Radio Resource Management And QoS Guarantee In Wireless Networks

The rapid progress of wireless applications results in the scarcity of radio resources and demands higher efficiency of radio resource management mechanisms. Improving the utilization of radio resources has ever been one important research topic in wireless networks, and also been the objective of this paper, which concentrates on radio resource management and QoS provisioning.To support packet services in WCDMA system, the combined DCHs with different spreading factors are considered as transport channels. For the application model, a MAC-measurement-based packet scheduling algorithm has been put forward. The algorithm conducts transport channel switching between different rates of DCHs for packet transmission to improve the channel utilization and decrease packet transmission delay. To provide QoS guarantee for mixed packet services in HSDPA, a QoS provisioning framework has been developed. The scheme schedules packet transmission by jointly considering traffic QoS requirement and perceived QoS level. Therefore, each traffic queue can be provided with proper resource share proportional to their QoS requirement and system capacity can be improved. For multimedia application, the fairness of radio resource management algorithms has been studied and a novel QoS demand based fairness criterion has been proposed. Taking packet scheduling as analytical example, the paper proposes a theoretical analysis model for QoS demand fairness study in stochastic process and probability. Two throughput optimal real-time multimedia packet scheduling algorithms are analyzed in terms of QoS demand fairness for typical real-time voice and video application. Based on the theoretical model and analytical results, a new packet scheduling algorithms M-Exp is developed for providing enhanced QoS demand fairness and system capacity.The above topics emphasize the radio resource utilization within a specific system. However, there is an emerging cognitive radio system that aims at improving the spectrum utilization between two or multiple radio systems through spectrum sharing. The spectrum allocation and packet scheduling in the cognitive radio system are investigated for supporting mixed real-time and non-real-time packet traffics. A spectrum-aware spectrum allocation and packet scheduling mechanism has been developed for providing reliable QoS guarantee for real-time traffic. In addition, the transmission power control under interference temperature constraint has been investigated. Based on two existing equal-power allocation schemes provided in the IEEE 802.22 MAC protocol, a joint power control scheme considering traffic's data rate requirement has been put forward for multi-user uplink transmission in the constraint area for better QoS guarantee and higher system capacity.