Slotted idle signal multiple access scheme for two-way centralized wireless communication networks

We propose a random multiple access scheme named S-ISMA/CD (slotted idle signal multiple access with collision detection) for a centralized wireless communication network where upstream and downstream traffic are transmitted over separate channels. Two versions of the scheme, S-ISMA/CD1 and S-ISMA/CD2, are studied in this paper. The S-G (throughput versus offered load) performance of both schemes are evaluated. We also study the dynamic behavior of the system with finite population of terminals on the upward channel. By using EPA (equilibrium point analysis), a fluid approximation method, the throughput and delay performance is evaluated. As a result, it is shown that both schemes have high channel efficiency although S-ISMA/CD1 has a little better performance on the downward channel while S-ISMA/CD2, is easier in implementation and more reliable in operation