A Low-Complexity Soft-MIMO Detector Based on the Fixed-Complexity Sphere Decoder

Abstract

This paper presents a soft-output version of the fixed-complexity sphere decoder (FSD) previously proposed for uncoded multiple input-multiple output (MIMO) detection. Thus, the soft-FSD (SFSD) can be used in turbo-MIMO systems to exchange extrinsic soft-information with the outer decoder. For that purpose, the SFSD generates a list of candidates that approximates that of the list sphere decoder (LSD) while containing information about all the possible bit values, removing the need for clipping. In addition, it overcomes the two problems of the LSD: its variable complexity and the sequential nature of its tree search. Simulation results show that the SFSD can be used to approximate the performance of the LSD while having a considerably lower and fixed complexity, making the algorithm suitable for hardware implementation.

An Extendable Fixed-Complexity Sphere Decoder for Downlink Multi-User MIMO Communication System

“…하지만, 간섭 [10] . 이 때, FSD algorithm의 채널행렬 순서화을 통해 신호강 도가 작은 신호는 FS layer에서 반대의 경우는 SS layer에서 검출 되도록 채널행렬을 순서화한다 [8] .…”

“…첫 번째는 추가 검출 할 간섭신호의 스트림의 수를 제 한하는 방법이고 [7] , 두 번째는 전체 간섭신호 검출을 위한 수신기를 quasi-ML 성능을 갖는 저 복잡도 알고 리즘을 사용하는 방법이다. 본 논문에서는 qausi-ML 성능을 갖는 fixed-complexity SD(FSD) [9,10] …”

High-Speed RS(255, 239) Decoder Based on LCC Decoding

“…Focusing on detection methods with a fixed number of visited nodes, in [5,6] the hard-output FSD in [7] was extended to provide soft information by obtaining an improved list of candidates with respect to the one in [15]. Between the two soft-output-FSD proposals, the algorithm shown in [5] achieved good demod- ulation results in a turbo encoded system expanding a lower number of candidates than the one in [6].…”

“…Between the two soft-output-FSD proposals, the algorithm shown in [5] achieved good demod- ulation results in a turbo encoded system expanding a lower number of candidates than the one in [6]. Therefore, we selected the method in [5] among the previously described algorithms for our implementation on GPU. The high parallel processing capabilities of the FSD against the high complexity of the RTS and the variable complexity of the STS motivated this selection.…”

“…Both, the hard-and soft-output [5] versions of the method have been implemented and compared to the implementation of the same algorithms on a high-performance multi-core CPU. Focusing on real-time applications, the throughput of the algorithm is also evaluated and compared to that of some other recent implementations in the literature.…”