Lte - Advanced Femtocell Spectrum Allocation And Power Control In The System

Technologies like enhanced antenna used in LTE-Advanced networks have made the capacity of wireless communication system approximating to the theoretical limit. The prosperity of the intelligent terminal industry spurs an exploding demand for mobile data service. Femtocell has been proved to be efficient in expanding system capacity, improving coverage and enhancing users’quality of service. And there is a great chance that it will be of mass deployment in the near future. While femtocell does bring some gain, it also introduces some challenges due to the characteristics of the femtocell itself and the new dual layer network topology.Interference management is the most serious and important issue in all of the challenges, and it has become a research hotspot in recent years. Spectrum allocation and power control technology are important tools to avoid interference. In this paper, by deeply studying the characteristics of femtocell and analyzing the interference status of a dual-layered heterogeneous network in detail, we propose innovative Macro-Femto spectrum allocation scheme and power control algorithms. With the help of the LTE-Advanced system-level simulation platform we built, we do some verification of the strategies proposed and compare with the normal ways. The main work and contribution of the paper is as follows:(1) In the Macro-Femto spectrum allocation issue, we put forward the idea of considering the deployment purpose of femtocell. Based on the access mode of femtocell and the Fractional Frequency Reuse (FFR) strategy used in traditional cellular networks, we propose the hybrid Macro-Femto spectrum allocation scheme, which guaranties the system capacity requirements for cell center users and eliminates the dead zones of the cell edge. Through mathematical modeling and system simulation we verify the superiority of the scheme in comparison with Macro-Femto co-channel and orthogonal spectrum allocation.(2) In the power control of femtocell issue, firstly we analyze all the types of measurement a femtocell can execute. Based on this, we introduce several implementations of general power control algorisms and do comparative simulation of them. Then we innovatively introduce the water-filling thinking and channel inversion thinking into the design of power control algorithms, and improve them with the LTE-Advanced standardized signaling. Finally a comparison simulation is done to all the power control algorithms and the algorithms proposed are verified to achieve best compromise between system performance and overhead.