Multiband Network

Multiband Network Feature Parameter Description

Copyright Huawei Technologies Co., Ltd. 2010. All rights reserved.

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The information in this document is subject to change without notice. Every effort has been made in the preparation of this document to ensure accuracy of the contents, but all statements, information, and recommendations in this document do not constitute the warranty of any kind, express or implied.

Issue 02 (2009-09-30) Huawei Proprietary and Confidential Copyright Huawei Technologies Co., Ltd. i

BSS Multiband Network Contents

Issue 02 (2009-09-30) Huawei Proprietary and Confidential Copyright Huawei Technologies Co., Ltd.

iii

Contents 1 Introduction to This Document .............................................................................................1-1

1.1 Scope ............................................................................................................................................ 1-1 1.2 Intended Audience ........................................................................................................................ 1-1 1.3 Change History.............................................................................................................................. 1-1

2 Overview .....................................................................................................................................2-1

3 Technical Description ..............................................................................................................3-1 3.1 Multiband Network Principles........................................................................................................ 3-1

3.1.1 Overview of Multiband Network............................................................................................ 3-1 3.1.2 Cell Reselection.................................................................................................................... 3-1 3.1.3 Channel Allocation................................................................................................................ 3-1 3.1.4 Handover .............................................................................................................................. 3-1

3.2 Network Topologies ....................................................................................................................... 3-2 3.3 Overview of Enhanced Dualband Network ................................................................................... 3-5

3.3.1 Overview............................................................................................................................... 3-5 3.3.2 Channel Allocation................................................................................................................ 3-6 3.3.3 Handover .............................................................................................................................. 3-6

4 Engineering Guidelines...........................................................................................................4-1

5 Parameters .................................................................................................................................5-1

6 Counters......................................................................................................................................6-1

7 Glossary ......................................................................................................................................7-1

8 Reference Documents .............................................................................................................8-1

BSS Multiband Network 1 Introduction to This Document


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1 Introduction to This Document 1.1 Scope This document describes the functions of and technologies regarding multiband network and enhanced dual-band network, including cell reselection, channel allocation, handover, and network topologies.

1.2 Intended Audience It is assumed that users of this document are familiar with GSM basics and have a working knowledge of GSM telecommunication.

This document is intended for:

z Personnel working on Huawei GSM products or systems z System operators who need a general understanding of this feature

1.3 Change History The change history provides information on the changes on the Multiband Network feature in different document versions.

There are two types of changes, which are defined as follows:

z Feature change Feature change refers to the change in the Multiband Network feature of a specific product version.

z Editorial change Editorial change refers to the change in wording or the addition of the information that was not described in the earlier version.

Document Issues The document issues are as follows:

z 02 (2009-09-30) z 01 (2009-06-30)

02(2009-09-30) This is the second commercial release of GBSS9.0.

Compared with issue 01 (2009-06-30) of GBSS9.0, issue 02 (2009-09-30) of GBSS9.0 incorporates the changes described in the following table.

Change Type

Change Description Parameter Change

Feature change

None. None.

Editorial change

The structure of the document is optimized.

None.

1 Introduction to This Document BSS

Multiband Network

1-2 Huawei Proprietary and Confidential Copyright Huawei Technologies Co., Ltd.

Issue 02 (2009-09-30)

01(2009-06-30) This is the first commercial release of GBSS9.0.

Compared with issue 01 (2009-04-30) of GBSS8.1, issue 01 (2009-06-30) of GBSS9.0 remains unchanged.

BSS Multiband Network 2 Overview


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2 Overview A multiband network comprises the networks of different frequency bands.

In a multiband network, the BSC should support the cell reselection and handover of MSs between different frequency bands.

The following network topologies are applicable to a multiband network:

z Independent MSC network topology The network of each frequency band has an independent MSC, and different networks are connected through the MSCs.

z Co-MSC independent BSC network topology The network of each frequency band has an independent BSC, and different networks are connected through the same MSC.

z Co-BSC network topology The network of each frequency band has independent cells, and these cells are connected to the same BSC.

Table 2-1 describes the mapping between the frequency band and the absolute radio frequency channel number (ARFCN).

Table 2-1 Mapping between the frequency band and the ARFCN

Frequency Band Uplink Frequency

Downlink Frequency ARFCN

Fl(n) = 890 + 0.2 x n Fu(n) = Fl(n) + 45 P-GSM900 band

890-915 MHz 935-960 MHz

1 n 124

Fl(n) = 890 + 0.2 x n 0 n 124

Fl(n) = 890 + 0.2 x (n - 1024)

Fu(n) = Fl(n) + 45

975 n 1023

E-GSM900 band

880-915 MHz 925-960 MHz -

Fl(n) = 890 + 0.2 x n 0 n 124

Fl(n) = 890 + 0.2 x (n - 1024)

Fu(n) = Fl(n) + 45

955 n 1023

R-GSM900 band

876-915 MHz 921-960 MHz -

Fl(n) = 1710.2 + 0.2 x (n - 512)

Fu(n) = Fl(n) + 95 DCS1800 band

1710-1785 MHz 1805-1880 MHz

512 n 885

Fl(n) = 1850.2 + 0.2 x (n - 512)

Fu(n) = Fl(n) + 80 PCS1900 band

1850-1910 MHz 1930-1990 MHz

512 n 810

GSM850 band

Fl(n) = 824.2 + 0.2 x (n - 128)

Fu(n) = Fl(n) + 45 128 n 251

2 Overview BSS

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Frequency Downlink Band Uplink Frequency Frequency ARFCN

824-849 MHz 869-894 MHz

Two or more frequency bands can be combined into the same GSM network. The most common combination is P-GSM900 with DCS1800 and GSM850 with PCS1900. The combination between DCS1800 and PCS1900 is not possible because frequencies in DCS1800 overlap with frequencies in PCS1900.

The radio waves on different frequency bands have different path loss characteristics. If the transmit power is the same, the propagation distance of the radio wave from a low frequency band is longer than that of the radio wave from a high frequency band. For P-GSM900 and DCS1800, the number of frequencies available in DCS1800 is three times the number of frequencies available in P-GSM900, and thus DCS1800 can be used to provide additional capacity. In a dualband network of P-GSM900 and DCS1800, the characteristics of the two frequency bands can be optimally used to expand the network capacity.

Huawei BSC supports the enhanced dualband network. The purpose is to optimally share radio resources between P-GSM900 and DCS1800 and to enable the MS to measure the receive level of the two frequency bands.

A cell can operate on multiple frequency bands, for example, a co-BCCH cell. For details, see Co-BCCH Cell Parameter Description.

BSS Multiband Network 3 Technical Description


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3 Technical Description 3.1 Multiband Network Principles 3.1.1 Overview of Multiband Network In a multiband network, the MS and BSS should provide additional functions to support cell reselection and handover between cells of different frequency bands. These functions are as follows:

z Broadcasting system information 2ter and 5ter z Indication of the frequency band support capability of the MS z Measuring the neighboring cells of different frequency bands and reporting the measurement results

3.1.2 Cell Reselection When the cells operating on different frequency bands are adjacent, cell reselection between these cells is necessary.

To support cell reselection, the BSC needs to broadcast system information 2ter, informing a multiband MS of the neighboring cells on the frequency bands rather than the serving band. Then, the MS measures the receive level of the neighboring cells and decides whether to reselect a neighboring cell according to the cell reselection algorithm.

3.1.3 Channel Allocation In a co-BCCH cell, in a cell of the enhanced dualband network, or in a cell that is configured with frequencies in P-GSM900, E-GSM900, and R-GSM900, the BSC allocates a channel to an MS only when the MS supports the corresponding frequency band. For example, there is a frequency with ARFCN 975 available in E-GSM900. If the MS supports only P-GSM900, the BSC does not allocate ARFCN 975 to the MS. If the MS supports E-GSM900, the BSC may allocate ARFCN 975 to the MS.

The Classmark 3 information element (IE) specifies the frequency band support capability of the MS. From the Classmark 3 IE, the BSC obtains the frequency band support capability of the MS so as to allocate an appropriate channel. If the BSC does not obtain the Classmark 3 IE from the MS during channel allocation, the BSC regards that the MS supports only the frequency band that is compatible with the BCCH frequency. In this case, the BSC allocates the MS a channel on the frequency band compatible with the BCCH frequency.

The switch ECSC should be turned on so that the BSC can obtain the frequency band support capability of the MS at the earliest. After the switch is turned on, the BSC broadcasts system information 3, instructing the MS to report the Classmark 3 IE at the earliest after access. In this way, the MS need not wait for the Classmark Enquiry message from the network before reporting the Classmark 3 IE.

The channel allocation method described above is applicable only during the assignment phase. During the immediate assignment phase, an SDCCH compatible with the BCCH frequency is assigned preferentially.

3.1.4 Handover When the MS moves from one cell on a frequency band to another cell on a different frequency band during a call, a handover is performed if the MS supports multiple frequency bands. To support the handover, the BSC and MS should provide the following functions:

z System information broadcasting

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During a call, the BSS informs the MS of the information about neighboring cells through system information 5 and 5bis. If any neighboring cell operates on a frequency band rather than the serving band, the BSS needs to broadcast system information 5ter. System information 5ter carries the information about the neighboring cells of other frequency bands.

z Multi-band report After receiving system information 5, 5bis, and 5ter, the MS measures the signal strength of the neighboring cells specified in the system information and then sends the measurement results to the BSS through measurement reports (MRs). One MR contains the information about a maximum of six neighboring cells. If all the neighboring cells measured by the MS operate on the same frequency band, the MS reports the measurement results of the six strongest neighboring cells to the BSS. If the neighboring cells measured by the MS operate on different frequency bands, the number of neighboring cells on other frequency bands reported by the MS is specified by the parameter Multi-band report. The setting of this parameter is as follows: If Multi-band report is set to 0, the MS reports the six strongest neighboring cells irrespective of the

frequency bands used in the cells. If Multi-band report is set to 1, the MS reports the strongest neighboring cell on a different

frequency band to the BSC. The remaining positions in the MR are used for the neighboring cells of the serving band. If Multi-band report is set to 2, the MS reports the two strongest neighboring cells on different

frequency bands to the BSC. The remaining positions in the MR are used for the neighboring cells of the serving band. If Multi-band report is set to 3, the MS reports the three strongest neighboring cells on different

frequency bands to the BSC. The remaining positions in the MR are used for the neighboring cells of the serving band. The BSC informs the MS of the value of Multi-band report through system information 2ter and 5ter.

After receiving the MR from the MS, the BSC decides whether a handover should be performed. For details of the handover algorithms and procedures, see the handover feature.

3.2 Network Topologies There are three types of network topologies for a multiband network: independent MSC, co-MSC independent BSC, and co-BSC. The first two types are referred to as independent network topology, and the third type is referred to as hybrid network topology.

Independent MSC Network Topology In an independent MSC network topology, the GSM850 band, GSM900 band, DCS1800 band, and GSM1900 band use different MSCs. Figure 3-1 shows the independent MSC network topology in which the commonly used GSM900 band and DCS1800 band are applied.



3-3

Figure 3-1 Independent MSC network topology

MS

BTS

BTS

BSC

OMC

SMC

MSC/VLR 1

BTS

BTS

BSCMS MSC/VLR 2

EIR

HLR/AUC

GSM900M

DCS1800M

The characteristics of independent MSC network topology are as follows:

z No impact on the existing network z Convenient for network planning and data configuration, thus facilitating network deployment z Heavy load of signaling links due to frequent inter-BSC handovers and location updates z Meeting long-term capacity expansion requirements z Convenient for network management and service development z Requiring cooperation between equipment from different vendors z Big investment of network deployment at an early stage, but lowest average investment per user

With all these features, the independent MSC network topology is more efficient than the hybrid network topology in the long run.

Co-MSC Independent BSC Network Topology In a co-MSC independent BSC network topology, the GSM850 band, GSM900 band, DCS1800 band, and GSM1900 band use the same MSC but different BSCs. Figure 3-2 shows the co-MSC independent BSC network topology in which the commonly used GSM900 band and DCS1800 band are applied.


Multiband Network


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Figure 3-2 Co-MSC independent BSC network topology

DCS1800M

GSM900M

MS

BTS

BTS

BSC1

OMC

SMC

BTS

BTS

BSC2MS

MSC/VLR

EIR

HLR/AUC

The characteristics of co-MSC independent BSC network topology are as follows:

z Possible impact on the existing network. z Re-planning NSS is required, and network deployment is somewhat difficult. z Inconvenient for capacity expansion and network evolution. z Small investment of network deployment at an early stage, and lower average investment per user. z Competition among equipment vendors is introduced, which helps reduce equipment investment and

improve the quality of service (QoS). z Multiple BSCs cooperate with each other, and network security is guaranteed.

Co-BSC Network Topology In a co-BSC network topology, the GSM850 band, GSM900 band, DCS1800 band, and GSM1900 band use the same BSC, or multiband BTSs are connected to the same BSC. Figure 3-3 shows the co-BSC network topology in which the commonly used GSM900 band and DCS1800 band are applied.



3-5

Figure 3-3 Co-BSC network topology

BSC2

BSC1MS

BTS

BTS OMC

SMCBTS

BTS

MSC/VLR

EIR

HLR/AUC

BTS

BTSMS

DCS1800MGSM900M GSM900M/DCS1800M

The characteristics of co-BSC network topology are as follows:

z Possible huge impact on the existing network. The impact is inversely proportional to the capacity of the BSC.

z Re-planning NSS and BSS is required, and network deployment is difficult. z Inconvenient for capacity expansion and network evolution. z Inconvenient for service deployment. z Competition among equipment manufacturers cannot be introduced. It is difficult to cut down

investment and improve QoS.

3.3 Overview of Enhanced Dualband Network 3.3.1 Overview The enhanced dualband network is an improvement on the existing dualband network. It is implemented as follows: physically, two single-band cells are located at the same layer and have the same priority but different coverage areas; logically, the two cells serve as neighboring cells of each other and form a cell group, namely, one overlaid cell and one underlaid cell. The enhanced dualband network algorithm enables channel sharing and load balancing between the two cells in the cell group.

For details about cell layers and priorities, see Cell Layer and Cell Priority in Fast-Moving Micro Cell Handover.

The handover decision for the overlaid cell and the underlaid cell in the cell group is based on the MR. Figure 3-4 shows the cell structure of the enhanced dualband network.


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Figure 3-4 Cell structure of the enhanced dualband network

Distance

Overlaid cell A

Cell group

Underlaid cell B

Cell group

Overlaid cell A

Underlaid cell B

3.3.2 Channel Allocation When an MS attempts to access the enhanced dualband network, the BSC allocates a channel to the MS according to the following principles:

z When the MS in the underlaid cell attempts to access the network, the BSC should determine whether the receive level of the MS is higher than or equal to the minimum access level of the overlaid cell if the load in the underlaid cell is higher than UL Subcell General Overload Threshold. If the receive level of the MS is higher than or equal to the minimum access level of the overlaid cell, and the load in the overlaid cell does not exceed the specified threshold, the BSC assigns the MS a channel in the overlaid cell and initiates a directed retry procedure to hand over the MS to the overlaid cell. Otherwise, the BSC assigns a channel in the underlaid cell to the MS. If congestion occurs in the underlaid cell, the queuing procedure and preemption procedure are

initiated. If no channel is available in the underlaid cell, the MS performs cell reselection.

z When the MS in the overlaid cell attempts to access the network, the BSC assigns the MS a channel in the underlaid cell preferentially if the load in the underlaid cell is lower than UL Subcell Lower Load Threshold. Otherwise, the BSC assigns a channel in the overlaid cell to the MS. If congestion occurs in the overlaid cell, the queuing procedure and preemption procedure are

initiated. If no channel is available in the overlaid cell, the MS performs cell reselection.

3.3.3 Handover The handover algorithms for an enhanced dualband network are of two types: handover algorithm I and handover algorithm II. For details, see Enhanced Dual-Band Network Handover of Handover Decision Based on Handover Algorithm I and Enhanced Dual-Band Network Handover of Handover Decision Based on Handover Algorithm II in the Handover feature.

BSS Multiband Network 4 Engineering Guidelines


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4 Engineering Guidelines The principles of distributing traffic between different frequency bands in a multiband network are as follows:

z In the initial stage of network deployment, the DCS1800 cells should absorb traffic as much as possible.

z In hot spots, the DCS1800 network should provide continuous coverage. z When the number of multiband MSs reaches a certain level, different frequency bands should share

the traffic to reduce handovers and improve QoS.

The telecom operator can implement different traffic control strategies by adjusting related parameters in real time. The traffic control strategies also depend on the MS state. The detailed strategies are as follows:

z When an MS performs cell selection after being powered on or performs cell reselection in standby state, system parameters can be set in a way that a DCS1800 cell has a high priority. Therefore, the DCS1800 cell tends to be the serving cell of a multiband MS, and the MS tends to camp on the DCS1800 cell before a call is established.

z During a call establishment procedure, the traffic distribution can be adjusted through directed retry. z During an ongoing call, the traffic should be distributed to the DCS1800 cell of low layer and high

priority as much as possible. z Handovers can be performed between the cells of different frequency bands for optimal traffic

distribution.

BSS Multiband Network 5 Parameters


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5 Parameters This chapter describes the parameters related to multiband network.

For the meaning of each parameter, see Table 5-1. For the default value, value ranges, and MML commands of each parameter, see Table 5-2.

Table 5-1 Parameter description (1)

Parameter Description

ECSC

The early classmark sending control (ECSC) parameter specifies whether the MSs in a cell use early classmark sending. After a successful immediate assignment, the MS sends additional classmark information to the network as early as possible. The additional classmark information mainly contains the CM3 (classmark 3) information. The CM3 (classmark 3) information contains the frequency band support capability of the MS (used for the future channel assignment), power information about each frequency band supported by the MS (used for the handover between different frequency bands), and encryption capability of the MS.

Multi-band report

Used for requesting the MS to report the measurement information of neighboring cells in multiple frequency bands. This parameter is carried in the system information 2ter and 5ter.

UL Subcell General Overload Threshold

When the load of the underlay subcell is higher than this parameter, some of the calls in the underlay subcell will be switched to the overlay subcell, and channels in the overlay subcell will be preferentially assigned to calls initiated in the underlay subcell as well.

UL Subcell Lower Load Threshold

When the load of the underlay subcell is lower than this parameter, some of the calls in the overlay subcell will be switched to the underlay subcell, and channels in the underlay subcell will be preferentially assigned to channel requests initiated in the overlay subcell as well.

Table 5-2 Parameter description (2)

Parameter Default Value GUI Value Range

Actual Value Range

Unit MML Command Impact

ECSC NO

NO(No), YES(Yes) NO, YES None

SET GCELLCCBASIC (Optional) Cell

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GUI Actual Default MML Parameter Value Value Range Value Unit Impact Command Range

Multi-band report 0 0~3 0~3 None

SET GCELLCCBASIC (Optional) Cell

UL Subcell General Overload Threshold 80 0~100 0~100

per cent

SET GCELLHOEDBPARA (Optional) Cell

UL Subcell Lower Load Threshold 50 0~100 0~100

per cent

SET GCELLHOEDBPARA (Optional) Cell

BSS Multiband Network 6 Counters


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6 Counters For the counters, see the BSC6900 GSM Performance Counter Reference.

BSS Multiband Network 7 Glossary


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7 Glossary For the acronyms, abbreviations, terms, and definitions, see the Glossary.

BSS Multiband Network 8 Reference Documents


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8 Reference Documents z 3GPP TS 04.08: "Mobile radio interface layer 3: specification" z 3GPP TS 05.05: "Digital cellular telecommunication system (Phase 2+); Radio transmission and

reception" z 3GPP TS 05.08: "Digital cellular telecommunications system (Phase 2+); Radio subsystem link

control" z BSC6900 Feature List z BSC6900 Optional Feature Description z GBSS Reconfiguration Guide z BSC6900 GSM Parameter Reference z BSC6900 GSM MML Command Reference z BSC6900 GSM Performance Counter Reference

1 Introduction to This Document 1.1 Scope 1.2 Intended Audience 1.3 Change History 2 Overview 3 Technical Description 3.1 Multiband Network Principles 3.1.1 Overview of Multiband Network 3.1.2 Cell Reselection 3.1.3 Channel Allocation 3.1.4 Handover

3.2 Network Topologies 3.3 Overview of Enhanced Dualband Network 3.3.1 Overview 3.3.2 Channel Allocation 3.3.3 Handover

4 Engineering Guidelines 5 Parameters 6 Counters 7 Glossary 8 Reference Documents