Protocol Design And Research In Multi-Channel Wireless Ad Hoc Networks

In wireless Ad hoc networks, using multi-channel technique to increase the network capacity is a promising technology. We aim at utilizing multi-channel technique to improve the performance of network in bandwidth resource utilization, network throughput and so on. We mainly research on design and realization of multi-channel MAC protocol as well as routing protocol. By using the NS-2 simulation platform, we validate the proposed protocols while considering the performance indexes of network throughput, packets loss rate and bandwidth resource utilization. Simulation results show that the proposed protocols can achieve better performance comparing with both the traditional single-channel protocols and existing multi-channel protocols. The main research contents are as follows:First, we survey the development status and foreground of both MAC protocols and routing protocols design in multi-channel wireless Ad hoc networks. And then we analyze the problems and requests in the design of multi-channel MAC protocols and multi-channel routing protocols.Second, we design a busy tone-based multi-channel MAC protocol by using the RTS/CTS mechanism of IEEE 802.11 standard. The proposed protocol can overcome the multi-channel hidden terminal problem and Deafness problem and it can significantly improve the network throughput by using busy tone interface which can send busy tone signal to distribute the multiple channels. On the basis of the proposed protocol, we design a channel bandwidth-division scheme which divides a single channel into several orthogonal sub-channels. Simulation results show that using the technique of channel bandwidth-division can significantly improve the network performance without increasing the total bandwidth, since the collision probability can be reduced by bandwidth-division. It is also showed that even under the single-channel case, the proposed busy tone-based multi-channel MAC protocol can also obtain better performance comparing with the traditional 802.11 protocol.Third, to overcome the lack of researching on cognitive ability and bandwidth adaptive allocation in multi-channel MAC protocols, we propose a cognitive wireless networks multi-channel access algorithm based on the classical multi-channel MAC protocol LCM-MAC. Then, considering that the different real-time network traffic loads will require different bandwidth on each channel, we put forward an adaptive channel bandwidth allocation model. Combining with the adaptive channel bandwidth allocation model, the proposed cognitive multi-channel access algorithm realizes the adaptive bandwidth allocation according to the factors of network traffic loads, the changing of packets loss rate and the fairness of the bandwidth allocation. Simulation results validate the effectiveness of the proposed cognitive multi-channel LCM-MAC protocol as well as the channel bandwidth allocation model. It increases the network throughput performance and reduces the packet loss rate at the same time.Fourth, we analyze the realization process of single-channel AODV routing protocol, and then extend it to a multi-channel AODV routing protocol which can be applied in wireless Ad hoc network. Simulation results validate the multi-channel AODV protocol which can improve the network throughput performance efficiently.