A Semifixed Complexity Sphere Decoder for Uncoded Symbols for Wireless Communications

Juan Francisco CASTILLO-LEON  Marco CARDENAS-JUAREZ  Ulises PINEDA-RICO  Enrique STEVENS-NAVARRO  

Publication
IEICE TRANSACTIONS on Communications   Vol.E97-B   No.12   pp.2776-2783
Publication Date: 2014/12/01
Online ISSN: 1745-1345
Type of Manuscript: PAPER
Category: Wireless Communication Technologies
Keyword: 
sphere decoding,  wireless communications,  multi-antenna systems,  maximum likelihood,  complexity,  

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Summary: 
The development of high data rate wireless communications systems using Multiple Input — Multiple Output (MIMO) antenna techniques requires detectors with reduced complexity and good Bit Error Rate (BER) performance. In this paper, we present the Semi-fixed Complexity Sphere Decoder (SCSD), which executes the process of detection in MIMO systems with a significantly lower computation cost than the high-performance/reduced-complexity detectors: Sphere Decoder (SD), K-best, Fixed Complexity Sphere Decoder (FSD) and Adaptive Set Partitioning (ASP). Simulation results show that when the Signal-to-Noise Ratio (SNR) is less than 15dB, the SCSD reduces the complexity by up to 90% with respect to SD, up to 60% with respect to K-best or ASP and by up to 90% with respect to FSD. In the proposed algorithm, the BER performance does not show significant degradation and therefore, can be considered as a complexity reduction scheme suitable for implementing in MIMO detectors.