LTE-A系统中无线链路监测算法研究与实现
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摘要
本论文的研究课题是LTE-A系统中无线链路监测算法的研究与实现。根据3GPPTS36.213协议,无线链路监测是RRC_CONNECTED状态下的用户设备基于下行小区专用参考信号对服务小区下行无线链路质量的监测,无线链路监测是基于评估周期的,一个评估周期内通常包含一定数目的监测子帧,相邻监测子帧在时间上可以是连续或者非连续的,用户设备需要对一个评估周期内监测子帧的监测结果进行物理层滤波(层1滤波),尽量消除信道时变特性对监测结果的影响,得出能够反映一个评估周期内下行无线链路质量的指标,并向其高层指示同步和失步状态,以用于无线链路失败事件的决策。无线链路监测是无线资源管理的重要内容,对移动通信系统的性能和用户体验都会有很大的影响,因此有必要研究和无线链路监测相关的算法。
本论文的研究内容包括两个方面,首先研究non-DRX接收模式下不同带宽的维纳滤波信道估计对无线链路监测性能的影响,其次研究non-DRX接收模式下同步检测和失步检测的层1滤波算法以及DRX接收模式下评估周期的设置等问题。
本论文使用MATLAB仿真软件搭建了无线链路监测的链路级仿真平台,该平台包括发送模块、信道模块、接收模块和下行无线链路质量评估模块,平台严格按照LTE-A物理层协议搭建,可以为论文的研究提供可靠的仿真结果。通过对仿真结果的分析,最终得出了以下研究结论：
1.对non-DRX接收模式下不同带宽的维纳滤波信道估计的接收性能进行了量化分析,给出了AWGN和ETU70信道环境下采用3RB带宽、9RB带宽和全带宽维纳滤波信道估计时的BLER曲线；
2.用归一化方差来研究non-DRX接收模式下同步检测和失步检测的层1滤波算法,所研究的层1滤波算法有对评估周期内监测子帧的MMI值直接求平均和(?)滤波算法两种,并且分析了相邻监测子帧连续和非连续(每个无线帧中只监测一个子帧)两种情况下的层1滤波算法性能,确定了每个无线帧中只监测一个子帧情况下的a滤波因子；
3.研究了DRX周期为64ms和16ms且每个DRX周期中只监测一个子帧情况下的评估周期设置,验证了3GPP TS36.133中对DRX接收模式下评估周期设置的规定。
The subject of this paper is research and implementation of radio link monitoring algorithm in LTE-A system. According to3GPP TS36.213, radio link monitoring is defined as RRC_CONNECTED user equipment monitoring the downlink quality of serving cell based on downlink cell-specific reference signal. Radio link monitoring is based on evaluation period. One evaluation period commonly includes several detection subframes. The adjacent detection subframes can be continuous or discontinuous in time. User equipment is required to filter detection results of all the detection subframes in one evaluation period and gets the value which can indicate the downlink quality in one evaluation period. Then user equipment should send out-of-sync or in-sync state to its upper layer. Layer1filtering is aimed at eliminating the influence of wireless fading channel. Radio link monitoring is an important aspect of radio resource management. It can influence mobile communication system performance and user experience. Therefore, it is necessary to study the algorithm related to radio link monitoring.
This paper mainly includes two research points. The first point is research on influence of different bandwidth wiener filtering channel estimation on radio link monitoring performance in non-DRX reception mode. The second point is layer1filtering algorithm and evaluation period setting.
In this paper, a link level radio link monitoring simulation platform is built using MATLAB simulation software. The platform includes transmission module, channel module, reception module, downlink quality assessment module. The platform strictly accord with3GPP technical specifications and can provide reliable simulation data for the research. Research results are based on analysis of the simulation data, as follows:
1. This paper conducts quantitative analysis of different bandwidth wiener filtering channel estimation in non-DRX reception mode and gives BLER curves of3RB bandwidth,9RB bandwidth and whole bandwidth wiener filtering channel estimation in AWGN and ETU70channel environments;
2. This paper uses normalized variance to research on layer1filtering algorithm of out-of-sync and in-sync detection in non-DRX reception mode. The layer1filtering algorithm in this paper includes two types. In the first type, filtered value is got by averaging all the MMI values of detected subframes in one evaluation period. In the second type, filtered value is got by alpha filtering algorithm. The paper analyzes the performance of the two filtering algorithms by using normalized variance in the case of discontinuous detection subframes and continuous detection subframes. Finally, alpha filtering parameters of out-of-sync and in-sync detection are given when the gap of adjacent detection subframes is10ms (one radio frame);
3. This paper analyzes evaluation period setting in DRX reception mode. The DRX cycle is set as64ms and16ms. Moreover, this paper assumes that only one subframe is detected in one DRX cycle. Results in this paper verify the provision of evaluation period setting in DRX reception mode in3GPP TS36.133.
本论文的研究内容包括两个方面,首先研究non-DRX接收模式下不同带宽的维纳滤波信道估计对无线链路监测性能的影响,其次研究non-DRX接收模式下同步检测和失步检测的层1滤波算法以及DRX接收模式下评估周期的设置等问题。
本论文使用MATLAB仿真软件搭建了无线链路监测的链路级仿真平台,该平台包括发送模块、信道模块、接收模块和下行无线链路质量评估模块,平台严格按照LTE-A物理层协议搭建,可以为论文的研究提供可靠的仿真结果。通过对仿真结果的分析,最终得出了以下研究结论：
1.对non-DRX接收模式下不同带宽的维纳滤波信道估计的接收性能进行了量化分析,给出了AWGN和ETU70信道环境下采用3RB带宽、9RB带宽和全带宽维纳滤波信道估计时的BLER曲线；
2.用归一化方差来研究non-DRX接收模式下同步检测和失步检测的层1滤波算法,所研究的层1滤波算法有对评估周期内监测子帧的MMI值直接求平均和(?)滤波算法两种,并且分析了相邻监测子帧连续和非连续(每个无线帧中只监测一个子帧)两种情况下的层1滤波算法性能,确定了每个无线帧中只监测一个子帧情况下的a滤波因子；
3.研究了DRX周期为64ms和16ms且每个DRX周期中只监测一个子帧情况下的评估周期设置,验证了3GPP TS36.133中对DRX接收模式下评估周期设置的规定。
The subject of this paper is research and implementation of radio link monitoring algorithm in LTE-A system. According to3GPP TS36.213, radio link monitoring is defined as RRC_CONNECTED user equipment monitoring the downlink quality of serving cell based on downlink cell-specific reference signal. Radio link monitoring is based on evaluation period. One evaluation period commonly includes several detection subframes. The adjacent detection subframes can be continuous or discontinuous in time. User equipment is required to filter detection results of all the detection subframes in one evaluation period and gets the value which can indicate the downlink quality in one evaluation period. Then user equipment should send out-of-sync or in-sync state to its upper layer. Layer1filtering is aimed at eliminating the influence of wireless fading channel. Radio link monitoring is an important aspect of radio resource management. It can influence mobile communication system performance and user experience. Therefore, it is necessary to study the algorithm related to radio link monitoring.
This paper mainly includes two research points. The first point is research on influence of different bandwidth wiener filtering channel estimation on radio link monitoring performance in non-DRX reception mode. The second point is layer1filtering algorithm and evaluation period setting.
In this paper, a link level radio link monitoring simulation platform is built using MATLAB simulation software. The platform includes transmission module, channel module, reception module, downlink quality assessment module. The platform strictly accord with3GPP technical specifications and can provide reliable simulation data for the research. Research results are based on analysis of the simulation data, as follows:
1. This paper conducts quantitative analysis of different bandwidth wiener filtering channel estimation in non-DRX reception mode and gives BLER curves of3RB bandwidth,9RB bandwidth and whole bandwidth wiener filtering channel estimation in AWGN and ETU70channel environments;
2. This paper uses normalized variance to research on layer1filtering algorithm of out-of-sync and in-sync detection in non-DRX reception mode. The layer1filtering algorithm in this paper includes two types. In the first type, filtered value is got by averaging all the MMI values of detected subframes in one evaluation period. In the second type, filtered value is got by alpha filtering algorithm. The paper analyzes the performance of the two filtering algorithms by using normalized variance in the case of discontinuous detection subframes and continuous detection subframes. Finally, alpha filtering parameters of out-of-sync and in-sync detection are given when the gap of adjacent detection subframes is10ms (one radio frame);
3. This paper analyzes evaluation period setting in DRX reception mode. The DRX cycle is set as64ms and16ms. Moreover, this paper assumes that only one subframe is detected in one DRX cycle. Results in this paper verify the provision of evaluation period setting in DRX reception mode in3GPP TS36.133.
引文
[1]沈嘉.从宽带无线接入与宽带移动通信技术的融合看B3G技术的发展趋势.电信科学,2006(6)
[2]http://www.3gpp.org.
[3]3GPP Technical Report 25.913'Requirements for Evolved UTRA(E-UTRA) and UTRAN(E-UTRAN)(Release 7)',www.3gpp.org.
[4]刘乃安.无线局域网(WLAN)--原理、技术与应用.西安电子科技大学出版社,2004年4月第1版,第111-112页.
[5]Stefania Sesia, Issam Toufik, Matthew Baker.LTE/LTE-Advanced--UMTS长期演进理论与实践.人民邮电出版社,2012年11月第1版,第11-12页.
[6]Juho Lee, Jin-Kyu Han, Jianzhong Zhang.MIMO Technologies in 3GPP LTE and LTE-Advanced.EURASIP Journal on Wireless Communications and Networking, Volume 2009.
[7]3GPP R1-050766.Ericsson, Multiple Antenna Solutions for E-UTRA,3GPP TSG RAN WG1 meeting#42.
[8]杨峰义,覃燕敏,胡强.WCDMA无线网络工程.人民邮电出版社,2004年4月第1版,第43-49页.
[9]3GPP Technical Specification36.401(V10.0.0).Architecture description.
[10]3GPP Technical Report 25.814.Physical Layer Aspects for Evolved UTRA.www.3gpp.org.
[11]Stefania Sesia, Issam Toufik, Matthew Baker.LTE/LTE-Advanced--UMTS长期演进理论与实践.人民邮电出版社,2012年11月第1版,第481-482页,503-507页.
[12]3GPP Technical Specification 36.213(V11.1.0).4.2.1Radio Link Monitoring.
[13]3GPP Technical Specification 36.211(V11.0.0).Physical Channels and Modulation (Release 11)
[14]Arunabha Ghosh, Jun Zhang, Jeffrey G.Andrews, Rias Muhamed.Fundamentals of LTE.人民邮电出版社,2012年5月第1版,第212页.
[15]David Tse, Pramod Viswanath.Fundamentals of Wireless Communication.人民邮电出版社,2009年8月第1版,第10-41页.
[16]周炯槃,庞沁华,续大我,吴伟陵,杨鸿文.通信原理.北京邮电大学 出版社,第3版,第326-340页.
[17]Matthias Patzold.Mobile Fading Channels.电子工业出版社,2009年1月第1版,第27页.
[18]3GPP Technical Specification36.331 (V11.1.0).5.3.11 Radio link failure related actions.
[19]3GPP Technical Specification 36.133(V11.1.0).Requirements for Support of Radio Resource Management 7.6 Radio Link Monitoring.
[20]芮赞,李明齐,张小东,易辉跃,胡弘林.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.
[21]3GPP Technical Specification36.213(V11.0.0).Physical layer procedures(Release 11).
[22]沈嘉.3GPP长期演进(LTE)技术原理与系统设计.人民邮电大学出版社,2008年11月第1版,第158-162页.
[23]Stefania Sesia, Issam Toufik, Matthew Baker.LTE/LTE-Advanced--UMTS长期演进理论与实践.人民邮电出版社,2012年11月第1版,第342-343页.
[24]Matthias Patzold.Mobile Fading Channels.电子工业出版社,2009年1月第1版,第208-246页.
[25]Krishna Sayana, Jeff Zhuang, Ken Stewart. Short Term Link Performance Modeling for ML receivers with Mutual Information Per Bit Metrics.Global Communications Conference, Los Angeles, USA,2008.11, pp:1-6.
[2]http://www.3gpp.org.
[3]3GPP Technical Report 25.913'Requirements for Evolved UTRA(E-UTRA) and UTRAN(E-UTRAN)(Release 7)',www.3gpp.org.
[4]刘乃安.无线局域网(WLAN)--原理、技术与应用.西安电子科技大学出版社,2004年4月第1版,第111-112页.
[5]Stefania Sesia, Issam Toufik, Matthew Baker.LTE/LTE-Advanced--UMTS长期演进理论与实践.人民邮电出版社,2012年11月第1版,第11-12页.
[6]Juho Lee, Jin-Kyu Han, Jianzhong Zhang.MIMO Technologies in 3GPP LTE and LTE-Advanced.EURASIP Journal on Wireless Communications and Networking, Volume 2009.
[7]3GPP R1-050766.Ericsson, Multiple Antenna Solutions for E-UTRA,3GPP TSG RAN WG1 meeting#42.
[8]杨峰义,覃燕敏,胡强.WCDMA无线网络工程.人民邮电出版社,2004年4月第1版,第43-49页.
[9]3GPP Technical Specification36.401(V10.0.0).Architecture description.
[10]3GPP Technical Report 25.814.Physical Layer Aspects for Evolved UTRA.www.3gpp.org.
[11]Stefania Sesia, Issam Toufik, Matthew Baker.LTE/LTE-Advanced--UMTS长期演进理论与实践.人民邮电出版社,2012年11月第1版,第481-482页,503-507页.
[12]3GPP Technical Specification 36.213(V11.1.0).4.2.1Radio Link Monitoring.
[13]3GPP Technical Specification 36.211(V11.0.0).Physical Channels and Modulation (Release 11)
[14]Arunabha Ghosh, Jun Zhang, Jeffrey G.Andrews, Rias Muhamed.Fundamentals of LTE.人民邮电出版社,2012年5月第1版,第212页.
[15]David Tse, Pramod Viswanath.Fundamentals of Wireless Communication.人民邮电出版社,2009年8月第1版,第10-41页.
[16]周炯槃,庞沁华,续大我,吴伟陵,杨鸿文.通信原理.北京邮电大学 出版社,第3版,第326-340页.
[17]Matthias Patzold.Mobile Fading Channels.电子工业出版社,2009年1月第1版,第27页.
[18]3GPP Technical Specification36.331 (V11.1.0).5.3.11 Radio link failure related actions.
[19]3GPP Technical Specification 36.133(V11.1.0).Requirements for Support of Radio Resource Management 7.6 Radio Link Monitoring.
[20]芮赞,李明齐,张小东,易辉跃,胡弘林.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.
[21]3GPP Technical Specification36.213(V11.0.0).Physical layer procedures(Release 11).
[22]沈嘉.3GPP长期演进(LTE)技术原理与系统设计.人民邮电大学出版社,2008年11月第1版,第158-162页.
[23]Stefania Sesia, Issam Toufik, Matthew Baker.LTE/LTE-Advanced--UMTS长期演进理论与实践.人民邮电出版社,2012年11月第1版,第342-343页.
[24]Matthias Patzold.Mobile Fading Channels.电子工业出版社,2009年1月第1版,第208-246页.
[25]Krishna Sayana, Jeff Zhuang, Ken Stewart. Short Term Link Performance Modeling for ML receivers with Mutual Information Per Bit Metrics.Global Communications Conference, Los Angeles, USA,2008.11, pp:1-6.