The Power Control And Cooperative Communication In Ad Hoc Network

Ad hoc network is a self-organizing center-without and multi-hop wireless network. It does not have any fixed-based facilities at any time and can set up a temporary network. Because of this convenience, and with the wireless communication technology and mobile terminal performance improvement, especially for the personal communications' growing, it makes mobile Ad hoc network application gradually be extended. However, it is a new network, there are still many problems. New applications continue to set new challenges to its research and development. As the network, most of whose nodes use a battery as power, this restricted the practical application of Ad Hoc networks, thus needs to do research on energy saving problem in Ad Hoc networks.In this paper, we investigate the energy saving problem in mobile Ad Hoc network. Using the mixed methods of energy saving, on one hand, we give out an improved variable-range transmission power control algorithm based on minimum spanning tree algorithm (MST) to provide energy saving on network layer. On the other hand, we save more energy through data link layer without changing the topology of the network.Using previous work by Gomez and Campbell [1], we show that in consider of node's mobility, the previous variable-range transmission power control based on minimum spanning tree algorithm can not support nodes' mobility in mobile ad hoc network. So, we give out an improved variable-range transmission power control algorithm to support node's mobility and solve asymmetric graph problem. Furthermore, we give out a new method of network topology updating, which can reduces the amount of computation dramatically.To save more energy without changing the topology of the network, we give out two new data transmission mechanisms based on the idea of cooperative communication. We compare these two data transmission mechanisms with traditional data transmission mechanism by Markov random process, and prove their superiority in energy saving. Finally, we prove the correctness of our theory by software imitation and numerical simulation.The results of this paper enhance the possibility of using variable-range transmission power control in Ad hoc networks and give out a practicable cooperative communication mechanism. Furthermore, we point out some unsolved problems and give out some recommendations.