The Royal Institution for the Advancement of Learning / Mcgill University

University of California

Camille Leroux

Gabi Sarkis

Warren Jeffrey Gross

Alexander Vardy

Pascal Giard

Ido Tal

Alexandre Raymond

Modern communication systems must cope with varying channel conditions and differing throughput constraints. Polar codes despite being the first error-correcting codes with an explicit construction to achieve the symmetric capacity of memoryless channels are not currently employed against other older coding protocols such as low-density parity check (LDPC) codes as their performance at short/moderate lengths has been inferior and their decoding algorithm is serial leading to low decoding throughput. Accordingly techniques to address these issues are identified and disclosed including decoders that decode constituent codes without recursion and/or recognize classes of constituent directly decodable codes thereby increasing the decoder throughput. Flexible encoders and decoders supporting polar codes of any length up to a design maximum allow adaptive polar code systems responsive to communication link characteristics, performance, etc. while maximizing throughput. Further, designers are provided flexibility in implementing either hardware or software implementations.

Flexible polar encoders and decoders

A polar code decoder includes: processing elements each receiving a pair of input values and applying a first or a second predetermined mathematical function depending on a provided function control signal; a first memory that stores at least one of the outputs from processing elements and a plurality of channel values relating to a received polar code to be decoded; a second memory that stores indices of a plurality of frozen bits each representing a bit within an information-bit vector of the polar code being decoded; and a computation block that receives a plurality of inputs from a portion of the processing elements and generates an output that is can be set to a predetermined frozen value or to a calculated value, depending on whether a current index of the bit being decoded is indicated as frozen or not frozen.

Methods and systems for decoding polar codes

Growing community of inventors

Pessac, France

Camille Leroux