Mobile ad hoc networks represent a new form of communication consisting of mobile wireless terminals (e.g., handset, PDAs, notebooks). These type of networks are wireless multi-hop packet networks without any fixed infrastructure and centralized administration, in contrast to today’s wireless communications, which is based on a fixed, pre-established infrastructure. The design of wireless ad hoc networks faces many unique challenges. In this article, mobile ad hoc networks and their characteristics are described, and the design issues, applications and future trends of such networks will be discussed.
Mobile Ad Hoc Networks And Their Characteristics
A mobile ad hoc network (MANET) consists of a collection of mobile wireless and autonomous hosts –in this sense simply referred to as “nodes”– which spontaneously form a temporary network. The devices may be of various types (e.g., notebook computers, PDAs, cell phones, etc.) and various capacities (e.g., computing power, memory, disk, etc.).
The most important characteristic of such a network is its independence of any fixed infrastructure (e.g., base station or access point) or centralized administration. All networking functions, such as determining the network topology, multiple access, and routing of data over the most appropriate paths, must be performed in a distributed way. These tasks are particularly challenging due to the limited communication bandwidth available in the wireless channel.
Actually, the idea of ad hoc networking is sometimes also called infrastructureless networking (Frodigh, Johansson & Larsson, 2000). An ad hoc network is able to operate autonomously and is completely self-organized and self-configured. Therefore, it can be easily and rapidly installed. In an ad hoc environment people and vehicles can be interworked in areas without a pre-existing communication infrastructure, or when the use of such infrastructure requires wireless extension.
Key Terms in this Chapter
Cellular Networks: A network consisting of several cells served by fixed, pre-established infrastructure to cover a geographic area, for example, GSM, IS-95, UMTS.
Node: Mobile terminal.
MANET (Mobile Ad Hoc Networks): A network of wireless mobile nodes formed dynamically, self-organizing and without any central administration.
RTS/CTS (Request To Send/Clear To Send): Control packets between the transmitting and receiving nodes before initiating the transmission of a data packet.