Research On The Technology Of Network Selection And Radio Resource Management In Heterogenous Wireless Networks

Future heterogeneous wireless networks are intended to provide an open and flexible architecture for the coexistence of a wide variety of Radio Access Technologies(RATs) with diverse features and capabilities that should be able to support different applications and services with various Quality-of-Service(QoS) demands. The theis researches the technology of network selection and resource allocation in wireless resource management.Some general network selection algorithms will lead to network congestion or resource underutilized. In view of this, research a QoS based network selection algorithm, in which a utility value is assigned to the associated RATs. The heterogeneous networks are composed of GPRS, EDGE and HSDPA. Users will be divided into web browsing, e-mail, video and other different services. The algorithm demonstrates the ability of providing high service satisfaction levels while adequately exploiting the overall system resources.The thesis researches a RRM algorithm based on proportional fairness. LTE and WLANs operate on individual frequency bands without inter-network interference. In addition, there is no interference between WLANs. In general, it is assumed that a user can only access one network during one RRM time. Use the optimization method to get the optimal network selection scheme, with the aim to maximize the minimum normalized user data rate. The users which access WLAN follow the resource allocation strategies above. The users in LTE network are reallocated with the aim to maximize the MNU rate. It ?rst allocates one resource element to each user. Then, the remaining resource elements are greedily allocated to the user with minimum normalized rate. The algorithm performs well in the minimum normalized user rate and fairness index.The proposed CRRM scheme in this paper incorporates location prediction information with service and mobility model in HWNs consisting of GERAN, CDMA2000 and WLAN. The services are divided into voice and data. Potential of mobility direction of users is also taking into account, so as to avoid unnecessary VHOs. The algorithm also considers the load balancing of each network. At the same time, comparison threshold of loading is defined to distinguish impacts on different services in different networks. The algorithm reduces the blocking rate of the network access and the network vertical handoff blocking rate effectively.