Abstract

Multiple-Input Multiple-Output (MIMO) spatial multiplexing is a promising technique to increase the channel capacity without increasing bandwidth. One of the key to successful application of this technique is in receiver design. Recently, several detection algorithms have been developed for MIMO wireless communication systems and sphere decoding in particular, which provides a tradeoff between the performance and complexity by suitably choosing the "radius" or the number of candidates in the search space. Meanwhile, another approach, called poly-diagonalization and trellis detection, has been proposed to compromise the complexity and performance. Soft-output detectors generally achieve much better performance than hard output detectors do in coded MIMO systems but no person presented the soft-output derivation of Poly-diagonalization and tail-biting trellis detector before and, in this paper, we compare various MIMO receiver algorithms in terms of both performance and complexity. The performance is evaluated in frequency selective fading channel environment on the basis of orthogonal frequency division multiplexing with channel codes, where the generation of soft decision values is crucial. The results show that the performances of poly-diagonalization approach and sphere decoding have their own advantages at similar computational complexity.

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