Intra-Cell Interference Mitigation Scheme In Lte-Hi System

With the development of mobile Internet, people are more and more into data services. Thus, the data throughput is explosively increasing, and most of the data throughput appears in indoor and hotspot scenarios. However, the wireless spectrum is a scarce resource, and the bandwidth available for network operators cannot increase without limitation. Therefore, how to improve the system performance and support hotspot based services has become one of the most important research points in recent years.Long Term Evolution based Hotspot improvement (LTE-Hi) is considered to be a potential resource reuse technology, which can support hotspot based services and increase the system capacity. With high-density and low-power nodes, cellular networks with LTE-Hi will be able to achieve higher capacity and spectrum efficiency. LTE-Hi network and Macro cellular network work on adjacent channels with a high isolation, resulting in no co-channel interference between the two networks. In addition, dynamic TDD, which is the most important one among the key technologies of LTE-Hi, switches the configuration of the frame structure in physical layer, in order to adapt to the traffic demand in the network. The traffic adaptive scheme improves the system flexibility and thus improves the system performance.Although LTE-Hi networks have many advantages, there are also challenges in LTE-Hi networks. Dynamic TDD makes it more complex to solve the interference problem, as it brings the improvement in the system performance. The traffic adaptive scheme may result in the opposite transmission directions in neighboring cells, which will further cause the successive interference between the neighboring base stations. The intra-cell interference will influence the quality of communication and degrade the system performance.In this paper, we focus on the interference mitigation schemes in LTE-Hi networks. First of all, we evaluate the performance gain of introducing dynamic TDD. We design two schemes using dynamic TDD, which are based on resource block utilization and service priority respectively. The performance of the two schemes is evaluated and compared through both theoretical analysis and system-level simulation. The simulation results show that the schemes based on dynamic TDD can bring the performance gain and different schemes should be chosen with different service types. Then, the reason for the intra-cell interference in LTE-Hi network is analyzed. Based on that, two kinds of interference mitigation schemes are summarized. One is based on limiting the flexibility, and the other is based on limiting the interference impact. The performance of different interference mitigation schemes are evaluated, and the results show that all the interference mitigation schemes can achieve the performance gain, and different schemes fit different scenarios. Finally, we analyze the trend of the research on LTE-Hi network.