A Fast Optimal Non-Continuous Slot Reuse Scheme for CRMA High-Speed Networks

Abstract

Cyclic-Reservation Multiple-Access (CRMA) is an effective access scheme for high-speed networks. In CRMA, the headend periodically generates reserve commands. If necessary, each station may reserve a number of empty slots in each reserve command. For each reserve command, the headend generates a cycle of length equal to the total number of empty slots which are reserved to serve the reservations. Generally speaking, a longer cycle length means a longer access delay and a lower throughput. Therefore, it is desirable to study how to reduce the cycle length. However, it has been shown that the problem is NP-complete if all the empty slots used by a station in a cycle are required to be consecutive [1]. In this paper, we remove the slot-contiguity constraint and propose a fast, optimal non-continuous slot reuse scheme with low time complexity O(M^2), where M denotes the number of stations. Experimental results demonstrate that our new scheme has much shorter cycle lengths, much higher throughput, and much shorter MAC (Medium Access Control) delay than the original CRMA scheme.