A coded multiple access protocol (CMAP) to improve the delay-throughput performance of a global scheduling multiaccess model for data communication over a broadcast channel, which exhibits a short propagation delay, is described and analyzed. Upper and lower bounds on delay-throughput characteristics are obtained. It is shown that CMAP reduces system delay compared to the 1-out-of-Mcode. This reduction is attained at the expense of a dialogue exchange between the central scheduler and the users.

A satellite packet switching multiaccess model which employs a global scheduling assignment scheme is described and analyzed for batch Poisson arrivals. System performance in terms of buffer overflow probability and system delay is analyzed and simulated. The numerical results, presented in graphical form, indicate that the performance improves as the population size M increases. For large value of M the queueing delay decays approximately exponentially as the buffer length increases. Our results indicate that the system delay performance of our dynamic assignment (DA) algorithm is significantly better than that of a synchronous time-division multiplexing scheme.

The multiaccess model for satellite packet switching proposed by the authors [1] employs a frame format, with scheduling assignments broadcast from the satellite. The total delay recurred by a data packet in traversing the satellite channel consists of queueing delay, scheduling delay, transmission delay and propagation delay. In this paper we analyze the queueing and scheduling delays and compare the analytical and simulation results. For the queuemg delay analysis we model the multiaccess scheme using anM/D/Nqueue, whereNis the number of slots per frame. For the scheduling delay analysis we emply a round-robin scheduling assignment algorithm. We treat the cases with and without random transmission; our results indicate that random transmission improves the queueing delay performance.

A multiaccess model for packet switching with a satellite having the capability of interrogating the uplink header and creating the downlink header is proposed. The satellite broadcasts slot assignments, based on the users' reported queue status, to the users for transmission in the next frame. With the protocols being done at both the earth stations and at the satellite, the proposed multiaccess model avoids collisions that are prevalent in schemes of the ALOHA type. The actual model is too complex to handle analytically. We derive analytical equations for a two-group model. Calculated and simulated buffer overflow probabilities as a function of traffic intensity and buffer size are compared. We also evaluate the performance of the actual model in terms of average system delay as a function of traffic intensity by means of computer simulation.