1、 STD-CEPT ERC REPORT LOO-ENGL 2000 232b414 0017154 455 = ERC REPORT 100 European Radiocommunications Committee (ERC) within the European Conference of Postal and Telecommunications Administrations (CEPT) COMPATIBILITY BETWEEN CERTAIN RADIOCOMMUNICATIONS SYSTEMS OPERATING IN ADJACENT BANDS EVALUATION
2、 OF DECT / GSM 1800 COMPATIBILITY Naples, February 2000 STD.CEPT ERC REPORT LOO-ENGL 2000 H Z32b4L4 OOL7L55 391 ERC REPORT 100 EXECUTIVE SUMMARY 1.1 This report details the findings of the SE7 Project Team study into the compatibility issues between DECT and GSM 1800. This report supersedes all earl
3、ier JFT reports relating to DECTIGSM 1800. 1.2 Several interference scenarios were analysed to identify the scenarios that exhibited significant interference ranges. Compared to earlier reports DECT WLL and GSM 1800 indoor BTS scenarios have been added Two main interference mechanisms were identifie
4、d: (i) (ii) Interference of DECT from GSM 1800 base station carrier power (blocking) Interference of GSM mobile stations by DECT out of band emissions For the WLL scenarios one more interference mechanisms was identified: (iii) Interference of DECT from GSM 1800 base stations out-of-band emissions 1
5、3 The means for reducing the compatibility problems are given in detail below. Error correction and the possible escape mechanisms (dynamic channel selection, power control, hand over algorithms) for both systems to avoid local interference problems and the consequent reduction in capacity are also
6、considerd in the discussions leading the recommendations. 1.4 The important scenarios are when DECT and GSM operate in the same local environment. Important scenarios for the recommendations are when a GSM 1800 MS operates in the same indoor environment as a DECT indoor system, and when above roofio
7、p DECT WLL systems and GSM macro cell systems operate in the same local outdoor environment. From studying the critical scenarios it is observed and / or recommended that: 1.4.1 A guard band is not required, but specific restrictions should apply locally to the GSM sub-band 1878 - 1880 MHz. See Sect
8、ion 7. 1.4.2 Co-ordinated site engineering and system planning will be required to minimise interference from above roof -top GSM BTSs to DECT WLL systems. 1.4.3 DECT WLL applications would suffer less potential risk of range reduction due to GSM interference if installed DECT WLL equipment have imp
9、roved blocking performance above minimum specification. 1.4.4 ETSI Project DECT should make sure that the provisions for DECT to detect interference from a single GSM bearer are properly defined. STD-CEPT ERC REPORT LOO-ENGL 2000 H 232b4L4 OOL7L5b 228 II ERC REPORT 100 INDEX TABLE 1 INTRODUCTION 1 1
10、.1 THEDECT AND GSM 1800 DECT SYSTEMS . 1 1.2 EVOLUTION OF DECT AND GSM 2 1.3 THE INTERFERENCE SCENARIOS . 2 1.4 DECISIONS ON SPECTRUM FOR DECT AND GSM 2 1.5 PREVIOUS REPORT . 3 2 BACKGROUND . 3 3 METHODOLOGIES .-_ 4 MINIMUM COUPLING Loss (MCL) 4 ENHANCED MINIMUM COUPLING Loss (E-MCL) . 4 MONTE CARLO
11、 SIMULATION . 5 STUDY AND RESULTS OF THE INVESTIGATION 5 4.1 INTERFERENCE SCENARIOS . 5 4.1.1 Antenna gain and transmitter power levels 6 4.2 PROPAGATION MODELS 6 4.3 INTERFERENCE MECHANISMS 7 4.4 INTERFERENCE CALCULATIONS . 8 GSM 1800 BTS interferes with DECT WU systems. BTSs and CTAs. Case7 . 9 4.
12、4.1.1 Calculation results for case 7 9 4.4.1.2 Local site engineering with local external filters between BTS transmitters and antennas . 10 4.4.1.3 nie number of sites that may need site engineering 11 4.4.1.4 Means to reduce the Required Isolation 11 4.4.1.5 Requirements on DECT to detect interfer
13、ence from a GSM single bearer and requirements on GSM with implemented frequency hopping 12 4.4.1.6 Requirements on GSM BCCH broadcast channel . 13 4.4.1.7 Case 7 is also relevant for a limited number of DECT WLL CTAs 13 4.4.1.8 Proposal for requirements on the two operators for co-ordination of abo
14、ve roof-top system installations . 13 The DECT WLL system is already installed 14 The GSM 1800 system is already instailed 14 No GSM system and no DECT WLL system is instailed . 14 4.4.2 GSM 1800 BTS interferes with DECT WU CTAs. Cases 6 . 14 4.4.3 GSM1800 above rooftop BTS interferes with a private
15、 cordless telephone DECT FP in a neigh-bounng building . Case I . 1.5 4.4.4 DECT FP with 12 dBi gain antenna installed outdoors for a service like telepoint or DECT for WU DECT FP interferes with a GSM 1800 MS . Case 5. model F . 16 4.4.5 GSM above rooftop BTS interferes with DECT FP outdoors at str
16、eet level . Case 3 model E. . 16 4.4.6 DECT indoor system interferes with GSM 1800 MS in indoor usage . Case 2. model D 17 Locked to an outdoor GSM BTS . 17 Locked to an indoor GSM micro BTS 18 Indoor GSM 1800 micro BTS in interferes with DECT indoor system . Case 8 model D . 18 Effects of power red
17、uction for the GSM 1800 BTS on the interference to DECT 19 Monte Carlo Simulations for DECT CT as victim (Case 4) 19 Monte Carlo Simulations for DECT WLL as victim (Case 6) 20 5 PRACTICAL TESTS . 20 3.1 3.2 3.3 4 4.4.1 4.4.1.8.1 4.4.1.8.2 4.4.1.8.3 4.4.6.1 4.4.6.2 4.4.7 4.4.8 4.4.8.1 4.4.8.2 6 MEANS
18、 TO IMPROVE THE COMPATIBILIT . 21 6.1 INHERENT SYSTEM PROPERTIES . 21 6.2 IMPROVED PERFORMANCE . 21 6.3 PLANNING THE DEPLOYME NT 21 6.4 LOCAL SITE ENGINEERING . 22 6.5 FURTHER CONSERATIONS . 22 ERC REPORT 100 7 CONCLUSIONS 22 INTERFERENCE FROM DECT TO GSM 1800 . 23 Position of the GSM BCCH control c
19、hannel 23 GSM escape from DECT inte$erence by intra-cell handover . 23 7.1 7.1. I 7.1.2 7.2.1 7.2 INTERFERENCE FROM GSM 1800 TO DECT . 23 Above roof-top DECT WLL systems and GSM 1800 macro cell systems in the same local area 23 7.3 REQUIREMENTS To DETECT ASYNCHRONOUS MTERFERENCE FROM A SINGLE GSM CO
20、NNECTION . 24 APPENDIX 1: SYSTEM PARAMETERS FOR DECT 25 APPENDIX 2: SYSTEM PARAMETERS FOR GSM 1800 30 APPENDIX 3: PROPAGATION MODELS . 35 APPENDiX 4: OVERVIEW OF COMPATIBILITY CASE 37 APPENDIX 5: COMPATIBILITY CALCULATIONS . 38 APPENDIX 6: MARKET INFORMATION AND SYSTEM PROPERTIES FOR DECT AND GSM18
21、46 I STD*CEPT ERC REPORT LOO-ENGL 2000 2326434 0037L58 OTO ERC REPORT 100 Page i COMPATIBILITY BETWEEN CERTAIN RADIOCOMMUNICATIONS SYSTEMS OPERATING IN ADJACENT BANDS EVALUATION OF DECTIGSM 1800 COMPATIBILITY 1 INTRODUCTION The CEPT SE7 project team (PT) was set up to evaluate compatibility between
22、certain mobile radio communications systems operating in adjacent bands This report is a revision of the earlier reports of CEPT JPT FMlO/SE7 on the compatibility of DECT/GSM 1800 and provides a detailed technical study about the coexistence between DECT and GSM 1800. As with the past work of the PT
23、, both practical as well as theoretical studies were carried out in an attempt to assess the potential interference with real equipment, as well as with specification values on the basis of MCL (minimum coupling loss), E-MCL (enhanced minimum coupling loss) calculations and MC (Monte Carlo) analysis
24、. 1.1 DECT is the term used for the Digital Enhanced Cordless Telecommunications systems. DECT carriers are defined for the band 1880-1938 MHz. located between 1880 and 1930 MHz. Spectrum is available for DECT in about 80 countries. 1880 - 1900 MHz in Europe and Australia and in several African and
25、Asian countries (except China), 1900 - 1920 MHz in China and 1910 - 1930 MHz in several Latin American countries. During mid 1999 there were between 25 and 30 Million DECT terminals shipped worldwide. GSM 18002 is the term used for the Global Mobile System 1800 located between 1710 - 1785 MHz (mobil
26、e transmit band) and between 1805 and 1880 MHz (base station transmit band). Specrum is available for GSM 1800 in all the European countries and in several countries in Asia, Africa and Latin American countries. In march 1999, the number of GSM users was estimated to be between 110 and 115 Million.
27、Included in these figures, there are about 12 Million subscribers of GSM 1800 networks and 30 Million subscribers of dual-band networks. The DECT and GSM 1800 DECT systems In order to estimate the probabilities for harmful interference between DECT and GSM 1800, it is important to know how common di
28、fferent types of systems are, and to know their geographical distribution. To estimate which scenarios are important, below is a short description of different system applications and of the likelihood for different scenarios to occur. For a more detailed description of DECT and GSM 1800 features, p
29、rovisions and expected future development see Annex 6 “Market information and system properties for DECT and GSM1800“. Indoor DECT systems, with indoor Radio Fixed Parts, RFPs, and indoor Portable Parts, PPs (office and residential applications) are the most common DECT installations. They represent
30、 the vast majority of the shipments of DECT equipment, most of them are in Western Europe. The major growth of DECT system sales are expected from residential and office applications. Outdoor DECT systems, with below roof-top RFPs and outdoor PPs for public use (CTM) in arge numbers are only found i
31、n Italy, where streets, shopping centres and public buildings are covered in 31 cities. Total number of subscribers is about 130.000 (mid-99). With the success of GSM and heavy investment in mobile telephony, there is in general a reserved attitude towards the needs for public pedestrian DECT applic
32、ations. Outdoor RFPs and PPs also exist as outdoor coverage extensions (parking places etc.) of office systems. The largest is a Volvo plant with 2 sqkm area complete indoor/outdoor coverage for about 5000 subscribers. DECT WLL Systems, with above roof-top RFPs and above roof-top CTAs (subscriber un
33、its) installations are for the time being mainly found in Eastern Europe, Asia, Latin America and Africa. Outdoor GSM 1800 systems, with outdoor above roof-top macro base stations, BTSs, or below roof-top micro BTSs, and outdoor and indoor portable stations, MSs, is the most common application of GS
34、M 1800. The service is available in many European countries, soon in all. There is a substantial annual increase of systems and customers. Indoor GSM 1800 systems, with indoor micro base stations, BTSs, and indoor and indoor portable stations, MSs, have today a low penetration, but is expected to ha
35、ve increased penetration in the future. EN 300 175 “Digital Enhanced Cordless Telecommunications (DECT)” * EN 300 577 (GSM 05.05), Dec. 1998 (Phase 2) STDICEPT ERC REPORT LOO-ENGL 2000 m 2326434 DOL7359 “37 ERC REPORT 100 Page 2 1.2 For the present time speech is the dominant service both for DECT a
36、nd GSM, but data services are expected to substantially increase during the next years both for DECT and GSM 1800. Evolution of DECT and GSM The present evolutions of the DECT and GSM standards by introducing multi-step modulation options, have substantially increased the data service capabilities.
37、Investigation of the technology and other features of the implementations of the new modulation options show that the compatibility study in this report is relevant also for the emerging multi-step higher user bit rate of DECT and GSM applications. See Appendix 6, section 3. 1.3 The interference sce
38、narios Since GSM is an FDD system, DECT is a TDD system, the GSM BTS transmit band is adjacent to the DECT band and the GSM mobile transmit band is distant from the DECT band, it is seen that: - GSM BTSs are the main interferers to DECT RFF, PP and CTA victims. - GSM MSs are the main victims for int
39、erference from DECT RFP, PP and CTA interferers. See the table below for a simplified overview of relevant interference scenarios. GSM1800 DECT (Interferer and victim) Indoor system (Residential and office applications) Below roof-top outdoor system (CTM and outdoor extension of Above roof-top macro
40、 BTS (Interferer) Case 1 Cases 3 the effect of power control when it is used ; considering only a single interferer ; having a fixed frequency offset between interferer and victim for each calculation ; The E-MCL method tackles a number of these drawbacks to provide a more meaningful result. The vic
41、tim receiver is provided with a fixed wanted signal strength margin. This represents an average for a victim who could be located anywhere in the cell. The number of dB above sensitivity is determined by the availability of the victim system. A system with a high availability will have a greater ave
42、rage margin than a system with a low availability. The suggested way of determining the number of dB margin for a given availability is to use a set of curves proposed by W.C.Jakes in his book Microwave Mobile Communications. The engineer is able to read from the curves by assuming a specific path l
43、oss exponent and lognormal shadowing standard deviation. ERC Report 101 A comparison of the minimum coupling loss method, enchanced minimum coupling loss method and the Monte-Carlo simulation. 3 STD.CEPT ERC REPORT LOO-ENGL 2000 232b4LLi OOL7Lb2 52L ERC REPORT 100 Page 5 2 3 4 Each circular cell is
44、divided into a number of concentric rings with a circle in the middle. Each ring represents an area within which all interferers transmit at the same power. The use of power control leads to interferers who are closer to the centre of the cell being able to transmit at a lower power. Interferers in
45、the central circle will be transmitting at the lowest power allowed by the power control specification. The width of each ring is dependent upon the path loss model chosen by the user and the step size defined in the power control specification. The victim to interferer isolation requirement can be
46、calculated for each ring within the cell (each interferer transmit power). By calculating the ratio of the number of interferers within a specific ring, to the total number of interferers within a cell, the mean victim to interferer isolation requirement can be computed. More than a single interfere
47、r is considered in the sense of mean isolation requirements. However the interfering effect of multiple interferers is not summed and in this sense the E-MCL method is optimistic. A fixed frequency offset is assumed by the E-MCL in the same way as the MCL. This may have consequences when interferer
48、and victim have unwanted emission and receiver blocking masks respectively with significant steps. It may be possible to introduce variable frequency offsets in the E-MCL method but at the cost of added computation. The path loss figures used by the E-MCL method include fading on the victims wanted
49、signal link (assuming the curves derived by W.C.Jakes are used) but does not include fading in the victim to interferer link. This may have some effect at higher interferer densities. DECT base indoors GSM 1800 base outdoors GSM 1800 baqe outdoors GSM 1800 mobile indoors DECT base outdoors DECT mobile outdoors The curves derived from W.C.Jakes are used to determine the parameter N that is used in the E-MCL calculations. In this report we use N =10 dB. 5 6 7 8 The results of initial E-MCL calculations indicate results that are of the same order of magnitude as those generated by
