基于低峰均比最优导频序列的MIMO-OFDM信道估计

摘要

Channel estimation is the key of coherent demodulation for MIMO-OFDM system signal receiv-er. Aiming at the problem that the optimal pilot sequences( OPS) have high Peak to Average Power Ratio ( PAPR) ,this paper designs a kind of OPS based on low-PAPR to estimate MIMO-OFDM system. Firstly, on the basis of MIMO-OFDM system model, the OPS of MIMO-OFDM system is designed, and the theory of Partial Transmit Sequence( PTS) is applied to design the low-PAPR enhanced optimal pilot sequences ( EOPS) . Finally, the EOPS are used for MIMO-OFDM system channel estimation and the high complexity of the algorithm is simplified. And on this basis, the Complementary Cumulative Distribution Function ( CCDF) of the signal's PAPR in each transmitting antenna and the mean square error( MSE) , the bit er-ror rate( BER) performance of the OPS before and after the improvement are simulated and analyzed. The simulation results show that the EOPS distributed in more than one OFDM symbol can effectively reduce the PAPR of the system; at the same time, compared with the original OPS, it keeps the MSE and BER performance optimal.%信道估计是多输入多输出-正交频分复用( MIMO-OFDM)系统接收机进行信号相干解调的关键。针对最优导频序列( OPS)在进行信道估计时存在峰均比( PAPR)较高这一问题，设计了一种低PAPR的OPS 用于对 MIMO-OFDM 系统进行信道估计。在建立系统模型基础上，对 MIMO-OFDM系统的OPS进行了设计，并利用部分传输序列( PTS )思想设计出低峰均比最优导频序列( EOPS)；将设计的EOPS用于对MIMO-OFDM系统进行信道估计，并对复杂度较高的步骤进行了算法简化，在此基础上分别对各发射天线上信号PAPR的互补累积分布函数( CCDF)和OPS改进前后的均方误差(MSE)、误码率(BER)性能进行了仿真分析。结果表明，分布在多个OFDM符号上的EOPS能够有效降低系统PAPR；同时，与原来的OPS相比，保持了MSE和BER的最优性能。