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Liljana Gavrilovska 《Wireless Personal Communications》2006,37(3-4):271-290
Wireless ad hoc networks are temporary formed, infrastructureless networks. Due to the unstable channel conditions and network connectivity, their characteristics impose serious challenges in front of network designers. The layering approach to network design does not fit the ad hoc environment well. Therefore, various cross-layering approaches, where protocol layers actively interact, exchange inherent layer information and fine tune their parameters according to the network status are becoming increasingly popular. This paper presents an in-depth analysis of the latest cross-layering approaches for wireless ad hoc networks supported by several examples. A special emphasis is put on the link and network layer related cross-layer designs. Several link adaptation and efficient service discovery schemes are elaborated through analytical and simulation studies. Their performance shows the potentials of the cross-layering for boosting system characteristics in wireless ad hoc networks.
Liljana Gavrilovska currently holds a position of full professor at Faculty of Electrical Engineering, University “St. Cyril and Metodij” – Skopje, Macedonia. She is chief of Telecommunications Laboratory and teaches undergraduate courses in telecommunication networks, data transmission and switching and traffic theory, and graduate courses in wireless, mobile and personal networks, teletraffic engineering and planning, and broadband multiservices networks. In 2000 she joined the Center for PersonKommunikation, Aalborg University, Denmark, as a visiting professor and during 2001--2002 she held a position of associate research professor at the same university. Currently she holds a part-time position of associated research professor with Center for Teleinfrastructur (CTIF). Prof. Gavrilovska was involved in several EU (ACTS ASAP, IST PACWOMAN, MAGNET, TEMPUS) and national/international projects. She published numerous conference and journal papers and participated in several workshops. At the moment she is working on the book “Ad Hoc Networking Towards Seamless Communications” together with prof. R. Prasad. Her research interests include wireless and personal area networks, ad hoc networking, networking protocols, traffic analysis, QoS, and optimization techniques. She is a senior member of IEEE and serves as a Chair of Macedonian Communication Chapter. 相似文献
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Joseph Dunn Michael Neufeld Anmol Sheth Dirk Grunwald John Bennett 《Mobile Networks and Applications》2006,11(1):37-45
Many companies, organizations and communities are providing wireless hotspots that provide networking access using 802.11b wireless networks. Since wireless networks are more sensitive to variations
in bandwidth and environmental interference than wired networks, most networks support a number of transmission rates that
have different error and bandwidth properties. Access points can communicate with multiple clients running at different rates,
but this leads to unfair bandwidth allocation. If an access point communicates with a mix of clients using both 1 Mb/s and
11 Mb/s transmission rates, the faster clients are effectively throttled to 1 Mb/s as well. This happens because the 802.11
MAC protocol approximate “station fairness”, with each station given an equal chance to access the media. We provide a solution
to provide “rate proportional fairness”, where the 11 Mb/s stations receive more bandwidth than the 1 Mb/s stations. Unlike
previous solutions to this problem, our mechanism is easy to implement, works with common operating systems and requires no
change to the MAC protocol or the stations.
Joseph Dunn received an M.S. in computer science from the University of Colorado at Boulder in 2003, and B. S. in coputer science and
mathematics from the University of Arizona in 2001. His research interests are in the general area of computer systems, primarily
focusing on security and scalability in distributed systems. He is currently working on his Ph.D. in computer science from
the University of Colorado at Boulder.
Michael Neufeld received a Ph.D. in Computer Science from the University of Colorado at Boulder in December of 2004, having previously received
an M.S. in Computer Science from the University of Colorado at Boulder in 2000 and an A.B. in Computer Science from Princeton
University in 1993. His research interests are in the general area of computer system, specifically concentrating on wireless
networking, software defind/cognitive radio, and streerable antennas. He is currently a postdoc in the Computer Science department
at the University of Calorado at Boulder pursuing research related to software defined radio and new MAC protocols for steerable
phase array antennas.
Anmol Sheth is a Ph.D. student in Computer Science at the University of Colorado at Boulder. He received his B.S. in Computer Science
from the University of Pune, India in 2001. He has been co-leading the development of the MANTIS operating system. He has
co-authored three papers include MAC layer protocol design, energy-efficient wireless communication, and adapting communications
to mobility.
Dirk Grunwald received his Ph.D. from the University of Illinois in 1989 and joined the University of Colorado the same year. His work
addresses research and teaching in the broad area of “computer systems”, which includes computer architecture, operating systems,
networks, and storage systems. His interests also include issues in pervasive computing, novel computing models, and enjoying
the mountains. He is currently an Associate Professor in the Department of Computer Science and in Electrical and Computer
Engineering and is also the Director of the Colorado Center for Information Storage.
John Bennett is a Professor of Computer Science with a joint appointment in Electrical and Computer Engineering at the University of Colorado
at Boulder. He also serves as Associate Dean for Education in the College of Engineering and Applied Science. He joined the
CU-Boulder faculty in 2000, after serving on the faculty of Rice University for 11 years. While at Rice, Bennett pioneered
a course in engineering design for both engineering and non-engineering students that has been emulated at several universities
and high schools. In addition to other teaching awards, Bennett received the Keck Foundation National Award for Engineering
Teaching Excellence for his work on this course. Bennett received his Ph.D. in 1988 from the University of Washington. Prior
to completing his doctoral studies, he was a U.S. Naval Officer for several years and founded and served as President of Pacific
Mountain Research, Inc., where he supervised the design and development of a number of commercial computing systems. Bennett's
primary research interests are broadly focused in the area of distributed systems, and more narrowly in distributed information
management and distributed robotic macrosensors. 相似文献
4.
赵丽萍 《计算机与数字工程》2012,40(6):13-15,103
针对Ad Hoc网络中传统AODV协议不支持QoS的缺陷,提出了一种多约束QoS AODV跨层优化方法MQ-AODV(Multi-Constrained QoS AODV)。该方法采用跨层设计的思想,除以传统AODV协议的转发跳数作为路由选择判据之外,而且加入应用层的QoS需求信息和MAC层的多种QoS指标作为路由选择判据,并通过改进AODV路由表结构和路由查找算法,提高AODV路由协议性能。仿真测试结果表明MQ-AODV协议缩短了传输时延,增强了路由协议的适应性和鲁棒性。 相似文献
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在功率受限的机会频谱接入(OSA)研究中,大多使用完全可观测马尔可夫决策过程(MDP)对环境建模,以提高物理层或介质访问控制(MAC)层指标,但由于感知设备的限制,无法保证用户对环境完全感知。为解决该问题,提出一种基于部分可观测马尔可夫决策过程(POMDP)与Sarsa(λ)的跨层OSA优化设计方案。结合MAC层和物理层,采用POMDP对功率受限且有感知误差的次用户频谱感知和接入过程进行建模,并将其转换为信念状态MDP(BMDP),使用Sarsa(λ)算法对其进行求解。仿真结果表明,在功率受限条件下,该Sarsa(λ)-BMDP方案的有效传输容量、吞吐量和频谱利用率分别比完全可观测Q-MDP方案低9%、7%和3%左右,其误比特率比基于点的值迭代PBVI-POMDP方案低20%左右,比Q-MDP方案高16%左右。 相似文献
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为提高多信道无线多跳网络的效用,提出了一种实际可行的跨层优化机制. 利用该机制,每个节点在传输层使用联合设计算法分布式地调整流速率,在链路层根据所提出的分布式调度算法进行速率分配;网关节点使用所提出的干扰代价最小的信道分配算法集中式地分配信道. 通过在层间和节点间传递信息来协调这些层的工作,比集中式算法降低了复杂度,减少了信令开销. 仿真结果表明,该机制具有快速收敛性,且能保证业务流间的公平性;随着可用射频和信道数目的增加,业务流的速率和网络效用增加. 相似文献
10.
提出了一种跨层设计及路径质量感知的移动自组网(MANET)自适应Internet接入策略. 综合考虑网络剩余带宽、投递率以及节点负载等因素,设计一种综合多目标性能参数的路由判据,均衡网络负载,满足互联时多媒体业务的服务质量需求. 同时,根据网关负载和网络拓扑情况自适应调整网关通告的广播范围和发送间隔,实现网关的最佳覆盖. 仿真结果表明,该算法能有效提高网络的互联性能,并保持合理的控制开销. 相似文献