I am currently taking an online course on probabilistic graphical models. In the section on belief propagation (BP), specifically loopy BP, reference was made to Robert Mc Eliece's 1988 paper Turbo Decoding as an Instance of Pearl’s “Belief Propagation” Algorithm and turbo decoding.
As I understand it, the key breakthrough with turbo decoding is that one can obtain greater channel throughput by operating closer to the theoretical limit of attainability as given by Shannon's theorem. This increased throughput is achieved at the cost of greater computational complexity in the decoder.
Further I understand that turbo decoding has become widespread and virtually ubiquitous in modern communication channels.
Is my understanding correct?
Also is this currently an active field with development of new decoding algorithms or has it stabilized?