1、ETSI TR 125 991 V5.1 .O (2002-12) Technical Repor Universal Mobile Telecommunications System (UMTS); Feasibility study on the mitigation of the effect of Common Pilot Channel (CPICH) interference at the user equipment (3GPP TR 25.991 version 5.1.0 Release 5) 3GPP TR 25.991 version 5.1 .O Release 5 1
2、 ETSI TR 125 991 V5.1.0 (2002-12) Reference RTR/TSGR-042599151 O Keywords U MTS ETSI 650 Route des Lucioles F-O6921 Sophia Antipolis Cedex - FRANCE Tel.: +33 4 92 94 42 O0 Fax: +33 4 93 65 47 16 Siret No 348 623 562 00017 - NAF 742 C Association but non lucratif enregistre la Sous-prfecture de Grass
3、e (06) No 7803/88 Important notice Individual copies of the present document can be downloaded from: http:lwmv.etsi .arq The present document may be made available in more than one electronic version or in print. In any case of existing or perceived difference in contents between such versions, the
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10、. Foreword This Technical Report (TR) has been produced by ETSI 3rd Generation Partnership Project (3GPP). The present document may refer to technical specifications or reports using their 3GPP identities, UMTS identities or GSM identities. These should be interpreted as being references to the corr
11、esponding ETSI deliverables. The cross reference between GSM, UMTS, 3GPP and ETSI identities can be found under ht tn : Nweb ann. et si. og;kev/aiiervfom. asn . ETSI 3GPP TR 25.991 version 5.1 .O Release 5 3 ETSI TR 125 991 V5.1.0 (2002-12) Contents Intellectual Property Rights 2 Foreword . 2 Forewo
12、rd . 4 1 Scope 5 2 References 5 3 Definitions. Symbols. and Abbreviations . 6 3.1 6 3.2 6 3.3 6 4 Background and Introduction . 7 5 Performance Evaluation . 8 5.1 Radio Network Level Simulations . 8 5.1.1 Intel Simulation Results 8 Motorola Simulation Results 11 5.1.2 Nokia Simulation Results . 12 5
13、.1.3 5.1.4 Telia Simulation Results . 15 5.1.5 Summary of Radio Network Simulation Results 17 5.1.6 Pilot Interference Mitigation and HSDPA 18 5.2 Link Level Simulations 18 5.2.1 Intel Simulation Results 18 5.2.1.1 Simulation Assumptions . 18 5.2.1.2 Simulation Results 19 5.2.1.3 Reception Under Non
14、-Ideal Conditions 20 5.2.1.4 Mitigation Accuracy in the Presence of Multiple Neighbour Cells 191 . 21 5.2.2 Motorola Simulation Results 22 6 Complexity Evaluation . 23 6.1 Intel Complexity Ass 23 6.1.1 23 6.1.2 23 6.1.3 Multi-Code Operation 24 6.2 Motorola Complexity Assessment . 24 7 Potential Impa
15、cts to 3GPP Standard 24 8 Conclusions and Recommendations . 24 Annex A: Radio Network Simulation Assumptions 26 Annex B: Link Level Simulation Assumptions 27 Annex C: Change History 28 History 29 ETSI 3GPP TR 25.991 version 5.1 .O Release 5 4 ETSI TR 125 991 V5.1.0 (2002-12) Foreword This Technical
16、Report has been produced by the 3d Generation Partnership Project (3GPP). The contents of the present document are subject to continuing work within the TSG and may change following formal TSG approval. Should the TSG modiSl the contents of the present document, it will be re-released by the TSG wit
17、h an identiSling change of release date and an increase in version number as follows: Version x.y.z where: x the first digit: 1 presented to TSG for information; 2 presented to TSG for approval; 3 or greater indicates TSG approved document under change control. y the second digit is incremented for
18、all changes of substance, i.e. technical enhancements, corrections, updates, etc. z the third digit is incremented when editorial only changes have been incorporated in the document. ETSI 3GPP TR 25.991 version 5.1 .O Release 5 5 ETSI TR 125 991 V5.1.0 (2002-12) 1 Scope The present document assesses
19、 the feasibility of mitigating the effect of CPICH interference at the UE. The report includes performance evaluation of this feature using radio network level simulations and link level simulations, and complexity evaluation. 2 Re fe re nces The following documents contain provisions which, through
20、 reference in this text, constitute provisions of the present document. References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific. For a specific reference, subsequent revisions do not apply. For a non-specific reference, the latest vers
21、ion applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of the document in the same Release as theyresent document. 3GPP TSGR1-00-1371, “CPICH interference cancellation as a means for increasing DL capaci
22、ty,“ Intel, Nov. 2000. 3GPP TSGR1-00-0030, “Further Results on CPICH Interference Cancellation as A Means for Increasing DL Capacity,“ Intel Corporation, Jan. 2001. 3GPP TSGR4-01-0238, “CPICH Interference Cancellation as a Means for Increasing DL Capacity,“ Intel, Feb. 2001 3GPP TSGRP-01-0177, “Miti
23、gating the Effect of CPICH Interference at the UE,“ Intel Corporation, Mar. 2001. 3GPP TSGR4-01-0650, “On the Implementation Complexity of CPICH Interference Cancellation,“ Intel, May 2001. 3GPP TSGR4-01-1014, “On the potential capacity gain of CPICH interference mitigation,“ Intel, July 2001. 3GPP
24、TSGR4-01-1015, “Study description for SI: Mitigating the effect of CPICH interference at the UE,“ Intel, 7/01 3GPP TSGR4-01-0967, “CPICH cancellation,“ Motorola, July 2001. 3GPP TS 25.101, “UE Radio transmission and reception (FDD)“. 3GPP TS 25.942, “RF system scenarios“. 3GPP TS 34.12 1, “Terminal
25、conformance specification; radio transmission and reception (FDD)“ 3GPP TSGR4-01-1330, “Feasibility Assessment for CPICH Interference Mitigation“, Intel, September 2001. 3GPP TSGR4-01-1230, “CPICH cancellation, 2-way soft handoff capacity gain“ Motorola, September 2001. 3GPP TSGR4-01-1231, “CPICH ca
26、ncellation, UE sample time offsets“ Motorola, September 2001. 3GPP TSGR4-01-1232, “CPICH cancellation complexity“ Motorola, September 2001. 3GPP TSGR4-01-1202, “Simulation results for CPICH interference mitigation“ Nokia, September 2001. 3GPP TSGR4-01-1256, “Capacity gain from CPICH cancellation“, T
27、elia, September 2001. 3GPP TSGR4-01-1392, “Comments on the CPICH Interference Cancellation Scheme,“ Ericsson, Nov. 2001 3GPP TSGR4-01-1455, “CPICH Interference Mitigation Accuracy,“ Intel Corp., Nov. 2001. 3GPP TSGR4-01-1483, “Correction on CPICH Interference Mitigation Complexity“, Intel, November
28、2001 ETSI 3GPP TR 25.991 version 5.1 .O Release 5 6 ETSI TR 125 991 V5.1.0 (2002-12) 3 Definitions, Symbols, and Abbreviations 3.1 De fi nit ions For the purposes of the present document, the terms and definitions given in TR 21.905 apply. 3.2 Symbols void 3.3 Abbreviations For the purposes of the p
29、resent document, the following abbreviations apply: BLER DCH DL DPCCH DPCH DPCH - Ec EC - Ec Ior FDD HSDPA IO 10, 1 or 1 or A Node B OCNS OCNS-Ec P-CCPCH PCH PICH PPM SCH SIR STTD UE P-CPICH S-CPICH Block Error Ratio Dedicated Channel, which is mapped into Dedicated Physical Channel. Down Link (forw
30、ard link) Dedicated Physical Control Channel Dedicated Physical Channel Average energy per PN chip for DPCH. Average energy per PN chip. The ratio of the average transmit energy per PN clip for different fields or physical channels to the total transmit power spectral density. Frequency Division Dup
31、lex High Speed Downlink Packet Access The total received power spectral density, including signal and interference, as measured at the UE antenna connector. The power spectral density of a band limited white noise source (simulating interference from cells, which are not defined in a test procedure)
32、 as measured at the UE antenna connector. The total transmit power spectral density of the down link at the Node B antenna connector. The received power spectral density of the down link as measured at the UE antenna connector. A logical node responsible for radio transmissiodreception in one or mor
33、e cells to/from the User Equipment. Terminates the Iub interface towards the RNC Orthogonal Channel Noise Simulator, a mechanism used to simulate the users or control signals on the other orthogonal channels of a downlink link. Average energy per PN chip for the OCNS. Primary Common Control Physical
34、 Channel Paging Channel Primary Common Pilot Channel Paging Indicator Channel Parts Per Million Synchronization Channel consisting of Primary and Secondary synchronization channels Secondary Common Pilot Channel Signal to Interference Ratio Space Time Transmit Diversity User Equipment ETSI 3GPP TR 2
35、5.991 version 5.1 .O Release 5 7 ETSI TR 125 991 V5.1.0 (2002-12) Rx Signal 4 + RAKE Receiver Background and Introduction The present document provides the results of the 3GPP Study Item on Mitigating the Effect of CPICH (Common Pilot Channel) Interference at the UE. The objective of the study, and
36、thus, of the present document, is to assess the potential benefits of this UE capability and to evaluate its implementation complexity. Additional information on this topic can be found in a number of prior 3GPP contributions i to SI. The idea behind CPICH interference mitigation is to eliminate, or
37、 at least reduce, the effect of the multiple access interference (MAI) associated with the Common Pilot Channels (CPICHs) of the same-cell and other-cell Node Bs. Since each UE utilizing this ability sees less effective interference, it will require less transmitted power from the Node- B to obtain
38、its desired block error rate. This transmit power savings can be used to support additional cell capacity. The CPICH channel takes up a significant portion of the total Node-B transmit power, and thus, mitigating its interference effect is particularly advantageous. For example, a Primary CPICH (P-C
39、PICH) power allocation value of 10% (i.e., P-CPICH-Ec/Ior = -10 dB) is suggested in 9, which translates approximately to at least a 10% loss in capacity from pilot interference. In addition, since all of the surrounding Node-Bs are unlikely to be transmitting at full power (peak load) at the same ti
40、me, the percentage of interference attributable to the pilot channels may be larger, (since the CPICHEc/Ior is fixed and referenced to maximum available transmit power). If in addition to the P-CPICH channel there is a Secondary CPICH (S-CPICH) channel enabled, the total relative pilot power increas
41、es, e.g., to 20% as 9, annex C.3.21. In this case, mitigating the effects of both the P-CPICH and S-CPICH channels would provide approximately double the capacity gains. CPICH interference mitigation is particularly attractive because of its potentially low implementation complexity. The information
42、 content and structure of the pilot channels are known a priori at the UE, which can be exploited to simplisl the mitigation procedure. Thus, the more costly approaches needed for data channel interference mitigation, are not needed for pilot interference mitigation. There can be a number of ways to
43、 mitigate the effect of CPICH interference. One example approach to CPICH interference mitigation, (based on a form of interference cancellation), is shown in Figure 1 that illustrates the concept 3. Here, pilot crosscorrelation terms (i.e., interference terms) are computed and subtracted at the out
44、put of the RAKE receiver, reducing the interference level seen by the subsequent decoding stage of the detector. The link level simulation results presented here are based on this approach. Pilot P Code -4 Weighted Sum Of Pilot Crosscorrelations t + To Channel L - Decoder (Viterbirurbo) Figure 1: On
45、e example approach to mitigating the effect of CPICH interference at the UE ETSI 3GPP TR 25.991 version 5.1 .O Release 5 8 ETSI TR 125 991 V5.1.0 (2002-12) 5 5.1 Performance Evaluation Radio Network Level Simulations In this clause we evaluate the potential capacity gains of CPICH interference mitig
46、ation by means of radio network level simulations. A number of companies have submitted simulation results, which are detailed below. 5.1.1 Intel Simulation Results The radio network simulations presented here were originally reported in 121 to assess capacity gains available through CPICH interfere
47、nce mitigation. The proposed methodology for the simulations are very similar to the methodology defiied in document TR 25.942 lo for FDD to FDD coexistence studies. For each snapshot of the Monte Carlo simulation, users are randomly placed across the cells, and power control and handover are modele
48、d as described in TR 25.942. System capacity is defined as the number of users supported when the network is loaded to the point where 95% of the users are satisfied. The simulations will focus on a single operator, macro-cell environment and will compare system capacity for systems with and without
49、 pilot interference mitigation enabled. The assumptions for the radio network simulations that were used to generate the results reported in the next clause are shown in annex A, which mostly follow those first presented in 7, (and which are mostly identical to those found in lo). Two difference are that the maximum number of users in the Active Set was increased to 3, and 3 sector cells where used instead of omni-directional cells, (as requested by Work Group 4 delegates over the email reflector). In addition the 144 kbps service was added for simulation,
