无循环前缀单载波频域均衡及信道估计算法

摘要

Single Carrier Frequency Domain Equalization(SC-FDE)is a promising technique to alleviate Inter-Symbol Interference(ISI)for wideband wireless communications. It has been shown that SC-FDE has similar performance and complexity as Orthogonal Frequency Division Multiplexing(OFDM), while OFDM suffers from high Peak-to-Average Power Ratio(PAPR). However conventional SC-FDE must have enough Cyclic-Prefix(CP)to compensate multipath effectively. A virtual zero-padding technique is proposed to transform the linear convolution into cyclic convolution and the interferences is mitigated from the adjacent segments, thereby avoiding the spectral and power overheads. Computer simulation results demonstrate the proposed algorithm can achieve a similar bite error rate as the AWGN channel with same signal to noise ratio.%单载波频域均衡（Single Carrier Frequency Domain Equalization，SC-FDE）技术可以有效地消除符号间干扰（ISI），相对于OFDM，具有较低的峰均比（PAPR），因此成为宽带无线通信关键技术之一。传统的SC-FDE系统需要在发送帧前面加入循环前缀（Cyclic-Prefix，CP），且CP长度要大于信道最大多径时延，这就降低了频带利用率，使得发射机功率增加。在取消CP情况下，通过隐训练序列获得信道脉冲响应估计信息，之后利用虚拟补零技术，恢复发送信号和信道的循环卷积，并通过迭代处理消除干扰。仿真结果表明，在信噪比大于3 dB后，算法误码率便接近相同信噪比条件下的高斯白噪声信道，性能较为理想。