Performance Requirements for Integrated Voice/Data Networks

This paper addresses top-down end-to-end user-oriented performance requirements pertaining primarily to voice and digital data services. The discussion of requirements for voice parameters accounts for the performance of existing analog and mixed analog/digital networks, as well as the likely effects on performance of short, medium, and long term evolution toward the ultimate all digital ISDN. The requirements for digital data parameters necessarily reflect an evolutionary process which is less consistent than for voice, and therefore these requirements are less definitive in nature. The discussions of voice and digital data performance apply largely to a wide variety of appropriate network designs, transmission schemes, and switching architectures. Both traditional parameters, as well as contemporary parameters associated with new and evolving systems, are considered. The emphasis is on the performance of nation-wide public and private networks, but the paper also considers the constraints of international connections.     

Sequencial Routing Optimization for Circuit Switched Networks

Nonhierarchical alternate routing is the simplest extension to the hierarchical routing currently used in telephone networks. In order to evaluate the merits of such a technique, it is necessary to be able to optimize some performance measure over the routing variables. In a first step, a short discussion is presented of the evaluation algorithms used for computing the end-to-end blocking probabilities in networks operating under nonhierarchicai alternate routings. Then the results of a statistical sampling of the routing space for a small network are presented, to illustrate important characteristics of the routing problem. Next, two heuristic optimization techniques are discussed, one based on classical steepest descent and the other inspired from classical routing optimization of traffic flows in transportation and communication networks. Acceleration techniques are discussed in both cases, and the convergences rates of the alorgithms are presented for a number of networks. A brief discussion is finally given of the usefulness of nonhierarchical alternate routing in reducing the blocking probability in already existing networks, and in decreasing the number of trunks required to maintain a prespecified grade of service, both in real and artificially generated networks.     

电路交换网与IP网络发展趋势

分析了ＩＰ网发展成为新型公共网络的可能性;阐述 过渡期内我国电信网络的发展趋势;并就我国电信 网络建设提出建议。     

An Incremental Capacity-Allocation Algorithm for Voice/Data Networks

An algorithm is described by which TDM slots in many links of a network can be optimally allocated between voice and data. It is an adaptation of a convex-programming method due to Fox, by which a pool of resources is allocated to minimize a convex separable criterion function such as blocking probability for voice subject to a single convex separable constraint such as specified maximum mean delay to data. In our case the single pool of resources is the total of the available slots. The necessary adaptation of Fox's algorithm is described for the minimum blocking problem, and for minimum data delay subject to a blocking constraint.     

Packetized Service Integration Network for Dedicated Voice/Data Subscribers

This paper describes a new integrated service network using packetized voice/data technology which was developed in consideration of the sophisticated service demands for voice, data, and facsimile communication. A major problem in constructing this network is in the local distribution network, i.e., the subscriber interface unit, the local end office, and the subscriber loop which connects them. The concepts, choice of design parameters, and laboratory test results of the packetized service integration network are briefly discussed.     

Performance of Voice/Data Integration on a TDM System

Data queueing is of primary concern in a voice/data integrated TDM system. The data queueing model is represented in the discrete-time domain with multiple servers and voice is given a higher priority than data. The data arrival process is assumed to be Poisson and the voice arrival process is characterized by a Markov chain. The correlation coefficient of the number of on voice calls between consecutive frames is used to measure the correlation behavior of the voice process. While the generating function approach may be used to analyze the queueing process, it involves the evaluation of a large number of boundary terms. On the assumption that the voice traffic consists ofNi.i.d. two-state Markov chains, we derive a simple expression for the mean queue size as a function of two variables in the form of the traffic departure processes. The results clearly reveal a significant influence of the correlation coefficient on the data queueing process. Then, an approximate analysis based on the departure processes is introduced. The numerical and simulation results indicate that this approximate approach yields reasonably accurate results.     

Topological and Architectural Designs for Pre-ISDN Integration of Fiber Optic Voice and Data Networks

Several inter-LATA carriers in the United States are implementing fiber optic networks. The geographic coverage of these networks coupled with the bias to choose fiber as backbone links via traditional data network design yields an opportunity for pre-ISDN integration of voice and data. This paper presents three transitional models for pre-ISDN integration of voice and data. The impact of incorporating a fiber optic network in the traditional data design formulation is demonstrated. Based upon the theoretical considerations of fiber optic incorporation, data routing, delay, throughput, and reliability are redefined, yielding an inverse design problem formulation for data. Practical considerations are presented with each transitional model.     

Analytic Approximation of Blocking Probabilities in Circuit Switched Communication Networks

A method inspired from S. Katz's service evaluation algorithm [6] is presented. The new algorithm is recursive, rather than iterative, in nature, and especially suited for networks that do not contain cycles. It also introduces two new features which take existing theoretical results into account, and as such corresponds more closely to the current state of traffic theory.     

蜂窝网络的数据及语音综合接入方案

本文介绍了用于蜂窝网络的数据及语音综合接入方案,对这些接入方案的性能进行了比较.此外,本文对当前接入方案存在的问题进行了分析.     

GSM中的HSCSD技术

介绍了GSMHSCSD技术,及其与GSMphase2数据业务的异同。HSCSD作为从2G系统向3G系统演进的一种过渡方案,能灵活提供高速、多速率数据业务,具有较好的发展前景。     

Delay Related Issues in Integrated Voice and Data Networks

This paper focuses on network delays as they apply to voice traffic. First the nature of the delay problem is discussed and this is followed by a review of enhanced circuit, packet, and hybrid switching techniques: these include fast circuit switching (FCS), virtual circuit switching (VCS), buffered speech interpolation (SI), packetized virtual circuit (PVC), cut-through switching (CTS), composite packets, and various frame management strategies for hybrid switching. In particular, the concept of introducing delay to resolve contention in SI is emphasized, and when applied to both voice talkspurts and data messages, forms a basis for a relatively new approach to network design called transparent message switching (TMS). This approach and its potential performance advantages are reviewed in terms of packet structure, multiplexing scheme, network topology, and network protocols. The paper then deals more specifically with the impact of variable delays on voice traffic. In this regard the importance of generating and preserving appropriate length speech talkspurts in order to mitigate the effects of variable network delay is emphasized. The results indicate that a desirable length of talkspurt "hangover" of about 200 ms will accomplish this without unduly affecting speech activity, and that, under these circumstances, the perceptable threshold of variable talkspurt delay can be as high as about 200 ms average. As such, the results provide a useful guideline for integrated services system designers. Finally, suggestions are made for further studies on performance analysis and subjective evaluation of advanced integrated services systems.     

Hierarchically Switched Networks

The Internet of today is facing serious challenges including lack of routing system scalability, unpredictable network behavior, uncertainty of data packet paths, poor control and manageability, unachieved Quality of Service (QoS), vulnerability of network facilities to Distributed Denial-of-Service (DDOS) attacks, core router complexity, costliness, and high power consumption. All of these defects have their root causes in the routing system. This paper first proposes a new network architecture which combi...     

Improving Voice and Data Services in Cellular/WLAN Integrated Networks by Admission Control

In this paper, we study voice and data service provisioning in an integrated system of cellular and wireless local area networks (WLANs). With the ubiquitous coverage of the cellular network and the disjoint deployment of WLANs in hot-spot areas, the integrated system has a two-tier overlaying structure. As an essential resource allocation aspect, admission control can be used to properly admit voice and data calls to the overlaying cells and WLANs. A simple admission scheme is proposed in this study to analyze the dependence of resource utilization and the impact of user mobility and traffic characteristics on admission parameters. Both admission control and rate control are considered to limit the input traffic to the WLAN, so that the WLAN operates in its most efficient states and effectively complements the cellular network. The call blocking/dropping probabilities and data call throughput are evaluated for effective and accurate derivation of the admission parameters. It is observed that the utilization varies with the configuration of admission parameters, which properly distributes the voice and data traffic load to the cells and WLANs. Mobility and traffic variability have a significant impact on the selection of the admission parameters.     

A New MAC Scheme Supporting Voice/Data Traffic in Wireless Ad Hoc Networks

In wireless ad hoc networks, in addition to the well-known hidden terminal and exposed terminal problems, the location-dependent contention may cause serious unfairness and priority reversal problems. These problems can severely degrade network performance. To the best of our knowledge, so far there is no comprehensive study to fully address all these problems. In this paper, a new busy-tone based medium access control (MAC) scheme supporting voice/data traffic is proposed to address these problems. Via two separated narrow-band busy-tone channels with different carrier sense ranges, the proposed scheme completely resolves the hidden terminal and exposed terminal problems. Furthermore, with the use of transmitter busy-tones in the node backoff procedure, the proposed scheme ensures guaranteed priority access for delay-sensitive voice traffic over data traffic. The priority is also independent of the user locations, thus solving the priority reversal problem. The fairness performance for data traffic in a non-fully-connected environment is also greatly improved (as compared with the popular IEEE 802.11e MAC scheme) without the need for extra information exchanges among the nodes.     

TD-SCDMA中的高速电路交换数据业务的实现

本文提出了TD-SCDMA系统中移动终端的高速电路交换数据 (HSCSD) 的实现方案,以供参考.     

构建适应三网融合的城市有线IP数据网络

结合三网融合的大背景,对网络需求进行了分析,在此基础上介绍了石家庄有线IP数据网的建设方案,并对建设方案的特点进行了系统总结。     

An Approach to Multi-Service Subscriber Loop System Using Packetized Voice/Data Terminals

A new subscriber communication system and its design philosophy are described. In addition to telephone communication, the system is simultaneously able to offer data communication, still picture communication, etc. The system is composed of a packetized voice/data terminal, a multi-service switching equipment and the digital subscriber loop connecting between them. The system utilizes the existing subscriber line efficiently and is entirely suitable for coming telephone and data public digital network. 64 kbit/s PCM coded voice conversation and 48 kbit/s data communication were achieved simultaneously over 96 kbit/s digital subscriber line which was spanned up to 2 km.     

A Combined Forward Error Control and Multiple Access Protocol for Wireless Voice/Data Integration

Different strategies for error control are investigated, in conjunction with a MAC-level protocol, operating in a multimedia noisy cellular environment, where a base station co-ordinates mobile users within each cell. The channel multiplexing structure is based on Time Division (TDM), and the slots in each frame are dynamically assigned to the users and their service classes. The access rights are decided by an algorithm, namely, the Independent Stations Algorithm (ISA), at the cell base station, which broadcasts this information to the users. Each single mobile station is associated a bit error probability, which changes with time in a random fashion. Bit error probabilities are estimated and the protection level of the Forward Error Correction (FEC) code is dynamically adapted to the new conditions. The performance of the scheme is analyzed by simulation in the presence of mixed voice and data traffic, and with different error handling techniques (FEC and Automatic Retransmission Request (ARQ)).     

On-Chip Supply Noise Regulation Using a Low-Power Digital Switched Decoupling Capacitor Circuit

On-chip resonant supply noise in the mid-frequency range (i.e., 50–300 MHz) has been identified as the dominant supply noise component in modern microprocessors. To overcome the limited efficiency of conventional decoupling capacitors in reducing the resonant supply noise, this paper proposes a low-power digital switched decoupling capacitor circuit. By adaptively switching the connectivity of decaps according to the measured supply noise, the amount of charge provided by the decaps is dramatically boosted leading to an increased damping of the on-chip supply network. Analysis on the charge transfer during the switching events shows a 6-13X boost of effective decap value. Simulations verify the enhanced noise decoupling performance as well as the effective suppression of the first-droop noise. A 0.13 $ mu$m test chip including an on-chip resonance generation circuit and on-chip supply noise sensors was built to demonstrate the proposed switched decap circuit. Measurements confirm an 11X boost in effective decap value and a 9.8 dB suppression in supply noise using the proposed circuit. Compared with previous analog techniques, the proposed digital implementation achieves a 91% reduction in quiescent power consumption with improved tolerance to process-voltage-temperature (PVT) variation and tuning capability for obtaining the optimal switching threshold.