- 期刊
Performance Improvement for Multimedia Transmission Services based on Wireless Networks
無線網路上多媒體傳輸服務之效能改善
摘要
在有限頻寬的無線網路中，若要提供語音、數據、影像、甚至視訊等多媒體資料的傳輸服務，勢必要有效率地提高傳輸的效能並充分利用系統容量，以符合各種不同資料型態之服務品質的需求。而本論文經由歸納與分析相關的文獻報告，發現分封交換的無線網路環境中，以改良TDMA（Time Division Multiple Access）和Reservation-ALOHA之封包保留多工存取（Packet Reservation Multiple Access-PRMA）的方式，利用語音檢測器的技術釋放靜音時的多餘頻寬，能有效地改善系統使用率和語音封包資料的遺失率等，才較有可能提供多媒體的資料傳輸服務，並與有線的區域網路或網際網路相結合。另外，再深入地探相關PRMA論文的研究，發現以態調整所謂行動使用者的允許機率，即基地台允許其佔有某時槽通道傳輸資料機率，將更為有效地改善語音封包資料遺失率、數據資料的平均傳遞延遲與系統利用率等。所以，我們在同時提供語音、數據和視訊使用者的多媒體環境中，應用ITU-T H.263為視訊壓縮的方法，研究相對應的資料傳輸機制，以期在有限頻寬的無線網路中提升系統之服務品質，且分析模擬其效能改善的情況。
並列摘要
A new scheme for the integration of video and voice transmission over the Packet Reservation Multiple Access (PRMA) is proposed in this paper. We focus on low bit-rate video applications like video conferencing and visual telephony for wireless networks. The ITU-T H.263standard provides a solution to the need for low bit-rate video compression under 64Kbps. In this paper, the proposed protocol assumes that each voice terminal fol1ows a traffic pattern of talk spurts and silent gaps with dynamic permission probability. And each video terminal has the highest permission probability to access the available slot based on ITU- T H.263 standard. Again, we present a ”pseudo release” scheme to release slots reserved by video terminals according to the contents of each video transmission buffer, and the active voice or data terminals can temporarily access the additional slots to improve the performance without sacrificing the video capacity of the system. The packet dropping probability of the active voice terminals and throughput of the system are superior to the original PRMA, as indicated in analysis results.
延伸閱讀
- Lu, Y. J. (2012). 在隨建即連無線網路中提高頻寬利用率之多頻道媒體存取協定 [doctoral dissertation, Tamkang University]. Airiti Library. https://doi.org/10.6846/TKU.2012.00944
- 楊逢振（2007）。多重頻道無線網狀網路媒介存取控制協定之改進〔碩士論文，國立臺灣大學〕。華藝線上圖書館。https://doi.org/10.6342/NTU.2007.01465
- Liu, J. C. (2009). 在多通道無線區域網路中媒體接取控制協定之研究 [doctoral dissertation, National Tsing Hua University]. Airiti Library. https://www.airitilibrary.com/Article/Detail?DocID=U0016-0207200916272002
- Lin, C. J. (2009). 利用多重傳輸速率增進無線網狀網路之效能 [doctoral dissertation, National Taiwan University]. Airiti Library. https://doi.org/10.6342/NTU.2009.02966
- Chen, J. M. (2006). 異質無線網路中之多媒體串流系統 [doctoral dissertation, National Central University]. Airiti Library. https://www.airitilibrary.com/Article/Detail?DocID=U0031-0207200917342849