Improving utilization rate of semi-parallel successive cancellation architecture for polar codes using 2-bit decoding

Authors: DINESH KUMAR DEVADOSS, SHANTHA SELVA KUMARI RAMA PACKIAM

Abstract: Polar codes are the capacity-achieving error-correcting code proved to be a significant invention in coding theory. It can achieve channel capacity at infinite code length N due to its explicit code construction. However, the processing complexity along with the higher latency due to successive cancellation (SC) decoding is being a major design issue, which reduces the utilization rate in the decoder architectures. This paper presents a modified semi-parallel architecture for decoding polar code with a better decoding latency. Precomputation and look-ahead techniques are used to generate two bits in the final stage. Pipelined partial-sum unit with a less critical path reduces hardware complexity independent of code length. Hence, the fact that the proposed architecture reduces the latency by 2.7 times leads to increase in utilization rate than prior semi-parallel architecture. For a code length of $N=2^{10}$, the proposed architecture shows $ 62.7\% $ and $ 94\% $ improved utilization rate compared to the conventional semi-parallel architecture and 2-bit SC decoder, respectively. Compared to the conventional semi-parallel decoder for $N=2^{17}$, hardware resource such as look-up-tables (LUT) and flip-flops (FF) usage are reduced by 98\% in field programmable gate array (FPGA) leads to reduction in processing complexity. Hence, very large efficient polar decoders with a high utilization rate can be implemented in FPGA.

Keywords: Polar code, successive cancellation, semi-parallel, hardware architecture, field programmable gate array (FPGA)

Full Text: PDF