| Summary: | 碩士 === 國立臺灣科技大學 === 資訊工程系 === 93 === This thesis is composed of two topics. In the first topic, we design a scheme on the orthogonal variable spreading factor (OVSF) code tree management for the wideband code division multiple access (WCDMA) in the universal mobile telecommunication system (UMTS). In this scheme, we take the multimedia (including conversational, streaming, interactive, and background services) charactereistics defined by 3GPP (the third generation partnership project) and dynamic resource allocation (DRA) into consideration to make the management efficient and satisfy different quality-of-service (QoS) requirements requested by diverse multimedia applications. Through simulations, we demonstrate that the proposed scheme can not only adequately take care of QoS requirements but also significantly reduce the number of code reassignments, making it charming and more suitable for the real and complicated system. In the second topic, we adopt the open source codes of Vovida open communication application library (VOCAL) provided by Vovida to implement a SIP-based user agent (UA). For this topic, we first introduce how SIP works in voice over IP (VoIP) networks. Then, we solve the problems found in the original source codes and enhance its functions. Through the system test with the VOCAL SIP servers, we successfully show that the enhanced SIP UA works well with other UAs and PSTN networks.
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