Wireless Mobile Network Link Layer Cross-layer Piggyback

The ad hoc network is one of the most popular projects in nowadays, and the researches are mainly focusing on the MAC protocol and routing protocol design. Since the ad hoc network is a self-organizing, infrastructure less, multi-hoping and distributed network with a dynamic topology, the route protocol design in mobile network would be very different than the one in the regular wired network. Hence, the design pattern in wired network would not suitable for the mobile route protocol. Between the numerous key technologies of the mobile route protocol, the control spending problem would be an important one, as the wireless channel has its own characteristics, like narrower bandwidth, lower data rate and higher bit error rate .etc. On the other hand, the routing protocol will have to send out a mass amount of controlling packets like route updates, in order to set up a route and maintain it. And these packets are always short ones, comparing to the application data packets. If the network is crowded with these short packets, the natural transmission of the application data would be badly interfered. One solution to this problem is to reduce the quantity of the short packets in the network.The piggyback technology has been used in the wired network. A good example would be the piggybacked acknowledgement in TCP. And in a national 863 project, the"piggyback technology in the link layer"technology has been brought forward. It has been applied to an ad hoc network based on the ultra short radio and frequency-hopping broadcasting station, and earned a good evaluation. One of the mainly focus of this paper would be the use of piggyback technology in some different link layers, such as IEEE 802.11. The piggyback is used to decrease the number of short packets in the network, and to reduce the network controlling spending.Another research work would be the cross-layer designing, which is used to make the link layer piggyback technology to carry the route information in the network layer, and try to cut down the magnitude of the route packets in transmission. By this method, this paper is hoping the route cost will be hold in a lower level. Aiming at the problems showing above, this paper put forward a cross-layered data-link piggyback technology, and gives a fine designing plan. At the end of this paper, in the interest of verify the design purpose, this paper edits the AODV protocol in the NS-2 simulation tool, and carry out a sound wireless scenario to perform the simulations. The simulations results will be set out in this paper and validate the designing plans.