The Research Of Uplink Power Control On LTE System

With the development of wide application of mobile multimedia service and progress of various communication field, data services are explosive growth.Meanwhile, the popularity of smart terminals increased year by year, taking up the mobile communication network resources increasingly heavy, but the spectrum resources are limited. Therefore, On the basis of the 2nd Generation Mobile Communication(2G) and the 3rd Generation Mobile Communication(3G), the 3rd Generation Partner Project(3GPP) further launched Long Term Evolution system(LTE) project. LTE is a wireless communication system which provides lower transmission delay, higher data rate, wider bandwidth and better quality of service(Qo S). The user experience has greatly been enhanced.The uplink used single carrier frequency division multiple access(SC-FDMA) in LTE, the uplink signals of different users are orthogonal to each other in the cell. So there is no near-far effect as the Code Division Multiple Access(CDMA) system. The main purpose of LTE uplink power control is not to overcome the near-far effect, but to compensate the path loss and shadow loss of the channel, and to suppress the inter-cell interference.Until now, there are still some problems remain unresolved on uplink power control technology. Firstly, the existing power control algorithm set different target SINR values for different users based on path loss that the user to the serving cell. But user at the cell edge does not fully take into account the interference to neighbor cells, which result in lower cell throughput. Considering existing inter-cell power control algorithms, the adjusted quantity of power control is lack of flexibility, power control algorithms can not quickly and accurately track the change of interference, which affects the expectation of power control on the inter cell interference suppression, and ultimately affects the performance of the system.This paper mainly studies the uplink power control algorithm of LTE. Firstly, combined with the existing power control algorithms, the traditional power control algorithm, the partial path loss compensation power algorithm, and the path loss difference power control algorithm are studied and analyzed. On the basis of the path loss difference power control algorithm, the power control algorithm based on interference information is presented for the inter cell interference. The proposed new algorithm with the existing partial compensation power control algorithm and the path loss difference power control algorithm are simulated, Performance of user throughput and inter-cell interference between is analyzed and compared. Theory analysis and results of MATLAB system level simulation show that this new algorithm can reduce inter cell interference and improve the total cell throughput to a certain degree.