Research On Femtocell System QoS Provisioning Technology

HeNB is a kind of small, low-power cellular base station which is deployed indoors.Based on the IP protocol, It has simple structure and typically connects to the core networkof mobile communication system by cable broadband network. HeNB is Low cost, and hasplug and play features, it can achieve high-speed wireless coverage indoors without manualconfiguration. As the Femtocell network and the macrocell network using the samelicensed bands, it becomes a hotspot that adopting the idea of cognitive radio network toachieve QoS provisioning in Femtocell network.With the gradual deployment of femtocell network, the growing popularity of indoormultimedia applications, large amounts of traffic bound to the core network whichchallenges the transmission capacity and data processing capabilities of the core network.In order to improve the routing efficiency and reduce unnecessary transmission cost,3GPPproposed local IP access (LIPA) and selective IP traffic offload (SIPTO) in femtocellnetwork. Both ideas and features are basically the same, in the user plane, UE’s datadirectly go to a LAN or the Internet via HeNB/local gateway, without going through themobile core network, The technology enables the network flatten in the user plane level,improves the efficiency of data routing, at the same time, reduces the cost of datatransmission. More importantly, the realization of LIPA/SIPTO technology makes newvalue-added applications possible in indoor wireless communication scenarios.Taking Femtocell network as the background, based on the deep study of domesticand foreign QoS provisioning technology in femtocell system technology, this paper focuson two hotspots: the performance analysis of Femtocell system with QoS provisioning andthe traffic offload technology from the core network with QoS provisioning in Femtocellnetwork, aimed at achieving Femtocell system QoS guarantees in the access layer and thecore layer.To meet the QoS requirements of SU real-time service in cognitive Femtocell system,this paper employed Three-dimensional CTMC-based models to study the effects ofreserving channel to SU QoS indicators, i.e. blocking probability, call dropping probability,etc. During the modeling process, it separates the SU traffic into real-time andnon-real-time traffic, in terms of the occupancy of authorization spectrum, PU no longerhas absolute priority over SU. Meanwhile, for the problems that it’s difficult to get solutionusing Three-dimensional CTMC-based modeling to analyse system performance, this paper propose an approximate solution method, which greatly reduces the computationaldifficulty. Simulation results show that channel reservation method can effectively reducethe dropping probability of SU real-time traffic, improve SU QoE.And it also result in theincreasing blocking probability of SU non-real-time and real-time traffic.Taking into account the fact that UE’s communication behavior presents probabilityregional characteristics on location, based on the traditional core network traffic offloadmethod (TTO), in order to further increase the traffic offload from core network, this paperproposed a Traffic Offload With QoS Proisioning method(QPTO) in Femtocell network. Toachieve QoS provisioning of user traffic, HeNB classified traffice according to user trafficrequest information,. When a user initiates a traffic request, the reliable NEs of corenetwork, according to the request information and the current network environmentinformation, determine the direction of traffic. Simulation results show that the proportionof traffic offload from core network decreases with the improved network, at least15%higher than the TTO method, the delay of the regional traffic reduces20ms/MB than TTOmethod.