A High-Speed SDM-MIMO Decoder Using Efficient Candidate Searching for Wireless Communication

In this brief, a high-speed space-division multiplexing (SDM) multiple-input-multiple output (MIMO) decoder using efficient candidate searching is proposed by exploiting the characteristics of QR decomposition and sphere decoder for high throughput rate and low hardware-complexity. A process of efficient candidate searching by shifting the center of constellation with scalable radius reduces the processing time and improves the operational frequency. The proposed architecture can operate at a 166-MHz clock frequency, and the core area is smaller than results from using the K-best SD algorithm since large memory is not required to store extreme candidate paths. In our implementation, the core area is 0.675 mm using TSMC 90-nm technology. The average throughput of the proposed SDM-MIMO decoder is 95 Mbps with 64-QAM modulation at 30-dB signal-to-noise ratio.