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1.
On the teletraffic capacity of CDMA cellular networks 总被引:6,自引:0,他引:6
The aim of this paper is to contribute to the understanding of the teletraffic behavior of code-division multiple-access (CDMA) cellular networks. In particular, we examine a technique to assess the reverse link traffic capacity and its sensitivity to various propagation and system parameters. We begin by discussing methods of characterizing interference from other users in the network. These methods are extremely important in the development of the traffic models. We begin with a review of several existing approaches to the problem of handling other-cell interference before presenting a novel characterization of the interference in the form of an analytic expression for the interference distribution function in the deterministic propagation environment. We then look at extending the capacity analyses that assume a fixed and equal number of users in every cell to handle the random nature of call arrivals and departures. The simplest way to do this is by modeling each cell of the network as an independent M/G/x∞ queue. This allows us to replace the deterministic number of users in each cell by an independent Poisson random variable for each cell. The resulting compound Poisson sums have some very nice properties that allow us to calculate an outage probability by analyzing a single random sum. This leads to a very efficient technique for assessing the reverse link traffic capacity of CDMA cellular networks 相似文献
2.
José Alberto Hernández Javier Aracil Víctor López Jorge López de Vergara 《Photonic Network Communications》2007,14(1):49-62
In Optical Burst Switching (OBS), packets travel through the network core as part of longer-size optical bursts, which do
not suffer electronic conversion until they reach an eggress point. Typically, such optical bursts comprise tens or hundreds
of packets, which are assembled/deassembled at border nodes. During the burst-formation process, each arriving packet must
wait until the final burst is complete, which clearly adds an extra delay on each packet in the burst, especially on those
arriving earlier. However, such burst-assembly delay may be excessive for the appropriate performance of certain applications,
mainly real-time interactive ones. This work’s findings are twofold: first, it characterises the burst-assembly delay distribution
of each packet in a burst arisen by the main assembly algorithms found in the literature; and, second, it introduces a new
burst-assembly strategy that takes into account the particular delay constrains of packets in the formation of optical bursts,
along with a detailed study of its properties.
This work has been funded by the “Ministerio de Educación y Ciencia” of Spain under grant TEC2006-03246. 相似文献
3.
The advantages and drawbacks of standardization in TTE (teletraffic engineering) are examined. It is pointed out that the TTE recommendations of CCITT are intended to be international standards. Unlike signaling systems, interfaces, or protocols, the necessity for standardization in this area is not self-evident. However, standardization of grade of service (GOS) definitions, values, and relevant reference conditions seems to be necessary. Support for engineering methods also offers advantages. TTE-related activities in different CCITT study groups try to satisfy many often contradictory demands. Trends in telecommunications strongly support the view that concentration of TTE studies in CCITT would be desirable 相似文献
4.
Advances in enabling technologies and the explosive growth of Internet traffic has led to the widespread proliferation of
network systems in recent years. With their relatively low cost, high throughputs, high-bandwidth utilization, and low-transmission
latency, Optical Burst Switching (OBS) networks represent an ideal solution for next-generation Internet applications. However,
in OBS networks, Burst Header Packet (BHP) contentions occur when two or more BHPs are switched simultaneously to the same
output port of a given core node. These contention events result in significant losses of the corresponding data burst. Accordingly,
this study presents a Store-and-forward COntention-REsolution mechanism, designated as SCORE, which utilizes fiber delay line
buffers to resolve the BHP collision problem, thereby minimizing the burst loss rate. The results of a series of simulations
performed using an OIRC OBS-ns simulator confirm the effectiveness and efficiency of the proposed scheme.
相似文献
Tse-Sheng LinEmail: |
5.
Change detection in teletraffic models 总被引:1,自引:0,他引:1
We propose a likelihood-based ratio test to detect distributional changes in common teletraffic models. These include traditional models like the Markov modulated Poisson process and processes exhibiting long range dependency, in particular, Gaussian fractional ARIMA processes. A practical approach is also developed for the case where the parameter after the change is unknown. It is noticed that the algorithm is robust enough to detect slight perturbations of the parameter value after the change. A comprehensive set of numerical results including results for the mean detection delay is provided 相似文献
6.
7.
Daniel Morató Javier Aracil José Alberto Hernández José Luis García-Dorado 《Photonic Network Communications》2009,18(3):314-322
Given the bufferless nature of Optical Burst- Switched networks, data bursts are either transmitted or dropped; the latter
typically occurs when all the wavelengths of a given output port are occupied. Clearly, the amount of time during which a
given output port is blocked and cannot schedule incoming data bursts is a key performance measure of OBS networks. This work
shows that, under Poissonian burst arrivals, the blocking time distribution of a given output port in an OBS node approaches
the exponential distribution as the number of wavelengths increases. It is further shown that this behavior remains regardless
of the size distribution of incoming bursts, and therefore, regardless of the burst-assembly algorithms employed at the border
nodes. Finally, this result is also applied to the characterization of the amount of overspill traffic, that is, the number
of bursts that arrive within a blocked period, and therefore must be either dropped or diverted over alternative routes. 相似文献
8.
The performance evaluation of computer and communication networks gives rise to teletraffic problems of potentially large dimensionality. We summarize a unifying system theoretic approach to efficient solution of a diversity of such problems, and introduce TELPACK, a publicly available software that implements this approach 相似文献
9.
《Signal Processing Magazine, IEEE》2002,19(3):14-27
The analysis and modeling of computer network traffic is a daunting task considering the amount of available data. This is quite obvious when considering the spatial dimension of the problem, since the number of interacting computers, gateways and switches can easily reach several thousands, even in a local area network (LAN) setting. This is also true for the time dimension: Willinger and Paxson (see Ann. Statist., vol.25, no.5, p.1856-66, 1997) cite the figures of 439 million packets and 89 gigabytes of data for a single week record of the activity of a university gateway in 1995. The complexity of the problem further increases when considering wide area network (WAN) data. In light of the above, it is clear that a notion of importance for modern network engineering is that of invariants, i.e., characteristics that are observed with some reproducibility and independently of the precise settings of the network under consideration. In this tutorial article, we focus on two such invariants related to the time dimension of the problem, namely, long-range dependence, or self-similarity, and heavy-tail marginal distributions 相似文献
10.
A simple modification of the roulette method of teletraffic simulation is presented. At low traffic levels it may result in a reduction, by a factor of ten or more, of the computer time required to simulate a specified number of calls. 相似文献
11.
Teletraffic engineers provide models allowing communications networks to be planned and systems to be designed to meet the performance needs of users within a reasonable cost. The successful modeler combines analytical or simulation skills with a deep understanding of the technology. In the emerging information networking environment comprising new technologies such as ATM, Internet, wireless, etc., and new services such as video, multimedia, data and personal communications services, the old paradigms of circuit-switched calls and Erlang distributions have been severely challenged. The confluence of the shifts in technologies and services along with the convergence of computing, telecommunications, consumer electronics, and electronic media industries, and the shift from a monopolistic to competitive business paradigm, has created a tremendously rich lode of fundamental problems that need to be addressed by teletraffic engineers. In this article the author describes the historical role of the teletraffic engineer, reviews several of the major paradigm shifts, and discusses some of the challenges facing the teletraffic community with an emphasis on modeling wireless communications systems 相似文献
12.
An adaptive algorithm is presented which ensures that the probability of a mobile radio call in progress being forced to terminate during handover in highway microcells is always small, even in the presence of high new call request rates.<> 相似文献
13.
14.
Hong Xiaobin Zhou Jun Wu Jian Guo Hongxiang Zuo Yong Xu Kun Lin Jintong Key Laboratory of Information Photonics Optical Communications Ministry of Education 《中国通信》2010,7(2):87-91
Transmission Control Protocol (TCP) performance over Optical Burst Switching (OBS) is experimentally investigated on an OBS network testbed, concluding that burst losses will lead to a significant drop in the available TCP bandwidth. Two mechanisms are introduced to improve TCP performance. One is concerning the burst assembly optimization and another is based on the novel assembly and scheduling mechanism to reduce the burst losses. 相似文献
15.
GMPLS(通用多协议标签交换)是MPLS技术向光网络发展的产物。描述GMPLS和MPLS控制平台的区别,介绍引用GMPLS协议作为控制平面的OBS网络。提出的网络结构是在OBS的突发控制包中用通用标签代替源节点和目的节点地址,并使用GMPLS协议栈对路由协议、信令功能以及链路管理协议进行增强和扩展以便更好地支持OBS网络。 相似文献
16.
This paper quantitatively analyzes the queueing delay of the constant-bit-rate (CBR) traffic in a multiplexer, where the CBR traffic is mixed with the traffic of another session (interfering traffic) that has throughput and burstiness constraints. This paper focuses as a quality-of-service (QoS) measure on the fraction of the CBR traffic that fails to meet a certain delay requirement. Results include the worst-case QoS of CBR traffic as a function of the throughput and burstiness parameters imposed on the interfering traffic. Results of this paper can be applied to traffic management and call processing of asynchronous transfer mode (ATM) networks 相似文献
17.
Cox R.V. Haskell B.G. LeCun Y. Shahraray B. Rabiner L. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1998,86(5):755-824
The challenge of multimedia processing is to provide services that seamlessly integrate text, sound, image, and video information and to do it in a way that preserves the ease of use and interactivity of conventional plain old telephone service (POTS) telephony. To achieve this goal, there are a number of technological problems that must be considered, including: compression and coding of multimedia signals, including algorithmic issues, standards issues, and transmission issues; synthesis and recognition of multimedia signals, including speech, images, handwriting, and text; organization, storage, and retrieval of multimedia signals, including the appropriate method and speed of delivery, resolution, and quality of service; access methods to the multimedia signal, including spoken natural language interfaces, agent interfaces, and media conversion tools; searching by text, speech, and image queries; browsing by accessing the text, by voice, or by indexed images. In each of these areas, a great deal of progress has been made in the past few years, driven in part by the relentless growth in multimedia personal computers and in part by the promise of broad-band access from the home and from wireless connections. Standards have also played a key role in driving new multimedia services, both on the POTS network and on the Internet. It is the purpose of this paper to review the status of the technology in each of the areas listed above and to illustrate current capabilities by describing several multimedia applications that have been implemented at AT&T Labs over the past several years 相似文献
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19.
Recently, preemption techniques have attracted considerable attention as a means to provide differentiated quality of service
in optical burst switching (OBS) networks. This paper is focused on the analysis of preemption probabilities for bursts within
the same priority class. As proposed by Vokkarane and Jue ((2003)* IEEE J Select Areas Commun 21(7): 1198–1209) an incoming
burst will preempt the burst in service, within the same priority class, if the residual length of the burst in service is
smaller than the incoming burst length. For a general case with wavelength conversion, the preemption probability of contending
bursts with a generic service distribution, not necessarily exponential, is analyzed. First, we show that the size distribution
for the preempting bursts is shifted to larger values, in comparison to the original burst size distribution. Second, we obtain
an upper and lower bound for the preemption probability. Finally, the asymptotic behavior of the OBS switch is analyzed showing
that preemption will always occur for a very large number of wavelengths. 相似文献
20.
信道调度算法是提高光突发交换(OBS)网络性能的关键技术之一.结合ODBR重调度算法和FDL的延迟作用,提出来一种Improved-OBDR算法.仿真结果表明改进算法在保证高优先级低丢包率的同时,保证低优先级尽可能低的丢包率,提高了资源利用率. 相似文献