Interference Evaluation And Interference Suppression For Heterogeneous Network

Based on the requirements for higher data rates and wider bandwidth in the telecommunication industry,3GPP has been promoting the standardization of LTE/LTE-A. In order to support this galloping demand for data traffic, heterogeneous network (HetNet) has drawn the attention of3GPP LTE-A standardization. It can increase the system throughput, enhance the cell edge performance and improve the network energy efficiency. From Release10up to Release12, HetNet has always been one of the key issues discussed by the companies and research communities.According to the fast development of the current mobile communications and the backup of laboratory’s projects, the thesis mainly focuses on the interference evaluation and interference management of macro-pico, macro-micro and macro-small cell scenarios. The main research achievements of this thesis include the following aspects:This thesis first researched on the interference situation of macro-pico, macro-micro and macro-small cell coexistence scenarios. In the macro-pico scenario, the impact of CRE and ABS techniques was evaluated. Simulation results showed that the introduction of CRE can increase the footprint of pico and thus realize network load balancing. And ABS can protect the pico users from macro interference, improve the signal quality and therefore enhance the network performance. In the macro-micro scenario, reference sensitivity and blocking levels are simulated and according to the results, both of the above two parameters were given a certain value. In the macro-small cell scenario, both co-channel and separate-channel scenarios were taken into consideration. Simulation results showed the figures for the user ratio and system throughput. And on the basis of the analysis, it was recommended that when setting the actual deployment, we should take user demands and spectrum efficiency into consideration.Based on the above work for interference, the thesis investigated the interference suppression schemes for macro-pico and macro-small cell coexistence scenarios. In the macro-pico scenario, the thesis proposed a new coordinated interference management scheme to improve the signal quality of the pico users. The proposed method is to coordinate frequency and power resources within a set of resource allocation restrictions. Based on the3GPP LTE-A standardization, systemlevel simulation results show that compared with alternative approaches, the proposed method can mitigate outages, improve cell-edge UEs’performance and bring a significant increase in overall system throughput. In the macro-small cell scenario, the thesis introduced a dynamic power control scheme for small cells to handle the interference, HO and energy consumption problems. The proposed scheme initially exploits the Voronoi diagram to achieve maximal small cell coverage with minimized maximum required transmit power, which can reduce intra-layer interference. And then a location based dynamic power control scheme is applied for the transmit power setting to tightly serve the users, which can not only guarantee the Quality of Service (QoS) of the cell edge users but also decrease the network energy consumption. System level simulation results show that compared with alternative approaches, the proposed scheme can bring a significant increase in system throughput, reduce system outage probability as well as enhance the network energy efficiency.