FlexiChaP: A reconfigurable ASIP for convolutional, turbo, and LDPC code decoding

Future mobile and wireless communication networks require flexible modem architectures to provide seamless services between different network standards. In this paper we focus on the outer modem which has to support various advanced channel coding techniques like convolutional codes, turbo codes, and low-density parity-check (LDPC) codes. We present an application-specific instruction-set processor (ASIP) which supports convolutional codes, binary/duo-binary turbo codes, and LDPC codes. Special emphasis is put on the support of LDPC codes. The ASIP consists of a special pipeline which is completely optimized for channel decoding. Logic synthesis yields an overall area of 0.62 mm² for this ASIP in a 65 nm low power technology. Payload throughputs of, e.g., up to 257 Mbps are possible at 400 MHz for the WiMAX and WiFi LDPC codes, outperforming existing ASIP solutions for LDPC decoding by an order of magnitude.