Performance evaluation for low complexity cascaded Sphere Decoders using K best detection algorithm

In this letter a new detection scheme combining the conventional Sphere decoders and K best detection algorithm is proposed. This algorithm leverages the Sphere decoder (SD) results to use smaller values of K in K best algorithm to achieve better performance. Post K best detection algorithm Darlington pairs of SD- K SD, SD- K 1 SD, and K - K 1 SD are used to get the final detection results. The proposed K best detection algorithm finds out smallest K paths by counting and sorting the bits of every candidate, which is much simpler as used in conventional sphere decoders. The computational complexity has been calculated in terms of time taken to visit the average number of K paths taken by Conventional SDs K -SDs and Darlington pair of SDs. Extensive Monte Carlo simulations are used to demonstrate that the proposed approach exhibits significant performance gain over conventional SD schemes in terms of bit error rate and computational time. Besides, a complete analytical approach is provided to validate the simulation results.