Transmission Capacity And Multihop Routing Protocol For Ad Hoc Networks

The classical Shannon information theory provides a significant guideline and motivation for the development of the communication technology. One of the essential parts of the Shannon Information Theory is channel capacity, which defines the achievable and unachievable bound for the reliable data transmission rate on the physical link. The famous Shannon channel capacity formula works as the great guideline for the research on communication theory and the developing of the high rate communication device. With the thriving of the wireless mobile communication technology, people are requiring a growing number of information from the wireless network. Therefore, it is the long-term goal for researchers to try to generalize the Shannon Information Theory on a single link to the wireless networks made up of many communication nodes (containing multi-transmitters and multi-receivers, the interference and cooperation among them) and thus guide the optimization research for wireless network.Combining with this research demand in wireless communication field, this thesis chooses the Ad hoc network as the research object and derives the network capacity, by using both of the mathematics analysis and numerical simulation method. I divide the work in this thesis into two main lines.The first line is the single hop network, which is further divided into single network and overlaid networks. Combing the spread-spectrum modulation method (FH-CDMA and DS-CDMA) and using the stochastic geometry theory, I derive the asymptotical results for the transmission capacity of the single network. Further, I analyze the effects of small-scale Rayleigh fading and Channel Inversion power control on the transmission capacity. The second line is the multihop network. In multihop networks, routing protocol is the prerequisite for networks to realize the multihop transmission. Therefore, based on the thought to optimize the multihop network capacity, I propose a novel relay region based routing protocol for multihop networks and derive the optimization results for the parameters used in this routing protocol. In the analysis, I derive the results for the conditions of omnidirectional and directional antennas, respectively. The results show that using the directional antenna can increase the network capacity.