TMN implementation strategy based on OSI management standards

In order to facilitate the implementations ofTMN interface protocols/services studied inITU-T, it is very important to define profiles for supportingTMN management service. This paper proposes a concrete method for achieving this based on osi management standards as a promisingTMN implementation method. It proposes an idea of structuring theTMN ISP’S based on the structure of the osi managementISP’S. The paper discusses aTMN based on the osi managementISP’S. Finally the implementation as software is discussed and a software architecture for efficient application development is proposed.     

Transmission and distribution of a multichannel AM-VSB TV signal on a single mode optical fiber for CATV videocommunication networks

First of all, in this paper, we situate and recall the advantage of single mode fiber for transmission of a multichannel AM-VSB TV signal. Then we describe the prototype of a multichannel transmission system studied under a France Télécom contract and discuss the experimental results obtained on this system. Today the equipment issued from that study, is in current industrial development in order to be soon installed in networks. A few rules are given in terms of range, number of channels per fiber and number of subscribers to help the design of networks. After having identified the system limitations, solutions are proposed to improve the performances. Particularly the concept of a am-vsb optical repeater and the linearity improvement with that procedure are shown. We will also discuss the use of 1.54 μm dfb laser and compare the performances at both wavelengths. The interest of predistortion network to escape from the previously identified linearity constraint is justified. Then the extension of transport network to optical distribution network closer to the subscriber (fttc) is envisaged. We show how the trade-off between less stringent performances and higher distribution potentiality can be handled. At last the interest of external modulation in order to escape from the noise limitation and to extend the coverage of the network at both wavelengths is discussed.     

A management architecture for the international B-ISDN

This paper relates to basic management aspects of the interworking of national?-ISDNX. A general architecture of such an interconnection is proposed which is based on concepts of the worldwide intelligent network (WIN) and CCITT telecommunication management network (TMN). Various models supporting theTMN design are considered. Communication aspects of management information transfer within theTMN are discussed in more detail.     

Effects of quasi-periodic training signals on acoustic echo canceller performance

Filtered white noise is the training signal typically used to test the performance of echo cancellers. However, a system optimized for operation with such training signals may perform poorly when trained instead with voiced speech. This performance difference is a consequence of the quasi-periodic nature of voiced speech. In this paper, we explore the effects of quasi-periodic training signals on echo-canceller performance. In particular, we show that unlike filtered white noise, quasi-periodic training signals can actually limit the asymptotic echo-return loss of echo cancellers. In addition, we examine the ability of several existing techniques to improve performance when quasi-periodic signals are used to train echo cancellers.     

A static study of multilayered multiconductor transmission lines

Accurate knowledge of passive MIES and MMIGS has become as important as knowledge of active components. A rather classical method of analysis of multi-dielectric multistrip transmission lines is presented. This analysis, restricted to the quasi-static approach, is based on a variational method in the discrete spectral domain, combined with the transverse transmission line method devoted to the calculation of Green’s functions. This work, devoted only to the study of the distributed parameters of the structures, i.e. in any transverse section, is followed by a complete modal analysis with respect to the direction of propagation and the possible boundary conditions at the terminals. These calculations consist actually mostly of an eigenvalue problem. They are carried out analytically as far as possible by means of a block matrix algebraic formalism particularly well suited to the problem. The mode impedances and the impedance matrix are obtained analytically in a general manner. All the parameters of new structures with four conductors are completely made explicit.     

Migration strategy towards Q3 interfaces of switching systems : a look at France Telecom switches

Future telecommunication management network (TMN) will be based upon object-oriented modelling of interfaces. Nevertheless, in case of public switched telephone network, this process will be long and difficult. However, as current interfaces are not completely satisfactory, some evolution steps from today’s interfaces towards tomorrow’sTMN ones are planned. This paper presents the different steps chosen by France Telecom. At first, introduction of a new protocol as close as possible to the target Q3 is detailed. Unification of the different heterogeneous commands is then shown through creation of standard commands, last, integration toTMN through Q-adaptor is presented.     

Simplified weighted least squares design of 2-D FIR digital filters

A simple easy to use and very flexible approach is presented for the design of 2-D fir digital filters. It is illustrated by two examples, a rectangular filter and a diamond filter. Appropriate selection of the weighting function which is used in the weighted least squares method can yield very diverse characteristics, like the possibility to meet specifications on both frequency response and step response.     

An optimized model of the audiogram relation with physiological properties of hearing

The mathematical modelling of the audiogram seems to be an attractive tool to characterize the behaviour of the human auditory system. In this paper, the authors present the relations of a model based on a hyperbolic tangent function, prior and after optimization, with the properties of the auditory brainstem response (abr) and the evoked otoacoustic emissions (eoae). The correlations are carefully analyzed and the importance of the loss in high frequency is worth pointing out. The correlation between some physiological data of the abr and the eoae with the thresholds observed on an audiogram are not greatly modified by the modelling and by the optimization. Thus the modelling seems to be a theoretical performance which cannot be substituted, for the application considered, by the knowledge of the audio-gram. Nevertheless, this work could be a good starting point for future applications.     

The information layered architecture model,layers, methodology and their application for service activation

The authors propose a model (information layered architecture ILA) forTMN layering, that is based on grouping managed objects that share a common information perspective. The model provides an interfacing mechanism between layers that is based on referencing techniques between managed objects. We identified four levels ofTMN abstractions that can be used to represent a wide range of telecommunication processes. These are : customer, service, network and network element management. We then use the ILA to develop a model for the process of service activation. By doing so we demonstrate how modelling can be used as a technique to manage complicated processes.     

Dynamique des lasers à fibre dopée à I’erbium

The dynamics of the erbium doped fiber laser is analysed both experimentally and theoretically. This laser operates spontaneously in self-pulsing, in sinusoidal or in CW regime. Experiments have allowed to determine the control parameters : the cavity losses, the pumping rate and the ion pairs concentration. An antiphase dynamics is observed when the laser operates simultaneously at 1.55 µn and 1.536 µm. The self-pulsing behavior is attributed to a fast energy transfer which occurs between two neighboring ions (pair induced quenching). A simple model considering the active medium as a mixture of isolated ions and ions pairs is developped and leads to a good qualitative agreement with the experimental results.     

On the stochastic timed Pétri nets model and its application to the DQDB protocol

The goal of this paper is twofold : at first, to present the stochastic timed Pétri nets model by emphasizing its ability to express the main characteristics of real time distributed systems (parallelism, synchronization by message exchange, time attributes and in particular time constraints) and to allow both qualitative and quantitative analysis (concept of randomized states graph); second, to show a modeling methodology based on this model that allows a rigorous modeling of theDqdb protocol (Qa access, bwb mechanism role,Pa access influence). A new contribution to theQa mechanism has been done (1).     

A fast exact FTF adaptive algorithm

In this paper we present a new method for the efficient implementation of the fast transversal filter(ftf) algorithm. Reduction of the arithmetic complexity is obtained by making use of the redundancy in the successive computations of the forward prediction error and the filtering error in the joint process. The resulting algorithm is exactly equivalent to the originalftf algorithm, hence retaining the same theoretical convergence characteristics and offering the least squares(ls) estimate at each recursion step without delay. Furthermore, the algorithm can be numerically stabilized by using a simple and effective stabilization measure which needs only one additional multiplication per recursion step. The equivalence of the proposed algorithm to the originalftf algorithm is demonstrated by simulations of an acoustic room impulse response identification.     

A look at the video dial-tone network

As organisations with information to sell implement an array of multimedia services for the home, others, too, are hard at work. Telephone companies, as well as cable operators, are busy developing broadband intelligent networks to underpin those broadcast and interactive offerings. The phone companies define their network as a common-carrier transport service, in that it grants equal access to all information providers, including themselves, and enables consumers to "dial up" video or multimedia applications offered by third parties. This kind of service has become known as a video dial-tone network. The user first gets a menu from the network provider. He or she then picks an information provider, which sends its own interactive menu of services to the customer     

Modelling buffer admission mechanisms using stochastic automata networks

The stochastic automata networks formalism is an attractive technique to model complex systems with interacting components. Each component of the system is modelled by a single automaton; interactions between components are modelled by labels on the arcs which may represent synchronization and state-dependent transitions. Every automaton is associated with some matrices which allow to build the transition matrix of the underlying Markov chain, using tensor algebra. To illustrate this methodology, we introduce two buffer policies which could be used inAtm switching node. Every policy manages two priority levels which have distinct cell loss requirements. The first buffer policy is based on the push-out mechanism : a high priority cell replaces a low priority cell when the buffer is full. The second policy causes the discarding of all the low priority cells when the user transmits a request to send a burst of cells. In both studies, we compute the loss probabilities of each type of cells under various assumptions.     

Real-time automatic message accounting data transport

In today’s operation, all usage records for billing, regardless of their source, and service type are put into a file/stream and delivered to the downstream revenue accounting office for processing. The revenue accounting office operates in a batch mode, then scans through the records and separates those which are required for special processing by other applications, like fraud management and customer access to network usage data. However, there is a significant delay between the time the usage records are generated to the time they are available to the other systems. This paper proposes solutions to support real-time transfer of automatic message accounting (AMA) records and files. First, the existing automatic message accounting teleprocessing system (AMATPS) architecture is analyzed to study its limitations. Next, transport mechanisms are identified and analyzed. Finally, an alternative to the existing AMATPS architecture is discussed.     

Codage CRC parallèle pour cellules ATM

In this paper, it is shown that a parallel approach for CRC coding can be derived for a number of bits less than, or equal to, the degree of the code generator polynomial, or for larger values as well. In both cases if formulas are different, the logic diagrams are very similar and corresponding circuits are prone to efficient VLSI integration.     

Synthesis methods of array antenna excitation laws

Standard numerical optimization methods become very computational time consuming when dealing with synthesis of array antenna excitation laws, especially when number of elements exceeds a few tenths. Array antenna designer needs a fast and efficient synthesis tool, since the design phase implies several reoptimizations within the definition phase, in order to satisfy tradeoffs on antagonistic requirements : performances, size, cost,… We propose the use of an efficient, from the computational time point of view, and secured, from the convergence point of view, synthesis method illustrated by two examples. The optimized solution satisfies a sta-tionarity condition, which leads to steady solutions in frequency but also with regard to errors (manufacturing, …). Based on analytical calculus performed before any numerical resolution and together with the use of fast Fourier transform algorithms, this method leads to reduced optimization times (in the order of a minute) for arrays of some tenths up to some hundred feeds, computations being performed on a pc. Two theoretical applications are presented and for each of them a computed example is also shown; moreover possible extensions are considered.     

Transport and control issues in multimedia wireless networks

It is not an easy task in the UMTS environment to effectively design the transport and the management of traffic belonging to multimedia teleservices among those defined by ITU Recommendations, due to the hard communication requirements which this kind of application can call for. In this paper the results of an overall research work, dealing with an effective management of multimedia and multi-requirement services in enhanced third-generation mobile radio systems, are presented. The contemporary use of several bearers, one for each traffic component of the service, is proposed as a reference scenario for the transport of multimedia services in future mobile radio environments. The effectiveness of this choice is guaranteed by providing for innovative control techniques, on top of a PRMA-based access protocol, ad-hoc developed to recognise and jointly manage the different parts of a unique multimedia traffic. For this aim, a two-level priority (static and dynamic priorities) mechanism is proposed to be adopted by the higher protocol levels of UMTS for the adptation of call set-up, channel access, handover, and admission control procedures to the nature of multimedia services and for optimising the sharing of radio channel resources and the management of the reservation buffer. Achieved results demonstrate that the priority-based mechanism shows good performance especially during periods in which the system traffic load is high and well reacts to the worsening of multimedia service quality, both in terms of information loss and synchronisation of its different traffic components.     

Robust Multi-Path Zone Routing Protocol for Video Transport Over Reconfigurable Wireless Networks

Multimedia transport has stringent bandwidth, delay, and loss requirements. It is a great challenge to support such applications in reconfigurable wireless networks (RWNs). Using multiple paths in parallel for multimedia transport provides a new degree of freedom in designing robust multimedia transport systems. In this paper, we provide a multi-path extension to zone routing protocol (ZRP) to support video transmission over RWNs. We compare ZRP and our multi-path routing scheme by using NS-2 simulator. The experiments show that our method is effective in improving the robustness of video transport over RWNs.

Modeling of spontaneous emission noise in erbium-doped fibre amplifiers using the Green functions method

This article describes a study of the main characteristics of erbium-doped fibre amplifiers based on a non-quantum approach to the phenomenon of amplification in spatially inhomogeneous structures. The noise figure in particular is assessed theoretically and numerically on the basis of various amplifier parameters, including the reflection coefficients at the fibre input and output. The results show the importance of monitoring reflectivity at the amplifier input and the power of the incoming signal.