A joint uplink-downlink optimization framework for resource management in next generation wireless networks -

Abstract

The constant evolution in wireless technologies has allowed the advent of a plethora of applications with different quality of service (QoS) requirements. Resource allocation is the process by which the frequency and power resources are efficiently distributed to the users in the network to satisfy their QoS requirements while maximizing as much as possible the network performance. Existing resource allocation schemes have mainly focused on optimizing the users' performance, independently, on either the uplink or the downlink. However, next generation wireless services such as video conferencing and multiplayer gaming are expected to involve many end-to-end interactions between the users. For such services, there is a need to optimize a QoS metric that takes into account, jointly, the uplink and downlink performance of the users. In this dissertation, we propose a joint uplink-downlink resource management framework for the state-of-the-art, orthogonal frequency division multiple access (OFDMA)-based wireless standards. The developed framework will jointly exploit service flow QoS parameters, cross-layer network performance metrics, channel state information, and queue state information in both the uplink and downlink directions. A queue-level analysis of the joint resource allocation process is performed using decentralized Markov decision processes. This is complemented by the development of queue-aware joint uplink-downlink resource allocation approaches that induce a coupling in the queue dynamics at the base station and mobile user sides. Furthermore, several resource allocation problems in an OFDMA network are formulated and solved using optimization and game theoretic techniques. As a special case, we address the particular challenges in employing the time division duplexing (TDD) mode of operation by jointly optimizing the following important design aspects in multicellular TDD-OFDMA wireless networks: the uplink-downlink (UL-DL) switching points, the UL-DL subcarrier allocation, and the UL-DL power alloc