LTE-A异构网络中的无线链路监测研究
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摘要
本课题来源于华为高校合作项目——“华为无线标准研发部门无线资源管理研究项目”。项目面向第三代合作项目组织的第四代移动通信标准增强的长期演进技术标准预研,针对增强的长期演进中无线链路监测进行深入理论研究和仿真验证,向第三代合作项目组织会议输出提案,推动标准进展。本论文对异构网下无线链路监测的技术进行了研究。
为满足第四代移动通信系统的要求并且突破单载波带宽的限制(20MHZ),第三代合作项目组织在增强的长期演进技术系统中引入了异构网特性。新技术的引入给系统带来了巨大的性能上的提升的同时也由此引入了许多新的需要解决的问题。用户设备应监测下行无线链路质量,并反馈给基站,而下行链路质量的好坏取决于物理下行控制信道的误块率。在异构网络中,由于宏小区中覆盖了若干低功率节点并且在不同的小区层之间存在着发射功率的不平衡,控制通道遭受的干扰将比在同构网络下受的干扰更为严重。R8/9版本中推的出小区间十扰协调技术并不能充分有效地缓解控制通道的干扰。
本文通过链路级仿真,对LTE-A系统引入异构网后的RLM性能进行研究和性能评估验证；基于链路级仿真平台以及会议进展,对异构网小区干扰协调增强技术以及3GPP相关提案作进一步研究,主要内容包括：
(1)按照3GPP 36.133中的场景假设和3GPP相关协议的仿真参数,搭建了LTE-A无线链路监测基线平台,主要实现的功能有：服务小区信号的发送、信道建模、下行链路质量监测、PDCCH信道的解译码等功能模块。
(2)分析异构网下小区干扰的变化情况,确定了其干扰场景。在LTE-A基线仿真平台基础上搭建异构网的仿真平台,添加了干扰小区信号发送模块和ABS Pattern配置机制。
(3)针对异构网,对无线链路监测性能进行研究,提出了一种定义异构网下无线链路监测测量需求的方法,并完成仿真分析。通过链路仿真评估了在资源受限测量方案下ABS Pattern(?)寸无线链路监测性能的影响,以及重用现有R8/9无线链路监测测量需求的边界条件。仿真结果表明,ABS Pattern对无线链路监测性能的影响很小,ABS的位置可以灵活配置；当干扰小区信噪比小于5dB时,系统可以重用R8/9无线链路监测测量需求。
This paper derives from the cooperation project of Huawei Technologies Co., Ltd and Beijing University of Posts and Telecommunications, "Huawei wireless standard Radio Resource Management R & D projects." Project aims for the fourth generation mobile communication standard 3GPP LTE-A technical standards pre-research which concentrates theoretical study and simulation verification on LTE-A Radio Link Monitoring (RLM), output contributions to 3GPP conference to promote the standards of progress. This thesis focuses on RLM in heterogeneous network.
To meet the fourth generation mobile communication system requirements and breakthrough the single-carrier bandwidth limitation (20MHz),3GPP introduces a new technique feature; heterogeneous networks. The introduction of new technology feature to the system has brought great improvement on the performance while also introducing many new challenges to be solved. The user equipments (UE) shall monitor the downlink radio link quality, which depends on physical downlink control channel (PDCCH) block error rate (BLER), and provides feedback to the eNodeB. In heterogeneous networks, since a number of low power nodes are overlaid by a Macro cell and the unbalanced transmitting power are provided between different cell layers, the control channels would suffer more serious interference than in the case of homogeneous networks. Release 8/9 inter-cell interference coordination techniques are not fully effective in mitigating control channel interference, and hence, enhanced interference management is needed.
In this paper, RLM performances in heterogeneous LTE-A system are analysed and evaluated based on link level simulation. Further research about enhanced inter-cell interference coordination technology for heterogeneous networks and the related 3GPP proposals are provided through link level simulation platform and the meeting progress, the main contributions are as follows:
(1) Constructing the LTE-A RLM baseline link level simulator platform.The simulator is developed according to the RLM simulation parameters provided in 36.133 and the related proposals in 3GPP Working Groups,and consists of several modules,including serving cell signalling, channel modeling, downlink link quality monitoring, PDCCH decoding and etc.
(2) Analysis of cell interference variation in heterogeneous scenario, and interference scenarios is determined. Construction of link level simulator with heterogeneous network which is based on LTE-A baseline platform, adding interfering cell signalling and configuration mechanisms for ABS pattern.
(3) The RLM performances have been considered in heterogeneous network, and introduced a solution which defines the new RLM measurement requirements. ABS patterns impacts on RLM requirements and side condition of reusing R8/9 RLM measurement requirements are evaluated by link level simulation. Form the simulation results, the impacts of different ABS patterns on RLM performance are very small when the resource-specific scheme is adopted, and ABS position can be flexibly configured. the available generic side condition for interference level can be set as 5dB taking some implementation margin into account.
为满足第四代移动通信系统的要求并且突破单载波带宽的限制(20MHZ),第三代合作项目组织在增强的长期演进技术系统中引入了异构网特性。新技术的引入给系统带来了巨大的性能上的提升的同时也由此引入了许多新的需要解决的问题。用户设备应监测下行无线链路质量,并反馈给基站,而下行链路质量的好坏取决于物理下行控制信道的误块率。在异构网络中,由于宏小区中覆盖了若干低功率节点并且在不同的小区层之间存在着发射功率的不平衡,控制通道遭受的干扰将比在同构网络下受的干扰更为严重。R8/9版本中推的出小区间十扰协调技术并不能充分有效地缓解控制通道的干扰。
本文通过链路级仿真,对LTE-A系统引入异构网后的RLM性能进行研究和性能评估验证；基于链路级仿真平台以及会议进展,对异构网小区干扰协调增强技术以及3GPP相关提案作进一步研究,主要内容包括：
(1)按照3GPP 36.133中的场景假设和3GPP相关协议的仿真参数,搭建了LTE-A无线链路监测基线平台,主要实现的功能有：服务小区信号的发送、信道建模、下行链路质量监测、PDCCH信道的解译码等功能模块。
(2)分析异构网下小区干扰的变化情况,确定了其干扰场景。在LTE-A基线仿真平台基础上搭建异构网的仿真平台,添加了干扰小区信号发送模块和ABS Pattern配置机制。
(3)针对异构网,对无线链路监测性能进行研究,提出了一种定义异构网下无线链路监测测量需求的方法,并完成仿真分析。通过链路仿真评估了在资源受限测量方案下ABS Pattern(?)寸无线链路监测性能的影响,以及重用现有R8/9无线链路监测测量需求的边界条件。仿真结果表明,ABS Pattern对无线链路监测性能的影响很小,ABS的位置可以灵活配置；当干扰小区信噪比小于5dB时,系统可以重用R8/9无线链路监测测量需求。
This paper derives from the cooperation project of Huawei Technologies Co., Ltd and Beijing University of Posts and Telecommunications, "Huawei wireless standard Radio Resource Management R & D projects." Project aims for the fourth generation mobile communication standard 3GPP LTE-A technical standards pre-research which concentrates theoretical study and simulation verification on LTE-A Radio Link Monitoring (RLM), output contributions to 3GPP conference to promote the standards of progress. This thesis focuses on RLM in heterogeneous network.
To meet the fourth generation mobile communication system requirements and breakthrough the single-carrier bandwidth limitation (20MHz),3GPP introduces a new technique feature; heterogeneous networks. The introduction of new technology feature to the system has brought great improvement on the performance while also introducing many new challenges to be solved. The user equipments (UE) shall monitor the downlink radio link quality, which depends on physical downlink control channel (PDCCH) block error rate (BLER), and provides feedback to the eNodeB. In heterogeneous networks, since a number of low power nodes are overlaid by a Macro cell and the unbalanced transmitting power are provided between different cell layers, the control channels would suffer more serious interference than in the case of homogeneous networks. Release 8/9 inter-cell interference coordination techniques are not fully effective in mitigating control channel interference, and hence, enhanced interference management is needed.
In this paper, RLM performances in heterogeneous LTE-A system are analysed and evaluated based on link level simulation. Further research about enhanced inter-cell interference coordination technology for heterogeneous networks and the related 3GPP proposals are provided through link level simulation platform and the meeting progress, the main contributions are as follows:
(1) Constructing the LTE-A RLM baseline link level simulator platform.The simulator is developed according to the RLM simulation parameters provided in 36.133 and the related proposals in 3GPP Working Groups,and consists of several modules,including serving cell signalling, channel modeling, downlink link quality monitoring, PDCCH decoding and etc.
(2) Analysis of cell interference variation in heterogeneous scenario, and interference scenarios is determined. Construction of link level simulator with heterogeneous network which is based on LTE-A baseline platform, adding interfering cell signalling and configuration mechanisms for ABS pattern.
(3) The RLM performances have been considered in heterogeneous network, and introduced a solution which defines the new RLM measurement requirements. ABS patterns impacts on RLM requirements and side condition of reusing R8/9 RLM measurement requirements are evaluated by link level simulation. Form the simulation results, the impacts of different ABS patterns on RLM performance are very small when the resource-specific scheme is adopted, and ABS position can be flexibly configured. the available generic side condition for interference level can be set as 5dB taking some implementation margin into account.
引文
[1]Loutfi Nuaymi. WiMAX Technology for Broadband Wireless Access[M] John Wiley & Sons, Ltd. ISBN:0-470-02808-4
[2]S.M. Cherry, WiMAX and Wi-Fi:Separate and Unequal[J]. IEEE Spectrum, 2004,(41)pp:16.
[3]徐丹,周峰,杨大成.4G技术发展与挑战[J].移动通信,2007,(12)pp：39-41
[4]陈利.第三代移动通信系统TD-SCDMA的干扰测试[J].中国无线电,2011,(5)pp：50-51.
[5]沈嘉.3GPP长期研究(LTE)技术原理与系统设计[M].北京：人民邮电出版社,2008.
[6]叶卫明,袁媛,周红,王励颖.IMS及其在移动通信中的应用研究[J].电信科学,2006,22(2)pp：57-60.
[7]3GPP TR 25.913 (V9.0.0). Requirements for Evolved UTRA (E-UTRA) and Evolved UTRAN (E-UTRAN) [S].
[8]3GPP TS 36.300 (V10.0.0). Overall description, Stage 2 [S].
[9]3GPP TS 36.401 (V10.0.0). Architecture description [S].
[10]粟欣,吴佳,曾捷LTE-Advanced主导3G无线通信走向未来[J].移动世界,2009,(23)pp：48-54
[11]黄帆,吴梅,杨大成LTE-Advanced:强有力的4G候选标准[J].移动通信,2008,(24)pp：35-39.
[12]华为技术有限公司LTE-Advanced关键技术及标准进展[J].电信网技术2010,(5)pp：32-38.
[13]王安义,肖浩TD-SCDMA系统中无线链路检测算法的研究[J].科技广场,2007,(9)pp：48-50
[14]3GPP TR 36.814 (V9.0.0). Further advancements for E-UTRA physical layer aspects [S].
[15]罗伟民,陈其铭,罗凡云.TD-LTE同频组网可行性研究[J].移动通信,2007,(5)pp：27-31
[16]CMCC(Rapporteur). Summary of the description of candidate eICIC solutions [R]. 3GPP Std, R1-105081, TSG RAN WG1#62. Madrid, Spain, August,2010.
[17]3GPP TS 36.213 (V9.3.0). Physical layer procedures [S]..
[18]3GPP TS 36.133 (V10.0.0). Requirements for support of radio resource management [S].
[19]Qualcomm Incorporated. Improving control reliability in severe interference conditions [R].3GPP Std, R1-103561, TSG RAN WG1 #61bis. Dresden, Germany. June,2010.
[20]Vodafone, Ericsson, ST-Ericsson, Qualcomm Inc., CMCC, CATT, Alcatel Lucent, Verizon Wireless, Huawei. Way Forward on Candidate TDM Patterns for Evaluation of eICIC Intra-Frequency Requirements [R],3GPP Std, R4-104932, TSG RAN WG4#57. Jacksonville, US, November,2010.
[21]Qualcomm Incorporated, Verizon Wireless, Ericsson, ST-Ericsson, Nokia, CMCC, NTT DoCoMo. Way Forward on RAN4 eICIC RLM/RRM Framework[R].3 GPP Std, R4-103977, TSG RAN WG4#AH04. Xi'an, China, October,2010.
[22]王哗晖IMT-Advanced性能分析研究[J].黑龙江科技信息,2010,(14)pp：68.
[23]3GPP TS 36.211 (V9.1.0). Physical Channels and Modulation [S].
[24]3GPP TS 36.212(V9.3.0). Multiplexing and channel coding [S].
[25]师小琳.瑞利衰落信道改进模型及性能分析[J].计算机应用,2011,31(8)pp：2059-2061.
[26]芮赟,李明齐,张小东,易辉跃,胡宏林.两次一维维纳滤波信道估计的一种噪声方差优化方法[J].电子学报,2008,(8)pp：1577-1581.
[27]T. L. Jensen, S. Kant, J. Wehinger and B. H. Fleury. Mutual Information Metrics for Fast Link Adaptation in IEEE 802.11n[A]. International Conference on Communications [C], Beijing, China,2008.5, pp:4910-4915.
[28]Krishna Sayana, Jeff Zhuang, Ken Stewart. Short Term Link Performance Modeling for ML Receivers with Mutual Information per Bit Metrics [A]. Global Communications Conference[C], Los Angeles, USA,2008.11, pp:1-6
[29]NTT DOCOMO. Investigation on CRS Interference Transmitted to Downlink Control Channel[R].3GPP Std, R1-104036, TSG RAN WG1#61. Dresden, Germany, June,2010.
[30]InterDigital LLC. Impact of the TDM-based eICIC Scheme on ReL 8/9 UE's Performance[R].3GPP Std, R4-103493, TSG RAN WG4#AH04. Xi'an, China, October,2010.
[31]NTT DOCOMO. Simulation assumptions for e-ICIC RLM[R].3GPP Std, R4-110551, TSG RAN WG4#57AH. Austin, TX, US, January,2011.
[32]3GPP TS 36.104 (V9.5.0). Base Station radio transmission and reception [S].
[2]S.M. Cherry, WiMAX and Wi-Fi:Separate and Unequal[J]. IEEE Spectrum, 2004,(41)pp:16.
[3]徐丹,周峰,杨大成.4G技术发展与挑战[J].移动通信,2007,(12)pp：39-41
[4]陈利.第三代移动通信系统TD-SCDMA的干扰测试[J].中国无线电,2011,(5)pp：50-51.
[5]沈嘉.3GPP长期研究(LTE)技术原理与系统设计[M].北京：人民邮电出版社,2008.
[6]叶卫明,袁媛,周红,王励颖.IMS及其在移动通信中的应用研究[J].电信科学,2006,22(2)pp：57-60.
[7]3GPP TR 25.913 (V9.0.0). Requirements for Evolved UTRA (E-UTRA) and Evolved UTRAN (E-UTRAN) [S].
[8]3GPP TS 36.300 (V10.0.0). Overall description, Stage 2 [S].
[9]3GPP TS 36.401 (V10.0.0). Architecture description [S].
[10]粟欣,吴佳,曾捷LTE-Advanced主导3G无线通信走向未来[J].移动世界,2009,(23)pp：48-54
[11]黄帆,吴梅,杨大成LTE-Advanced:强有力的4G候选标准[J].移动通信,2008,(24)pp：35-39.
[12]华为技术有限公司LTE-Advanced关键技术及标准进展[J].电信网技术2010,(5)pp：32-38.
[13]王安义,肖浩TD-SCDMA系统中无线链路检测算法的研究[J].科技广场,2007,(9)pp：48-50
[14]3GPP TR 36.814 (V9.0.0). Further advancements for E-UTRA physical layer aspects [S].
[15]罗伟民,陈其铭,罗凡云.TD-LTE同频组网可行性研究[J].移动通信,2007,(5)pp：27-31
[16]CMCC(Rapporteur). Summary of the description of candidate eICIC solutions [R]. 3GPP Std, R1-105081, TSG RAN WG1#62. Madrid, Spain, August,2010.
[17]3GPP TS 36.213 (V9.3.0). Physical layer procedures [S]..
[18]3GPP TS 36.133 (V10.0.0). Requirements for support of radio resource management [S].
[19]Qualcomm Incorporated. Improving control reliability in severe interference conditions [R].3GPP Std, R1-103561, TSG RAN WG1 #61bis. Dresden, Germany. June,2010.
[20]Vodafone, Ericsson, ST-Ericsson, Qualcomm Inc., CMCC, CATT, Alcatel Lucent, Verizon Wireless, Huawei. Way Forward on Candidate TDM Patterns for Evaluation of eICIC Intra-Frequency Requirements [R],3GPP Std, R4-104932, TSG RAN WG4#57. Jacksonville, US, November,2010.
[21]Qualcomm Incorporated, Verizon Wireless, Ericsson, ST-Ericsson, Nokia, CMCC, NTT DoCoMo. Way Forward on RAN4 eICIC RLM/RRM Framework[R].3 GPP Std, R4-103977, TSG RAN WG4#AH04. Xi'an, China, October,2010.
[22]王哗晖IMT-Advanced性能分析研究[J].黑龙江科技信息,2010,(14)pp：68.
[23]3GPP TS 36.211 (V9.1.0). Physical Channels and Modulation [S].
[24]3GPP TS 36.212(V9.3.0). Multiplexing and channel coding [S].
[25]师小琳.瑞利衰落信道改进模型及性能分析[J].计算机应用,2011,31(8)pp：2059-2061.
[26]芮赟,李明齐,张小东,易辉跃,胡宏林.两次一维维纳滤波信道估计的一种噪声方差优化方法[J].电子学报,2008,(8)pp：1577-1581.
[27]T. L. Jensen, S. Kant, J. Wehinger and B. H. Fleury. Mutual Information Metrics for Fast Link Adaptation in IEEE 802.11n[A]. International Conference on Communications [C], Beijing, China,2008.5, pp:4910-4915.
[28]Krishna Sayana, Jeff Zhuang, Ken Stewart. Short Term Link Performance Modeling for ML Receivers with Mutual Information per Bit Metrics [A]. Global Communications Conference[C], Los Angeles, USA,2008.11, pp:1-6
[29]NTT DOCOMO. Investigation on CRS Interference Transmitted to Downlink Control Channel[R].3GPP Std, R1-104036, TSG RAN WG1#61. Dresden, Germany, June,2010.
[30]InterDigital LLC. Impact of the TDM-based eICIC Scheme on ReL 8/9 UE's Performance[R].3GPP Std, R4-103493, TSG RAN WG4#AH04. Xi'an, China, October,2010.
[31]NTT DOCOMO. Simulation assumptions for e-ICIC RLM[R].3GPP Std, R4-110551, TSG RAN WG4#57AH. Austin, TX, US, January,2011.
[32]3GPP TS 36.104 (V9.5.0). Base Station radio transmission and reception [S].