2.0MHz Central Frequency Point Separation Between GSM and UMTS Mode(SRAN6.0_02)

2.0MHz Central Frequency Point Separation Between GSM and UMTS Mode SRAN6.0

Feature Parameter Description

Issue 02

Date 2011-04-30

HUAWEI TECHNOLOGIES CO., LTD.

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2.0MHz Central Frequency Point Separation

Between GSM and UMTS Mode Contents

Issue 02 (2011-04-30) Huawei Proprietary and Confidential

Copyright Huawei Technologies Co., Ltd

i

Contents

1 Introduction ................................................................................................................................ 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 Intra-Frequency Buffer Zone ......................................................................................................... 3-1

3.2 Feature Implementation ................................................................................................................ 3-2

3.2.1 Functions on the UMTS Network ......................................................................................... 3-2

3.2.2 Functions on the GSM Network ........................................................................................... 3-3

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

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

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

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

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

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Between GSM and UMTS Mode 1 Introduction



1-1

1 Introduction

1.1 Scope

This document describes the feature of 2.0 MHz central frequency point separation between GSM and UMTS mode. The ID of this feature is MRFD-211703 for GSM and MRFD-221703 for UMTS.

1.2 Intended Audience

This document is intended for:

Personnel familiar with basic principles of GSM and WCDMA

Personnel who need to understand this feature

Personnel who work with Huawei products or systems

1.3 Change History

This section provides the information on the changes in different document versions.

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

Feature change refers to the change in the 2.0MHz Central Frequency Point Separation Between GSM and UMTS Mode feature of a specific product version.

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:

02 (2011-04-30)

01 (2011-03-30)

Draft A (2010-12-30)

02 (2011-04-30)

This is the document for the second commercial release of SRAN6.0.

Compared with issue 01 (2011-03-30) of SRAN6.0, issue 02 (2011-04-30) of SRAN6.0 incorporates the changes described in the following table.

Change Type Change Description Parameter Change

Feature change None None

Editorial change Chapter 3 "Technical Description" is added. Descriptions of Chapters 2 "Overview" and 4 "Engineering Guidelines" are optimized.

None

01 (2011-03-30)

This is the document for the first commercial release of SRAN6.0.

Compared with issue Draft A (2010-12-30) of SRAN6.0, this issue optimizes the description.

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Between GSM and UMTS Mode 1 Introduction



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Draft A (2010-12-30)

This is the document for the draft release of SRAN6.0.

This is a new document.

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Between GSM and UMTS Mode 2 Overview



2-1

2 Overview

The propagation performance of the 900 MHz or 850 MHz band is better than that of the 2100 MHz band but spectrum resources of the 900 MHz or 850 MHz band are much less than those of the 2100 MHz band. Therefore, there is a conflict between the increasing demand for radio services and the limited spectrum resources. Some telecom operators are unable to reserve a standard bandwidth of 5 MHz from the 850 MHz or 900 MHz band by refarming for UMTS services. This feature is introduced to solve this problem. It supports a non-standard bandwidth of 3.8 MHz for a UMTS carrier, thereby providing a new UMTS deployment scheme for telecom operators.

Though the GSM network capacity decreases after refarming, this feature significantly improves the capacity of the whole network (GSM network plus UMTS network) because UMTS has higher spectral efficiency than GSM.

Figure 2-1 shows the application of 3.8 MHz bandwidth for the UMTS network and 2.0 MHz frequency spacing between GSM and UMTS carriers.

Figure 2-1 Application of 3.8 MHz bandwidth for the UMTS network and 2.0 MHz frequency spacing between GSM and UMTS carriers

Refarming indicates that telecom operators replan frequency resources and improve the spectral efficiency and data throughput by introducing new wireless telecommunications technologies.

Central frequency is a measure of a central frequency between the upper and lower cutoff frequencies. The central frequency of a UMTS non-standard 3.8 MHz bandwidth is 1.9 MHz away from both the upper and lower cutoff frequencies. The GSM system uses a 200 kHz bandwidth carrier. A GSM central frequency is 100 kHz away from the upper and cutoff frequencies. When the spacing between the central GSM and central UMTS frequencies is 2.0 MHz, the UMTS has a bandwidth of 3.8 MHz.

A UMTS bandwidth of less than 5 MHz is regarded as a non-standard bandwidth. The GSM frequencies that are less than 2.6 MHz away from the central UMTS frequency are termed small-spaced frequencies.

This feature improves frequency utilization. Instead of providing a 5 MHz bandwidth dedicated to UMTS services, this feature allocates a 3.8 MHz bandwidth to UMTS and reserves a 1.2 MHz bandwidth for GSM.

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Between GSM and UMTS Mode 3 Technical Description



3-1

3 Technical Description

3.1 Intra-Frequency Buffer Zone

The UMTS network inside a refarming area uses frequencies that were previously used by the GSM network. Outside the refarming area these frequencies are still used by the GSM network. The GSM and UMTS sites near to the edge of the refarming area may experience co-channel interference because some frequencies are used by both networks. The GU intra-frequency buffer zone is introduced to minimize this interference. Figure 3-1 shows the GU intra-frequency buffer zone.

Figure 3-1 GU intra-frequency buffer zone

In Figure 3-1, Area C (UMTS900/UMTS850) and area A (GSM900/GSM850) can use same frequencies, but area B (GSM900/GSM850) cannot use the frequencies that cover area C to avoid co-channel interference. Area B is the intra-frequency buffer zone.

Figure 3-2 shows co-channel interference near the edge of the refarming area.

Figure 3-2 Co-channel interference

The intra-frequency buffer zone in the uplink or downlink of GSM or UMTS can be obtained on the basis of the interference in the same direction. The entire intra-frequency buffer zone is the combination of the four intra-frequency buffer zones in the four directions.

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3.2 Feature Implementation

After refarming, GSM BTSs and UMTS NodeBs interfere with each other. An interference minimizing or anti-interference function, therefore, should be enabled on both networks to minimize the interference. Specifically, this feature consists of the following functions:

NodeB 3.8 MHz static filter

UMTS anti-interference function: WRFD-020136 Anti-Interference Scheduling for HSUPA

GSM interference minimizing function: Active Power Control (GBFD-117602), Optimized Huawei III Power Control algorithm (part of the feature Huawei III Power Control Algorithm GBFD-117601), and Discontinuous Transmission (DTX)-Downlink (GBFD-114801)

Figure 3-3 shows the feature implementation.

Figure 3-3 Feature implementation

3.2.1 Functions on the UMTS Network

The functions on the UMTS network are NodeB 3.8 MHz static filter and anti-interference scheduling for HSUPA.

NodeB Static Filter

With a static filter, the NodeB can support the 3.8 MHz bandwidth. To configure a static filter, telecom operators need to run the SET FREQBWH command on the NodeB side, with FMBWH set to 3800.

Anti-Interference Scheduling for HSUPA

Principles

Some UMTS sites in a commercial network experience random interference strong as 8 dB or over 10 dB from GSM for duration from several minutes to half an hour. This interference significantly reduces the HSUPA throughput in cells of these sites and negatively affects user experience. The anti-interference scheduling for HSUPA function counteracts this interference, thereby ensuring high HSUPA throughput and improving user experience without significantly affecting system stability and coverage.

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3-3

With this function, scheduling is performed on HSUPA UEs based on the RTWP of the cell and the traffic volume of the R99 and HSUPA UEs in the cell with strong uplink interference. As long as the traffic volume is lower than the predefined threshold, sufficient resources can be ensured for the R99 and HSUPA UEs even if the Received Total Wideband Power (RTWP) of the cell increases to a very high value. This ensures high HSUPA throughput for the cell.

The available uplink resources increases, leading to decreased coverage. The access success rate and call drop rate consequently deteriorate. This feature ensures basic coverage by keeping the uplink load under a predefined upper limit.

Purposes

This function significantly reduces the impacts on UMTS performance of instantaneous strong interference caused by user access in the GSM network.

This function is optional in the 2.0MHz Central Frequency Point Separation Between GSM and UMTS Mode feature.

For details on this function, see the related description in the RAN document HSUPA Feature Parameter Description.

3.2.2 Functions on the GSM Network

Active power control, optimized Huawei III power control algorithm, and DTX are used on the GSM network to minimize the interference to UMTS that is caused by high GSM transmit power.

Active Power Control

Principles

Active power control enables the immediate calculation of uplink and downlink transmit power after an MS successfully gains access to the network or an intra-BSC handover is successful. The BSC then informs the MS of the uplink transmit power. In this way, the BTS and MS can transmit signals at a proper power.

Purposes

When this feature is enabled, the access signal level on the RACH is high during the initial access of an MS to the GSM network. The high signal level produces strong uplink interference to the co-sited UMTS 3.8 MHz bandwidth and significantly decreases the HSUPA data rate. Active power control is enabled for the UMTS 3.8 MHz bandwidth to avoid the drastic decrease in HSUPA data rate.

Optimized Huawei III Power Control Algorithm

Principles

Power control is an important method of radio link control. The BSC decides whether to adjust the transmit power of the MS and the BTS based on the expected parameter values and measurement reports on the uplink/downlink receive level and the receive quality from the BTS. Power control is performed to achieve the desired Quality of Service (QoS) with minimum possible transmit power.

Compared with Huawei III power control algorithm, optimized Huawei III power control algorithm stabilizes DT quality and ratio of periods during which the realtime speech quality is poor. The improvement in DT quality further improves power control performance.

DT quality, a measure of network quality, is converted from receive quality.

Purposes

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3-4

Optimized Huawei III power control algorithm must be enabled together with this feature. It lowers the overall interference from GSM MSs to UMTS NodeBs and from GSM BTSs to UMTS UEs.

For details on GSM power control functions, see the GBSS document Power Control Feature Parameter Description.

DTX

Principles

DTX consists of the silence insertion descriptor (SID) frames and the voice activity detection (VAD) technique. In addition, the system automatically generates comfortable noise to ensure service continuity.

DTX lowers the transmit power of the BTS and MS, reduces co-channel interference on the air interface, and meanwhile reduces the sensitivity of the GSM voice signals to errors on a radio interface.

Purposes

It is recommended that uplink and downlink DTX be enabled together with this feature. This reduces the interference of GSM voice calls to UMTS, improving UMTS throughput and user experience.

For details on DTX, see the GBSS document Discontinuous Transmission and Discontinuous Reception Feature Parameter Description..

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Between GSM and UMTS Mode 4 Engineering Guidelines



4-1

4 Engineering Guidelines

Application Scenarios

Rural areas, where the distance between BTSs is equal to or greater than 3 kilometers.

GSM spectrum of 7.4 MHz or broader (continuous spectrum greater than or equal to 5 MHz).

The GSM and UMTS networks are deployed by the same operator using Huawei equipment. These two networks can share one site, one BBU, or one RF module.

The GSM network and UMTS network share the same site and cover the same area.

When the GSM and UMTS networks do not share the same site or cover the same area, a GSM BTS is blocked when a UMTS UE in the cell under the GSM BTS transmits signals at full power. This leads to coverage holes in GSM cells. Configuration Requirements

It is recommended that in a GSM network small-spaced frequencies be used for non-BCCH carriers, and PDCHs be not configured on small-spaced frequencies.

Configuring this feature involves the following procedures:

Set the effective bandwidth of the UMTS carrier on the UMTS side.

Change frequencies on the GSM and UMTS sides to ensure that the effective bandwidth of the UMTS carrier is 3.8 MHz and the frequency spacing between GSM and UMTS carriers is 2.0 MHz.

Configure the following features on which this feature depends:

GSM feature optimized Huawei III power control algorithm (mandatory)

GSM feature active power control (mandatory)

GSM feature DTX (recommended)

UMTS feature anti-interference scheduling for HSUPA (optional)

For details on how to configure this feature, see the related description in the Feature Activation Guide. Impacts on system performance

This feature decreases the frequency spacing between GSM and UMTS carriers to 2.0 MHz, and therefore it may impose the following impacts on network performance:

The throughput of UMTS HSPA services decreases because the GSM and UMTS networks interfere with each other and the UMTS network uses a 3.8 MHz bandwidth filter.

The throughput of GSM EDGE services decreases because of UMTS interference.

The mean opinion scores (MOSs) of GSM and UMTS decrease.

GSM KPIs may deteriorate because 3.8 MHz GSM bandwidth is allocated to UMTS.

This feature is not applicable to HSPA+ services such as 64QAM, MIMO, and DC.

UMTS UEs using 64QAM can only reach the data rate of 16QAM because GSM interferes with UMTS.

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Between GSM and UMTS Mode 5 Parameters



5-1

5 Parameters

Table 5-1 Parameter description

Parameter ID NE MML Command Description

FMBWH NodeB SET FREQBWH Meaning: Indicates the minimum effective bandwidth of the carrier.

GUI Value Range: 5000, 4800, 4600, 4400, 4200, 3800

Actual Value Range: 5000, 4800, 4600, 4400, 4200, 3800

Unit: kHz

Default Value: 5000

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Between GSM and UMTS Mode 6 Counters



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6 Counters

There are no specific counters associated with this feature.

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Between GSM and UMTS Mode 7 Glossary



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7 Glossary

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

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Between GSM and UMTS Mode 8 Reference Documents



8-1

8 Reference Documents

1. GBSS document Power Control Feature Parameter Description

2. GBSS document Discontinuous Transmission and Discontinuous Reception Feature Parameter Description

3. RAN document HSUPA Feature Parameter Description

1 Introduction1.1 Scope1.2 Intended Audience1.3 Change HistoryDocument Issues02 (2011-04-30)01 (2011-03-30)Draft A (2010-12-30)

2 OverviewFigure 2-1 Application of 3.8 MHz bandwidth for the UMTS network and 2.0 MHz frequency spacing between GSM and UMTS carriers

3 Technical Description3.1 Intra-Frequency Buffer ZoneFigure 3-1 GU intra-frequency buffer zoneFigure 3-2 Co-channel interference

3.2 Feature ImplementationFigure 3-3 Feature implementation3.2.1 Functions on the UMTS NetworkNodeB Static FilterAnti-Interference Scheduling for HSUPA

3.2.2 Functions on the GSM NetworkActive Power ControlOptimized Huawei III Power Control AlgorithmDTX

4 Engineering GuidelinesApplication ScenariosConfiguration RequirementsImpacts on system performance

5 ParametersTable 5-1 Parameter description

6 Counters7 Glossary8 Reference Documents1. GBSS document Power Control Feature Parameter Description2. GBSS document Discontinuous Transmission and Discontinuous Reception Feature Parameter Description3. RAN document HSUPA Feature Parameter Description

2.0MHz Central Frequency Point Separation Between GSM and UMTS Mode(SRAN6.0_02)

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