电力线OFDM/OQAM通信系统信道相位预处理均衡算法
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摘要
针对电力线通信(PLC)正交频分复用(OFDM)系统存在频率掩码和频谱资源利用率低等问题,提出将正交频分复用/偏移正交幅度调制(OFDM/OQAM)技术应用到PLC系统中。该技术通过选用频率选择性较好的滤波器来抑制带外干扰,且不需要循环前缀,但是OFDM/OQAM系统在PLC频域复数信道下会产生严重的自干扰,传统的均衡算法并不能有效地消除OFDM/OQAM系统的固有干扰。针对这种情况提出了一种基于信道相位预处理的均衡算法。该算法的思想是让接收信号乘以一个信道相位调整因子,使等效信道的虚部尽量小,以此来减小接收信号中的干扰分量。仿真结果表明,与传统的均衡算法相比,所提算法在误比特率为1.0×10~(-6)时可以获得0.5 d B的性能提升。
Aiming at the problem of frequency mask and low spectrum resource utilization in Power Line Communication( PLC) OFDM system,the Orthogonal Frequency Division Multiplexing/Offset Quadrature Amplitude Modulation( OFDM/OQAM) technology is proposed to be applied to PLC systems. The technique uses a filter with better frequency selectivity to suppress the out-of-band interference,and it doesn't require a cyclic prefix. However,the OFDM/OQAM system will cause severe self-interference in PLC frequency domain channel which is complex. The traditional equalization algorithm doesn't effectively eliminate the inherent interference of OFDM/OQAM system,so an equalization algorithm based on channel phase preprocessing is proposed for this situation. The idea of this algorithm is that the received signal is multiplied by a channel phase adjustment factor,so that the imaginary part of the equivalent channel is as small as possible,thus reducing the interference component in the received signal. The simulation results show that compared with the traditional equalization algorithm,the proposed algorithm can achieve the performance improvement of 0. 5 d B when the bit error rate( BER) is 1. 0 × 10~(-6).
Aiming at the problem of frequency mask and low spectrum resource utilization in Power Line Communication( PLC) OFDM system,the Orthogonal Frequency Division Multiplexing/Offset Quadrature Amplitude Modulation( OFDM/OQAM) technology is proposed to be applied to PLC systems. The technique uses a filter with better frequency selectivity to suppress the out-of-band interference,and it doesn't require a cyclic prefix. However,the OFDM/OQAM system will cause severe self-interference in PLC frequency domain channel which is complex. The traditional equalization algorithm doesn't effectively eliminate the inherent interference of OFDM/OQAM system,so an equalization algorithm based on channel phase preprocessing is proposed for this situation. The idea of this algorithm is that the received signal is multiplied by a channel phase adjustment factor,so that the imaginary part of the equivalent channel is as small as possible,thus reducing the interference component in the received signal. The simulation results show that compared with the traditional equalization algorithm,the proposed algorithm can achieve the performance improvement of 0. 5 d B when the bit error rate( BER) is 1. 0 × 10~(-6).
引文
[1]ACHAICHIA P,BOT M L,SIOHAN P.OFDM/OQAM:a solution to efficiently increase the capacity of future PLCnetworks[J].IEEE Transactions on Power Delivery,2011,26(4):2443-2455.
[2]RAZAVI R,XIAO P,TAFAZOLLI R.Information theoretic analysis of OFDM/OQAM with utilized intrinsic interference[J].IEEE Signal Processing Letters,2014,22(5):618-622.
[3]ALESSANDRO D S,TONELLO A M,LAMPE L.Adaptive pulse-shaped OFDM with application to in-home power line communications[J].Telecommunication Systems,2012,51(1):3-13.
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[5]LIN H,SIOHAN P,TELECOM F.HS-OQAM PLC:long filter or equalizer?[C]//Proceedings of the Third Workshop on Power Line Communications(WSPLC).Udine,Italy:IEEE,2009:1-4.
[6]SAVAUX V,BADER F,NAOUES M.Blind equalization using constant modulus algorithm adapted to OFDM/OQAM modulation[C]//Proceedings of 2016 International Symposium on Wireless Communication Systems.Poznan,Poland:IEEE,2016:28-33.
[7]孙希东.OFDM/OQAM系统在瑞利信道下的信道估计与均衡方法[J].自动化技术与应用,2016,35(3):36-41.SUN Xidong.Channel estimation and equalization method for OFDM/OQAM systems over Rayleigh channels[J].Automation Technology and Applications,2016,35(3):36-41.(in Chinese)
[8]LIN B,TANG X,FANG X,et al.Efficient frequency-domain channel equalisation methods for OFDM/OQAM-PON with intensity modulation and direct detection[J].IET Communications,2017,11(6):872-877.
[9]LIN H,SIOHAN P.Capacity analysis for indoor PLC using different multi-carrier modulation schemes[J].IEEE Transactions on Power Delivery,2010,25(1):113-124.
[10]ABENOV R,POKAMESTOV D,GELTSER A.Multipath powerline communications channel(PLC)modelling[C]//Proceedings of 2015 IEEE International Conference on Microwaves,Communications,Antennas and E-lectronic Systems.Tel Aviv,Israel:IEEE,2015:1-4.
[11]国家电网公司.Q/GDW 374.3-2016低压电力线宽带载波通信技术规范第4-1部分:物理层通信协议(报批稿)[S].北京:国家电网公司,2016.
[12]ZIMMERMANN M,DOSTERT K.A multipath model for the powerline channel[J].IEEE Transactions on Communications,2002,50(4):553-559.
[2]RAZAVI R,XIAO P,TAFAZOLLI R.Information theoretic analysis of OFDM/OQAM with utilized intrinsic interference[J].IEEE Signal Processing Letters,2014,22(5):618-622.
[3]ALESSANDRO D S,TONELLO A M,LAMPE L.Adaptive pulse-shaped OFDM with application to in-home power line communications[J].Telecommunication Systems,2012,51(1):3-13.
[4]IKHLEF A,LOUVEAUX J.An enhanced MMSE per subchannel equalizer for highly frequency selective channels for FBMC/OQAM systems[C]//Proceedings of 2009Workshop on Signal Processing Advances in Wireless Communications.Perugia,Italy:IEEE,2009:186-190.
[5]LIN H,SIOHAN P,TELECOM F.HS-OQAM PLC:long filter or equalizer?[C]//Proceedings of the Third Workshop on Power Line Communications(WSPLC).Udine,Italy:IEEE,2009:1-4.
[6]SAVAUX V,BADER F,NAOUES M.Blind equalization using constant modulus algorithm adapted to OFDM/OQAM modulation[C]//Proceedings of 2016 International Symposium on Wireless Communication Systems.Poznan,Poland:IEEE,2016:28-33.
[7]孙希东.OFDM/OQAM系统在瑞利信道下的信道估计与均衡方法[J].自动化技术与应用,2016,35(3):36-41.SUN Xidong.Channel estimation and equalization method for OFDM/OQAM systems over Rayleigh channels[J].Automation Technology and Applications,2016,35(3):36-41.(in Chinese)
[8]LIN B,TANG X,FANG X,et al.Efficient frequency-domain channel equalisation methods for OFDM/OQAM-PON with intensity modulation and direct detection[J].IET Communications,2017,11(6):872-877.
[9]LIN H,SIOHAN P.Capacity analysis for indoor PLC using different multi-carrier modulation schemes[J].IEEE Transactions on Power Delivery,2010,25(1):113-124.
[10]ABENOV R,POKAMESTOV D,GELTSER A.Multipath powerline communications channel(PLC)modelling[C]//Proceedings of 2015 IEEE International Conference on Microwaves,Communications,Antennas and E-lectronic Systems.Tel Aviv,Israel:IEEE,2015:1-4.
[11]国家电网公司.Q/GDW 374.3-2016低压电力线宽带载波通信技术规范第4-1部分:物理层通信协议(报批稿)[S].北京:国家电网公司,2016.
[12]ZIMMERMANN M,DOSTERT K.A multipath model for the powerline channel[J].IEEE Transactions on Communications,2002,50(4):553-559.