No abstract

Two pols nomial time algorithms are given for scheduling conversations in a spread spectrum radio networh. The constraint on converrations is that each station can conver\e with at most one other station at a time. The first algorithm is strongly polynomial and finds a schedule of minimum length which allows each pair of neighboring stations to directly converse for a prescribed length of time. The second algorithm is designed for the situation in which messages must be relaled multiple hops. The algorithm produces, in polynomial time, a routing vector and compatible link schedule which joint11 meet a prespecified end-to-end demand, such that the schedule has the smallest possible length.

Bounds of exponential type are derived for the first-hitting time and occupation times of a real-valued random sequence which has a uniform negative drift whenever the sequence is above a fixed level. The only other assumption on the random sequence is that the increments satisfy a uniform exponential decay condition. The bounds provide a flexible technique for proving stability of processes frequently encountered in the control of queues.Two applications are given. First, exponential-type bounds are derived for a GI/G/1 queue when the service distribution is exponential type. Secondly, geometric ergodicity is established for a certain Markov chain in which arises in the decentralized control of a multi-access, packet-switched broadcast channel.

Information theory has not yet had a direct impact on networking, although there are similarities in concepts and methodologies that have consistently attracted the attention of researchers from both fields. In this paper, we review several topics that are related to communication networks and that have an information-theoretic flavor, including multiaccess protocols, timing channels, effective bandwidth of bursty data sources, deterministic constraints on datastreams, queuing theory, and switching networks.Index Terms-Communication networks, effective bandwidth, multiaccess, switching. I. INTRODUCTIONI NFORMATION theory is the conscience of the theory of communication; it has defined the "playing field" within which communication systems can be studied and understood. It has provided the spawning grounds for the fields of coding, compression, encryption, detection, and modulation, and it has enabled the design and evaluation of systems whose performance is pushing the limits of what can be achieved. Thus it constitutes a scientific success story of almost unparalleled proportions to which we pay tribute during this golden anniversary year of its birth.However, information theory has not yet made a comparable mark in the field of communication networks, the sister field and natural extension of communication theory, that is today, and is likely to remain for many years, the center of activity and attention in most information technology areas. The principal reason for this failure is twofold. First, by focusing on the classical point-to-point, source-channel-destination model of communication, information theory has ignored the bursty nature of real sources. Early on there seemed to be no point in considering the idle periods of source silence or inactivity. However, in networks, source burstiness is the central phenomenon that underlies the process of resource sharing for communication. Secondly, by focusing on the asymptotic limits of the tradeoff between accuracy and rate of communication, information theory ignored the role of delay as a parameter that may affect this tradeoff. In networking, delay is a fundamental quantity, not only as a performance Manuscript

No abstract