Prototype Implementation of Real-Time ML Detectors for Spatial Multiplexing Transmission

Toshiaki Koike, Yukinaga Seki, Hidekazu Murata, Susumu Yoshida, Kiyomichi Araki

Abstract: We developed two types of practical maximum-likelihood detectors (MLD) for multiple-input multiple-output (MIMO) systems, using a field programmable gate array (FPGA) device. For implementations, we introduced two simplified metrics called a Manhattan metric and a correlation metric. Using the Manhattan metric, the detector needs no multiplication operations, at the cost of a slight performance degradation within 1 dB. Using the correlation metric, the MIMO-MLD can significantly reduce the complexity in both multiplications and additions without any performance degradation. This paper demonstrates the bit-error-rate performance of these MLD prototypes at a 1 Gbps-order real-time processing speed, through the use of an all-digital baseband 4<cd0215f.gif>4 MIMO testbed integrated on the same FPGA chip.