Throughput performance of multiuser detection in unslottedcontention channels

摘要

Analyzes the throughput of a centralized packet receiver whichutilizes multiuser detection in an unslotted contention channel. Thereceiver is capable of demodulating all overlapping, unit-lengthpackets, provided that the T-length packet headers do not overlap, andat most K packets overlap at any one time. If one of these conditions isviolated, the remainder of the busy period is assumed to beunresolvable. Assuming that the aggregate packet arrival process isPoisson, the authors analyze the throughput as a function of the totaloffered load (λ), the maximum number of resolvable overlappingpackets (K), and the fractional header duration (T). They derive aniterative expression for the throughput for K=2 or 3, generalizable tolarger K, which permits solution of the throughput to arbitraryaccuracy. A closed form solution is given for the case K=2 and T=0.5.The authors provide bounds on the throughput for arbitrary K, λ,and T, which are more convenient than the exact approach for T>0 orlarge K. Numerical results illustrate the improvement in throughput dueto multiuser detection, and suggest a technique for finding the minimumcomplexity multiuser receiver (minimum K) as a function of other systemparameters