| Limited frequency resource becomes the leading factor to hamper the improvement of the system performance along with the development of mobile telecommunication. How to improve the frequency efficiency is one of the most popular topics. In LTE systems, since OFDM technology provides orthogonal sub-carriers, intra-cell interference is avoided. However, in a mull-cell scenario, inter-cell interference will degrade the system performance, especially for cell-edge users. Therefore, it is motivated to mitigate the inter-cell interference in order to attain the high frequency efficiency and system capacity.Two inter-cell interference control schemes have been studied and analyzed in the thesis. After introducing traditional beamforming techniques, Pareto boundary and virtual SINR beamforming, a novel multi-cell joint beamforming algorithm is developed under the condition that base station doesn't know the whole channel state information. The algorithm apparently decreases cell-edge users'interference, improves SNR and system capacity. Next, based on SFR, a novel power control algorithm is designed to help the interference coordination, which leverages the power level between SINR and interference at eNodeB. |
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