A Variable Partition Duplex Scheme with Enlarged Reservation Duration on Packet Reservation Multiple Access Protocol

摘要

A variable partition duplex scheme on packet reservation multiple access protocol (VPD-PRMA) is analyzed in this paper. We assume a four-state speech model for a conver- sational pair and successfully obtain performance measures by approximate Markovian analysis. Analytical results show that they quite fit simulation results; and VPD-PRMA can get higher statistical multiplexing gain than fixed partition duplex (FPD)- PRMA, due to the trunking effect. We further investigate the ef- fect of design parameters of permission probability and enlarged reservation duration on system performance by computer simu- lation. Simulation results shows that it exists appropriate values for these two design parameters so that the packet dropping prob- ability can be minimized. The adjustment of permission proba- bility can greatly improve the performance of uplink traffic with slight deterioration of the performance of downlink traffic, the provision of enlarged reservation duration scheme can enhance the system performance.