Small-area and low-energy K-best MIMO detector using relaxed tree expansion and early forwarding

This paper proposes a new K-best detection method that can realize a small-area and low-energy MIMO detector. To reduce the complexity required in K-best operations, tree expansion is relaxed by early evicting inferior children. Additionally, an efficient pipeline scheduling called early forwarding is proposed to reduce the overall processing latency and the number registers. A 4×4 16-QAM MIMO detector integrating four K-best detection units is implemented to demonstrate the proposed method. In a 0.18-μm CMOS technology, the entire detector occupies 1.9 mm² and shows a throughput of 584 Mbps. The energy consumption is 443 pJ per bit at 1.8 V.