| 內容/備註 |
南台科技大學電子系專題演講
主題:
QoS Constrained Cellular Ad Hoc Augmented Networks for Next-Generation (Hybrid) Wireless Networks
主講人:
陳啟東 博士
時間：2005 /5/24 星期二 下午1:00 ~ 2:10
地點:
南台科技大學 S棟703
南台科技大學 (台南縣永康市南台街一號)
網路報名:
http://www.eecs.stut.edu.tw/~eecs/index1.html (點選 研討會議)
聯絡人: 南台科技大學電子系 余兆棠 教授 或 涂玟妤小姐
電話: 06-2533131 轉 3101或 3137
Email: ctyu@mail.stut.edu.tw
主辦單位:南台科技大學電子系
南台科大積體電路設計與應用技術研發中心
摘要(Abstract)
Provisioning of quality of service (QoS) for multimedia traffic in wireless networks is complicated due to user mobility and limited wireless resources. Next generation system will evolve to those that include dynamic adaptation to traffic and QoS needs. In the presentation, based on different design criteria, three novel QoS constrained cellular ad hoc augmented network (CAHAN) architectures are proposed for next generation wireless networks. The CAHAN architectures have a hybrid architecture, in which each mobile terminal (MT) of CDMA cellular networks has ad hoc communication capability. The CAHAN architectures are an evolutionary approach to conventional cellular networks. The proposed architectures have good system scalability and high system reliability.
The first proposed architecture is the QoS constrained minimum-power cellular ad hoc augmented network architecture (QCMP CAHAN). The QCMP CAHAN can find the optimal minimum-power routes under the QoS constraints (bandwidth, packet-delay, or packet-error-rate constraint). The total energy consumed by the MTs is lower in the case of QCMP CAHAN than in the case of pure cellular networks. As the ad hoc communication range of each MT increases, the total transmitted power in QCMP CAHAN decreases. However, due to the increased number of hops involved in information delivery between the source and the destination, the end-to-end delay increases. The maximum end-to-end delay will be limited to a specified tolerable value for different services. An MT in QCMP CAHAN will not relay any messages when its ad hoc communication range is zero, and if this is the case for all MTs, then QCMP CAHAN reduces to the traditional cellular network.
A QoS constrained network lifetime extension cellular ad hoc augmented network architecture (QCLE CAHAN) is proposed to achieve the maximum network lifetime under the QoS constraints. The network lifetime is higher in the case of QCLE CAHAN than in the case of pure cellular networks or QCMP CAHAN. In QCLE CAHAN, a novel QoS-constrained network lifetime extension routing algorithm will dynamically select suitable ad-hoc-switch-to-cellular points (ASCPs) according to the MT remaining battery energy such that the selection will balance all the MT battery energy and maximizes the network lifetime. As the number of ASCPs in an ad hoc subnet decreases, the network lifetime will be extended. Maximum network lifetime can be increased until the end-to-end QoS in QCLE CAHAN reaches its maximum tolerable value.
Geocasting is the mechanism to multicast messages to the MTs whose locations lie within a given geographic area (target area). Geolocation-aware CAHAN (GA CAHAN) architecture is proposed to improve total transmitted power expended for geocast services in cellular networks. When the size of geocast target area is large, GA CAHAN can save larger transmitted energy.
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