Research Of Uplink Interference Mitigationin Long Term Evolution

Along with the development of mobile communication, high data-rate transmission becomes the target that several standard organizations pursuit. And improving efficiency and expanding the spectrum can helps to reach such a goal. As broadband wireless technology mature gradually, the 3GPP need to have a broadband standard of its own. In order to cater to such development concept, a more competitive and more revolutionary concept, the Long Term Evolution system was put forward by 3GPP in 2004.In order to realize the target of high frequency efficiency and capacity, LTE system needs efficient solutions to deal with the interference within the system. OFDM technology adopted by the LTE system can provide orthogonal sub-carriers, so intra-cell interference can be avoided. However, due to the limited frequency resources, the cells in the LTE system need to reuse the frequency resources, and the inter-cell interference is unavoidable. The inter-cell interference relates to the whole system performance and efficiency. So the inter-cell interference problem has become a hot points during the 3GPP meetings, also it will affect the realization of LTE system.Different kinds of inter-cell interference management schemes have been proposed by many companies. The schemes proposed first were mostly based on the frequency reuse. As the deepening of the research, the emphasis is transferred to power control schemes. Thereafter, the methods based on the power control or frequency reuse have become the main means to depress the interference. In this paper we studied from this two aspects, and put more emphasis on the power control. We compare three different power control algorithms, then simulate and analyze their performances. Based on the intra-cell power control algorithm, we propose a novel power control scheme on the basis of inter-cell interference information. The simulation results show that the scheme we proposed can improve the system capacity and the performance of the cell-edge users. For the Overload Indicator is one of the signaling carrying the interference information, we optimize the format of OI and simulate the performance differences. The work for LTE-Advanced standardizing begins as soon as the standard work of LTE has been finished. Due to new service points such as relay introduced, the interference environment of the system varied. New methods were proposed for different occasions. We propose that the original access method could not fit the new system, for the new service points change the interference environment a lot. We suggest another three methods to replace the original one and give the simulation results.