Power Control Based On Channel Probing And Multiple Controllers Switching In Ad Hoc Networks

ABSTRACT:Ad Hoc wireless network is characterized by the facts that they are capable of operating without the support of any fixed infrastructure and they can be setup quickly and flexibly. As a new branch of the wireless communication technologies, Ad Hoc network has been developed rapidly and widely used in both military and civil applications. As the network nodes are generally limited by the energy of the battery power, Ad Hoc networks are facing challenges such as lifetime, throughput, network capacity, delay and so on. Therefore, power control in Ad Hoc Networks is an important direction. In this research, power control problems of Ad Hoc networks are discussed from the view of control theory, and control theory methods are used to solve the problem of MAC (Medium Access Control) layer transmitter power dynamic adjustment.Focusing on the practical application of Ad Hoc networks, Ad Hoc Network development history, architecture and future applications are introduced. The power control schemes based on the communication technology and control theory are introduced, and their advantages and disadvantages are discussed, too. Then, the Ad Hoc network performance evaluation indices of power control are summarized, and the performance of several power control methods are evaluated by these performance evaluation indices. A channel probing approach is introduced, which can make fast and accurate estimation by transmitting power signals. Based on multiple controllers adaptive switching control method utilized in wireless network power control, a combination method of channel probing and multiple controllers adaptive switching method is proposed. Multiple controllers switching method with channel probing using accurate information of time-varying network environment, transmitter power can quickly converge to the optimal value, while improving other aspects of network performance. In order to prevent the disturbance of controller output from affecting the stability of the system when the controllers switch, a bumpless transfer method based on slow-fast decomposition is introduced to improve the transient response of the system.Finally, to verify the performance the algorithm above in a real network, a simulation software named NS2 which can simulate the real network is used. Simulation results show that adding channel probing to multiple controllers switching can make the transmitter power convergence faster, thus the overall network performance can be increased.