基于接收信号重构的OFDM系统盲信道估计

Blind Channel Estimation for OFDM Systems Based on Received Signal Reconstruction

对OFDM系统的盲信道估计问题进行了研究,提出基于接收信号重构的子空间算法。该算法利用OFDM循环前缀(CP)重构接收信号,将传输方程中的信道矩阵变换为块Toeplitz高矩阵,然后利用重构接收信号噪声子空间与信号子空间的正交性,获取信道估计特征方程。为消除虚拟子载波对算法的影响,引入等效发射信号的SVD分解。通过将重构前的信号进行虚拟子载波归零处理进一步提升了算法的性能。仿真结果表明,所提算法相比于已有算法具有较高的估计精度和较快的收敛速度。

Blind channel estimation for OFDM systems is discussed, and a subspace-based blind channel estimation algorithm is proposed by re-constructing the received signal. The algorithm chan- ges the channel matrix of the transfer function into a block Toeplitz high matrix by exploiting OFDM cyclic prefix, and the channel estimation characteristic equation is obtained with the orthogonality between the signal subspace and the noise subspace of the reconstructed signal. In order to eliminate the influence of virtual carriers, the singular value decomposition of the equivalent transmit signal is imported. The performance is further improved through a preprocessing of virtual carrier recovery method. Simulation results illustrate the performance of the proposed algorithm via numerical experi- ments compared with the others.