Wireless Ad Hoc and Sensor Networks

Background on Networking 11as delay, hop count, reliability, and bandwidth. Further details are providedin Chapter 8 for wireless ad hoc and sensor networks. Next wepresent an overview of wireless networking.1.3 Overview of Wireless NetworkingWireless networking in recent years is becoming an integral part of residential,commercial, and military computing applications. The eliminationof unsightly and cumbersome wiring, and the increase in mobilitymade possible by wireless networks are only some of the advantages thathave led to the widespread acceptance and popularity of such networks.The rapid worldwide growth in cellular telephone industry and the numberof subscribers demonstrate that wireless communication is a robust andviable data and voice transport mechanism.Recent developments in ad hoc wireless networking have eliminatedthe requirement of fixed infrastructure (central base station as required incellular networking) for communication between users in a network andexpanded the horizon of wireless networking. These networks termed asmobile ad hoc networks (MANET) are a collection of autonomous terminalsthat communicate with each other by forming a multihop radionetwork and maintaining connectivity in a decentralized manner.MANET and, in particular, wireless sensor networks (WSNs) are findingincreasing applications in communication between soldiers in a battlefield,emergency-relief-personnel coordinating efforts, earthquake aftermath,natural disaster relief, wired homes, and in today’s highly mobilebusiness environment.Wireless communication is much more difficult to achieve than wiredcommunication because the surrounding environment interacts with thesignal, blocking signal paths while introducing noise and echoes. Consequently,poor quality connections are observed as compared to wiredconnections: lower bandwidth, high error rates, and more frequent spuriousdisconnections. Wireless communications can also be degradedbecause of mobility and inefficient battery power control. Users may enterregions of high interference or out-step the coverage of network transceivers.Unlike typical wired networks, the number of devices in a cellvaries dynamically, and large concentrations of mobile users, such as atconventions and public events, may overload network capacity. MANETand WSNs offer many challenging problems to solve, such as routingprotocols in the presence of topology changes, QoS constraints, and soon. Separate standards and protocols are being developed for cellular, adhoc wireless and sensor networks.