一种循环前缀为PN序列的OFDM信道估计算法

A OFDM channel estimation algorithm based on PN sequence as a cyclic prefix

与传统的正交频分复用(OFDM)频域信道估计方法不同,提出了一种循环前缀为PN序列的OFDM信道估计方法:在时域OFDM符号中不插入传统意义上的循环前缀,而是插入PN序列作为训练序列,将PN序列与对应的接收序列作圆周相关处理获得信道频率响应估计;而由于PN序列周期性出现,它也起到了循环前缀的作用。仿真结果表明:在多径瑞利衰落信道中,在相同信噪比和相同信道利用率的条件下,提出的算法比频域梳状导频插入的时域滤波算法具有更高的信道估计精度。

It is different from conventional frequency-domain channel estimation algorithm of orthogonal frequency division multiplexing （OFDM）, a OFDM channel estimation algorithm based on PN sequence as a cyclic prefix is proposed： instead of typical cyclic prefix, PN sequence as training sequence is inserted into OFDM symbol in time domain; the cross-correlation between the PN sequence and its corresponding received sequence is performed, then the channel frequency response can be acquired. PN sequence also have a same function as cyclic prefix because of its periodic appearance. The simulation results show that, in multipath Rayleigh fading channels, with the same signal-to-noise ratio （SNR） and channel utilizing efficiency, the proposed algorithm can implement a much accurate estimation than the time-domain filtering algorithm based on frequency-domain comb pilots.