No abstract

Ad hoc wireless networks consist of mobile nodes interconnected by multihop communication paths. Unlike conventional wireless networks, ad hoc networks have no fixed network infrastructure or administrative support. The topology of the network changes dynamically as mobile nodes join or depart the network or radio links between nodes become unusable. This article addresses some of the quality of service issues for ad hoc networks which have recently started to receive increasing attention in the literature. The focus is on QoS routing. This is a complex and difficult issue because of the dynamic nature of the network topology and generally imprecise network state information. We present the basic concepts and discuss some of the recent results. The article concludes with some observations on the open areas for further investigation.

The spectrum of deployed wireless cellular communication systems is found to be underutilized, even though licensed spectrum is at a premium. To efficiently utilize the bandwidth left unused in a cellular system, the primary system (PRI), we propose an overlaid ad hoc secondary network (ASN) architecture, with the ASN operating over the resources left unutilized by the PRI. Our basic design principle is that the ASN operates in a nonintrusive manner and does not interact with the PRI. In this article we present the ad hoc secondary medium access control (AS-MAC) protocol to enable PRI-SEC interoperation, address a number of technical challenges pertinent to this networking environment, and evaluate the performance of the AS-MAC. In a single-hop ASN the AS-MAC transparently utilizes 75 percent of the bandwidth left unused by the PRI, while in multihop ASNs, due to spatial reuse, the AS-MAC can utilize up to 132 percent of the idle PRI resources in our experiments.

The spectrum of deployed wireless cellular communication systems is found to be underutilized, even though licensed spectrum is at a premium. To efficiently utilize the bandwidth left unused in a cellular system, the primary system (PRI), we propose an overlaid ad hoc secondary network (ASN) architecture, with the ASN operating over the resources left unutilized by the PRI. Our basic design principle is that the ASN operates in a nonintrusive manner and does not interact with the PRI. In this article we present the ad hoc secondary medium access control (AS-MAC) protocol to enable PRI-SEC interoperation, address a number of technical challenges pertinent to this networking environment, and evaluate the performance of the AS-MAC. In a single-hop ASN the AS-MAC transparently utilizes 75 percent of the bandwidth left unused by the PRI, while in multihop ASNs, due to spatial reuse, the AS-MAC can utilize up to 132 percent of the idle PRI resources in our experiments.

No abstract