.FLYINGHEAD WIRELESS INFRASTRUCTURE
.TITLE Internet Mobile Ad-hoc networks
.AUTHOR Humayun Bakht
.SUMMARY Mobile ad-hoc networks are based on the idea of establishing a network without taking any support from a centralized structure. Due to the growing interest in the Internet, it becomes important to consider the integration of MANET with the Internet. In his latest piece on mobile ad-hoc networks, Contributing Editor Humayun Bakht discussing bringing Internet access to the ad-hoc network.
.DEPT
Wireless networks can generally be classified as wireless fixed networks, and wireless, or mobile ad-hoc networks. MANETs (mobile ad-hoc networks) are based on the idea of establishing a network without taking any support from a centralized structure. By nature these types of networks are suitable for situations where either no fixed infrastructure exists, or to deploy one is not possible.
Their deployment is more complicated in fluid, tactical situations where special challenges emerge, and where the price of dropped communications can cause heavy loss. There are a number of requirements that have to be fulfilled in order to complete the life cycle of ad-hoc networks. Ad-hoc networks require mobile devices to stay in touch, while having the ability to move around. The network must therefore sustain itself if other communications devices go out of range, are damaged, or destroyed.
The history of peer-to-peer, or ad-hoc networks goes back to 1972 when they were first implemented for testing purposes in military exercises. The main aim was to monitor the performance of small radio devices in a military environment. Packet radio network was the first development based on the theory of ad-hoc networking.
In 1992, the idea of commercial ad-hoc networks emerged. Later on, it was implemented on a number of different platforms. Bluetooth and ad-hoc sensor networks are some of the latest development of ad-hoc networks.
.BREAK_EMAIL To learn more about Internet mobile ad-hoc networks, click here.
Communication in mobile ad-hoc networks is normally achieved through other mobile devices in the network. Each node of an ad-hoc network is the destination of some information packets, while at the same time it also functions as an intermediate station for other packets on the way to their final destination. This multi-hop support in ad-hoc networks makes communication between nodes outside direct radio range of one another possible. It’s also the main difference between mobile ad-hoc networks and wireless LANs.
Due to the growing interest in the Internet and associated technologies, it becomes important to consider the integration of MANET with the Internet. A mobile ad-hoc network may be connected at the edges to the fixed, wired Internet. In this case, mobile ad-hoc networks will expand the present Internet, and wireless access to the same. A Mobile Internet Router is one of the main requirements for an ad-hoc network to gain access to the Internet. Mobile ad hoc networks must have a router capable of supporting Mobile IP features in order to provide mobility to the entire ad-hoc network and connect to the Internet.
The Mobile Internet Router will act as an interface between the wired network and an ad-hoc network. In other words, these routers will act as a Mobile Node that roams between heterogeneous access networks. This roaming capability is required for the mobile router to maintain a constant connection, either via WLAN or General Packet Radio Service (GPRS). WLAN access is required to be online when high data bandwidth is available.
Under this scenario, the mobile terminals in ad-hoc networks communicate with each other through ad-hoc communication protocols. Among mobile terminals, some of them can directly connect to the Internet and serve as Access Points for the rest of the mobile terminals in the Internet mobile ad-hoc network. Therefore, an Access Point will provide a gateway for the Internet, and is assumed to have access to any information.
In the future, there’ll be a need for non-infrastructure IP domains in order to exchange data between mobile users. This type of interaction between mobile users can be provided by ad-hoc protocols, which allow IP connectivity in a limited domain without Internet access. There will be scenarios in the future where ad-hoc users want Internet access via routers to be online.
In this case, the entire ad-hoc network can be attached via one router to the Internet, where the router is part of the ad-hoc domain. In scenarios where the ad-hoc network is stationary, located on different objects, such as in trains, planes, and buses, the router must have a wireless link to the Internet. General Packet Radio Service connectivity is required when an ad-hoc network has to provide high mobility, as in vehicles with high velocity. GPRS offers high mobility and always on connectivity, but with low bandwidth. This can be supported by WLAN access with high data bandwidth.
In conclusion, one of the active research topics is the connectivity of mobile ad-hoc networks with the Internet. There are a number of different constraints associated with mobile terminals as an obstacle in figuring out the final model of Internet mobile ad-hoc networks. Not all mobile terminals can access the Internet. Due to mobility, a set of mobile terminals can be separated from the rest of the network and get disconnected from the Internet. Finally, a mobile terminal requiring multi-hop connection to access the Internet may incur longer access time than those that have direct access to the Internet. Resolution of these issues could provide a good means of information access over the Internet in a highly dynamic environment.
.BIO
