A High-Throughput Scheduling Technique, With Idle Timeslot Elimination Mechanism

Abstract

A new media-access-control protocol is introduced in this paper. The authors consider a wavelength-division-multiplexing (WDM) network with star topology. A single-hop WDM system is considered, so that there is a full connectivity between every node-pair in just one hop. The protocol adopted is pretransmission coordination-based, so the protocol coordinates nodes before the actual transmission. The coordination is achieved with one demand (or traffic) matrix, which saves the predetermination of the timeslots each node transmits. Each transmission frame (or cycle) has two phases: the control phase and the data phase. In order to eliminate the possible delay added by the schedule computation between the two phases of each frame, they consider a traffic prediction scheme, which is based upon the hidden Markov chain model. The control phase functions as a learning period in which the predictor is trained. The training is based on the traffic of the network. During the data phase, each station transmits its packets based on the predicted reservations, which are the predictor's output. In the same frame, the predictor computes the reservations for the next frame. They show that their protocol, although suffering from small packet delay loss, introduces a new method of computing the reservations of the demand matrix and brings some performance improvement in terms of channel utilization and results in higher network throughput, which is proven by extensive simulations