With Varying Delay Cdma Adaptive Power Control And Its Matlab Simulation

CDMA (Code Division Multiple Access) technology is one of the most important technologies in wireless communication systems, and it is the key technology for3G and4G communications. Thus, how to improve the performance of CDMA system and increase the user capacity is a hot topic in the wireless field. In order to minimize the various interferences in CDMA wireless communication system and improve the system performance, many kinds of technologies are adopted, such as RAKE receiver technology, smart antenna technology, and so on. Power control technology is also one of these technologies to improve system performance.A better power control to the BS (base station) and MS (mobile station) can improve the communication quality and reduce the battery's consumption. However, there is little power control method which can propose a better solution to the problem of parameter uncertainty and time-varying delay.This paper develops adaptive power control to CDMA wireless systems with uncertainty parameter and time-varying delay. The adaptive power control algorithm presented here is based on channel parameter and time delay estimations. It can estimate the time-varying delay and the parameter uncertainty effectively, and adjust the power stably as well as fleetly.The algorithm is proposed in three steps:first, analyze the SIR mathematics model of CDMA wireless communication system, and get the generalized iteration system model which can be used in Least Squares algorithm; second, estimate the system delay time as well as the system parameters are estimated, then calculate the adaptive control law according to the estimation results; finally, do the simulation work to demonstrate the effectiveness of the proposed algorithm.Simulation results show that the proposed algorithm can estimate and compensate for the affects of time-varying delay and parameter uncertainty rapidly. It can also adjust the transmission power smoothly and fast.