A wireless ad hoc network is a decentralized wireless network.^[1] The network is ad hoc because it does not rely on a preexisting infrastructure, such as routers in wired networks or access points in managed (infrastructure) wireless networks. Instead, each node participates in routing by forwarding data for other nodes, and so the determination of which nodes forward data is made dynamically based on the network connectivity.

The earliest wireless ad hoc networks were the "packet radio" networks (PRNETs) from the 1970s, sponsored by DARPA after the ALOHAnet project.

Contents 1 Application 2 Medium Access Control 3 References 4 External links

[edit] Application

The decentralized nature of wireless ad hoc networks makes them suitable for a variety of applications where central nodes can't be relied on, and may improve the scalability of wireless ad hoc networks compared to wireless managed networks, though theoretical^[2] and practical^[3] limits to the overall capacity of such networks have been identified.

Minimal configuration and quick deployment make ad hoc networks suitable for emergency situations like natural disasters or military conflicts. The presence of a dynamic and adaptive routing protocol will enable ad hoc networks to be formed quickly.

Wireless ad hoc networks can be further classified by their application:

• mobile ad hoc networks (MANETs)
• wireless mesh networks
• wireless sensor networks.

[edit] Medium Access Control

In most wireless ad hoc networks the nodes compete to access the shared wireless medium, often resulting in collisions. Using cooperative wireless communications improves immunity to interference by having the destination node combine self-interference and other-node interference to improve decoding of the desired signal.

[edit] References

1. ^ C K Toh, Ad Hoc Mobile Wireless Networks, Prentice Hall Publishers , 2002.
2. ^ P. Gupta and P.R. Kumar. Capacity of wireless networks. IEEE Transactions on Information Theory, Volume 46, Issue 2, March 2000, doi:10.1109/18.825799
3. ^ Jinyang Li, Charles Blake, Douglas S. J. De Couto, Hu Imm Lee, and Robert Morris, Capacity of Ad Hoc Wireless Networks, in the proceedings of the 7th ACM International Conference on Mobile Computing and Networking, Rome, Italy, July 2001

[edit] External links

• Guide to creating an ad hoc network
• The Mesh DebateDailywireless Article on Structured mesh network scalability.