Hybrid Access Strategy Of LTE Heterogeneous Network Based On Subscribers Spectral Optimization

In cellular network, there are almost two-thirds voice services and ninety percent data services happened in the house, therefore, it’s important for carries to provide great services for house users. Compared to lots of house coverage solution, Femtocell is the best choice for study because of its low price and random new location.According to 3GPP (3rd Generation Partnership Project), the access control scheme of the femtocell could be classed into three categories:Closed Access mode, Open Access mode and Hybrid Access mode. Closed Access mode is the first mode of femtocell, due to maximizing subscribers benefits. However, considering the impact of interference, the second mode, Open Access mode, is showed. Open Access mode can be used to avoid cross-tier interference, and reduce the negative impact of the femtocell tier on the macrocell network, however, it has a main drawback that it reduces the performance of the Femtocell User due to being exploited the resources by nonsubscribers and frequent handover, Which is made it be rejected by carries. In Hybrid Access method, it reaches a compromise between the impact on the performance of subscribers and the level of traffic for nonsubscribers.There are two basic mechanisms of Hybrid Access mode. One is defining the nonsubscriber access number, which is like Open Access mode that nonsubscribers allowed to access have the same right with subscriber who can get better service, but the excessive number of nonsubscribers will influence QOS (Quality of Service) of subscribers. Another is that defining spectrum resource managements, which don’t care the nonsubscriber access number and just focus on the spectrum resource that can be used by nonsubscribers. In the second mechanism of Hybrid Access mode, the prior proportion is defined by carries, which can protect the subscriber well, but it is not the best for two reasons, one is that it’s not flexible to allocate the sharing resource, another is that it ignores the frequency selective to channels in LTE system. Therefore, there is something trouble in high SE (Spectrum Efficiency) for the second mechanism.Considering the characteristic of down link in LTE system, HYBRID ACCESS STRATEGY OF LTE HETEROGENEOUS NETWORK BASED ON SUBSCRIBERS SPECTRAL OPTIMIZATION is provided for solving spectrum efficiency insufficiency. The key of new proposal is that allocate sharing PRB (Physical Resource Block) to nonsubscribers, those PRBs is not very good for all subscribers, which can be got by a kind of intersection operation, covering the spectrum selection characteristic. Due to those sharing PRBs are normal for subscribers, this new plan can enhance the subscriber’s SE based on having no impact on the nonsubscriber’s SE. Meanwhile, the more PRBs can be allocated to share because of the subscriber’s SE gain, the more throughputs can be got by nonsubscribers. Besides, the new plan can be fit for different services by the dynamic adjustment of sharing PRB proportion, which makes the new plan flexible. Finally, this paper testifies the improvement of enhancing SE by to analyzing the theory and simulating the results.