LTE-Advanced异构网中的干扰控制策略
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摘要
当前,3G网络的部署和商业化日渐成熟,通信界的关注点已经转移到第四代移动通信系统LTE-Advanced的标准制定和产业部署上。LTE-Advanced系统具有超过IMT-2000的通信潜力,支持大于1Gbit/s的峰值速率、100MHz带宽。LTE-Advanced以OFDM技术为基础,上行根据链路特点采用单载波DFT-SOFDM、下行采用OFDMA作为多址方式,通过在发射端和接收端采用多天线技术(如MIMO、COMP等)成倍地提升系统容量。但与此同时,小区间的干扰也在成倍的增加,干扰的情况更加趋于复杂,给系统性能和用户感知的提升带来了不利的影响。
小区间的干扰来源于接入不同小区的多个用户使用相同的时频资源,理论上可以通过合理的频率协调方案和功率控制技术对时频资源进行有效管理从而规避和降低干扰。针对LTE-Advanced系统独有的特点,我们需要设计更加有针对性的方案来抑制小区间的干扰。一方面,为了更好地进行热点覆盖和边缘覆盖,LTE-Advanced系统引入了Relay和Pico等小功率基站形成蜂窝小区下的异构网络,系统结构趋于复杂,需要专门设计针对非等功率基站间的频率协调方案和功率控制技术；另一方面,3GPP Release10要求LTE-Advanced系统具有支持载波聚合的功能,为小区间干扰控制提供了新的思路,我们可以利用不同载波间的频率隔绝和干扰感知技术进行合理的设计来规避干扰。
本文着眼于LTE-Advanced系统异构网环境下的干扰控制技术,重点研究适合异构网环境下数据信道和控制信道的干扰协调方案、功率控制方案,结合实验室的LTE-Advanced通信系统仿真平台对各种方案进行了系统级的仿真和验证,从系统吞吐量、SINR累积分布曲线、干扰信号强度等参数上观察,得出了改进方案能够有效抑制LTE-Advanced系统异构网环境下的干扰、提升系统性能的结论。本文对基于Pico的干扰感知方案也进行了简单的分析和介绍,并设计了一套比较简化的LTE-Advanced系统异构网干扰感知实现过程。
At present, with the maturity of 3G network deployment and commercialism, the communication industry focus has shifted to the standard formulation and industrial deployment of the fourth generation mobile communication system LTE-Advanced. LTE-Advanced has greater communication potential than IMT-2000 system to support more than 1Gbit/s peak rate and 100MHz bandwidth. LTE-Advanced bases on OFDM technology, its uplink uses single-carrier DFT-SOFDM and its downlink uses OFDMA as multiple access method. Through using multiple antennas technologies (MIMO, COMP, etc.) in the transmitter and receiver, the system capacity improves exponentially, but at the same time, the inter-cell interference is also increasing exponentially, and tends to be more complex, which adversely affect the improvement of system performance.
The inter-cell interference comes from multiple users which connect to different cells use the same time-frequency resources. In theory, a reasonable frequency coordination solution and power control techniques can be used to effectively manage the time-frequency resources to avoid or reduce interference. On the one hand, As the LTE-Advanced system introduces Relay/Pico and other small power base stations which forms the heterogeneous environment in order to better meet the hot spot coverage and edge coverage demands, the system architecture becomes more complex, which requires specially designed frequency coordination and power control techniques between base stations using non-equal transmit powers. On the other hand,3GPP Release10 requires that the LTE-Advanced system supports carrier aggregation technique, which provides us a new train of thoughts for the inter-cell interference control strategy, the isolation between different carriers and interference sensing technology can be made full use of in solution design to avoid interference.
This paper gives an eye to interference control technologies in LTE-Advanced heterogeneous network environment, and focus on the interference coordination scheme and power control technology of both data channel and control channel, through system simulation of the various ICIC schemes and technologies based on the laboratory LTE-Advanced simulation platform, we analyze the system throughput, SINR cumulative distribution curve, interference on the observed signal strength and other parameters and obtain the conclusion that our improved solution can effectively inhibit the interference in LTE-Advanced heterogeneous network environment and enhance the system performance. In this paper, we also give a brief introduction and analysis of interference-aware scheme which based on Picos and design a simplified LTE-Advanced system interference-aware implementation process.
小区间的干扰来源于接入不同小区的多个用户使用相同的时频资源,理论上可以通过合理的频率协调方案和功率控制技术对时频资源进行有效管理从而规避和降低干扰。针对LTE-Advanced系统独有的特点,我们需要设计更加有针对性的方案来抑制小区间的干扰。一方面,为了更好地进行热点覆盖和边缘覆盖,LTE-Advanced系统引入了Relay和Pico等小功率基站形成蜂窝小区下的异构网络,系统结构趋于复杂,需要专门设计针对非等功率基站间的频率协调方案和功率控制技术；另一方面,3GPP Release10要求LTE-Advanced系统具有支持载波聚合的功能,为小区间干扰控制提供了新的思路,我们可以利用不同载波间的频率隔绝和干扰感知技术进行合理的设计来规避干扰。
本文着眼于LTE-Advanced系统异构网环境下的干扰控制技术,重点研究适合异构网环境下数据信道和控制信道的干扰协调方案、功率控制方案,结合实验室的LTE-Advanced通信系统仿真平台对各种方案进行了系统级的仿真和验证,从系统吞吐量、SINR累积分布曲线、干扰信号强度等参数上观察,得出了改进方案能够有效抑制LTE-Advanced系统异构网环境下的干扰、提升系统性能的结论。本文对基于Pico的干扰感知方案也进行了简单的分析和介绍,并设计了一套比较简化的LTE-Advanced系统异构网干扰感知实现过程。
At present, with the maturity of 3G network deployment and commercialism, the communication industry focus has shifted to the standard formulation and industrial deployment of the fourth generation mobile communication system LTE-Advanced. LTE-Advanced has greater communication potential than IMT-2000 system to support more than 1Gbit/s peak rate and 100MHz bandwidth. LTE-Advanced bases on OFDM technology, its uplink uses single-carrier DFT-SOFDM and its downlink uses OFDMA as multiple access method. Through using multiple antennas technologies (MIMO, COMP, etc.) in the transmitter and receiver, the system capacity improves exponentially, but at the same time, the inter-cell interference is also increasing exponentially, and tends to be more complex, which adversely affect the improvement of system performance.
The inter-cell interference comes from multiple users which connect to different cells use the same time-frequency resources. In theory, a reasonable frequency coordination solution and power control techniques can be used to effectively manage the time-frequency resources to avoid or reduce interference. On the one hand, As the LTE-Advanced system introduces Relay/Pico and other small power base stations which forms the heterogeneous environment in order to better meet the hot spot coverage and edge coverage demands, the system architecture becomes more complex, which requires specially designed frequency coordination and power control techniques between base stations using non-equal transmit powers. On the other hand,3GPP Release10 requires that the LTE-Advanced system supports carrier aggregation technique, which provides us a new train of thoughts for the inter-cell interference control strategy, the isolation between different carriers and interference sensing technology can be made full use of in solution design to avoid interference.
This paper gives an eye to interference control technologies in LTE-Advanced heterogeneous network environment, and focus on the interference coordination scheme and power control technology of both data channel and control channel, through system simulation of the various ICIC schemes and technologies based on the laboratory LTE-Advanced simulation platform, we analyze the system throughput, SINR cumulative distribution curve, interference on the observed signal strength and other parameters and obtain the conclusion that our improved solution can effectively inhibit the interference in LTE-Advanced heterogeneous network environment and enhance the system performance. In this paper, we also give a brief introduction and analysis of interference-aware scheme which based on Picos and design a simplified LTE-Advanced system interference-aware implementation process.
引文
[1]沈嘉、索士强等,3GPP长期演进(LTE)技术原理与系统设计,人民邮电出版社,2008年11月.
[2]胡宏林、徐景,3GPP LTE无线链路关键技术,电子工业出版社,2008年5月.
[3]王映民、孙韶辉,TD-LTE技术原理与系统设计,人民邮电出版社,2010年6月.
[4]吴伟陵、牛凯,移动通信原理,电子工业出版社,2005年1月.
[5]啜刚、王文博等,移动通信原理与系统,北京邮电大学出版社,2005年9月.
[6]续大我、吴伟陵等,通信原理,北京邮电大学出版社,2005年11月.
[7]Stefania Sesia, Issam Toufik, Matthew Baker著.马霓、邬钢等译LTE_UMTS长期演进理论与实践北京：人民邮电出版社2009年9月.
[8]张帆,张欣,房英龙,郑瑞明,杨大成.LTE系统中Femtocell对宏蜂窝用户的干扰研究[J].移动通信,2009年9月(下),64-68页.
[9]程顺川,张欣,郑瑞明,杨大成.载波聚合技术在LTE-Advanced系统中的应用[J].移动通信.2009年4月(下)：52-55页.
[10]张治元,蒋清泉,宋燕辉,TD-SCDMA系统扰码规划算法及仿真,通信技术,第43卷第6期,2010年.
[11]庞国莉,高焕芝,刘庆杰等,TD-SCDMA中的扰码性能分析及分配算法,计算机工程,第35卷第23期,2009年.
[12]Yang K, Zhang J, Chen H,'A flexible QoS gateway for heterogeneous wireless networks', IEEE2007, pp.6-12
[13]Seung Chan Bang and Youngnam Han, Performance of a fast forward power control using power control bits for the reverse power control as power measurement, in proc. of VTC 1998, Page(s):1414-1418 vol.2.
[14]Miaoyin Wang,Fei Ji and Gang Wei, Simulation Analysis of Adaptive Power Control Method in LTE system, in proc. of SIEDS 2009, Page(s):12-34.
[15]Peng Xue,Jae Hyun Park and Eun Heon Kim, "Adaptive Channel Estimation and Data Detection for Discontinuous Transmission in LTE Systems", in proc. of VTC 2009, Page(s):320-324.
[16]Gao Xin, Zhang Xiaofei and Feng Gaopeng," An Improved Joint Detection Approach for TD-SCDMA System over Multipath Channels",in proc. of ICISE 2009, Page(s):2551-2554.
[17]Kang Shaoli, Qiu Zhengding and Li Shihe, Comparison of ZF-BLE and MMSE-BLE in TD-SCDMA System, in proc. of ICII 2001, Page(s):297-302.
[18]Min Suk Kang, Bang Chul Decentralized Intercell Interference Coordination in Uplink Cellular Networks using Adaptive Sub-band, in proc. of ASIC 2003, Page(s):796-799.
[19]3GPP TR 25.967 v9.0.0
[20]R1-103214, "Downlink data channel performance of interference management for Macro+outdoor hot zones" ZTE
[21]R1-102804, "UE Control Channel Outage Mitigation", Alcatel-Lucent, Alcatel-Lucent Shanghai Bell
[22]R1-102805,"Control Channel Performance for HetNet", Alcatel-Lucent, Alcatel-Lucent Shanghai Bell
[23]R1-102307, "Interference Coordination for Non-CA-based Heterogeneous Networks", NTT DOCOMO
[24]R1-103126, "Enhanced ICIC for control channels to support HetNet", Huawei
[25]3GPP TR 36.814, "Further Advancements for E-UTRA Physical Layer Aspects", v 9.0.0, March 2010
[26]3GPP TS 36.213, "Physical layer procedures", v9.1.0, March 2010
[27]Rl-103214, "Downlink data channel performance of interference management for Macro+outdoor hotzones", ZTE
[28]R4-082332, "Multi User PUCCH Simulation Results", Huawei
[29]R1-100559, "Fast-fading modeling for outdoor Relay scenario", CMCC
[30]Seung Chan Bang and Youngnam Han, Performance of a fast forward power control using power control bits for the reverse power control s power measurement, in proc. of VTC 1998, Page(s):1414-1418 vol.2.
[31]3GPP TS 25.223 V8.4.0, Spreading and modulation (TDD) (Release 8),2009.5.
[32]3GPP TS 25.222 V8.5.0, Multiplexing and channel coding (TDD) (Release 8), 2009.5.
[33]3GPP TS 25.102 V9.1.0, User Equipment (UE) radio transmission and reception (TDD) (Release 9),2010.3.
[34]3GPP TS 25.221 V8.5.0, Physical channels and mapping of transport channels onto physical channels (TDD) (Release 8),2009.5.
[35]3GPP TS 25.224 V8.4.0, Physical layer procedures (TDD) (Release 8),2009.
[2]胡宏林、徐景,3GPP LTE无线链路关键技术,电子工业出版社,2008年5月.
[3]王映民、孙韶辉,TD-LTE技术原理与系统设计,人民邮电出版社,2010年6月.
[4]吴伟陵、牛凯,移动通信原理,电子工业出版社,2005年1月.
[5]啜刚、王文博等,移动通信原理与系统,北京邮电大学出版社,2005年9月.
[6]续大我、吴伟陵等,通信原理,北京邮电大学出版社,2005年11月.
[7]Stefania Sesia, Issam Toufik, Matthew Baker著.马霓、邬钢等译LTE_UMTS长期演进理论与实践北京：人民邮电出版社2009年9月.
[8]张帆,张欣,房英龙,郑瑞明,杨大成.LTE系统中Femtocell对宏蜂窝用户的干扰研究[J].移动通信,2009年9月(下),64-68页.
[9]程顺川,张欣,郑瑞明,杨大成.载波聚合技术在LTE-Advanced系统中的应用[J].移动通信.2009年4月(下)：52-55页.
[10]张治元,蒋清泉,宋燕辉,TD-SCDMA系统扰码规划算法及仿真,通信技术,第43卷第6期,2010年.
[11]庞国莉,高焕芝,刘庆杰等,TD-SCDMA中的扰码性能分析及分配算法,计算机工程,第35卷第23期,2009年.
[12]Yang K, Zhang J, Chen H,'A flexible QoS gateway for heterogeneous wireless networks', IEEE2007, pp.6-12
[13]Seung Chan Bang and Youngnam Han, Performance of a fast forward power control using power control bits for the reverse power control as power measurement, in proc. of VTC 1998, Page(s):1414-1418 vol.2.
[14]Miaoyin Wang,Fei Ji and Gang Wei, Simulation Analysis of Adaptive Power Control Method in LTE system, in proc. of SIEDS 2009, Page(s):12-34.
[15]Peng Xue,Jae Hyun Park and Eun Heon Kim, "Adaptive Channel Estimation and Data Detection for Discontinuous Transmission in LTE Systems", in proc. of VTC 2009, Page(s):320-324.
[16]Gao Xin, Zhang Xiaofei and Feng Gaopeng," An Improved Joint Detection Approach for TD-SCDMA System over Multipath Channels",in proc. of ICISE 2009, Page(s):2551-2554.
[17]Kang Shaoli, Qiu Zhengding and Li Shihe, Comparison of ZF-BLE and MMSE-BLE in TD-SCDMA System, in proc. of ICII 2001, Page(s):297-302.
[18]Min Suk Kang, Bang Chul Decentralized Intercell Interference Coordination in Uplink Cellular Networks using Adaptive Sub-band, in proc. of ASIC 2003, Page(s):796-799.
[19]3GPP TR 25.967 v9.0.0
[20]R1-103214, "Downlink data channel performance of interference management for Macro+outdoor hot zones" ZTE
[21]R1-102804, "UE Control Channel Outage Mitigation", Alcatel-Lucent, Alcatel-Lucent Shanghai Bell
[22]R1-102805,"Control Channel Performance for HetNet", Alcatel-Lucent, Alcatel-Lucent Shanghai Bell
[23]R1-102307, "Interference Coordination for Non-CA-based Heterogeneous Networks", NTT DOCOMO
[24]R1-103126, "Enhanced ICIC for control channels to support HetNet", Huawei
[25]3GPP TR 36.814, "Further Advancements for E-UTRA Physical Layer Aspects", v 9.0.0, March 2010
[26]3GPP TS 36.213, "Physical layer procedures", v9.1.0, March 2010
[27]Rl-103214, "Downlink data channel performance of interference management for Macro+outdoor hotzones", ZTE
[28]R4-082332, "Multi User PUCCH Simulation Results", Huawei
[29]R1-100559, "Fast-fading modeling for outdoor Relay scenario", CMCC
[30]Seung Chan Bang and Youngnam Han, Performance of a fast forward power control using power control bits for the reverse power control s power measurement, in proc. of VTC 1998, Page(s):1414-1418 vol.2.
[31]3GPP TS 25.223 V8.4.0, Spreading and modulation (TDD) (Release 8),2009.5.
[32]3GPP TS 25.222 V8.5.0, Multiplexing and channel coding (TDD) (Release 8), 2009.5.
[33]3GPP TS 25.102 V9.1.0, User Equipment (UE) radio transmission and reception (TDD) (Release 9),2010.3.
[34]3GPP TS 25.221 V8.5.0, Physical channels and mapping of transport channels onto physical channels (TDD) (Release 8),2009.5.
[35]3GPP TS 25.224 V8.4.0, Physical layer procedures (TDD) (Release 8),2009.