Sequential decoding for multiple access channels

Sequential decoding is a decoding algorithm for tree codes originally developed for single-user channels (i.e., channels with one transmitter and one receiver). Sequential decoding relies on what is called a metric to direct its search and find the path in the tree that corresponds to the encoded message. The decoding complexity in sequential decoding, that is, the number of computations to decode a source digit, is a random variable. A rate is said to be achievable by sequential decoding if it is possible to select a code with that rate and a metric such that the expected value of the decoding complexity is finite. In the single-user case, the largest achievable rate is called the cut-off rate of sequential decoding. Multiple access channels are models of communication systems where there are a number of users all sharing the same transmission medium to communicate their messages to a common receiver. This thesis explores the possibility of using sequential decoding on multiple access channels.