Research On Power Control Technologies In Wireless Communication Systems

Transmit power is an important resource in the wireless communication, and how to takeadvantage of the power resources to improve the capacity of the system performance hasbecome a hot research subject for many years. The reasonable power control and powerallocation scheme can effectively improve the performance of wireless communicationsystems. The system can satisfy the communication quality on the minimum transmissionpower by power control, while reducing the waste of radio resources and improving theresource utilization. Through the rational allocation of power, it can effectively improve thecapacity of the system to meet the needs of users on a variety of business. In this paper, itstudied on the power control in MIMO systems and the power allocation strategy indistributed MIMO system, the major elements as follows:Firstly, the development of wireless communication system was introduced, and then theresearch status of power control technology was described. Characteristics of the transmissionchannel are analyzed in the wireless communication system, and the basic principle and theframe structure of the MIMO system has been studied. The distributed MIMO system has agood coverage performance compared with the centralized MIMO system, and it can increasethe channel capacity of the system.Secondly, various power control method and power control should follow the guidelineswere described in wireless communication system. Distributed power control technology wasstudied in MIMO system, distributed power control algorithm based on the SIR was proposed.We have adopted the average signal-to-interference ratio (SIR) outage probability of thereceiving end as indicators to measure the performance of the algorithm. This algorithmminimized the outage probability of the receiving SIR in the end. Through the simulation ofthe algorithm, we compared it with the centralized power control algorithms and the unusedpower control algorithms. The results show that the performance of the two power controlalgorithms is superior to no power control. Meanwhile, the performance of the distributedpower control algorithm is slightly lower than the centralized performance, but almost close.The complexity of this algorithm is much less than the centralized power control algorithm,easier to implement, the outage probability in the receiving end can meet the demand of thesystem.Finally, power allocation algorithm in system was studied, the principle of equal powerallocation algorithms and water-filling power allocation algorithm were analyzed, and tomeasure the performance of the system with the traditional MIMO system by capacity of the channel. At the same time, we conducted the water-filling power allocation algorithm andequal power allocation algorithm in the traditional centralized MIMO system, and comparedthe performance.The results show that the system capacity of the water-filling powerallocation algorithm is advantage. Then the performance of two different power allocationalgorithms was simulated in distributed MIMO system. Through the comparison of capacitywith the traditional MIMO system, the capacity of the distributed MIMO system higher thanthe traditional centralized MIMO system, regardless of equal power or water-filling powerallocation algorithm used.