Merged Processing Element for Polar Code Decoder
Federico Guillermo Krasser, Mónica Liberatori, Leonardo Coppolillo, Leonardo J. Arnone, Jorge Castiñeira Moreira · 2019
Polar codes are a class of forward error correction codes that can provably achieve the capacity of discrete memoryless channels. In some polar decoding schemes, successive cancellation decoders carry out estimations of the original messages, using update rules from two functions that involve arithmetic operations. Processing elements are basic blocks of the decoder that implement these functions. The interconnection of a great number of these elements forms a network which operates on the log-likelihood ratios from the channel to finally achieve the best possible estimation of the original message bits, hence the importance of a thorough design of them. Any simplification or resource saving in the design of these elements directly impacts the hardware complexity of the decoder. Also, any improvement in their throughput should have a similar effect in the performance of the decoder. In this work we present two generic, fully combinational designs for processing elements. They take into consideration the possibility of overflow of the quantized values, and use pre-computation to reduce latency. These designs can be used in different hardware decoder architectures to improve their throughput and area requirement.