| Summary: | 碩士 === 國立中央大學 === 資訊工程研究所 === 93 === Wideband code-division multiple-access (WCDMA) is selected as the radio interface technology in the coming 3G wireless network to meet different QoS requirements of heterogeneous traffics. Since the capacity in WCDMA system is limited by interference, an efficient radio resource mechanism is important to enhance overall performance. In the future network, we believe that the server may move to the mobile client resulting that the data volume in uplink will increase considerably, and we concentrate on improving the performance of transmission in uplink.
Previous researches have shown that uni-access mode is an efficient way to reduce intracell interference caused by other transmitting users, and hence higher performance is attained compare to traditional multi-access mode. However, the challenge of such scheduled transmission is that higher delay may occur in waiting for service, and this may violate the delay requirements of real-time traffics. The delay problem produced in uni-access mode is due to the constraint in the practical system that a single user might not fully utilize the available bandwidth. Consequently, the system capacity as well as throughput will be not optimized.
This thesis introduces a novel Transport block size based Adaptive Scheduling Scheme (TASS) that utilizes radio resource more efficiently and sufficiently. Different from both uni-access and multi-access mode, the TASS can be seen as a mix version of them called hybrid-access mode. Via the transmission strategy, less power is required while achieving equivalent throughput and thus higher performance is expected. In order to guarantee the delay time of each user, the scheduling algorithm earliest deadline first (EDF) is applied. As a result, the TASS is suitable for real-time traffics. The experiment results demonstrate that this new transmission strategy carries advantages in system capacity, average delay and overall throughput.
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