A Study of Real-Time Data Access in Next Generation Mobile System

• Main Authors: Chiang-Shiang Wan, 萬江祥
• Other Authors: Ruei-Chuan Chang
• Format: Others
• Language: en_US
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/43179365396356047028

博士 === 國立交通大學 === 資訊科學系 === 91 === The development of an all IP-based network is the future for the next generation mobile system. The all IP-based network enables Packet-switched connections to offer real-time multimedia services. The Wideband Code Division Multiple Access (WCDMA) is the most popular 3rd Generation (3G) mobile standards. To support packet multimedia services, the WCDMA system must provide efficient radio management for real-time services quality-of-service (QoS) provisioning. In a WCDMA system, the base station power and channelization codes are two most important radio resources. In this dissertation, we propose resource management polices for real-time data access to decrease mobile users' power consumption within a cell, and to improve channelization codes utilization. First, the concept of the management framework is introduced to solve above problems. Based on the management framework, we present the Real-Time Generic Scheduling (RTGS) algorithm to schedule real-time packet traffic, which guarantee the real-time QoS. Moreover, we design the Real-Time Bandwidth Scheduling (RTBS). The RTBS algorithm implements the early-deadline-first (EDF) scheme to do the schedulability analysis. Applying the dynamic code assignment (DCA) scheme, the Real-Time Code Scheduling (RTCS) algorithm is used to increase the probability of schedulable sessions and improve the radio resource utilization. Furthermore, we also propose the Real-Time Imprecise Scheduling (RTIS) to serve mixed real-time and non-real-time packets efficiently in a multimedia environment. With the improvement in new access technology, the High Speed Downlink Packet Access (HSDPA) is used to support real-time multimedia services in next generation mobile system. We devise new High Speed-Downlink Shared Channel (HS-DSCH) code management schemes that efficiently assign the HSDPA resource - HS-DSCH codes for real-time packet traffic. Based the code management schemes, the Real-Time Code Allocation (RTCA) employs the admission control and the packet scheduling schemes to guarantee the bit rates and delay attributes for the real-time data session QoS requirement. Extending from the RTCA algorithm, the Real-Time Sharing Code (RTSC) algorithm applies the EDF scheme to do the schedulability analysis, increasing the schedulable probability for the real-time sessions and, thus, improving the utilization of HS-DSCH codes. The WCDMA system supports high-rate bandwidth and variable-rate transmission for various applications according to the channelization code allocation. The channelization codes spread information for each mobile user base on the orthogonal variable spreading factor (OVSF) technique. We present a Fast Dynamic Code Assignment (FDCA) algorithm to assign a channelization code for a mobile user request. We evaluate a cost for an OVSF-code allocation. The cost is obtained by calculating the number of available and occupied descendant codes of the code. The FDCA algorithm can assign a suitable code for the bit rate requirement and, in addition, the cost obtained by the evaluation scheme is small.