- Wireless ad hoc network
A wireless ad hoc network is a decentralized
wireless network. [C K Toh, [http://www.informit.com/store/product.aspx?isbn=0130078174 Ad Hoc Mobile Wireless Networks, Prentice Hall Publishers ] , 2002.] The network is ad hocbecause each node is willing to forward data for other nodes, and so the determination of which nodes forward data is made dynamically based on the network connectivity. This is in contrast to wired networks in which routers perform the task of routing. It is also in contrast to managed (infrastructure) wireless networks, in which a special node known as an access pointmanages communication among other nodes.
The earliest wireless ad hoc networks were the "
packet radio" networks (PRNETs) from the 1970s, sponsored by DARPA after the ALOHAnetproject.
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 [P. Gupta and P.R. Kumar. [http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel5/18/17872/00825799.pdf Capacity of wireless networks] . IEEE Transactions on Information Theory, Volume 46, Issue 2, March 2000, doi|10.1109/18.825799] and practical [Jinyang Li, Charles Blake, Douglas S. J. De Couto, Hu Imm Lee, and Robert Morris, [http://pdos.csail.mit.edu/papers/grid:mobicom01/paper.pdf Capacity of Ad Hoc Wireless Networks] , in the proceedings of the 7th ACM International Conference on Mobile Computing and Networking, Rome, Italy, July 2001] limits to the overall
capacityof 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.
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 communicationsimproves immunity to interference by having the destination node combine self-interference and other-node interference to improve decoding of the desired signal.
[http://jamus.dannz.net.nz/technology/adhoc.htm Guide on making an ad hoc network]
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