Showing papers on "Channel allocation schemes published in 1980"

Access-Control Schemes for Real-Time and Store-and-Forward Multiple-Access Communication Channels

Abstract: : Demand-Assignment TDMA schemes, a class of hybrid TDMA/Collision- Resolving schemes, governing the sharing of multiple-access communication channels are studied. Sources communicate with each other through a synchronized (slotted), fully-connected communication medium. This communication medium can be a terrestrial radio or line communication channel (inducing low propagation delay or a satellite channel (inducing high propagation delay). The Demand- Assignment TDMA schemes studied are used to allocate channel capacity among sources which require real-time transmission. A non-preemptive cutoff priority discipline is employed to offer priority services to important messages. The performance of the schemes is measured in terms of the message blocking (loss) probability and the message delay vs. channel throughput functions. For sources which transmit at multiple rates, a maximum normalized average waiting time is introduced as an overall system performance measure. The latter is used as an objective function in finding the optimal channel frame structure. The class of store-and-forward hybrid TDMA/Collision-Resolving schemes are composed of a TDMA component and a Tree Search component. Groups of Sources are served on a TDMA basis. Collisions among sources within each group are resolved by following a Tree Search technique. Message arrivals in a sequence of slots are assumed to be i.i.d., governed by an arbitrary distribution. The messages are assumed to contain single packets, except in the pure TDMA case where the message length distribution is arbitrary. Two cases are studied. Fixed Reservation schemes, operating on a store-and-forward basis, are also investigated.