Resource Allocation For Future Wireless Communication:the Trade-off Between Resource Utilization And QoS Guarantee

With the rapid development of wireless communication technology and the Internet, the demand for communication services is gradually changed from simple voice services to complex mixed services, such as audio, video, data, and so on, resulting in the demand of people for the Quality of Service (QoS) requirements is continuously increased. Hence, how to efficiently use resources in wireless communication network, where the resource is constrained and channel environment is poor, are becoming increasingly important. Therefore, the trade-off between resource utilization and QoS requirements are considered as the clue throughout this dissertation. According to the order of network structure from simple to complex, several hot issues in the wireless resource allocation are studied thoroughly.1. In the basic single-hop homogeneous network, the resource allocation problem based on the effective capacity is studied. Based on the theory of effective capacity, we derive the continuous (discrete) effective capacity region for a wireless multiuser Orthogonal Frequency Division Multiple Access (OFDMA) network, and prove that the effective capacity region is a convex region. With convex optimization theory and the Taylor expansion approximation, the asymptotically optimal resource allocation scheme which achieves the boundary points of the effective capacity region is proposed. Based on the derived effective capacity region, we further consider the time-varying characteristics of the arrival process and service process, as well as the heterogeneous nature of the traffic. And then, the effective capacity-based resource allocation problem in multiuser OFDMA networks are studied with heterogeneous traffic, i.e., improve the utilization of system resources with the delay QoS requirement guaranteed. With effective capacity and convex optimization tools, two optimization problems are formulated in continuous and discrete scenarios, and the asymptotically optimal subcarrier and power allocation schemes are proposed.2. The problem of resource allocation based on cooperative communication and heterogeneous network technology is studied. We design a novel heterogeneous cooperative system architecture. In this system, the mobile stations (MSs) are dual-mode with both cellular OFDMA and Ad Hoc radios. And MSs communicate with the base station (BS) by OFDMA network, while they communicate with each other by Ad Hoc network. Based on the heterogeneous cooperative system architecture, we study the resource allocation problem with a single Ad Hoc relay, where the MSs with data to be transmitted (active MSs) only can choose a single inactive MS as its relay station. The resource allocation problem for this system is modeled as an optimization problem, and a fair and efficient joint resource allocation algorithm is given. Subsequently, based on the heterogeneous cooperative system architecture, we further extend the system model to multiple Ad Hoc relays, where the active MSs can choose multiple inactive MSs as its relay stations. The resource allocation problem for this system is also modeled as an optimization problem, i.e., improving the utilization of system resources and maximizing the system throughput with the QoS requirement of each MS guaranteed. We propose a dual-based resource allocation scheme to solve the problem fairly and efficiently, and then we propose a fully distributed resource allocation scheme to decrease the computational complexity.3. In the multi-cell scenario, the energy saving and the base station management problem in the area of green communication is studied. The problem of base station management in practical networks is formulated as an optimization problem, in which the ON/OFF decision must be made dynamically in order to improve the utilization of system resources and maximize the energy saving of the network, as well as guarantee the quality of service constraint of all users. To solve this problem, we propose a novel coalition formation algorithm with two mobile station association policies, that is, the coalition formation with fully association (CF-FA) and the coalition formation with Energy-Efficient association (CF-EEA). Moreover, the stability of the proposed coalition formation algorithm is analyzed with a new concept of defection function D. In addition, in order to reduce the overall network signaling overhead, and in order to facilitate the expansion of the network, we propose a distributed base station management algorithm and the corresponding protocol implementation. And the cost is that the distributed algorithm need to spend more time than the centralized algorithm. However, in such an application scenario, a longer algorithm (protocol) execution time in exchange for the distributed implementation is entirely desirable. Then, in order to provide a direction for the research of base management, and in order to provide a reference standard for our proposed base station management algorithms, the upper bound of the energy saving for the network is derived. Finally, based on simplified typical network and traffic characteristics, the proposed algorithm is analyzed, and the BS switching decision results, MS association result and the close form of the energy savings are derived and analyzed.