Mackay-Neal Codes for High-Speed Wireless and Free-Space Optical Links

Explore the design and application of rate-adaptive MacKay-Neal (MN) codes based on protographs in this 31-minute lecture. Delve into the code construction that employs an outer distribution matcher (DM) coupled with an inner protograph-based low-density parity-check (LDPC) code to adapt the scheme's rate. Analyze the performance of this nonlinear code structure through an equivalent communication model, reducing the problem to the analysis of the inner linear LDPC code with parallel transmission over the communication channel and a binary symmetric channel. Examine examples of code designs that demonstrate how a single LDPC code ensemble can operate within 1 dB from the Shannon limit across a wide range of code rates by adjusting DM parameters. Discover the advantages of this construction for pipeline decoder implementations targeting high-throughput wireless and free-space optical links, offering rate flexibility with constant blocklength and a fixed inner LDPC code.