Research On Resource Management In Two-tier Macrocell\Femtocell Network

Femtocell can improve indoor coverage to provide better service quality for the users of the indoor scenes, such as family and business office. Hence femtocell is widely deployed and constitutes heterogeneous network together with traditional macro network. At the same time, the deployment of femtocell will bring some problems. On one hand, due to the shortage of spectrum, femtocell needs to share spectrum with traditional macro network, which results in cross-layer interference. On the other hand, the addition of femtocell also can increase the energy consumption of the whole network. Focusing on the two problems stated above, this paper mainly studies sub-channel allocation and power control wireless resource management methods in two-tier Femtocell. The main work and innovation points can be summarized as follows:(1) Research on jointly sub-channel allocation and power control scheme. In the uplink of a two-tier femtocell network, this article proposes a joint power control and sub-channel allocation method to minimize the energy consumption of all of the femtocell users (FUEs), subjecting to limiting the cross-tier interference caused to the macro-base stations by the FUEs, and satisfying the Quality of Service (QoS) of the FUEs. The problem is formulated as a mixed integer programming problem. To solve the problem, a distributed algorithm based on Lagrangian multiplier method is proposed. In the algorithm, time-sharing factor is introduced to reduce the complexity, finally the dual decomposition approach is used to solve the problem. The results of the paper are verified by simulations. Simulation results show that the proposed scheme has obvious effect on reducing the energy consumption of femtocell network and guaranteeing the FUEs’QoS.(2) Research on Power Control Based on Stackelberg Game. In the downlink of a two-tier femtocell network, this article proposes a non-uniform price power control algorithm based on Stackelberg game. In the game, macro base station (MBS) acts as the leader, who makes decision of the interference price and adjusts its transmit power to maximize its utility, subjecting to macro user equipments’(MUE) and FUEs’QoS requirement. Femtocell base stations (FBSs) act as the followers, who make decision of their transmit power according to the interference price made by the MBS to maximize their utility. The game operates in an iterative way and converges to Stackelberg Equilibrium (SE) in the end. The results of the paper is verified by simulations. In the simulation an uniform price power control algorithm is proposed for performance comparison. Simulation results show that the proposed non-uniform price power allocation scheme performs better in terms of total revenue of MBS and energy efficiency of FBSs than the uniform one.