Research On Heterogeneous Radio Access Network Oriented Joint Resource Management Technologies

The rapid developments of both telecommunication technologies and wireless services drive the evolutions of radio access technologies and mobile terminal technologies continuously. Promoted by radio access heterogeneity and mobile terminal mode diversity, heterogeneity, cooperation and convergence are the most promising trends of the future wireless communication system, which will integrate and manage multiple heterogeneous radio access networks. It aims at fully meeting the users’growing demands under different application scenarios by providing multi-mode terminals a universal heterogeneous radio access environment. Joint radio resource management technologies uniformly configure and schedule the resources of each radio access technologies. By jointly utilizing multiple radio access technologies, it can achieve the interconnection and coordination of network and terminal, so as to enhance the overall performance of communication system.The research of this dissertation focuses on heterogeneous radio access network oriented joint resource management technologies. The dissertation put emphasises on the joint utilization of multi-mode terminal to each radio access technologies, namely, the terminal accesses multiple heterogeneous radio access networks and carries out data transmission in parallel, obtains the diversity gain from multiple networks, which is defined as Multi-Radio Transmission Diversity. The disstertation studies the mechanisms of network access selection, data traffic allocation and radio resource allocation for multi-mode terminals. Base on the actual demands of network and terminal, the dissertation employs the operable resources of heterogeneous radio access networks and multi-mode terminals, and it puts our research work at different levels. The purpose of the dissertation is to form a set of joint resource management system for heterogeneous wireless access networks. The content of this dissertation can be summarized as follows:1) For the issues on network access selection when multi-mode terminal utilizing Multi-Radio Transmission Diversity, the dissertation proposes a multi-access selection mechanism for multi-mode terminals in heterogeneous radio access environment. Controlled by terminal, the mechanism aims at increasing the energy efficiency of multi-mode terminal’s data transmission, while guaranteeing multi-mode terminal’s demand on data transmission rate and restriction on power consumption. The framework of network access selection is designed, which includes independent parameter collection modules for the network interface cards of radio access technologies, and a unified network access selection management module for the decision of network access selection according to the collected parameters. The parameter collection module handles the measured parameters via the exponential smoothing method, which can reduce the "ping-pong effect"; network access selection management module uses state transition model to manage the network access selection strategies of multiple network interface cards, and adopts utility function method to dynamically balance the terminal’s power consumption and data transmission rate. The mechanism can flexibly optimize the network access selection according to the application’s data rate demand and the terminal’s actual situation of energy constraint, thus can enhance the energy efficiency of multi-mode terminal’s data transmission. The simulation results demonstrate that the proposed mechanism can significantly reduce the unnecessary network access re-selection. Compared with the traditional switched network access selection, the proposed mechanism can increase the energy efficiency of data transmission while guaranteeing the terminal’s power consumption and data throughput.2) For the issues on the traffic allocation for the connections between the terminal and each participating radio access technologies when multi-mode terminal utilizing Multi-Radio Transmission Diversity, the dissertation proposes a traffic allocation mechanism with consideration of the resource constraints of multi-mode terminals. The mechanism includes an energy efficient traffic allocation mechanism constrained by transmission delay, and a transmission efficient traffic allocation mechanism constrained by communication power consumption. The dissertation designs a data transmission model for multi-mode terminal carrying out parallel data transmission via Multi-Radio Transmission Diversity, builds numerical optimization models, and adopts the queue size control to avoid buffer overflow. A traffic allocation algorithm is designed based on the prime-dual interior point method for minimizing the multi-mode terminal’s communication power consumption under data transmission delay constraint, and also a traffic allocation algorithm is designed based on modified particle swarm optimization for minimizing the multi-mode terminal’s data transmission delay under communication power constraint. The simulation results prove that the proposed traffic allocation mechanism can optimally allocate the traffic under different parameters. Compared with the traditional proportion based allocation algorithm, in the energy efficient traffic allocation mechanism, the multi-mode terminal’s communication power consumption is significantly reduced, and in the transmission efficient traffic allocation mechanism, the multi-mode terminal’s data transmission delay is obviously decreased.3) For the issues on the radio resource allocation when multi-mode terminal utilizing Multi-Radio Transmission Diversity with the software defined radio technologies introduced, the dissertation proposes a radio resource allocation mechanism for maximizing the capacity of heterogeneous radio access networks. It dynamically allocates the transmission powers of multi-mode terminals and bandwidths of multiple radio access technologies. The dissertation firstly gives an overview of the Multi-Radio Transmission Diversity in heterogeneous radio access networks from the perspective of network. Aiming at further enhancing the capacity of heterogeneous radio access network under the Multi-Radio Transmission Diversity, the dissertation proposes a network utility maximization based numerical optimization model, which optimally allocates the transmission power of multi-mode terminal and the bandwidth of the terminal’s associated radio access technologies. According to the multi-mode terminals’configurations and users’ demands, the model fully considers the difference of multi-mode terminals on radio access technology support and network access selection, so as to effectively reflect the diversity characteristics of multi-mode terminals in actual application environment. The dissertation designs an improved cevolutionary genetic algorithm, which can flexibly and efficiently solve the optimization problem through parallel evolutionary searching. Base on this algorithm, a central resource allocation algorithm is raised. In the joint radio resource management entity of heterogeneous radio access networks, the algorithm optimally allocates the resource periodically via the intercommunication between network and terminal. The simulation results show that, compared with other algorithms, the proposed algorithm has high efficiency, and can generate relatively stable and precise resource allocation results; compared with the traditional switched data transmission, using Multi-Radio Transmission Diversity, the parallel data transmission can effectively promote the system capacity via the proposed algorithm.