Adaptive Fractional Frequency Reuse In Cellular Network

Due to the limited frequency resource and widely deployment of wireless systems, how to improve the utilization ratio of frequency and therefore increase the system throughput of communication network is becoming one of the key problems to be solved in the cellular network. For the full frequency network with reuse factor one, although it can take advantage of the limited frequency resource, the fact that its outline is a fixed honeycomb and every cell is connected with each others, especially in the verge of cell, may lead to poor communication quality and inter-cell interference for users in verge district. Currently Fractional Frequency Reuse(FFR), interference randomization processing and interference cancellation are proposed for solving this problem. Compared with interference randomization processing and interference cancellation, adaptive FFR has the advantage of lower complexity and higher frequency utilization, so FFR is better in improving communication of users in verge district, decreasing the Inter-Cell interference, increasing the system throughput. Fractional Frequency Reuse technology has been used in LTE and WIMAX.OFDM technology is used in LTE, Inter-Cell interference is one of the factors to restrict performance of LTE, Fractional Frequency Reuse technology may be used to decrease the inter-cell interference effect and therefore to improve system throughput and frequency utilization. This paper analyzes the FFR principle and proposes a dynamic FFR mechanism that selects the optimal frequency allocation based on the cell total throughput and user satisfaction. Simulation has confirmed it effectiveness.In the same network, whether high power consumption node or low power consumption node has similar frequency allocation, efficient interference cooperation and radio frequency management are very important to owning highest network throughput and users service quality. The thesis proposes a dynamic power transmit scheme based on FFR technology, whose purpose is to enable more users to access the network with an acceptable interference tolerance. Simulations are provided to validate its performance with cooperation among high power consumption and low power consumption nodes.