Research On Power Allocation In LTE-A Dvanced Two-Tier Networks

Long Term Evolution-Advanced(LTE-A) is a preliminary mobile communication standard, which is standardized by the 3rd Generation Partnership Project (3GPP), and is submitted as a candidate 4G system to International Telecommunications Union (ITU). LTE-A acts as an great enhancement of Long Term Evolution (LTE), and several new technologies are introduced, which makes the performance of LTE-A reach a new level of mobile communication. One of the new technologies is femtocell. A femtocell is a small cellular base station, typically designed for use in a home or small business, it aims to improve the coverage of indoor environment, where the mobile service is limited or unavailable. Femtocell has vast potential for future development, so 3GPP take it as a part of standardization of LTE-A at the beginning.In this paper, femtocell in LTE-A network has been investigated deeply. Firstly, the problem of indoor coverage of mobile communication and several potential solutions are introduced and femtocell is highlighted. Then the concept, network structure and deployment of femtocell is introduced. A system-level simulation platform of LTE-A two-tire network (Network contains both macrocell and femtocell) is developed according to the standard of 3GPP. On the basis of former research two femtocell power allocation algorithm are proposed:Cognitive Radio based-QoS Guaranteed Power Allocation (CR-QGPA) and Cognitive Radio based-Non-cooperative Game Power Allocation with Pricing (CR-NGPAP), then the algorithms are verified in the system-level simulation platform. Simulation results show that the CR-QGPA can reach a better balance between performance of femtocell network and the protection of macrocell users, comparing with previous power allocation methods; CR-NGPAP is based on flexible pricing while take the demand of data rate of different femtocell into consideration, it limits the interference in two-tier networks while guarantee the fairness between femtocells.