Research On Interference Management Coordination In 5G Utral Dense HetNets

In December 2014, Next Generation Mobile Network(NGMN) published the 5G whitepaper. In the whitepaper, NGMN envisions 5G as a dense heterogeneous network combined with various radio access technologies, which includes both Macro-eNB with a basic signal coverage and small-eNB with a better signal quality in hot-spot. Among the mass of lower power network nodes, some of them may be set to opened subscriber group, and the others are set to closed subscriber group. Hence, the characteristic of the whole network will become extremely complicated. This thesis focus on the downlink interference coordination management in dense heterogeneous network, which is one of the key technologies of 5G network evolution.This thesis summarizes usual interference coordination schemes in the past research, and expounds the basic idea and deployment environment of different schemes from timedomain, frequency-domain and space-domain. Then, advantages and disadvantages of those schemes are pointed out after a series of comparisons of major parameters in schemes. Meanwhile, basing on the present technologies development and research, this thesis also offers a brief analysis about future development of interference coordination management.To eliminate interference from pico evolved Node with the closed subscriber group control, a dynamic load-aware-based enhanced inter-cell interference coordination(eICIC) scheme was proposed. Firstly, the scheme forecasts network load by the Markov chain model. Hence, the incorrect configuration of almost blank subframes(ABS) caused by time latency in the LTE system can be avoided. Such incorrect configuration reduces system capacity. Secondly, the scheme is used to reconfigure ABS dynamically based on the forecasted Markov chain. An optimized system model based on dynamic reconfiguration of ABS is proposed to maximize system throughput. Simulation demonstrates that the proposed scheme do increase overall system throughput significantly compared with traditional eICIC schemes.The Ultra-dense Heterogeneous Network(HetNet), which consists of macro-cells and pico-cells, has been recognized as a key technique to improve network performance. However, the increasing number of pico-cells also causes severe interference including inter-cell interference and intra-cell interference. Therefore, interference management has become an important issue in ultra-dense HetNets, and the traditional enhanced inter-cell interference coordination(eICIC) scheme is no longer fit for the high density of small cells. In this paper, a hybrid interference management method based on dynamic eICIC and coordinated multi-point transmission(CoMP) is proposed. Firstly, a virtual cell is established based on the characteristics of ultra dense HetNets. Then, a novel joint dynamic eICIC scheme combined with multi-user beamforming is deployed to eliminate the intercell interference, and improve the throughput of virtual cell significantly without sharp decrease of throughput of macro-cell. Furthermore, a virtual cell based joint transmission scheme is deployed with a power control algorithm, which can obviously increase the spectrum efficiency of virtual cell edge. Simulation results verify that the proposed scheme can achieve better spectrum efficiency both at macro-cell and virtual cell edges, and the network throughput is also improved.