| With the development of wireless networks, cellular wireless network's structure becomes more and more complex; the traditional manual planning cannot meet the requirements of the wireless network. Wireless network planning by computer has become a trend. The wireless network planning software provides implementation of planning scheme by coverage prediction module and capacity simulation module for network planning engineer. Capacity simulation which provides network interference situation, system capacity and other important indicators, is one of the important functions providing by wireless network planning software. Capacity simulation of wireless network planning software is a system level simulation, its accuracy decides by power control algorithm. Power control algorithm can be divided into several classifications, such as open-loop power control, closed loop power control; or centralized power control and distributed power control and so on. Power control guidelines are also diverse, mainstream way of guidelines are balance of power and balance of signal to noise ratio. System-level simulation's power control algorithm research in wireless network planning software is different with link-level simulation's power control research. It does not concern the concrete realization of the link layer, but also focus on power control steps, step and convergence criteria and other factors, and because of the capacity simulation in the wireless network planning software usually calculate on a large area, power control algorithm's performance is very important. This article describes the power control algorithm in software implementation, the interaction with other module, its own sub-module division and the basic processes. On this basis, we research three power control algorithm's implementation, there are power control algorithm which using power balance criteria and fixed step, power control algorithm which using variable step guidelines and power control which using joint power control criteria and variable step. This article describes the scope of application of the three algorithms, and its implementation, analysis its performance through comparison of simulation results. Finally, this article studies the step factor which affects the convergence and performance, and analysis the criteria which affect accuracy of power control. |
