Adaptive Frequency Reuse In Femtocell Interference Management

Long Term Evolution (LTE) has developed a new technology in order to enhance indoorcoverage. This new technology is called femtocells and is achieved with the use of access pointsdeployed by home users, it has the advantages of low power consumption, strong mobility andindependent deployment. Compared with the Distributed Antenna System (DAS) and WIFIcoverage technologies, femtocell has the obvious advantages in cost, private information securityand users’ QoS gurantee. However, bring the femtocell into the existing Macro cellular network,inevitably come with interference problems and challenges to users and base stations.This paper firstly introduces the development and evolution of the indoor coverage technology,point out the advantages and disadvantages of previous technology, and then introduces the conceptof femtocell. Next, this paper introduces the development background of LTE, discusses currentlyinterference mitigation technology development status, and presents the heterogeneous networkdevelopment and convergence, after that this paper elaborate the co-channel and adjacent channelinterference principle, and then some usual frequency reuse methods. From uplink and downlinkaspects, analyzed and study the interference problem between the femtocell and the macrocell (twotier network), then presents some interference cacellation and avoidance technology. Consideringthe decreases of the system’s capacity and users’ throughput, based on the frequency reuse, thispaper discuss currently IFR and FFR mechanism, with the FFR model this paper study theinterference mitigation techniques in femtocell/macrocell networks and propose a frequency reusemechanism that leads to increased overall system performance.In particular, the mechanism aims tomaximize throughput via a variety of combinations between inner cell radius and frequencyallocation to the macrocell, mathematical analysis and simulation of the mechanism. Additionally, aposition minded frequency allocation to the femtocells targets to further optimize the totalthroughput of the cell.