Analyzes the performance of the unslotted 1-persistent carrier sense multiple access with collision detection (CSMA-CD) protocol for fiber optic bus networks with a finite number of stations M, each of which has an infinite storage buffer for storing packets with its length fixed or exponentially distributed. Treating the bus network as an M-class priority queueing system with a preemptive repeat-identical retransmission strategy, the authors show numerically that this 1-persistent retransmission strategy provides better delay-throughput performance than the non-persistent one. To satisfy the fairness of equal delays among stations in the bus network, the authors next present the unslotted p/sub i/-persistent CSMA-CD protocol. Under this protocol, the first packet arriving at station i is forced to enter into the backoff procedure with the probability of (1/spl minus/p/sub i/). After backoffs, transmission begins until the station becomes empty. The authors determine the persistent probability p/sub i/ and show that the delay-throughput performance of the p/sub i/-persistent strategy is better than that of the 1-persistent one, and further it is robust for any packet lengths. Simulation results are presented to verify the analytical results.>

Three call handling schemes for a base station which can handle both originating calls (OCs) and prioritized handoff calls (HCs), and which serves these calls under the blocked-call-delayed basis, are presented and compared. Delayed calls are assumed to be stored in a finite storage buffer. One scheme (Scheme I) exclusively allows handoff calls to be stored and to use a fixed number of guard channels. The other two schemes without guard channels (Scheme II-using the last-in/first-out policy for OC's and Scheme III-using the first-in first-out policy for OC's) allow both types of calls to be stored, and allow prioritized handoff calls to pushout originating calls if the buffer is full. For these three schemes, the blocking probabilities and delay distributions of both types of calls are numerically obtained, and a boundary for call handling schemes between with and without guard channels is found. From the numerical results, it is shown that Scheme II can be considered a good candidate for a call handling scheme for microcellular systems.>