Mobile wireless networks allow a more flexible communication structure than traditional networks. Wireless communication enables information transfer among a network of disconnected, and often mobile, users. Popular wireless networks such as mobile phone networks and wireless local area networks (LANs), are traditionally infrastructure based—that is, base stations (BSs), access points (APs), and servers are deployed before the network can be used. A mobile ad hoc network (MANET) consists of a group of mobile hosts that may communicate with each other without fixed wireless infrastructure. In contrast to conventional cellular systems, there is no master-slave relationship between nodes, such as base station to mobile users in ad-hoc networks. Communication between nodes can be supported by direct connection or multi-hop relays. The nodes have the responsibility of self-organizing so that the network is robust to the variations in network topology due to node mobility as well as the fluctuations of the signal quality in the wireless environment. All of these guarantee anywhere and anytime communication. Recently, mobile ad-hoc networks have been receiving increasing attention in both commercial and military applications.