An efficient modeling and dimensioning approach for integrated streaming and elastic traffic

Recent studies show that both data traffic and real-time traffic grow very fast in wired and wireless networks. To provide better performance guarantee, these applications need efficient network modeling and planning. In this paper, the problem where the total bandwidth of a link is shared by streaming traffic (real time traffic such as voice or video etc.) and elastic traffic (such as data) is studied. Integrating streaming traffic and elastic traffic presents a unique dimensioning problem. This paper considers dimensioning a link to satisfy both quality of service (QoS) requirements for streaming traffic, such as loss probability, and elastic traffic, such as mean waiting (delay) time. The Erlang loss model is applied to streaming traffic and a bursty traffic model is applied to the elastic traffic. Efficient dimensioning algorithms based on classical Markovian models and time-scale decomposition are then proposed. Numerical results show that the proposed methods have good accuracy.     

QoS‐based radio network dimensioning for LTE networks with heavy real‐time traffic

Applications of video streaming and real‐time gaming, which generate large amounts of real‐time traffic in the network, are expected to gain considerable popularity in Long Term Evolution networks. Maintaining the QoS such as packet delay, packet loss ratio, median, and cell border throughput requirements in networks dominated by real time traffic, is critical. The existing dimensioning methodology does not consider QoS parameters of real‐time traffic in network dimensioning. Moreover, exhaustive and time‐consuming simulations are normally required to evaluate the performance and QoS of real‐time services. To overcome this problem, we propose an improved radio network dimensioning framework that considers the QoS of real‐time traffic in network dimensioning. In this framework, an analytical model is proposed to evaluate the capacity and performance of real‐time traffic dominant Long Term Evolution networks. The proposed framework provides a fast and accurate means of finding the trade‐off between system load, packet delay, packet loss ratio, required median, and cell border throughput. It also provides network operators with an analytical means for obtaining the minimum number of sites required by jointly considering coverage, capacity and QoS requirements. The accuracy of the proposed model is validated through simulations. Copyright © 2012 John Wiley & Sons, Ltd.     

Performance of a Shared Packet Wireless Network with Interactive Data Users

This paper studies the user-perceived performance of a shared packet wireless network for interactive data applications such as Web-browsing. We have defined a new measure: the Equivalent Circuit Rate (ECR) for a user in a shared access network is the dedicated access circuit rate that would be required by the user in order to have an equivalent user experience. The ECR measure is intuitive, useful and robust. We present a simple analytical model based on a closed queueing network with a finite population of interactive data users whose traffic can be modeled as ON/OFF traffic with feedback. The analytical results are consistent with our detailed simulations, where we study TCP-based Web traffic simulations for an EDGE (Enhanced Data Rates for GSM Evolution) TDMA system using realistic workload models. Our study incorporates constant bit-rate channels, variable bit-rate channels, as well as mixed user groups with different channel conditions. We show that a shared wireless network is well characterized by simple parameters that depend only on mean statistics, for a broad range of scenarios. ECR is well approximated by R×(1–U), where U is the utilization and R is the effective shared channel rate; this result holds even if different user groups have different rates or the channel rates are variable. These results will be useful in network dimensioning, admission control, and for defining quality of service targets for different user groups.     

Network dimensioning at the call level for the always‐on network

It is becoming common for the network to provide always‐on access services, where subscribers are guaranteed that their call requests will never be blocked. This paper studies the call‐level link dimensioning for the always‐on network with single‐class traffic. The call‐level QoS requirement is expressed in terms of the probability of a poor‐quality call, which is the probability that a call experiences packet‐level QoS violation at any time during its duration, as opposed to the probability of blocking in the network with call admission control (CAC). The system is modelled as the M/M/infinite system with finite population and an analytic expression for the probability of a poor‐quality call is derived based on performability analysis. The effects of the call‐level traffic characteristics on the required link resources are studied. It is also shown that the call‐level link dimensioning for the always‐on network needs more link resources than the network with CAC, and the call‐level link dimensioning based on the analytic expression can be used to conservatively dimension the always‐on network with arbitrarily distributed call holding time and inter‐call time. The paper also studies the problem of estimating the call‐level traffic characteristics when the knowledge of call boundaries is not available. Copyright © 2004 John Wiley & Sons, Ltd.     

Cost models for QoS-differentiated interconnecting and wholesale access services in?future generation networks

Currently, network operators and Internet service providers are offering ??Triple Play?? products integrating services with different Quality of Service (QoS) requirements. It is leading to Internet traffic with strong service integration under an all-IP-based broadband network platform. However, new multimedia service offers require individual QoS guarantees for each type of services. The interconnection between different providers necessitates the reconsideration of the actual cost schemes. Interconnection and wholesale access services (It is an extension of ??wholesale network?? definition, where Telco??s physical network and equipment are ??shared?? to many independent Service Providers. If the incumbent offers broadband access services, the rest of the alternative providers have recourse to the incumbent??s ??wholesale access service??. Bitstream service is the most important service of this type, actually regulated over DSL and cable networks.) appear to be a simple solution, but the consideration of QoS parameters requires an extension of the current network dimensioning methods based mainly on the average bandwidth demand from each user. This paper proposes a cost model which considers QoS parameters and, based on the ??Total Element based Long Run Incremental Cost?? (TELRIC) model, is applied to the wholesale access and interconnection paradigm. Three traffic engineering methods are considered and studied for network dimensioning. Hereby the aim is to guarantee the QoS of the different services: complete traffic segregation under virtual tunnels, complete traffic integration by over-engineering and partial traffic integration using a priority queuing scheme. The proposed method enables the development of a specific cost scheme based on a complete scenario considering different types of users. The variety of used IP applications suppose direct implications over different levels of interconnection, mainly at the low-level Metro access and the high-level edge node.     

On the eNB‐based energy‐saving cooperation techniques for LTE access networks

Energy efficiency is one of the top priorities for future cellular networks, which could be accomplished by implementing cooperative mechanisms. In this paper, we propose three evolved node B (eNB)‐centric energy‐saving cooperation techniques for long‐term evolution (LTE) systems. These techniques, named as intra‐network, inter‐network, and joint cooperation, involve traffic‐aware intelligent cooperation among eNBs belonging to the same or different networks. Our proposed techniques dynamically reconfigure LTE access networks in real time utilizing less number of active eNBs and thus, achieve energy savings. In addition, these techniques are distributed and self‐organizing in nature. Analytical models for evaluating switching dynamics of eNBs under these cooperation mechanisms are also formulated. We thoroughly investigate the proposed system under different numbers of cooperating networks, traffic scenarios, eNB power profiles, and their switching thresholds. Optimal energy savings while maintaining quality of service is also evaluated. Results indicate a significant reduction in network energy consumption. System performance in terms of network capacity utilization, switching statistics, additional transmit power, and eNB sleeping patterns is also investigated. Finally, a comprehensive comparison with other works is provided for further validation. Copyright © 2013 John Wiley & Sons, Ltd.     

Analysis and dimensioning of switchless networks for single-layeroptical architecture

The “switchless” all-optical network is an alternative networking approach being developed in the framework of the ACTS project named SONATA, which aims to provide a future single layer, advanced transport architecture on a national scale. The single hop, shared access network employs time and wavelength agility (a WDMA/TDMA scheme), using fast tunable transmitters and receivers, to set up individual customer connections through a single wavelength router (suitably replicated for resilience). The dimensioning of this type of network is one of the main tasks for the design of networks serving a certain number of customers, connected together by means of passive optical networks (PONs). This paper reports an analytical model which allows the network dimensioning according to some relevant design parameters: the number of customers per PON, the number of PONs, the offered traffic per single user (either considering residential or business user), and the required system performance expressed in terms of blocking probability. Furthermore, relevant issues related to the dimensioning of switchless networks are discussed and some results achieved for relevant network scenarios are reported, to assess the feasibility of the system concept     

Modeling of systems with overflow multi-rate traffic

The article proposes an analytical method for determining occupancy distribution and blocking probability in systems which are offered overflow traffic composed of multi-service traffic streams. The described analytical model enables determination of parameters of traffic overflowed from primary groups in hierarchically constructed telecommunication networks. The proposed method is based on an appropriate modification of the Kaufman-Roberts recursion for the full-availability group with multi-rate traffic and uses the modified Fredericks & Hayward’s approximation. Additionally, an approximate method for dimensioning systems with multi-service overflow traffic is also presented. The analytical results of the blocking probability and the results obtained in the dimensioning processes calculated using the presented methodology are compared with the data obtained from the system simulation process.     

Performance evaluation of a priority‐based resource allocation scheme for multiclass services in IoT

Recently, the deployment of novel smart network concepts, such as the Internet of things (IoT) or machine‐to‐machine communication, has gained more attention owing to its role in providing communication among various smart devices. The IoT involves a set of IoT devices (IoTDs) such as actuators and sensors that communicate with IoT applications via IoT gateways without human intervention. The IoTDs have different traffic types with various delay requirements, and we can classify them into two main groups: critical and massive IoTDs. The fundamental promising technology in the IoT is the advanced long‐term evolution (LTE‐A). In the future, the number of IoTDs attempting to access an LTE‐A network in a short period will increase rapidly and, thus, significantly reduce the performance of the LTE‐A network and affect the QoS required by variant IoT traffic. Therefore, efficient resource allocation is required. In this paper, we propose a priority‐based allocation scheme for multiclass service in IoT to efficiently share resources between critical and massive IoTD traffic based on their specific characteristics while protecting the critical IoTDs, which have a higher priority over the massive IoTDs. The performance of the proposed scheme is analyzed using the Geo/G/1 queuing system focusing on QoS guarantees and resource utilization of both critical and massive IoTDs. The distribution of service time of the proposed system is determined and, thus, the average waiting and service times are derived. The results indicate that the performance of the massive IoTDs depends on the data traffic characteristics of the critical IoTDs. Furthermore, the results emphasize the importance of the system delay analysis and demonstrate its effects on IoT configurations.     

Network dimensioning and performance of multiservice, multirateloss networks with dynamic routing

We address a multiservice, multirate loss network environment with dynamic routing. In this setting, we consider multiple traffic load periods (multihour) during the day, and by observing network dynamics, we present a network dimensioning model that consists of two steps: a bandwidth estimation step, followed by a multicommodity flow model for multiple services and traffic loads. For network operations, we discuss a probabilistic admission control policy and three multiservice routing schemes. We have used a ten-node network with multiple asymmetric traffic data sets (partially extracted from an actual network) for our study. It was found that the capacity obtained using the analytic network dimensioning model provides a good estimate of network capacity required for meeting the grade-of-service goal for each service type in each traffic load period; this observation is based on a simulated network environment that uses the proposed admission control and the dynamic routing schemes. Our observation suggests that it may not be not necessary for the dimensioning model to explicitly incorporate an admission control policy, but admission control is needed for network operation to provide desirable grade-of-service     

一种基于Kalman的实时话务量预测算法

移动网话务量的预测可以为解决移动网的网络拥塞、覆盖规划、负载均衡和接入控制等方面的问题提供决策支持。日益复杂的移动网络环境对移动网话务量预测的实时性提出了新的要求,针对这一问题进行了研究,结合卡尔曼滤波算法在预测时效性方面的优点,提出了一种基于卡尔曼滤波的移动网实时话务量预测算。该算法通过对呼叫时延的实时预测实现对移动网实时话务量的预测。仿真结果表明,所提算法具有良好的实时性和预测质量。     

A Distributed Channel Access Scheme with Guaranteed Priority and Enhanced Fairness

Although the IEEE 802.11e enhanced distributed channel access (EDCA) can differentiate high priority traffic such as real-time voice from low priority traffic such as delay- tolerant data, it can only provide statistical priority, and is characterized by inherent short-term unfairness. In this paper, we propose a new distributed channel access scheme through minor modifications to EDCA. Guaranteed priority is provided to real time voice traffic over data traffic, while a certain service time and short-term fairness enhancement are provided to data traffic. We also present analytical models to calculate the percentage of time to serve voice traffic and the achieved data throughput. Both analysis and simulation demonstrate the effectiveness of our proposed scheme.     

Cross-Layer Design of ASE-Noise-Limited Island-Based Translucent Optical Networks

This paper considers the design and dimensioning of translucent optical networks based on the concept of optical transparent islands. In systems with dispersion compensation, amplified spontaneous emission (ASE) noise becomes a dominant physical-layer impairment in constraining the maximal transparent reach limit of a lightpath. Taking this dominant impairment into account, an efficient transparent island division algorithm is proposed to divide a large transport network into a few optical transparent islands and to minimize the total number of opaque island-border nodes. Optimization models for translucent network dimensioning are presented to maximize served traffic demand given certain network capacity and to minimize the required wavelength capacity given a certain traffic demand matrix. Simulation studies show that the proposed transparent island division approach and network-dimensioning optimization models require only 25% opaque nodes to overcome the constraint of transparent reach limit and achieve performance as good as that of a more expensive 100% opaque network.      

LTE网络覆盖规划技术研究

为了保障高质量的网络部署,LTE系统的覆盖规划对网络的建设成本及质量发挥着至关重要的作用。文章基于LTE实际组网的规划需求,结合系统化的理论及仿真分析,对LTE无线接入的链路及网络特征进行了深入的研究。在此基础上,开发形成一套完整的LTE蜂窝网络覆盖规划理论及应用方法,为LTE无线网络规划提供了基础性的技术指导。     

Optical Data Network Based on the Switchless Concept: Analysis and Dimensioning

The switchless all-optical network aims to provide a future single-layer, advanced transport architecture on a national scale. The single-hop, shared-access network employs time and wavelength agility (a WDMA/TDMA scheme), using fast tuneable transmitters and receivers, to set up individual customer connections through a single wavelength router, which is suitably replicated for resilience. While in a recent paper we reported the analysis and dimensioning of a switchless network assuming just the telephone traffic, we provide in this paper a new model, which contains innovative elements, and report original results assuming to deal with data traffic of two different types: constant bit rate (CBR) and variable bit rate (VBR). The innovation is based on the fact that the model considers more traffic flows with different traffic requirements (e.g., bandwidth, duration) as input to a group of time-slot connections on the same wavelength between two passive optical networks (PONs). We obtained analytical expressions of the main traffic characteristics (loss probability, throughput and overflowing traffic) both for the primary group of time-slots and for the secondary group of time-slots, to which the overflowing traffic streams enters.Moreover, we show that the innovative network structure, i.e., use of a passive wavelength router node (PWRN), works also perfectly with more different traffic streams.The analytical model presented in this paper has been compared with a simulation model. The comparison has revealed very good agreement. Relevant network cases are considered, and the dimensioning of the network in such cases is reported, in terms of the key network parameters, loss probability and throughput.     

LTE网络中业务识别方案的研究与实现*1

为了实现对长期演进(Long Term Evolution,LTE)网络的业务识别,分析了S1接口用户面协议栈,利用模块化设计思想实现了对S1接口流量的业务识别.针对传统业务识别系统识别度低、统计能力不强的缺陷,在传统的业务识别系统基础上,提出了一个多识别的业务识别方案,实现了对业务类型的精确识别.经过现网数据测试验证,所设计的多识别的业务识别方案达到了预期的效果,在LTE移动通信网络业务识别领域具有推广意义.     

Comparative Performance Study of LTE Downlink Schedulers

Long time evolution (LTE) represents an emerging and promising technology for providing broadband, mobile Internet access. Because of the limitation of available spectrum resource, high spectrum efficiency technologies such as channel-aware scheduling need to be explored. In this work, we evaluate the performance of three scheduling algorithms proposed for LTE downlink transmission. The evaluation takes place in mixed traffic scenarios and aims at exploring strengths and weaknesses of the proposed algorithms. Simulation results illustrate the importance of real-time traffic awareness by schedulers when a specified level of quality of service is required. The research shows that lack of prioritisation of multimedia traffic will lead to severe degradation of video and VoIP services even with a relatively low network load.     

Recognizing and characterizing dynamics of cellular devices in cellular data network through massive data analysis

The user clients for accessing Internet are increasingly shifting from desktop computers to cellular devices. To be competitive in the rapidly changing market, operators, Internet service providers and application developers are required to have the capability of recognizing the models of cellular devices and understanding the traffic dynamics of cellular data network. In this paper, we propose a novel Jaccard measurement‐based method to recognize cellular device models from network traffic data. This method is implemented as a scalable paralleled MapReduce program and achieves a high accuracy, 91.5%, in the evaluation with 2.9 billion traffic records collected from the real network. Based on the recognition results, we conduct a comprehensive study of three characteristics of network traffic from device model perspective, the network access time, the traffic volume, and the diurnal patterns. The analysis results show that the distribution of network access time can be modeled by a two‐component Gaussian mixture model, and the distribution of traffic volumes is highly skewed and follows the power law. In addition, seven distinct diurnal patterns of cellular device usage are identified by applying unsupervised clustering algorithm on the collected massive traffic data. Copyright © 2014 John Wiley & Sons, Ltd.     

Topology Design of OXC-Switched WDM Networks

This paper attempts to find a new analytical framework to identify cost-effective topological architectures of optical cross-connect (OXC)-switched wavelength-division multiplexing (WDM) networks. To keep the analysis tractable, we first focus on regular networks and a deterministic uniform traffic model. Regular topologies with symmetries are good approximations of metropolitan area and local area networks but only a fair resemblance of wide area networks. We find that for a regular topology the minimum-hop distance, which is normally used for gauging the size of the network, is an important parameter in dimensioning switching resources. By setting up a first-order cost model and evaluating the tradeoff between network resources, we obtain closed form solutions for the optimal node degree and network cost. For network design under stochastic traffic, we study the worst case capacity dimensioning and blocking probability among the set of all possible stochastic traffic distributions with the same mean and variance. The analytical approach presented in this paper helps us gain insights of parametric dependency of an optimal network architecture on key network design parameters.     

针对密集城区场景的VoLTE语音性能研究

在LTE网络大规模部署的现阶段,4G用户规模和业务量持续攀高,4G手机渗透率迅速提升,而语音业务作为运营商重要的收入来源,其重要性不言而喻.针对LTE的语音终极实现方案VoLTE(Voice over LTE),研究了实现VoLTE的关键技术,分析了影响语音质量的多种因素,提出了一种基于E-model的VoLTE语音性能评估方法,在LTE网络率先部署的密集城区场景中,基于不同网络配置和并发用户数,对VoLTE业务性能进行仿真,并采用E模型进行语音质量分析,最终实现对VoLTE的语音性能评估.