Research On Interference Management In LTE-A

By adopting OFDMA technology, LTE-A can provide orthogonal sub-carriers and maintain the orthogonality of inter-symbol, therefore, the inter-symbol interference(ISI) can be avoided effectively and the system throughput can be improved significantly. However,inter-cell interference (ICI) usually has a strong influence on the data rate to the cell-edge users,at the same time, because the scarce of the spectrum resources,the interference between femtocell and macro-cell will also reduce the throughput of the system. This paper mainly conducts the research about the interference in the LTE-A system, as well as carries out further reflection and work on the inter-cell interference and the interference between femtocell and macro-cell.For the inter-cell interference problem, this thesis tries to improve a kind of coordinated beamforming algorithm to settle the interference between intra-cell users and inter-cell users. The main improvement is that a cooperation model with limited base stations is propounded, and under this model to realize the interference elimination between inter-cell users and intra-cell users by adopting coordinated beamforming technology. Compare with the model without coordination, this algorithm can improve the throughput when SIR is small. Aiming at the interference problem after the femtocell is introduced into LTE-A, this thesis puts forward a multi-service and cross-layer resource allocation algorithm between macro-cell and femtocell. This method considers that some femtocells are distributed in a macro-cell, each macro user and femto user have their own QoS requirements. The adopting of the resource allocation algorithm makes every user can meet their own QoS requirements in the allocated recourses block and avoid the interference with other users, thereby improve throughput of the whole system.