Research Of Key Technologies On Radio Resource Management In LTE-A Heterogeneous Network

In order to meet the requirements of higher data rate and lower delay in the next generation wireless communication system,3GPP proposed LTE and LTE-A. As the smooth evolution of LTE, LTE-A introduced some key technologies such as carrier aggregation, CoMP and heterogeneous network, which further improve the system capacity and expand the network coverage as well. By deploying low-power nodes such as home eNB, pico eNB, relays in the coverage of macrocell, heterogeneous network can effectively improve the spectrum efficiency, reduce the load of MeNB and eliminate the coverage hole. Heterogeneous network brings a very good gain for the system. However, it also brings some drawbacks, such as the complexity of the network architecture makes the inter-cell interference more complicated. So the radio resource management in LTE-A becomes a new research topic.To solve the cross-tier interference between MeNB and low power nodes, Time domaion elCIC and frequecy domain eICIC were proposed in3GPP R10, while FeICIC was proposed in R11. This paper mainly studies frequency domain eICIC and FeICIC which is based on LP-ABS in Macro-Pico scenario.Firstly, a power control scheme which is based on the modified frequency-domain eICIC is proposed to improve the utilization ratio of resources. By adjusting the price and power of each sub-channel on the low power band, Macrocell and picocell can reach Stackelberg equilibrium and finally realize the maximization of system efficiency. Simulation results show that the proposed scheme can improve UE average data rate effectively compared with fixed power allocation scheme.Secondly, to guarantee MUE’s minimum data rate and protect ER PUEs from excessive cross-tier interference, we propose a novel subchannel and power allocation scheme aiming at maximizing the throughput of MUEs on LPB. It is modeled as a non-convex optimization problem then transformed into a convex problem and solved by dual decomposition method. It is shown that the proposed algorithm can converge to the optimal value with a small number of iterations and achieve substantial transmission rate gains over the existing suboptimal EPA-SSA algorithm.Finaly, the strategy of LP-ABS power arrangement and resource allocation in FeICIC was researched. Assuming that LP-ABS power has positive correlation with its coverage area, we formulate the resource allocation problem into a network throughput optimization considering both of LP-ABS power and sub-channel, and then propose a suboptimal resource allocation scheme. We divide the primal problem into several subproblems and conduct the subchannel allocation using the Faireness Guranteed Subchannel Allocation algorithm. Compared with traditional eICIC, the proposed resource allocation scheme based on FeICIC is shown to significantly improve the average data rate of all UEs.