Average distance structures of random convolutional codes

[[abstract]]Summary form only given. The authors let the number of fundamental paths of weight d in a convolutional code be denoted by Ad and let α be defined by lim sup log Ad/d = log α as d &rarr α. They have observed experimentally that the α's for codes of fixed constraint length and rate are very nearly equal and seem to approach a limit for very large constraint length. To explain this, they have studied the ensemble of fixed convolutional codes as a subset of the ensemble of time-varying convolutional codes.[[fileno]]2030174030016[[department]]電機工程學