Flexible Multistandard FEC Processor Design With ASIP Methodology

Designing decoder for forward error correction (FEC) is more and more challenging because of the requirements on simultaneous supporting of various wireless standards within one IC module. The flexibility, silicon cost and throughput efficiency are all necessary to be traded off. In this paper, by using ASIP methodology, software-hardware co-design is introduced to offer sufficient flexibility of FEC decoding. The decoding procedure can be programmable for decoding QC-LDPC, Turbo and Convolutional Codes. Firstly, the common features from all mentioned algorithms and their corresponding datapaths are analyzed and a unified multi-standard datapath is introduced. Based on it, an application specific instruction-set is proposed and an ASIP (Application Specific Instruction-set Processor) for the FEC algorithms is designed. The firmware FEC codes are developed to adapt to standards. Synthesis results show that the proposed FEC processor is 1.54mm(2) under 65nm CMOS process. It offers QC-LDPC decoding for WiMAX, Turbo decoding for 3GPP-LTE, and 64 states Convolutional code (CC) decoding at the throughput of 193 Mbps, 62 Mbps and 60 Mbps respectively under clock frequency of 200 MHz. The proposed ASIP provides programmable high throughput compared to other tri-mode hardware modules.