Document No.Product nameCDMA2000

UserHuawei engineersProduct Version

Compiled by:Wireless Network System DepartmentVersionV1.0

Guide to Antenna Isolation Analysis of Site-Shared CDMA2000-450MHz BTS and GSM-900MHz BTSPrepared by:Antenna Feeder GroupDate:2002/11/04

Reviewed by: Jing SunDate:2002/11

Reviewed by: Shuhui ZengDate:2003/01/07

Approved by:Date:

Huawei Technologies Co., Ltd.All rights reserved.Revision RecordDateRevised versionDescriptionAuthor

2002/11/041.00First draft completedAntenna Feeder Group

2003/01/041.00Convert the document of WORDPRO format into that of Word format according to Technical Document TemplateReview and revise the document according to Checklist for Technical Document Template Invoking. Ming Wang

Guide to Antenna Isolation Analysis of Site-Shared CDMA2000-450MHz BTS and GSM-900MHz BTS

Keywords: Spurious emission, intermodulation, interfering, receiver sensitivity, antenna, isolation, interferenceAbstract: In terms of spurious emission, interfering and intermodulation, the document describes the mutual interferences between CDMA2000-450MHz BTS and GSM-900MHz BTS that share the same site, and the installation requirements for their antennae according to the interference analysis.Abbreviations: PA: Power amplifier

LNA: Low noise amplifier

TTA: Tower amplifier

Reference List:Reference list

NameAuthorDocument No.

Release dateAvailable place or channel for reference

Publisher

IS-97D

Digital Cellular Telecommunications system Phase (2+) (GSM 05.05)

1 OverviewWith the increase of mobile operators and the application of new mobile systems, more and more systems are required to share the same site. The short distance between antennae will consequently result in the interference between different systems. Hence, how to reduce or even avoid their mutual interferences has become an urgent issue.

When two different systems share the same site, and the spurious or inter-modulation signals transmitted by the BTS antenna of one system are received by the BTS antenna of another system, the interference (or blocking) will come into being. That is the so-called site-shared interference.This document details the mutual interferences between the site-shared CDMA2000-450MHz BTS and GSM-900MHz BTS, and summarizes the installation requirements for antennae of the two systems through calculation (or empirical data). Such requirements can serve as the guidance or advice for antenna installation of site-shared BTSs.

2 Relevant Indices of Two BTS SystemsThe interference is analyzed from three aspects: spurious emission, intermodulation, and receiver interfering. The indices requirements that are defined in the protocol and related to the two systems are provided, and then the interference analysis will be made according to such requirements.

2.1 Relevant Indices of CDMA2000-450MHz BTSThe protocol concerning the CDMA2000-450MHz BTS has, in details, defined items of the BTS, such as receiver sensitivity, spurious emission, intermodulation, etc. as follows: Working frequency range of Class 5 subclass A: Tx 463.35--467.1MHz, Rx 453.35--457.1MHz

Working frequency range of Class 5 subclass C: Tx 460.525--464.275MHz, Rx 450.525--454.275MHz

Requirements for spurious emission

The requirements for out-band spurious emission specified in CDMA2000 1X protocol are listed in Table 2-1:Table 2-1 CDMA 2000 1X spurious emission BandSpurious emissionRemark

9KHz - 150KHz(-13dBm/1KHz

150KHz - 3MHz(-13dBm/10KHz

30MHz - 1GHz(-13dBm/100KHz

1 GHz - 12.75GHz(-13dBm/1MHz

Requirements for interfering:Table 2-2 Requirements for interferingOffset from Center frequencyInterfering signal levelWanted signal levelType of interfering signalRemark

750KHz -67dBm-117dBmCWFor class 5

900KHz -30dBm-117dBmCWFor class 5

Requirements for receiver intermodulation:

Table 2-3 Requirements for receiver intermodulationInterfering signal levelOffset from center frequencyType of interfering signal

-45dBm900KHzCW signal

-45dBm1700KHzCW signal

2.2 Relevant Inidces of GSM 900MHz BTS2.2.1 IndicesIndices related to GSM BTS spurious emission, intermodulation and interfering are as follows:Working frequency range of GSM BTS: Tx: 935960MHz

Rx: 890915MHz Requirements for spurious emissionTable 2-4 Requirements for GSM BTS spurious emissionBandSpurious emission

9KHz-1GHz( -36dBm

1805-1880MHz( -47dBm

1-12.75GHz( -30dBm

Table 2-5 and Table 2-6 list the requirements for spurious emission test.Table 2-5 Requirements (A) for GSM BTS spurious emission testBandFrequency offsetMeasurement bandwidth

Relevant transmit bandOffset from carrier>=1.8MHz>=0.6MHz30KHz100KHz

Table 2-6 Requirements (B) for GSM BTS spurious emission testBandFrequency offsetMeasurement bandwidth

100KHz-50MHz50MHz-500MHzAbove 500MHz outside the Relevant transmit band--(Offset from edge of the relevant above band)>=2MHz>=5MHz>=10MHz>=20MHz>=30MHz30KHz100KHz30KHz100KHz300KHz1MHz3MHz

Requirements for intermodulation:The output of the transmitter:Table 2-7 Requirements for GSM emission intermodulationBandRequirement

935-960MHz( -36dBm (or 70dBc)

890-915MHz( -98dBm

Requirements for receiver intermodulation:Level of interference signal before entering the receiver: ( -43dBm

Requirements for interfering:Table 2-8 Requirements for GSM BTS band interfering

Table 2-9 Requirements for GSM BTS band interfering

3 Composition of RF Front End and Features of FilterTo facilitate the analysis, the composition of front ends of two BTS systems are illustrated as follows: The front end modules of two BTS systems have filters (or duplexer) in their transceiving channels. Filters or duplexers are used to restrain spurious emissions from system itself, external out-band interference and the interference between the transmitter and receiver of the same system.The working frequency band of the CDMA2000-450MHz BTS is: Class 5 subclass A working frequency range: Tx: 463.35--467.1MHz; Rx: 453.35--457.1MHz. Class 5 subclass C working frequency range: Tx: 460.525--464.275MHz; Rx: 450.525--454.275MHz.As the frequency band of CDMA2000-450MHz BTS is far from that of the GSM BTS. Following is the analysis of the interference relation between subclass A and the GSM frequency band only. However, the frequency band of subclass C can be referred directly.

3.1 CDMA2000-450MHz BTS Front End CDMA2000-450MHz DFU (A)The composition of the front end of CDMA2000-450MHz DFU (A) is shown in Figure 1. Table 3-1 and Table 3-2 list the suppression indices of filters on receive/transmit channels in each frequency band. Diversity channel is the same as main receive channel.

Figure 2 Composition of CDMA2000-450MHz DFU front end moduleTable 3-10 Items of CDMA2000-450MHz DFU (A) transmit channelElectrical Specificationnotes

TX PATH

1) Frequency 463.35-467.1MHz

2) AttenuationTX(TX/RXM-ANT