Microprocessors in telecommunication systems

An overview of the ways in which the microprocessor is impacting the design of telecommunication systems is presented. The concept of the microprocessor as a software customized, catalog device is discussed. The various processor structures which are being employed in telecommunication systems utilizing microprocessors are emphasized and several examples are described.     

Interplanetary spacecraft telecommunication systems

During the past six years, a class of telecommunication systems designed to provide tracking, telemetry, and command functions at interplanetary, multi-million-kilometer distances has been developed and proved out on flights along heliocentric orbits and into the vicinity of the planets Venus and Mars. These developments are contributing substantially to the exploration of the solar system and, in addition, are one measure of the state of the electronic arts. If the capability continues to increase over the next several years at the same rate, we shall soon be able to transfer large quantities of information to the earth from the surface of Mars.     

Testing embedded memories in telecommunication systems

Extensive system testing is mandatory nowadays to achieve high product quality. Telecommunication systems are particularly sensitive to such a requirement; to maintain market competitiveness, manufacturers need to combine reduced costs, shorter life cycles, advanced technologies, and high quality. Moreover, strict reliability constraints usually impose very low fault latencies and a high degree of fault detection for both permanent and transient faults. This article analyzes major problems related to testing complex telecommunication systems, with particular emphasis on their memory modules, often so critical from the reliability point of view. In particular, advanced BIST-based solutions are analyzed, and two significant industrial case studies presented     

Development of information and telecommunication systems

Modern Communication technologies have developed through the process of evolution rather than revolution. The growth of telecommunications and computers have made high quality, high speed and low cost global communication a reality. These and additional benefits to people worldwide will continue to accrue with the blending of, in an intimate way, data processing and telecommunications. Future trends based on extrapolation of the present will surely be to provide greater communications and computer capability into the home and the office, at even lower cost. However, history teaches us that new, unanticipated ideas arise not simply as extrapolations of the past.     

Optical fiber amplifiers for telecommunication systems

Optical amplification is of strategic importance for telecommunications. Optical amplifiers compensate for propagation losses in long distance links and branching losses in access networks, at the same time avoiding costly two-way conversions between optical and electrical signals. The devices available up to now are mainly represented by rare-earth-doped active fiber optical amplifiers. This article presents the state-of-the-art of optical amplifiers for telecommunications. However, erbium-doped fibre amplifiers are having a strong impact on the telecommunication market, thanks to the excellent performance of commercial devices. They are widely employed in long distance networks for the third transmission window, which is centered at λ=1550 nm, while in the second window, around λ=1310 nm, the role of semiconductor optical amplifiers is still competitive     

Bibliography of literature on telecommunication systems reliability

This paper presents an extensive list of selective references on telecommunication systems reliability.     

Hardware/software co-design of digital telecommunication systems

We reflect on the nature of digital telecommunication systems. We argue that these systems require, by nature, a heterogeneous specification and an implementation with heterogeneous architectural styles. CoWare is a hardware/software co-design environment based on a data model that allows to specify, simulate, and synthesize heterogeneous hardware/software architectures from a heterogeneous specification. CoWare is based on the principle of encapsulation of existing hardware and software compilers and special attention is paid to the interactive synthesis of hardware/software and hardware/hardware interfaces. The principles of CoWare are illustrated by the design process of a spread-spectrum receiver for a pager system     

WDM光纤通信系统中PMD自动补偿的研究

文章提出采用粒子群优化算法,提取信号的偏振度(DOP)作为反馈信号来补偿多信道光纤通信系统中的偏振模色散(PMD).作为例子,对两信道的波分复用(WDM)系统中的PMD进行了自动补偿,并进行了数值模拟,得到了两个信道补偿前后的DOP以及眼图变化情况.模拟结果表明这种算法对补偿多个信道的PMD是有效的.     

Generic fault isolation concept for telecommunication systems in access networks

This paper presents an approach for a generic fault isolation (FI) concept for telecommunication systems in the access network area. Based on a distributed processor architecture, a universal software structure for a FI unit is proposed. It is able to isolate faults, field replaceable units and is easily portable to different hardware platforms. The reusability of the FI unit is achieved by separating the software into generic control functionality and fully hardware-dependent software parts, i.e. user configurable tables and hardware-dependent control routines. The implementation of the concept is discussed in a ‘fiber to the building’-system which has already entered into mass-production. © 1997 John Wiley & Sons, Ltd.     

MOEMS devices and their applications to optical telecommunication systems

This paper describes first the basicmoems technologies and attempts to point out the various degrees of freedom that are available for the designer. Then, it will review some of the most important architectures ofmoems demonstrated up to now, for optical switching and wavelength management inWDM networks. These technologies are also very promising for optical connectorization, and could open the way to new components that could be cheap enough for being used at the subscriber level. An analysis of the present status ofmoems technologies, the main short term issues, and some development prospects will finally be given.     

Evaluation of location area planning scenarios in future mobile telecommunication systems

In third generation mobile telecommunication systems, signalling requirements due to location updating and paging are expected to be remarkable, mainly because of the huge number of mobile subscribers. Location area planning is characterised by the trade-off between the number of location updates and the amount of paging signalling that the network has to deal with. Location area planning should be based on criteria which guarantee that signalling load will be kept under tolerable levels. Various approaches for location area planning in a city environment—the worst case environment—are discussed in this paper. The simplest approach is the use of heuristic algorithms for approximating the optimum location area configuration. Then more complex scenarios which are based on geographical criteria (population distribution, highway topology, etc.) are investigated. Finally, user mobility characteristics are taken into account in the most complex scenarios. All scenarios are applied over a simulation model representing a city area, providing us with a very clear view of their performance characteristics.This paper has been partially funded by the CEC through the RACE 2066 MObile NETwork (MONET) project. The paper does not present the views of the project as a whole, but those of the authors.     

Intelligent home systems

The home automation system module, communications standards developed in the US by the Electronic Industry Association (EIA) and known as the Consumer Electronic Bus (CEBus) is reviewed. The CEBus network node architecture application layer, network layer, data link layer, physical layer, and access protocol are discussed. The different media used for CEBus communication are described     

Some aspects of the need for redundancy in telecommunication transmission systems

The high inherent reliability of the electronic equipment as well as the greatly simplified replacement of functional units makes all duplication superfluous in a multiplex terminal on the apparatus level. An economically justifiable availability of a telecommunication network can be achieved, however, by appropriate planned transmission systems with automatic or manual re-routing possibilities in combination with an adequate maintenance and well-considered stock of spares.     

Differentially detected GMSK signals in CCI channels for mobilecellular telecommunication systems

The performance of conventional and decision feedback differential detection receivers for Gaussian minimum-shift keying (GMSK) signals transmitted in the presence of cochannel interference (CCI) and additive white Gaussian noise (AWGN) is evaluated. For the interference, the authors adopt a model which includes N statistically independent static as well as faded CCI. Various bit-error-rate (BER) performance evaluation results have indicated that the receiver under investigation performs better as compared to other more conventional receiver structures. Especially significant BER improvements are obtained for the static CCI channel. For example, it is shown that with a carrier-to-interference ratio of 14 dB, the performance of a 2-b decision feedback differential receiver outperforms a conventional 2-b differential detector by more than 14 dB (at a BER 10^-3). For the faded CCI, the improvement is less: mainly they result in error-floor reductions of about half an order of magnitude. By comparing the performance of static and faded CCI, it was also found that for a given C/I, the performance of the former would depend on the number of interferers, whereas this is not the case for the latter     

Electromagnetic interference on medical equipment by low-powermobile telecommunication systems

There have been a number of reports of electromagnetic interference (EMI) on electronic medical equipment caused by mobile telecommunication systems. In Japan, the use of the personal handy-phone system (PHS) has greatly expanded within urban areas, PHS handsets transmit EM signals at a frequency of 1.9 GHz and have a peak radiated power of 80 mW. This power level is lower than that of other mobile telecommunication systems. Two studies were carried out. One was to determine whether or not PHS interferes with electronic medical equipment in hospitals. We observed no EMI on electronic medical equipment when the PHS handset was in either the speaking mode or on standby. The second study was to observe EMI from 1.9-GHz signals at several radiation power levels. Although EMI was not observed at the radiated peak power of the PHS handset, EMI on some of the tested equipment was observed when the radiated power was ten or more times higher than that of the PHS handset     

Traffic model for third generation cellular mobile telecommunication systems

Traffic analysis for third generation mobile telecommunication systems should take into account a variety of services (e.g., voice, data, video) and environments (private, public outdoor, public indoor) as well as the user mobility behavior. The analytical traffic model presented in this paper incorporates all the above mentioned features. The model utilizes a set of simplifying assumptions regarding the distribution of certain random time intervals (e.g., call duration and cell residence time) and the handover arrival process. The core of the model focuses on the estimation of the cell border crossing rate and the time it takes a busy mobile user to leave a cell area. This allows for the estimation of the handover rate and the call duration within a cell, which in turn, utilizing an iterative method, allows for the calculation of the offered traffic load per cell. The major advantages of the model are: (a) the simple closed form solutions, (b) its independence from the applied radio resource management scheme, and (c) its accuracy. The latter is validated via a simulation tool, which accommodates different cell-layout scenarios over a geographical area, representing a typical city center, modeled as a Manhattan grid.     

Quality of telecommunication systems after sales: evaluation offield data

The hardware reliability of telecommunications systems is subject to extremely stringent demands. A computer-based quality information system used to record field experience with digital switching systems in use throughout the world is described. The evaluation and use of the field data are discussed, and methods of failure rate prediction are examined. These approaches are compared to predictions made using the standard SN 29500 for some typical integrated circuits     

Ultra-low-power and high-speed SiGe base bipolar transistors forwireless telecommunication systems

Ultra-low-power and high-speed SiGe base bipolar transistors that can be used in RF sections of multi-GHz telecommunication systems have been developed. The SiGe base and a poly-Si/SiGe base-contact were formed by selective growth in a self-aligned manner. The transistors have a very small base-collector capacitance (below 1 fF for an emitter area of 0.2×0.7 μm) and exhibit a high maximum oscillation frequency (30-70 GHz) at low current (5-100 μA). The power-delay product of an ECL ring oscillator is only 5.1 fJ/gate for a 250-mV voltage swing. The maximum toggle frequency of a one-eighth static divider is 4.7 GHz at a switching current of 68 μA/FF     

软交换--未来电信开放式体系结构的基础

互联网技术的发展促进了开放式体系结构的发展，在电信领域中软交换技术异军突起，它提供了一种未来的电信开放式体系结构，具有很好的市场前景。