基于NSFC-OFDM的非协作式虚拟MIMO

A Non-cooperative virtual MIMO based on NSFC-OFDM

针对多用户配对虚拟MIMO(multiple input multiple output)安全性差,对信道估计器依赖性强的问题,提出一种基于非相干空频码(non-coherent space frequency code,NSFC)和正交频分复用(orthogonal frequency division multiplexing,OFDM)的非协作式虚拟MIMO。在分析NSFC成对错误概率的基础上,给出能满足全分集阶数和最大编码增益的编码准则。为了获得平行子信道传输效果,利用信道循环矩阵奇异值分解(singular value decomposition,SVD)后得到的酉矩阵分别进行预编码和预解码。基于最优NSFC和OFDM预编解码,提出一种新颖的虚拟MIMO策略。该虚拟MIMO在收发两端均无需信道瞬时信息,以非协作方式在单天线内模拟多天线收发效果。理论和仿真分析结果表明,虚拟MIMO系统能有效逼近实际理想MIMO的系统容量和误比特率性能,显著降低了虚拟MIMO系统的检测门限。

In this work, a non-collaborative virtual MIMO （ multiple input multiple output ） based on NSFC （ non-coher-ent space frequency code ） and OFDM （ orthogonal frequency division multiplexing ） is proposed to counter the poor secur-ity performance and strong dependence on channel estimation of virtual MIMO using user-pairing algorithm. Basing on the analysis of the pair-wise error probability for NSFC, we define the coding criterion to obtain full diversity and optimal coding gain. Then, we present a valid pre-encoding and decoding for virtual MIMO utilizing the unitaiy matrices, which are ob-tained by singular value decomposing on the channel cyclic matrix. A novel virtual MIMO, based on the optimized NSFC and OFDM pre-encoding and decoding is proposed. Although the instantaneous channel state information is unavailable at both sender and receiver, the single-antenna users even gain the multiple antennas transmission effect in a non-cooperative way. Theoiy analysis and simulation results show that the proposed scheme achieves similar performance on the capacity and bit error rate to ideal MIMO.