Design And Realization Of A Small Wireless Ad Hoc Network Based On Multi-Channels

Ad Hoc wireless networks are self-organizing, self-configuring and instantly deployable in response to application needs without a fixed infrastructure. Because of these characters, Ad Hoc network can be widely used in military, sensor network, emergency and personal area network. Researches on Ad Hoc network have been widely developed in all over the world and a lot of results have been achieved. But because of the particularity of Ad Hoc, there is still no one solution that can be suit for all the situations. These achievements can only be useful in one particular scene or some scenes. After discussed about the special characters about the Ad Hoc network, this paper introduced the method to design and realize a small Ad Hoc network based on multi-channels. Each node of the network uses MSP430F149 of TI as the MCU and nRF905 of Nordic as RF IC. In data link layer, a MAC protocol based on multi channels is used. That is, there are one control channel and several communication channels. A mechanism called CTS/RTS/BROAD/DATA/ACK is used. During communication, the two nodes should first shake hands in the control channel, then transfer the data in a chose communication channel. Collisions inside the system can be avoided effectively in this way. In net layer, the fisheye state routing is used. The network is divided into multi-level fisheye scope to reduce routing update information. Nodes exchange link state entries with their neighbors with a frequency which depends on the distance to destination. From link state entries, nodes construct the topology map of the entire network and compute optimal routes. And in the last of the paper, the future developments of the system are discussed.