A receiver-based handshake (RBHS) protocol for multipacket channels, such as code-division multiple-access (CDMA) networks, is proposed and its throughput and delay performance is analyzed. This scheme is based on a sensing period and a handshake procedure which can avoid collision and eliminates unwanted transmissions. Several system models under different assumptions, such as completely orthogonal codes and very large processing gain (we call it perfect channel) or with quasiorthogonal codes (nonperfect channel), are investigated. We assume the channel error probability due to other users' interference to be a function of the number of transmissions in a given slot as well as other system parameters. Under a slotted structure with uniform traffic assumption, the system is modeled as a discrete-time two-dimensional Markov chain. The analysis, based on various channel conditions, demonstrates that the average throughput and delay are significantly improved over other spreading code protocols, especially when the channel is likely to accommodate more channel errors, and when the handshaking time is reasonably short compared to the average packet length.>

The optimal control of arrivals to a two-station token ring network is analyzed. By adopting a maximum system throughput under a system time-delay optimality criterion, a social optimality problem is studied under the assumption that both stations have global information (i.e. the number of packets in each station). The controlled arrivals are assumed to be state-dependent Poisson streams and have exponentially distributed service time. The optimality problem is formulated as a dynamic programming problem with a convex cost function. Using duality theory, it is then shown that the optimal control is switchover when both queues have the same service rate and sufficiently large buffers. Nonlinear programming is used to numerically approximate the optimal local controls for comparison purposes. The results obtained under global and local information can be used to provide a measure of the tradeoff between maximum throughput efficiency and protocol complexity. Numerical examples illustrating the theoretical results are provided.>