Mathematical analysis of dynamic channel selection in indoor mobilewireless communication systems

Dynamic channel selection (DCS) is an algorithm for flexible resource sharing in mobile radio systems. The digital enhanced cordless telecommunications (DECT) standard implements a version of DCS based on time as well as frequency multiplexing. In this paper, mathematical models are developed to evaluate the probabilities of channel availability, desired carrier power, and the carrier-to-interference ratio (CIR) for a constant traffic load. These results can be used to compute the call setup blocking probability. The models reported in this study are based on a decentralized DCS according to the DECT standard specifications. The results show that blocking due to availability of a channel (resource blocking), not interference blocking, generally is the most important factor in overall call blocking. Furthermore, it is seen that resource blocking is sensitive to the implementation of portable sets. Also, with homogeneous static traffic, this type of DCS ran be as good as fixed channel allocation (FCA) with respect to resource blocking     

Where there's a WILL [wireless in the local loop]

Linking telephone subscribers into the network via wireless in the local loop (WILL) promises to boost telephone usage and enhance the effectiveness of telecommunications liberalisation. There is a wide choice of wireless technology potentially suitable for deployment in WILL applications. Candidates include the various analogue cellular technologies, digital cellular including GSM, and cordless systems including CT2 and DECT. The author discusses the FDMA/TDMA based fixed radio access system of Ionica, and the CDMA based system of Liberty. Both are in competition with BT. The choice of radio technology is discussed as are the problems caused by telecommunications liberalisation     

An expert system approach for cellular CDMA

The demand for cordless communication has forced suppliers to exploit digital technology to satisfy the increasing demand for service. This demand has led to severe capacity limitations in many areas and spread spectrum techniques are being considered as one means to support these services. It is generally accepted that system control in the future will make use of intelligent processors. In this study we delineate an expert system to be used as an intelligent controller for a cell site working in a CDMA (Code Division Multiple Access) mobile cellular telecommunications system. An existing AI shell is used for program development and simulation and the results are discussed in terms of the benefits obtained by using an expert system approach in the highly dynamic environment of cellular mobile communications     

A simulation study of speech traffic capacity in digital cordlesstelecommunications systems

A computer simulation tool for evaluating the speech traffic handling capability of digital cordless telecommunications systems has been developed. The focus of the paper lies on the teletraffic engineering problems posed by time division multiple access (TDMA) systems operating with time division duplex (TDD) on one radio transceiver in radio environments. The impacts of fixed station separation, fixed station capacity, spatial traffic variability, dynamic channel assignment, microdiversity, and propagation model on the system capacity are investigated. The simulator serves as an invaluable tool for conducting sensitivity studies and its outputs provide useful insights on traffic performance of digital cordless systems     

Simultaneous Dual Band Transmission Over Multimode Fiber-Fed Indoor Wireless Network

Performance measurements of different combinations of digital enhanced cordless telecommunications packet radio service, global system for mobile communications, universal mobile telecommunication service, and 802.11g (54 Mbps) signals in a dual band configuration transmitted over an indoor wireless network fed by a low-cost 850-nm vertical-cavity surface-emitting laser (VCSEL)-300m multimode fiber link are presented. The feasibility of such a system is demonstrated with error vector magnitude measurements which are within the required specifications     

Emerging mobile and personal communication systems

The market demand for wireless communications has been demonstrated by the rapid growth of different second-generation wireless technologies that are optimized for particular applications and environments. Obvious examples include: digital cellular systems like GSM, ADC, PDC,and DCS1800 for widespread vehicular and pedestrian services, and cordless telecommunication systems based on CT2, DECT, and PHS standards for residential, business, and public cordless access applications. Efforts are also underway to consolidate the various radio environments and applications under a single standard for third generation wireless, i.e., FPLMTS. In the area of personal mobility, with the recent availability of “personal” numbers in various countries (e.g., 500 numbers in the United States), many fixed network operators are starting to offer such personal mobility services as “personal number service” and “number portability”. These services represent initial stages of full personal mobility that will be provided by UPT in both wireline as well as wireless environments. The expected heavy demand for PCS in the United States and the underlying market/regulatory forces are driving the standardization and business activity. A number of air interface standards for the 1900 MHZ PCS band are being considered, which are based on TDMA, CDMA, and FDMA technologies singly or in combination. Many are variations of existing digital cellular and cordless telecommunications technologies. PCS networking standards are also being developed; both for standalone systems and for systems that will utilize public switched network capabilities     

无绳通信的技术和发展

本文综观无绳通信的发展，结合作者的科研实践，首先对发展无绳通信所要研究的主要课题进行了阐述，接着介绍了几种典型的无绳系统，最后对发展我国的无绳通信提出了几点建议。     

Personal communications-the dream and the reality

Mobile communications promises to be one of the biggest growth areas in electronics in the 1990s. The author aims to set out some of the basic issues: some of the questions that remain to be resolved, and others to which the answers are gradually becoming clear. The author discusses cellular systems and digital technology. The author then describes CT2, second generation cordless telephony. The concept of personal telephone handsets is also discussed. The competition to develop a `personal communicator', and the challenges faced by the telecommunications industry are discussed. The EC's RACE Mobile programme is discussed     

Personal communications-a viewpoint

A personal view of an extended concept of personal communications is discussed. The relationship between low-power digital cordless technology and some alternatives (analog cordless, digital mobile radio, and cellular mobile radio) is examined. Personal communication network (PCN) power requirements, circuit quality, level of network integration, and access to network intelligence (e.g. call forwarding, call transfer, and personal number calling) are emphasized     

Multipath channel modeling with chaotic attractors

Previous works have introduced models based on deterministic chaos equations, aiming to simulate transmission processes over mobile radio digital channels at the level of the post detection error stochastic process and to reproduce their renewal or nonrenewal behaviors. In particular bursts and clusters of errors are generated by these models, exploiting the correlation between successive points sampled from the trajectories of suitable strange attractors. In this paper chaos equation models are reviewed and relevant results are discussed. Different approaches have been tested, using one or more attractors, and calling for light or heavy preprocess procedures to cope with the statistical characteristics of target gap-time series. Models derived from hidden Markov chains have been implemented to provide comparison of results. Target sequences were supplied by simulation of digital enhanced cordless telecommunications (DECT) channels or derived from reception of DECT signals by a mobile unit in indoor environments     

移动通信和个人通信发展动向

本文陈述了以欧，美，日为代表的移动通信三大技术走向，着重分析了目前第二代系统中蜂窝通信，ＰＣＳ，无绳电话和移动卫星通信等各个分支的发展状部况；介绍了欧美在从模拟蜂窝向数字蜂窝过渡时采用的策略，提出了实现第三代系统的３个步骤；最后，分析了移动 市场趋势。     

Basic performance of a direct conversion DECT receiver

The measured operating performance of a new incoherent direct-conversion receiver for high-data-rate mobile communication systems is presented. The results prove the suitability of such a receiver for the future digital European cordless telecommunication (DECT) standard.<>     

公用无绳电话系统的技术及其发展策略

本文回顾了公用无绳电话系统从模拟到数字的演变过程，分析和比较了ＣＴ２、ＤＥＣＴ、ＰＨＳ和ＰＡＣＳ等几各数字无绳电话技术，进而提出了我国发展无绳电话的策略。     

Theory of the performance of a DECT receiver in a static channel

The performance of a digital enhanced cordless telecommunications (DECT) receiver in a static channel is studied. The theoretical results are then compared with computer-based simulations. The following issues were investigated: bit-error-rate performance of the differentially coherent detector with and without decision feedback, performance of both the frequency offset estimation from the DECT preamble, and the signal-to-noise ratio obtained from both the DECT preamble and the data field     

Universal broadband mobility target for post-TINA infrastructure:toward the fourth generation

Future universal broadband mobile services present a challenge for telecommunications architectures, control, and management. The focus of the future mobile (fourth) generation vision is turned from capacity to services, from radio to network-wide issues. New types of applications will evolve that should be supported by an adequate programmable intelligent telecommunications infrastructure. A convergence between telecom and datacom networks will happen based on the communications middleware concept, which will provide universal secure connectivity between mobile users and their applications. Actual specifications of TINA-C do not address all such necessary issues. There is a need for technology evolution, enhancement, and integration to meet these new requirements at different levels. The author the concept of the universal broadband mobile telecommunications systems (UBMTS, or simply UBM) described as fourth-generation mobile systems. The UBMTS objective is both to extend mobile user access to the range of broadband services that will exist for broadband integrated services digital network (B-ISDN) users, and to extend the customization of new services related to personal communications systems (PCS) users     

Ensuring mobile communication transmission quality in the year 2000

The traditional view of mobile telecommunications is to allow a customer to communicate away from his base. However, the vision for the end of the century is to make the mobile communication system the first choice for telecommunications. By the year 2000 there will be a large number of mobile systems operating in Europe, from the current analogue cellular systems to digital GSM cellular systems and potentially the Universal Mobile Telecommunication System (UMTS). The challenge is to ensure that customers, be they fixed or mobile, are provided with acceptable speech quality, no matter what system they are using and what it is interconnecting to. The paper examines the speech transmission parameters which effect the perceived quality and shows how they are apportioned within the mobile systems. It then goes on to show how the transmission quality can be optimised through the transmission plan to ensure that the customer perceives acceptable speech quality     

Relationship between performance and timing recovery mechanisms for a DECT link in dispersive channels

The performance of DECT (digital European cordless telecommunications) radio links under dispersive channel conditions is studied as a function of clock recovery strategies. It is shown that due to the non-optimal sampling, analytical and practical results based on fixed timing will not be acceptable above delay spreads of approximately 40ns. On the other hand, a burst-adaptive clock recovery scheme can more than double this range.<>     

Overview of wireless personal communications

This article presents an overview of the current state of wireless communications, including relevant ongoing activities in technology development, standards, and spectrum allocation. The authors discuss cellular radio, cordless telephony, and wireless data systems. Ongoing and planned future developments are summarized. The presentation is oriented toward broad coverage rather than technical depth. However, brief discussions of the air interfaces for existing digital cellular and digital cordless systems are provided, because the air interface bears heavily on system capacity and the environments in which the system can be used, as well as on the cost and complexity of the equipment     

The development of personal communications

The rapid development and take-up of personal communications services has been effected as much by marketing and regulatory changes as the introduction of second generation, digital technology. The traditional boundaries between fixed and mobile and between consumer and business services have been crossed. Increasingly, customers will be offered all their communication needs from a single supplier. This will lead to composite architectures formed from several networks. In the short term, dual-mode terminals will link networks based on cordless, cellular, satellite and fixed network technologies. As intelligent network techniques are used more fully, least-cost routing and consistent service features will be achieved. Third generation standards will extend the range of services, including those utilising higher speed data. These mobile systems will provide the primary access to the `Information Society'