Interference Suppression Research Of Small Cell Based On Lte

As a effective and new technology, small cell is used to coverage the holes and weak zone in LTE system, and it play a good job in sharing load. However, due to the deployment of a large number of small cell, it has changed the network structure from single network into double network which contains macrocell and small cell, so the interference also changes. The single interference among macro has changed into macrocell and macrocell, small cell and small cell. So, it is significant to study the interference suppression in Hetnet.Based on the problem of interference and low spectral efficiency in femtocell, according to the existing slotted soft frequency reuse scheme, this thesis presents a spectrum allocation algorithm which using soft frequency reuse. This algorithm is divided into three steps, the first two are the spectrum allocation of macrocell and Hetnet. The main contents of these two steps are to determine the optimal threshold of SINR on macrocell and assign a full band for the Hetnet which on the edge of a macrocell base station. Because of the orthogonality of the edge femtocell between macrocell and the femtocell between femtocell, coupled with the large-scale fading characteristics of the femtocell, so it solve the problem of interference perfect.In addition, due to the low utilization in the existing network, I improve the subcarrier allocation based on the above two steps to increase the spectrum efficiency. This method is improved on the Round Robin. Set a new approach for transmission depend on SINR. This algorithm requires a user who has high SINR to use the subcarriers that has good Channel quality, so it ensure a high spectral efficiency, not only increasing the SINR, but also improving the system interference.Then, I simulated the interference and throughput for the original algorithm and existing algorithm by using MATLAB. The results show that both algorithms can be more effective to suppress interference and improve the throughput of the system.Finally, the thesis gives the interference deployment recommendations of small cell in China Unicom, which based on the test of small cell interference scenario in China Unicom in2013.