A Heterogeneous Reconfigurable Cell Array for MIMO Signal Processing

This paper presents a heterogeneous reconfigurable cell array, designed for high-throughput baseband processing of multiple-input multiple-output (MIMO) systems. To achieve high performance and energy efficiency while retaining high flexibility, the proposed architecture adopts heterogeneous and hierarchical resource deployments. Additionally, extensive vector computation enhancements and flexible memory access schemes are employed to better support MIMO signal processing. Implemented in a 65 nm CMOS technology, the cell array occupies 8.88 ${rm mm}^{2}$ core area and is capable of running at 500 MHz. For illustration, three computationally intensive blocks, namely channel estimation, channel matrix pre-processing, and hard-output data detection, of a 4 $times$ 4 MIMO processing chain in a 20 MHz 64-QAM 3GPP long term evolution advanced (LTE-A) downlink are mapped and processed in real-time. Implementation results report a maximum throughput of 367.88 Mb/s with 1.49 nJ/b energy consumption. Compared to state-of-the-art designs, the proposed solution outperforms programmable platforms by several orders of magnitude in energy efficiency, and achieves similar level of efficiency to that of ASICs.