一种新的LTE系统频偏估计算法
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摘要
相位差分算法是LTE系统中经典的频偏估计算法,受LTE信号结构的限制,其估计范围较小且不能工作于跳频传输模式。针对相位差分算法的缺点,提出了一种基于互相关函数能量比的频偏估计算法。该算法根据LTE上行链路PRACH信道中ZC序列循环移位和频偏之间的关系,利用接收ZC序列与原始序列的互相关函数和接收ZC序列与原始序列的单位循环移位序列的互相关函数的能量比来估计频偏,可增大频偏估计范围,减少信噪比对估计误差的影响,且不受跳频传输的影响。仿真结果表明,相比传统的相位差分算法,该算法频偏估计范围更大,估计精度随信噪比变化较小,可有效改善LTE系统频偏估计性能。
Phase difference algorithm is the classical frequency offset estimation algorithm of long term evolution(LTE) system,which has small estimation range and fails in frequency hopping(FH) transmission mode due to the limitation of LTE signal structure.A cross correlation function power ratio algorithm is proposed to overcome the defects of phase difference algorithm.According to the relation between the cyclic shift of ZadoffChu(ZC) sequence and frequency offset in LTE uplink physical random access channel(PRACH),the cross correlation function between received ZC sequence and original sequence and the power ratio of cross correlation function between received ZC sequence and unit cyclic shift of original sequence are used to estimate frequency offset,which can expand the estimation range and decrease the influence caused by Signal-to-Noise Ratio(SNR),and are not affected by FH transmission mode.The simulation results show that the proposed algorithm has larger estimation range and lower MSE compared with traditional phase differential algorithm and can improve the frequency offset estimation performance of LTE system.
Phase difference algorithm is the classical frequency offset estimation algorithm of long term evolution(LTE) system,which has small estimation range and fails in frequency hopping(FH) transmission mode due to the limitation of LTE signal structure.A cross correlation function power ratio algorithm is proposed to overcome the defects of phase difference algorithm.According to the relation between the cyclic shift of ZadoffChu(ZC) sequence and frequency offset in LTE uplink physical random access channel(PRACH),the cross correlation function between received ZC sequence and original sequence and the power ratio of cross correlation function between received ZC sequence and unit cyclic shift of original sequence are used to estimate frequency offset,which can expand the estimation range and decrease the influence caused by Signal-to-Noise Ratio(SNR),and are not affected by FH transmission mode.The simulation results show that the proposed algorithm has larger estimation range and lower MSE compared with traditional phase differential algorithm and can improve the frequency offset estimation performance of LTE system.
引文
[1]王文博,郑侃.宽带无线通信OFDM技术[M].2版.北京:人民邮电出版社,2007.
[2]3GPP TS 36.211 V8.4.0,Evolved Universal Terrestrial Radio Access(E-UTRA);Physical Channels and Modulation[S].Valbonne;3GPP Organizational Partners Publications Offices,2008.
[3]王秋才,袁超伟,张金波,等.SC-FDMA上行系统中一种频域迭代块DFE均衡方法[J].西安电子科技大学学报(自然科学版),2013,40(2):33-38.
[4]Moose P H.A technique for orthogonal frequency division multiplexing frequency offset correction[J].IEEE Transactions on Communications,1994,42(10):2908-2914.
[5]杨春萍,王键,李道本.MIMO-OFDM系统的同步算法[J].中南大学学报(自然科学版),2010,41(2).
[6]倪浩,任光亮,白云,等.LTE上行链路高速铁路应用场景中的频偏估计方法[J].上海交通大学学报,2010,44(9):1235-1240.
[7]梁文娟.LTE系统下行同步算法的研究[D].西安:西安科技大学,2012.
[8]廖腾达,谢显中,郑品莲.基于循环前缀的LTE系统多普勒频偏估计算法[J].电视技术,2010,34(1):56-58.
[9]唐宏,方文平,孙伟.一种LTE系统中基于循环前缀的载波频偏估计方法[J].电子测试,2010(4):4-7.
[10]张俊杰,葛万成.Zadoff-Chu序列在LTE下行链路频偏估计中的应用[J].电子技术,2010(12):65-66.
[11]3GPP TS 36.104 V9.6.0,Evolved Universal Terrestrial Radio Access(E-UTRA);Base Station(BS)Radio Transmission and Reception[S].Valbonne;3GPP Organizational Partners Publications Offices,2010.
[2]3GPP TS 36.211 V8.4.0,Evolved Universal Terrestrial Radio Access(E-UTRA);Physical Channels and Modulation[S].Valbonne;3GPP Organizational Partners Publications Offices,2008.
[3]王秋才,袁超伟,张金波,等.SC-FDMA上行系统中一种频域迭代块DFE均衡方法[J].西安电子科技大学学报(自然科学版),2013,40(2):33-38.
[4]Moose P H.A technique for orthogonal frequency division multiplexing frequency offset correction[J].IEEE Transactions on Communications,1994,42(10):2908-2914.
[5]杨春萍,王键,李道本.MIMO-OFDM系统的同步算法[J].中南大学学报(自然科学版),2010,41(2).
[6]倪浩,任光亮,白云,等.LTE上行链路高速铁路应用场景中的频偏估计方法[J].上海交通大学学报,2010,44(9):1235-1240.
[7]梁文娟.LTE系统下行同步算法的研究[D].西安:西安科技大学,2012.
[8]廖腾达,谢显中,郑品莲.基于循环前缀的LTE系统多普勒频偏估计算法[J].电视技术,2010,34(1):56-58.
[9]唐宏,方文平,孙伟.一种LTE系统中基于循环前缀的载波频偏估计方法[J].电子测试,2010(4):4-7.
[10]张俊杰,葛万成.Zadoff-Chu序列在LTE下行链路频偏估计中的应用[J].电子技术,2010(12):65-66.
[11]3GPP TS 36.104 V9.6.0,Evolved Universal Terrestrial Radio Access(E-UTRA);Base Station(BS)Radio Transmission and Reception[S].Valbonne;3GPP Organizational Partners Publications Offices,2010.