In the recent years communication technology and services have advanced. Mobility has become very important, as people want to communicate anytime from and to anywhere. In the areas where there is little or no infrastructure is available or the existing wireless infrastructure is expensive and inconvenient to use, Mobile Ad hoc Networks, called MANETs, are becoming useful. They are going to become integral part of next generation mobile services.
A MANET is a collection of wireless nodes that can dynamically form a network to exchange information without using any pre-existing fixed network infrastructure. The special features of MANET bring this technology great opportunity together with severe challenges.
The military tactical and other security-sensitive operations are still the main applications of ad hoc networks, although there is a trend to adopt ad hoc networks for commercial uses due to their unique properties. However, they face a number of problems.. Some of the technical challenges MANET poses are also presented based on which the paper points out the related kernel barrier. Some of the key research issues for ad hoc networking technology are discussed in detail that are expected to promote the development and accelerate the commercial applications of the MANET technology.During the last decade, advances in both hardware and software techniques have resulted in mobile hosts and wireless networking common and miscellaneous. Generally there are two distinct approaches for enabling wireless mobile units to communicate with each other:
Wireless mobile networks have traditionally been based on the cellular concept and relied on good infrastructure support, in which mobile devices communicate with access points like base stations connected to the fixed network infrastructure. Typical examples of this kind of wireless networks are GSM, UMTS, WLL, WLAN, etc.
As to infrastructureless approach, the mobile wireless network is commonly known as a mobile ad hoc network (MANET) [1, 2]. A MANET is a collection of wireless nodes that can dynamically form a network to exchange information without using any pre-existing fixed network infrastructure. It has many important applications, because in many contexts information exchange between mobile units cannot rely on any fixed network infrastructure, but on rapid configuration of a wireless connections on-the-fly. Wireless ad hoc networks themselves are an independent, wide area of research and applications, instead of being only just a complement of the cellular system. In this paper, we describes the fundamental problems of ad hoc networking by giving its related research background including the concept, features, status, and applications of MANET. Some of the technical challenges MANET poses are also presented based on which the paper points out the related kernel barrier. Some of the key research issues for adhoc networking technology are discussed in details that are expected to promote the development and accelerate the commercial applications of the MANET technology.
Difference between MANET and WLAN
MANETs are dynamically created and maintained by the individual nodes comprising the network. They do not require a pre-existing architecture for communication purposes and do not rely on any type of wired infrastructure; in an ad hoc network all communication occurs through a wireless median. MANET comprises a special subset of wireless networks since they do not require the existence of a centralized message-passing device. Simple wireless networks require the existence of access points or static base stations (BS), which are responsible for routing messages to and from mobile nodes (MNs) within the specified transmission area. Ad hoc networks, on the other hand, do not require the existence of any device other than two or more MNs willing to cooperatively form a network.
Instead of relying on a wired BS to coordinate the flow of messages to each MN, the individual MNs form their own network and forward packets to and from each other. This adaptive behavior allows a network to be quickly formed even under the most adverse conditions. Other characteristics of ad hoc networks include "team collaboration of a large number of MN units, limited bandwidth, the need for supporting multimedia real time traffic and low latency access to distributed resources (e.g. distributed database access for situation awareness in the battlefield).