Certain Generalizations on the Collision Channel without Feedback

In this paper, certain generalizations on the collision channel without feedback are presented, based on the original work of Massey and Mathys. We are concerned with situations in which, given a collision in a slot, the channel capacity is a non-zero, decreasing function of the number of users involved. This corresponds, for example, to spread-spectrum type of signaling. Due to this model, concatenated coding schemes are employed to efficiently exploit the time-varying nature of the channel, upon using reliability information from the inner code decoding process, at the outer code decoding process. Results concerning capacity and coding/decoding tradeoffs will be presented.