A Low Complexity Equalization Method for Cooperative Communication Systems Based on Distributed Frequency-Domain Linear Convolutive Space-Frequency Codes

In this paper, we consider the cooperative communication system based on distributed frequency-domain linear convolutive space-frequency codes (FLC-SFC) with multiple carrier frequency offsets (CFOs) when the channels from relay nodes to destination node are flat fading. Through the mathematical derivation, the cooperative system model is simplified. Then, the equivalent banded system model is obtained and the related analysis shows the banded property of the equivalent channel matrix. Furthermore, a banded block minimum mean square error (MMSE) equalization method applying LDLH matrix decomposition is proposed for the banded system model. Besides, a special class of mask matrix is utilized to realize the banded operation. Compared with the traditional MMSE equalization method, the proposed equalization method has a relatively low computational complexity with satisfactory system performance.