دانلود کتاب Sequential decoding for reliable communication

Shannon's coding theorem for noisy channels states that it is possibleto communicate information, with arbitrarily small error, at anyrate of transmission less than the channel capacity. The attainableprobability of error has previously been bounded as a function of capacity,transmission rate, and delay. This investigation considers thebehavior of a new parameter, the average number of decoding computations.A convolutional encoding and sequential decoding procedureis proposed for the particular case of the binary symmetric channel.With this procedure, the average number of decoding computations perinformation digit can be constrained to grow less rapidly than thesquare of the delay. The decoding process converges for constantrates of transmission that are not too close to capacity. Although ithas not been possible to prove this rigorously, it appears that theprobability of error decreases exponentially with delay, and is essentiallyoptimum for transmission rates near the limit of convergence.It also appears that the sequential decoding technique can be extendedto more general channels.