Protocol Sequences for the Multiple-Packet Reception Channel Without Feedback

Consider a time-slotted communication channel that is shared by K active users transmitting to a single receiver. It is assumed that the receiver has the ability of the multiple-packet reception to correctly receive up to γ (1 ≤ γ <; K) simultaneously transmitted packets. Each user accesses the channel following a deterministic binary sequence, called the protocol sequence, and transmits a packet within a channel slot if the sequence value is equal to one. If the users are not time synchronized, the relative shifts among them can cause significant fluctuation in throughput. If the throughput of each user is independent of relative shifts, then the adopted protocol sequence set is said to be throughput-invariant (TI). If we define worst-case system throughput as the minimal system throughput that can be guaranteed for any set of relative shifts, then TI sequences maximize it and hence are of fundamental interest. This paper investigates TI sequences for γ ≥ 1. Several new results are obtained including throughput value as a function of the duty factors, a lower bound on the sequence period, a construction that achieves the lower bound on the sequence period, and theorems on the intrinsic structure that establish connections with some other families of binary sequences.