Design and Implementation of a Low-Complexity and High-Throughput MIMO Symbol Detector Supporting up to 256 QAM

Abstract

This paper presents a low-complexity and high-throughput symbol detector for two-spatial-stream multiple-input multiple-output systems based on the modified maximum-likelihood symbol detection algorithm. In the proposed symbol detector, the cost function is calculated incrementally employing a multi-cycle architecture so as to eliminate the complex multiplications for each symbol, and the slicing operations are performed hierarchically according to the range of constellation points by a pipelined architecture. The proposed architecture exhibits low hardware complexity while supporting complicated modulations such as 256 QAM. In addition, various modulations and antenna configurations are supported flexibly by reconfiguring the pipeline for the slicing operation. The proposed symbol detector is implemented with 38.7K logic gates in a 0.11-µm CMOS process and its throughput is 166 Mbps for 2 × 3 16-QAM and 80Mbps for 2 × 3 64-QAM where the operating frequency is 478 MHz.