Breadth-first tree search MIMO signal detector design and VLSI implementation

Efficient VLSI implementation of multiple-input multiple-output (MIMO) signal detectors plays an important role in the real-life MIMO communication systems. This paper presents a nonlinear MIMO detector design solution, called relaxed K-best detector, which can support efficient VLSI implementation, while maintaining good detection performance. To the best of our knowledge, this is the first nonlinear detector ever reported in the open literature, capable of supporting 4times4 MIMO transmission with 64 quadrature amplitude modulation (QAM). A soft-output relaxed K-best detector has been designed and synthesized using Synopsys with 0.18 mum CMOS technology. With the silicon area of 20 mm², the detector can achieve up to 50 Mbps throughput for 4times4 MIMO with 64-QAM modulation. The detector can achieve almost the same performance as the detectors using the sphere decoding algorithm