Multipath cellular networks for quality assured multimedia delivery

Future growth in wireless multimedia services with significantly high bandwidth requirements cannot be sustained alone by the emerging high-bandwidth technologies e.g., the fourth generation long term evolution, unless efforts are also driven to deal with spatially and temporally varying wireless channel imperfections. In this thesis, a novel wireless wide area network architecture is proposed with overlapped coverage from multiple base stations offering necessary path diversity to enhance the existing single-path services and support multipath services with efficient bandwidth aggregation and load balancing to provision quality-of-services demands of multimedia applications. Extensive network simulations, implementing obstacles to the line-of-sight communications and realistic user mobility along Voronoi paths, have confirmed the effectiveness of this architecture in provisioning feasible alternative wireless paths to avoid communication blind spots. In order to exploit the achieved path diversity, the thesis also develops a packet scheduling algorithm for the network proxy nodes to decide the appropriate base station to forward the packets guided by the short-term goal of minimizing the packet drop rates of delay-bound packets created by real-time multimedia applications and the long-term goal of balancing the load on all paths, especially when the network is underutilized. Comparative simulation studies reveal the superiority of the proposed scheduling algorithm in terms of predicting the delivery time of the packets as well as maintaining agreed packet load distributions. Finally, the thesis extends the proposed scheduling algorithm to select different paths for logically different data flows from the same user to validate the proposed architectures superiority in provisioning emerging multi-path services such as multiple description coding of video, developed to combat the detrimental effects of wireless channel imperfections and error resilient codes on delay-bound packets. Although the proposed architecture is analyzed in the thesis with homogenous cellular structure, it can be easily extended to heterogeneous structure and/or super networks with cooperation among the operators even using different wireless technologies and thus supporting the future trend in wireless multimedia communications.