Research On Inter-cell Interference Coordination Of LTE-Advanced System

In response to the trend of mobile, broadband and IP technology of global wirelesscommunications, and compete with emerging technologies, such as WiMAX and Wi‐Fi, 3GPPproposed the 3G long‐term evolution (LTE) at the end of 2004. The orthogonal frequencydivision multiple access (OFDMA) adopted in the downlink of LTE has no capability to mitigatethe inter‐cell interference. Therefore, effective measures must be taken to mitigate inter‐cellinterferences. In this thesis, the inter‐cell interference coordination (ICIC) techniques aresimulated and analysed, and the major work can be reflected in the following three parts.In the first part, some widely discussed interference coordination technologys are given,among which the soft frequency reuse (SFR) proposed by Huawei is very popular.This thesisanalyzed the main parameters that influence the SFR system,and by changing the parameterswe can see the throughput of cell edge and cell center change too. It is shown that the systemperformance is greatly improved by using interference coordination technology; in the realsystem different traffic demands should be taken into account to allocate the bandwidth andpower, so that system performance can get maximal improvement.In the second part, some key technologies introduced in LTE‐Advanced system are analyzed,among which coordination multi‐point (CoMP) transmission and relay can be considered aseffective techniques to improve cell edge throughput. Interference coordination in downlinkLTE‐Advanced can be realized by Joint Processing/Precoding, so this thesis analyzed precodingalgorithms of CoMP transmission system, including ZFBF, MMSE, and BD. From the simulationresults we can see that coordination transmission can effectively improve the performance ofcell edge users.The third part gives a relatively new scheme that combines the Fractional Frequency Reuse(FFR) and coordination transmission. The traditional frequency reuse schemes are not suitablefor coordination transmission, therefore we can devide a cell into three sectors, so as to fullfillthe requirements of coordination transmission. Through the simulation we can see that theproposed scheme performs better in system capacity.