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941.
On the Performance of TETRA Short Data Service-Transport Layer 总被引:1,自引:0,他引:1
This paper presents the results of an extensive measurement survey on the performance of Short Data Service Transport Layer
(SDS-TL) of Terrestrial Trunked Radio (TETRA) cellular networks. We developed a novel software measurement platform that runs
over the TETRA Peripheral Equipment Interface (PEI), generates SDS-TL traffic, performs measurements, and presents statistics
of QoS metrics. The measurement platform was utilized in two measurement campaigns: in the first one, two terminals were co-located
in the same TETRA cell, and in the second campaign the terminals were positioned in different cells. Measurements were taken
for SDS-TL sizes varying from 10 to 190 bytes (excluding the TL header) with an increment of 5 bytes. For each SDS-TL size,
1,500 messages were exchanged through the measurement platform between the TETRA mobile terminals. We repeated all measurements
for three intertransmission intervals, namely 2, 1.5, and 1 s, corresponding to measurement durations-for each set of 1,500
SDS-TL- of ≈ 3,000, 2,250 and 1,500 s, respectively. Hence, 166,500 SDS-TL messages were exchanged between two terminals for
each measurement campaign. Results obtained include the end-to-end transmission delay (mean and standard deviation) and the
percentage of lost SDS-TL versus the message size for the three intertransmission intervals. The effects of inadequate radio
capacity as well as gaps in the radiocoverage can be easily identified through the measurement platform, and we analyze such
representative cases. 相似文献
942.
聂飞翔 《电信工程技术与标准化》2003,(11):43-45
本对目前常用的3.5G、LMDS设备的业务平台、业务特性及对某些特殊业务支持能力进行了探讨。 相似文献
943.
944.
赵旭凇 《电信工程技术与标准化》2003,(5):66-70
本首先介绍了OFDM的原理、采用基带FFT算法的系统实现及其优缺点,随后着重阐述了OFDM在无线局域网中应用的优势和存在的问题,最后给出了一个实例——IEEE 802.11a标准中的OFDM。 相似文献
945.
Michael B. Pursley Harlan B. Russell Jeffrey S. Wysocarski 《International Journal of Wireless Information Networks》2004,11(3):147-159
The use of adaptive-transmission protocols in wireless, store-and-forward, packet communication networks may result in large differences in the energy requirements of the alternative paths that are available to the routing protocol. Routing metrics can provide quantitative measures of the quality and energy efficiency of the paths from the source to the destination. Such measures are required if the routing protocol is to take advantage of the potential energy savings that are made possible by an adaptive-transmission protocol. An energy-efficient protocol suite for routing and adaptive transmission in frequency-hop wireless networks is described and evaluated, several routing metrics are compared, and tradeoffs among energy efficiency, delay, and packet success probability are investigated. 相似文献
946.
947.
948.
福田作为中国全系列商用汽车领军企业,为了能够确立竞争优势,积极打造服务体系。在无线技术被广泛利用的今天,福田为了避免库存,时效,准确率等问题,经过慎重选型,选择了美国讯宝科技公司及其合作伙伴。条形码结合无线技术不但降低了库存成本,提高了客户响应速度,而且提供了准确及时的库存信息,大大提高了福田汽车在商用车市场的竞争力。 相似文献
949.
Wireless Local Area Networks have gained popularity at an unprecedented rate over the last few years. However, as the spectrum of applications they are called to support broadens, their inefficiency in meeting the diverse requirements of a wider range of applications becomes evident. Most existing access mechanisms cannot provide Quality-of-Service (QoS) assurances. Even those that are QoS aware can only provide relative service differentiation. In this work, we propose a dynamic priority medium access scheme to provide time-bounded services. By approximating an ideal Earliest Deadline First (EDF) scheduler, the proposed scheme can offer delay and delay jitter assurances while achieving high medium utilization. Analytical studies and simulation experiments document and confirm the positive characteristics of the proposed mechanism.
Orestis Tsigkas received his Diploma in electrical and computer engineering from the Aristotle University of Thessaloniki, Greece in 2002. He is currently working towards his Ph.D. degree in the same department. His research interests include medium access, as well as quality-of-service provisioning.
Fotini-Niovi Pavlidou received the Ph.D. degree in electrical engineering from the Aristotle University of Thessaloniki, Greece, in 1988 and the Diploma in mechanical-electrical engineering in 1979 from the same institution. She is currently a Professor at the Department of Electrical and Computer Engineering at the Aristotle University engaged in teaching for the under- and post-graduate program in the areas of mobile communications and telecommunications networks. Her research interests are in the field of mobile and personal communications, satellite communications, multiple access systems, routing and traffic flow in networks and QoS studies for multimedia applications over the Internet. She is being involved with many national and international projects in these areas (Tempus, COST, Telematics,IST) and she has been chairing the European COST262 Action on “Spread Spectrum Systems and Techniques for Wired and Wireless Communications”. She has served as member of the TPC in many IEEE/IEE conferences and she has organized/chaired some conferences like, the “IST Mobile Summit 2002”, the 6th “International Symposium on Power Lines Communications-ISPLC2002”, the “International Conference on Communications-ICT1998” etc. She is a permanent reviewer for many IEEE/IEE journals. She has published about 80 papers in refereed journals and conferences. She has served as guest-editor on special issues as: “Mobile Ad Hoc Networks (MANETs): Standards, Research, Applications” in the International Journal of Wireless Information Networks and “Power Line Communications and Applications” in the International Journal on Communications Systems. She is a senior member of IEEE, currently chairing the joint IEEE VT&AES Chapter in Greece. 相似文献
950.
An approach to camera location determination based on the perspective projection geometry of three points is proposed, which is simple and straightforward. No rigid restrictions are placed on the original positional and orientational relationships between the camera and the mark. Experimental results verify the feasibility of the proposed approach. 相似文献