Soft-Output Detection Based on Multi-hop-return Sphere Searching for Distributed Space-Frequency Coded Cooperative Communication System

This paper proposes a soft-output detection algorithm based on multi-hop-return sphere searching for distributed space-frequency coded cooperative communication system over frequency-selective fading channels. The algorithm finds out the vector point of the sphere center through the sphere decoding quickly at first, and then returns to collecting soft decoding information layer by layer. Theoretical analysis and simulation results show the proposed algorithm not only reduces the complexity of symbol detection, but also improves the accuracy of the channel decoding of the distributed space-frequency coded cooperative communication systems by effectively exacting the bit-level soft information from the received signal using Low Density Parity Check Codes (LDPC).