period starting from the assignment request during which the target cell evaluation for the directed retry handover is not allowed. Range: 1..14 (s).

• max time limit directed retryThis parameter determines the maximum time period starting from the assignment request during which the target cell evaluation for the directed retry handover is allowed. Range: 0..15 (s).

• BTS load thresholdDADL/B is applied if DADL/B is enabled in the BSC and if the load of the accessed cell is higher than the BTS load threshold defined for the accessed cell and

Priority Cell types Cell reselect offset

Penalty time Temporary offset RxLevAccess Min

highest π 900 60 dB 20 s. 60 dB - 95 dBm

M1800 30 dB 20 s. 0 dB - 98 dBm

lowest M900 0 dB 20 s. 0 dB - 110 dBm

Table 10 Example of the C2 parameters

50 DN9814105Issue 11-1



there are adjacent cells defined as DADL/B handover target cells with the target cell of direct access to desired layer(n) parameter. Range: 0..100%.

• target cell of direct access to desired layerAdjacent cells handled by the BSC, considered as DADL/B target cells with a signal level exceeding HO level umbrella, are sorted according to the adjacent cell priority and load factor (HO priority level or HO Priority Level(n) - HO load factor(n) (if the adjacent cell is loaded) to be used as target cells for the DADL/B handover. Range: Y/N.

• Ho level umbrellaThis parameter defines the minimum level for the target cell of direct access to desired layer to be selected. The same parameter is used for the umbrella and SMMS handover. Range: -110..-47 (dBm).

☞ If the cell is congested, a directed retry is triggered and the network does not take DADL/B into account.

Directed RetryDirected Retry redirects an MS in a congested situation to attempt access to another cell from a predefined list. The target cells are ranked in the order of signal levels and the best is chosen for the handover.

5.4.1.3 Features used during call All Nokia handover types can be used to transfer traffic between the bands. Which is the most suitable in each case depends on the network structure. The suggested handover types are:

• The umbrella handover may be used for transferring traffic from the GSM 900/800 to the 1800/1900 band, as this only takes into account the performance in the target cell. If it meets the specified criteria (level threshold of the target cell), the handover is made.

• Negative power budget handover can also be used to transfer traffic from the GSM 900/800 to the 1800/1900 layer. If the Fast Moving Mobile algorithm is used to direct traffic from the GSM 900/800 layer to the microcells, the umbrella HO algorithm cannot be used and the negative power budget HO is the only possible solution.

• Once the call is on the GSM1800/1900 band, it should be kept there, if possible. This is best accomplished by normal power budget handovers (that is, the call is kept in the strongest cell). The same method is used in the GSM 900/800 band.

• The call may be returned to the GSM 900/800 layer by RX level/quality/interference (RR HO) handovers. Prioritisation can be used with RR HOs to give a higher priority for the GSM 1800/1900 or microcells.

• The MS Speed Detection or a Fast Moving Mobile algorithm can be used to direct slow moving traffic to the microcells and to keep the fast moving mobiles in the macro layer.

By balancing the parameters of the handovers between each band it should be possible to balance the traffic load on each band.

Power Budget HandoverPower Budget (PBGT) handovers are normally used to keep the calls inside one layer. The idea is to keep the mobile in the strongest cell.

DN9814105Issue 11-1

51



In a standard network, unwanted consecutive PBGT handovers between the source and the target cell are avoided by using a positive margin. However, a negative margin can be used for a special multi layer configuration, for example when moving the traffic from the GSM 900/800 layer to the GSM 1800/1900 layer. The PBGT handover must be disabled from the GSM 1800/1900 layer back to the GSM 900/800 layer in this case (high PBGT margin).

Radio Reason HandoversThe level and quality handovers are normally used as safety handovers to transfer traffic back from the GSM 1800/1900 or micro layer to the GSM 900/800 layer in a bad qual-ity/level situation.

The level and quality handovers are performed if the target cell has a level exceeding the level of the source cell of HO margin lev/qual dBm. Normally, the margin for quality handovers has been set to 0 or to a negative value to favour handover to call drop.

The level and quality handovers target all kinds of cell, without any relation to the cell layer. Prioritisation can, however, be used with Radio Reasons handovers to give a higher priority for a certain layer or cells.

Umbrella HandoverThe umbrella handover can be used to transfer mobiles from the 900/800 layer to the 1800/1900 layer when the level in the target cell, that is, 1800/1900, meets a specified criterion, usually higher than -85 dBm to -90 dBm. This algorithm introduces a simple way to "suck" the traffic towards the 1800/1900 layer.

The implementation of this algorithm does not require the usage of the parameter adjacent cell layer. In that case the Power Budget handover from the GSM 1800/1900 layer to the GSM 900/800 layer should be manually prevented by setting the PB margin to –63 dB.

If adjacent cell layer is used, it is reasonable to define the 1800/1900 layer as a lower layer for the 900/800 layer. Thus, all Power Budget handovers are automatically prevented between the upper-lower layers.

Fast Moving MS Handling and MS Speed DetectionFast Moving MS Handling software product includes the adjacent cell layer parameter. An adjacent cell can be of the SAME, UPPER, or LOWER layer, depending on the source cell.

The Fast Moving MS handover algorithm allows you to direct a mobile to the right layer regarding its speed, that is, the fast mobile uses the upper layer cell (large coverage area cell), while the slow mobile uses the lower layer cell, supposed to be the capacity-oriented one. This algorithm is mostly used in microcellular networks. In a dual band configuration, the 1800/1900 cell provides the capacity but its range is not similar to a microcell and thus it has to be used carefully. Normally, the GSM 1800/1900 cell can be defined as the same-layer cell as the GSM 900/800 cell to avoid an unwanted microcell handover when going to the 1800/1900 macro layer.

When the speed measurements are not taken into account, the umbrella handover is triggered as soon as one target cell meets the equation criterion.

☞ The speed measurement in the BTS does not work if the MS is using frequency hopping.

52 DN9814105Issue 11-1



Handover priorities and load managementWhen several layers of cells exist in the network, it is necessary to balance the load between the layers to achieve the maximum capacity. By using the Adjacent Cell Prior-ities and Load Factors it is possible to direct the mobiles to a particular band (or cell) based on the priority factor of the handover candidate cells and the traffic load in those cells.

The target cell priority can be set in each cell for each adjacent cell. A load threshold can be defined to dynamically change this priority according to the traffic load of the cell. The use of this load management is an intra-BSC feature.

The table HO priority and load factor parameters describes the parameters of each adjacent cell associated with this feature and the feature’s functionality.

If the load in the target cell exceeds the Load Threshold value, the priority of that cell as a handover candidate is reduced by the HO Load Factor according to following equation.

For example, the coverage from the GSM 900 macrocell, GSM 900 microcell, and GSM 1800 macrocell is overlapping. The mobile is served by the GSM 900 macrocell but has acceptable (from the RF point of view) handover candidates to both the GSM 900 micro-cell and the GSM 1800 macrocell.

Figure 20 Handover candidates for GSM 900 macrocell

The cell parameters are given in the following table.

Parameter Value/Function

HO priority level 0 to 7. Highest priority is 7.

HO load factor 0 to 7. The amount by which Priority Level is reduced when cell Load Threshold is exceeded.

load threshold 0 to 100%. Threshold above which the attractiveness of the cell is reduced.

Table 11 HO priority and load factor parameters

Equation 5. If (Load > Load Threshold), New Priority = HO Priority LevelHO Load Factor

GSM900 Macro

GSM1800 Macro

GSM900 Micro

HO Candidate HO Priority Level

Load HO Load Factor

Load Threshold New Priority

900 Micro 2 60% 1 70% 2

1800 Macro 4 80% 3 70% 1

Table 12 Example of handover priority and load factors

DN9814105Issue 11-1

53



From the RF measurement point of view, the GSM 900 microcell would be the best can-didate. The HO priority level of the 1800 cell is, however, higher - it becomes the higher handover candidate. But the 1800 cell is already overloaded, so its priority level is reduced by the HO load factor. The highest priority is given to the 900 microcell which is chosen for the handover.

Load Management proceeds in the BSC for an MS entering a target cell. To trigger a handover for load reasons in the serving cell (Traffic Reason HO), MSC support is needed.

Priorities and load factors are set on a cell adjacency basis and can be set for a whole layer.

Advanced Multilayer HandlingAdvanced Multilayer Handling can be used to balance the load between the layers or to improve network quality. It includes, for example, a traffic-reason handover triggered by traffic load to transfer the calls from occupied cells to less occupied ones. Adjustable Power Budget margins based on the traffic load can also be used.

For more information on Handover cases and equations see Handover cases in the chapter Functionality of Dual Band Network.

5.4.2 Traffic management between network layersYou can choose different ways to implement dual band cells in the network. This choice also influences the strategy to be used for handling the MS between the bands. The dif-ferent strategies are presented and explained below.

5.4.2.1 Two-layer dual band networkThis first strategy is the simplest one to use. It works when the network uses only 2 layers: a GSM 900/800 macro layer and a GSM 1800/1900 macro layer.

The GSM 1800/1900 layer is defined as a LOWER layer for the GSM 900/800 layer and the handovers used are:

• Umbrella handover to go from 900/800 to 1800/1900, with a typical threshold of -85 dBm.

• Radio reason (Level or Quality) handover to go from 1800/1900 to 900/800. • Power budget handover within the same layer, with a margin of 6 dB.

54 DN9814105Issue 11-1



Figure 21 Two-layer network

In this strategy, it is assumed that there are only two layers in the network, which means that microcells are not defined as another lower layer. This case will be discussed later.

Dual band mobiles are directed to the 1800/1900 layer during the call by using an umbrella handover and are kept in the suitable band with a power budget handover. When the quality or the level becomes poor, the mobile returns to the 900/800 layer (or stays in the 1800/1900 layer). When the 1800/1900 and 900/800 cells are co-located, only one 1800/1900 neighbour - the co-located cell - can be defined from each 900/800 cell (in the case of a coverage limited macrocell). This is justified by the low capacity needed in the beginning and the level is always better in that cell than in the other ones.

5.4.2.2 Three-layer networkA three-layer network contains two macro layers, 900/800 and 1800/1900, and one micro layer, 900/800 or 1800/1900.

The traffic management strategy must be chosen to push the dual band MS towards the layers which offer more capacity and have better quality. Normally, this kind of layers are the 1800/1900 layer and the micro layer. The 900/800 macro layer is seen as a col-lector layer where the calls are set up. When the calls are processed, they are routed by following the chosen strategy (the selection of the “right layer” can also be done during the idle mode by using the C2 parameter).

Basically, there are two reasonable ways: the highest priority is given to the 1800/1900 layer or the 900/800 π -layer.

Priority to Microcell LayerThe figure Three-layer network strategy No.1, priority to microcell layer shows the general idea of this strategy:

Power Budget HO within the SAME layer

GSM 900/800

Umbrella HO to LOWER layer Radio reason HO to UPPER layer

Power Budget HO within the SAME layer

GSM1800/1900

DN9814105Issue 11-1

55



Figure 22 Three-layer network strategy No. 1, priority to microcell layer

The 1800/1900 and 900/800 macro layers are defined as the same-level layers and the microcellular layer is defined as the lower layer from the 1800/1900 and 900/800 macro by using the adjacent cell layer parameter.

The dual band mobiles are sent to the 1800/1900 layer with a Power Budget handover with a negative margin, that is, the capture is done very quickly (the default value for the measurement window is 6 SACCH frames, which means approximately 6 seconds) - similar to an umbrella handover. The recommended value for the margin is -24 dB and the recommended RxLevMin (the minimum level value to access the cell during a han-dover) is -90 dB (in the 1800 cell). The negative power budget handover is used here, because the umbrella handover cannot be used together with the Fast Moving Mobile algorithm.

The microcellular layer can be used for slow mobiles only. The capture is done using the Fast Moving Mobile algorithm from the 900/800 macro and from the 1800/1900 cells. The recommended value for fast moving threshold is 32 SACCH frames, and the adjacent umbrella cell level is set to -85 dB. The same parameters are used in the 1800/1900 and 900/800 source cells. This ensures that all slow moving dual band mobiles go down to the microcellular layer.

The figure Strategy No. 1, priority to microcell layer, main parameter values summarises the main parameter values.

GSM Micro

Power Budget

GSM1800/1900

Power Budget

GSM 900/800

Radio Reasons

Radio ReasonsFast Moving MS

Power Budget

( to same layer )

( to lower layer )

( to same layer )( to same layer )

( to same layer )

( to upper layer )

56 DN9814105Issue 11-1



Figure 23 Strategy No. 1, priority to microcell layer, main parameter values

Within a layer, 900/800 macro, 1800/1900 macro or micro, the mobiles use Power Budget algorithms with a positive margin (+ 6 dB) to stay on the best cell. The mobiles are going from one layer to another using radio-reason handover algorithms (level or quality handovers).

If the 1800/1900 layer coverage is not seamless, special parameterisation is used at the border areas. The power budget margin is set at + 12 dB instead of + 63 dB to allow the mobiles to go back to the 900/800 layer before the level or the quality becomes poor. This is shown in the figure Parameter change at coverage border. This could also be applied to the microcellular layer.

MS Speed S5

M1800/1900

RxLevMinCell(n)=-95 dBmFastMovingThreshold(n)=32

Filtering :

RxLevMinCell(n)=-95 dBmhoLevelUmbrella(n)=-85 dBmadjCellLayer(n)=Lower

MS Speed S5

Triggering :

RxLevMinCell(n)=-95 dBFastMovingThreshold(n)=32

Filtering :


Triggering :

M900/800

Negative PBGT

Triggering :

hoMarginPBGT(n)=-24 dBmadjCellLayer(n)=samehoPeriodPBGT(0)=6 SACCHs

Filtering :

RxLevMinCell(n)=-90 dBmhoMarginPBGT(n)=-24 dBmadjCellLayer(n)=same

900

DN9814105Issue 11-1

57



Figure 24 Parameter change at coverage border

The same strategy can be achieved by using the umbrella handover instead of the negative power budget from macro 900/800 to macro 1800/1900.

The 1800/1900 is defined as a LOWER layer from the 900/800 macro layer and the microcellular layer is defined as a LOWER layer from the 1800/1900 and 900/800 macro by using adjacent cell layer parameter.

The dual band mobiles are sent to the 1800/1900 layer with an S5 MS speed algorithm with the fast moving threshold set to 1 SACCH, which means that the capture is done nearly instantly. The recommended value for RX lev min (the minimum level value to access the cell during a handover) is -85 dB (in the 1800/1900 cell).

The microcellular layer must be used for slow mobiles so the capture is done by using the Fast Moving mobile algorithm from the 900/800 macro and from the 1800/1900 cells. The recommended value for the fast moving threshold is 32 SACCH frames and the adjacent umbrella cell level is set to -85 dB. The same parameters are used in the 1800/1900 and 900/800 source cells. This ensures that all slow moving dual band mobiles go down to the microcellular layer.

GSM 900

SAME

PBGT + 12 dBPBGT + 63 dBPBGT -24 dB

"last" cell

GSM 1800

SAME

58 DN9814105Issue 11-1



Priority to 1800/1900 Layer

Figure 25 Three-layer network strategy No. 2, priority to 1800 layer

The 1800/1900 and 900/800 macro layers are defined as the same-level layers and the microcellular layer is defined as a lower-level layer from 1800/1900 and 900/800 macro by using the adjacent cell layer parameter.

The dual band mobiles are sent to the 1800/1900 layer with a power budget handover with a negative margin, that is, the capture is done very quickly (the default value for the measurement window is 6 SACCH frames, or approximately 6 seconds) - the same as an umbrella handover. The recommended value for this margin is -24 dB, RX lev min (the minimum level value to access the cell during a handover) is -85 dB (in the 1800 cell).

The microcellular layer must be used for slow mobiles, so the capture is done by using the Fast Moving mobile algorithm from the 900/800 macro. The recommended value for the fast moving threshold is 32 SACCH frames and the adjacent umbrella cell level is set to -85 dB.

In this case, dual band MSS must be routed to the 1800/1900 layer, even if they are analysed as slow moving mobiles. In that order, the 1800/1900 layer is defined as a lower layer from the micro layer, and the umbrella handover is enabled with a HO period of 6 SACCH. This parameterisation ensures a fast capture of the dual band MS in the 1800/1900 layer. Another possibility would be to define the fast moving threshold to equal 0 and to also disable the speed measurements.

Within a layer, 900/800 macro, 1800/1900, or micro, the mobiles use Power Budget algorithms with a positive margin (+ 6 dB) to stay on the best cell.

The figure Strategy No. 2, main parameter values summarises the main parameters used:

SAME

GSM Micro LOWER

Power Budget

GSM1800

Power Budget

GSM 900

SAME

Radio ReasonsPower Budget

Fast Moving MS

Modified FastMoving MS

DN9814105Issue 11-1

59



Figure 26 Strategy No. 2, main parameter values

5.4.2.3 Traffic management in multivendor environmentIn a multivendor dual band network, the handovers within each vendor's band are per-formed normally in the same way they would be done in a single band network.

Regarding the handovers from the BSS to vendor X's BSS, the situation is similar to a single band multivendor network situation. All the basic BSS handover features can be used, except some of the more sophisticated Nokia features, like IUO and MS Power Optimisation in handovers. In addition, the features that require the BSS to have the knowledge of the target cell (other vendor's MSC and/or BSS) might not fully work. These features include, for example, prioritisation, traffic load control, MS speed detec-tion, and intelligent retry.

Handovers from the vendor X BSS cells to the BSS cells depend on the other vendor’s BSS handover features and system capabilities.

The BSS features that can be used in a multivendor environment include at least the fol-lowing:

• C1 and C2 (to direct the dual band MS to the GSM 1800/1900 cells in idle mode) • Direct Retry, with some limitations • Basic handover functionality (RX level, quality, interference, distance based han-

dovers) • Power budget handover (within a layer) • Umbrella handover (between layers)

MS Speed S5

M1800

RxLevMinCell(n)=-95 dBmFastMovingThreshold(n)=32

Filtering :


Umbrella

Triggering :

hoLevelUmbrella(n)=--85 dBmadjCellLayer(n)=LowerhoPeriodUmbrella(0)=6 SACCHs

Filtering :


Triggering :

M900

Negative PBGT

Triggering :

hoMarginPBGT(n)=-24 dBmadjCellLayer(n)=samehoPeriodPBGT(0)=6 SACCHs

Filtering :

RxLevMinCell(n)=-90 dBmhoMarginPBGT(n)=-24 dBmadjCellLayer(n)=same

900

60 DN9814105Issue 11-1



• Adjacent cell priorities in prioritising microcells and macrocells (Nokia to other vendor OK, other vendor to Nokia Siemens Networks requires support from other vendors, load information does not normally work)

• Rapid field drop handover • IUO, with certain limitations (reporting) • Fast Moving Mobile, with some limitations

For more information on interworking, see section Interworking with other features in chapter System impact of Dual Band.

By carefully planning the network, Nokia’s advanced features can be efficiently used in areas where the GSM 900/800 or 1800/1900 band has a more continuous coverage, therefore gaining the additional benefits in those areas.

DN9814105Issue 11-1

61


Implementing Dual Band


6 Implementing Dual Band

6.1 Performing Dual Band functionality testsBefore introducing Dual Band (DB) functionality into the network, some tests have to be performed to ensure that the basic actions operate without faults in systems such as MOC, MTC, SMS, cell reselection and different handover strategies between different layers.

These tests are performed with one dual band BTS as a part of the system and with single and dual band mobile phones with engineering functionality (basic functionality tests), or with a bigger configuration with 2 BSCs and multiple DB cells (operational tests).

6.1.1 Basic functionality tests The basic functionality tests indicate if the MS can operate in the GSM 900/800 and GSM 1800/1900 frequency bands and if it can make seamless handovers between the GSM 900/800 and GSM 1800/1900 frequency bands.

With GSM 800 and GSM 1900, the test categories should involve the following:

Idle mode tests

• Cell selection • Cell reselection • C2 • Short messages

Dedicated mode tests

• Basic calls • Handovers • Directed retry • Data and fax calls • Emergency calls

Handover types

• Intra-BSC, inter-cell HO • Inter-BSC, inter-cell HO • Inter-MSC handover

6.1.2 Monitoring and troubleshooting The monitoring tools for the air interface are: MS engineering display, TOM (NMS/X) (NEMO), and TEMS (Ericsson Erisoft).

The key things to monitor when troubleshooting the air interface are:

• Classmark change (CM3) • Uplink • System information 2ter • Downlink (in idle mode)

62 DN9814105Issue 11-1



Implementing Dual Band

• System information 5ter • Downlink (in dedicated mode)

The monitoring tools for the Abis and A-interface (MAP) are: Nethawk GPA (X-Net) and Siemens K1103.

The key things to monitor when troubleshooting the A-interface are:

• Classmark update • Uplink and inclusion of CM3 in HO request message (in external HOs) • Downlink

When troubleshooting the MAP interface, the following should be monitored:

• Inclusion of CM3 in HO request message (in inter-MSC HOs) from source MSC to target MSC

DN9814105Issue 11-1

63



6.2 Implementing Dual Band overviewPurposeThis procedure describes how to implement Dual Band. The procedure is similar for all frequency bands (GSM 900/1800, GSM 800/1900, GSM 800/1800).

Steps

1 Perform Dual band functionality tests.For instructions, see Performing Dual Band functionality tests.

2 Activate Dual Band.

3 Test the Dual Band activation.

Further information

• For detailed activation instructions, see Activating and testing BSS5050, BSS10118, BSS11116 and BSS8085: Dual Band Network Operation .

• Implementing Parameter Plans in NetAct Product Documentation gives instructions on how to plan and prepare parameter changes, for example, when activating new features in the GSM and WCDMA networks.

Dual Band Network Operation

Documents

Transcript of Dual Band Network Operation