Research On Radio Resource Management Method Femtocell Perception

At this stage of the cellular network, people’s requirement on wireless business has a continuous increase progressively. Meanwhile, users are considering more and more about the condition that whether the services of voice and video, or some other business on the support of high data rates, will fulfill their requirement. Nowadays,70%of the wireless data services occur indoors. According to the survey, however,45%of the residential and30%of the enterprise consumers are facing the problem that the signal coverage is limited. Therefore, how to improve the indoor coverage and how to provide a high rata service that is stable and reliable, is a great challenge faced by current mobile communication. In order to accomplish the communications with high data rates, the early method in Macrocell has shown plenty of disadvantages, especially in long range communications. After that, people were trying a solution to shorten the distance between base stations and mobile stations, but existing the problem that the cost was too high. Consequently, a new network technology is proposed, that is, Femtocell. Femtocell network is a complement to Macrocell networks, when the coverage from Macrocell signal is insufficient. By enhancing the received signals from indoor Femtocell deployed by users, Femtocell will reduce the load of Macrocell dramatically. The two-layer network, which consists of Femtocells and Macrocell, has become an emerging technology in the next generation wireless communication networks such as3GPP LTE and WiMAX.This paper will superimpose Femtocells onto Macrocell as a two-layer framework. In the light of cognitive radio technology, the interference between the two layers and the utilization of the wireless radio are researched. To accomplish the two-layer framework better and make the service quality guaranteed, the interference between Femtocell and Macrocell network needs to be mitigated inevitably. Be aimed at the existing problems above, this paper, firstly, discusses some key technologies in Femtocell, compares Femtocell with Wi-Fi and other cellular networks, such as Picocell, and then introduces OFDMA into this analysis, elaborating the system model and the transmission structure of resources. Secondly, to mitigate the interference between the networks, we model and analysis the interference, mainly discussing the situation that what negative influence will happen from the traditional Macrocell base station to Femtocell mobile station which is communicating with its Femtocell base station. According to the analysis, Femtocell base station is able to adjust its transmission power. Finally, cognitive radio technology is developed into Femtocells, playing a important role to mitigate the interference. Then the effective capacity under estimation error is further researched. Applying the scheme proposed, users will utilize the radio resources effectively. In this scheme, the resource blocks will firstly sense the channel and identify whether a resource block is occupied by a Macrocell, and assign the resource block which is not occupied to Femtocells. By means of sensing the utilization in resource blocks, conflicts between Macrocell and Femtocells are minimized, and the system capacity increases. The simulation results indicate that this scheme will increase the system capacity and make the radio resources effectively utilized.