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推导了一种在快衰落频率选择性信道下适用于多输入多输出正交频分复用(MIMO-OFDM)技术的系统模型.应用这个模型,分析了信道在一个传输符号内的时变特性带来的影响,它破坏子载波间的正交性,从而引起严重的子载波间干扰(ICI).针对这一问题,提出一种频域迭代子载波间干扰消除算法.通过将信道传输矩阵分离为数据部分和ICI部分,首先利用迫零算法获得发送信号的初始估计值,由信道的ICI矩阵生成干扰信号,从接收信号中减去干扰,之后利用数据矩阵和并行干扰抵消算法来消除不同发送天线上相同子载波的多流干扰.仅考虑邻近18个子载波带来的干扰,在其性能与原算法几乎相同的条件下,可以极大地降低计算复杂度.仿真结果表明该算法在不同的多普勒频移条件下能有效消除子载波间干扰,并且在低信噪比下逼近准静态信道下系统的性能.
A system model suitable for multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) under fast-fading frequency-selective channels is derived. Using this model, the time-varying characteristics of channels in a transmission symbol , Which undermines the orthogonality between subcarriers and causes serious inter-subcarrier interference (ICI) .Aiming at this problem, this paper proposes a frequency-domain iterative sub-carrier interference cancellation algorithm, Separated into the data part and the ICI part, the initial estimate of the transmitted signal is first obtained using the zero-forcing algorithm, the interference signal is generated from the ICI matrix of the channel, the interference is subtracted from the received signal, and then the data matrix and the parallel interference cancellation algorithm are used to eliminate the difference It can greatly reduce the computational complexity under the condition that its performance is almost the same as that of the original one.It is shown by the simulation results that the proposed algorithm can effectively reduce the interference between different subcarriers Doppler shift can effectively eliminate the inter-subcarrier interference and approach the performance of the system under quasi-static channel with low signal-to-noise ratio.