| Summary: | This thesis covers several research problems in the area of multimedia transmissions over wireless communication systems. The objective is to enhance the quality of service (QoS) provisioning for multimedia transmissions over wireless communication systems. Recent advances in signal processing techniques have enabled wireless networks to have multi-packet reception (MPR) capability at the physical layer, where it is possible to receive more than one packet when concurrent transmissions occur. In this thesis, a multi-reservation, multiple access (MRMA) scheme for wireless multimedia networks, based on an MPR channel model, is proposed to differentiate the QoS provisioning for multimedia traffic and best effort traffic on MPR-enabled channels. Another advance in recent wireless technologies is the cross-layer optimization over wireless links. In this thesis, a cross-layer QoS provisioning method is proposed. Specifically, the data frame drop ratio (FDR) in the medium access control layer and the bit error rate (BER) in the physical layer are jointly optimized to provide a better data frame loss ratio (FLR) seen by the higher layers. In this thesis, a cross-layer enhanced scheduling (CEPS) method is proposed for providing QoS optimization for multimedia traffic in multi-code code-division multiple access (MC-CDMA) systems. CEPS also provides flexible fairness provisioning among different traffic flows. Then, the cross-layer QoS FLR in the MC-CDMA systems is further optimized by accounting for not only the predesigned QoS requirements, the historical QoS experienced, and the current buffer status, but also the statistical traffic models of different traffic flows. Results show that the system performance and the QoS provisioning can be greatly improved by the cross-layer QoS consideration and the proposed optimizations. The thesis also adopts the cross-layer QoS consideration in adaptive modulation and coding (AMC)-enabled wireless systems. A QoS-based cross-layer scheduling scheme (QoS-CLS) is proposed for AMC-based systems. It can guarantee the QoS provisioning for multimedia traffic flows and/or share the QoS among different traffic flows by making scheduling and coding/modulation decisions based on the buffer status, traffic status, channel status, and other information for different traffic flows. Results show that QoS-CLS can greatly enhance the system performance.
|
|---|
