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Introduction.doc

  1. 1. ETSI/MTG1(95)4 rev2 introductiondoc951.doc Pierre-Yves Hébert / PYH j June 水曜日 page 1 of 34 1st Mobile Topic Group Meeting Paris, 28-29 September 1995 Source: User Group Chairman Title: Preliminary Survey : Wireless Communications. Agenda item: 6 Document for: Discussion This document presented at the conference hold on 28 September 1995 was elaborated by the means of a preliminary survey in order that the Topic Group members have the same information level. A French version is also available.
  2. 2. ETSI/MTG1(95)4 rev2 page 2 of 34 WIRELESS COMMUNICATIONS Meeting on 28 & 29 September 1995 Working Document SEE/ETSI/AFUTT - Wireless meeting Version 3
  3. 3. ETSI/MTG1(95)4 rev2 page 3 of 34 Tatiana Crescitz - EDF VŽronique Daniel - ARCOME SEE/ETSI/AFUTT - Wireless meeting Version 3
  4. 4. TABLE OF CONTENTS
  5. 5. Introduction It is clear that mobility is a major concern; it includes multiple aspects for which a variety of solutions are proposed. Unfortunately, one solution can solve only part of the problems. The aims of this report are to present user expectations in the radio communications field and study how operators and suppliers offerings meet user needs. Its only claims are to shed light on the various presentations made throughout the day and serve as a basis for the workshop discussions following the presentations. The situation in the area of standardisation is mentioned in order to make a better assessment of the expected evolution in the short-term and evaluate possible gaps to be filled. As this is a wide subject, the study is limited to corporate mobile communications (vocal services) and interworking problems between networks (fixed/mobile and private mobile/public mobile) which seem to constitute major expectations. Data transmission aspects are only partly broached, but these services will probably lead to the same interworking needs. We have excluded professional radio networks from the study. Indeed, professional radio network users have needs that remain highly specific, for instance, group communications (group calls, broadcasting, emergency calls, etc.). Those services have nothing in common with supplementary vocal services. The demand for interworking with fixed and mobile networks is less obvious than in cordless telephony. On the other hand, the sizeable work carried out for TETRA seems to respond to user expectations.
  6. 6. Executive summary User expectations in the area of wireless telephony are far from unanimous. Everything depends on the function and the profession exercised by the final user, his degree of mobility, along with existing telecommunications equipment in the company. The novice user who does not have the means for wireless telephony usually finds it difficult to express his needs. The user who already has wireless telephony available knows its advantages and limits. Also, the telecommunications manager who has already carried out a study of needs with potential final users in the company has real expectations. The principal user expectations concern the following points: * Comfort ¥ Comfort is first of all the possibility of not answering a call while having the means to be informed of the call, ¥ Terminal ergonomy and availability of services such as voice mail. * Compatibility at various levels: ¥ Interchangeability of terminals when purchased: the professional wants to be able to purchase the terminals he wants and to be able to use them on his companyÕs cordless PBX along with the preservation of most service facilities; ¥ Network interchangeability as seen by the user, who can use the same terminal for the companyÕs cordless PABX, the public network in the street and his radio terminal at home; ¥ Network interworking for the same user, which implies transfer of mobility information from one system to another of the roaming or hand-over type of management of private and public data bases. * Vocal quality and the quality of radio coverage. * Geographical extension of the initial communication zone with the usage of systems. * Cost control and evaluation: ¥ Above all, the telecommunications manager seeks to control communications costs. Users want better information from actors in the market. ¥ The telecommunications manager also wants to make the best evaluation of investments made when acquiring a private mobile system. However, mobile network engineering can only be carried out step by step, in function of the existing structure and building materials. * Confidentiality of communication: Communication coding is highly desired for the exchange of sensitive information. The first observation that can be made is that the user must face a multiplicity of offerings. This expansion, due to the evolution of offerings Ñin particular because of the passage from analog to digitalÑ and the evolution of regulations, does not really respond to user needs. The user can choose between numerous systems, but his needs in terms of coverage and services go beyond existing systems. In order to respond to user expectations, important standardisation work on wireless communication systems are being carried out by ETSI. GSM, DCS1800 and DECT standardisation continues and concerns in particular the technical improvement of systems and their interworking. In the long term, the goal of standardisation will be the conception of UMTS, a more universal and effective system. Numerous supplementary services have been developed for GSM, but it is possible to ask whether some of them are superfluous. In the standardisation of future mobile networks, perhaps it would desirable to identify the supplementary services that are the most pertinent for the user and limit future growth to the development of corresponding standards.
  7. 7. To conclude, the thinking of the work group and future studies should particularly concern: - the ergonomy of utilization for services offered to users, - interactivity of services between fixed and mobile terminals, - the extension of corporate services to public networks, - the non multiplication of terminals with the development of multi-mode terminals, - the uniqueness of the numbering scheme, - control, - the coupling of fixed private networks/mobile private networks, then fixed private networks/ mobile public networks, fixed VPNs/mobile VPNs,
  8. 8. USER TYPOLOGY AND Expectations Users have various functions and professions that require diverse telephone services and a more or less extensive degree of mobility, limited to the corporate site, a region, a country, or even more than one country. Their needs are thus highly heterogeneous. Firstly, we have described the profiles of some users and have given a glimpse on existing practices in the area of corporate wireless telephony. The main expectations of users are then classified into two categories: the expectations of final users and the expectations of telecommunications buyers and managers. These needs are quite different and sometimes opposing since final users do not care with cost as much as the corporate or telecom managers. These needs have been assessed in the following companies and associations: RATP, Laboratoires ROCHE, RITME International, American Express, CIGREF, AFUTT, ETDE. These needs have been completed with reactions from several manufacturers (MATRA, ALCATEL, ASCOM TATECO, MOTOROLA, ERITELCOM) as well as by the knowledge acquired in this area by the consultants. Cases of interworking of networks presenting an interest for users are commented at the end of the chapter. User Typology Below are listed the profiles of a few final users according to their degree of mobility and their function. • Technical staff: This concerns on-site maintenance and security teams. They need to be reached quickly, must be able to note the call and eventually call back or respond immediately with respect to the security nature of the user's function. • Administrative and supervisory staff: They must move around to attend on-site meetings, meetings on other sites or outside the enterprise. Above all, they want an extension of the company fixed telephone. • Technical production staff on industrial sites: When they work in difficult security conditions, above all, they need to communicate among themselves and need to be able to make emergency calls. When their function requires numerous contacts with other services or divisions of the company, above all they need to be able to be contacted at any time and to have an extension of their telephone line available. • Pre-sales staff: They usually travel outside the company and sometimes within the company itself. They need to make calls and need to be contacted by their company or clients, to whom they want to offer a pleasant telephone reception. Also, as they move around a great deal, they need to communicate for professional as well as for personal needs. • After-sales staff: This concerns, for example, maintenance and delivery services outside the enterprise. These users need to be reached rapidly by their company, and in certain cases, their company would like to locate them for greater efficiency of deliveries and repairs. In addition, their calls must be limited. This list is not complete, and other users can have needs that do not correspond to the profiles described above. For example, in supermarkets, heads of sections must be contacted quickly by cashiers who need to know the price of a product. The final goal is improvement in efficiency and customer satisfaction. In the health care domain, one can mention hospital staff who needs to be contacted rapidly within the hospital.
  9. 9. Wireless Communications Systems Currently in Use Existing systems can be separated into two categories with respect to the extent of the wireless communication area. • Needs limited to one or several sites: The system the most widely used is the private radio paging system connected to a PBX. This product, when it displays the callerÕs number, is generally appreciated by users who have been using it for a long while. However, it appears insufficient to some, especially those who need to call back the caller quickly; However, it presents the advantage of giving a priority to calls and tasks to be accomplished. Certain extended sites are equipped with analog radio networks like trunk systems. • Needs for communication outside the enterprise: Until now, the user outside the company had cellular radio networks that offer good nationwide radio coverage and now have GSM available. Public radio paging networks are also widely used. Final User Expectations Simplicity of Utilization, Ergonomy of the Terminal Above all, the user seeks simplicity of utilization: ergonomy of the terminal, duration and ease in changing the battery, weight and size. Needs in terms of ergonomy and size are very different according to function: • Administrative or pre-sales staff want a lightweight terminal small enough to go into a pocket or to be attached to a belt. • Technical staff prefer a sturdy terminal with keys that are accessible (even with gloves) with an emergency button if required by the work environment. In addition, the terminal must have a certain number of accessories (for example, head phones that can be necessary in a noisy environment). As for the battery, needs are nearly unanimous: battery capacity must be sufficient for daily use and must be able to be recharged during a very short lapse of time. In addition, a recharge indicator prevents from an unexpected failure. Vocal Transmission Quality Users familiar to the high vocal quality of the fixed telephone often complain of the poor quality of radio transmission, lacks in radio coverage (notably by crossing through tunnels) and untimely carrier interruption in public networks, whether they are analog or digital. Extension of the Area of Coverage Once the user has a cordless terminal available, he experiences a growing need to communicate and increase the cordless communication area: when he can be reached, he wants to be reached in the largest number of places possible. It is that much more true in the case where users who are in the process of renewing their cordless communication tools: they not only want more functions but above all they want radio coverage that is at least equivalent to what they had in the previous system. This is the case for example: • of users who go from an analog cellular network to a digital cellular network (GSM) and whose coverage at the opening of the service was not extensive. of users of paging systems that move to wireless telephony or cordless PABX (CT2 or DECT) whose radio range is inferior to paging systems. Improvement of Reception on the Telephone For administrative and pre-sales staff, the wireless terminal must be part of the reception function as is the case for voice mail and call forwarding facilities. It must allow improvement of reception of the companyÕs external or internal corespondents.
  10. 10. The multiplication of voice mail systems (one per system of cord or wireless communication) is to be prohibited. The user must be able to access all of his messages within one call. Also, unavailability due to a terminal outside the area of radio coverage must be handled during a call: • either by a greeting message, • or by automatic call forwarding to a fixed telephone. Flexibility of Utilization The advantage of a mobile telephone come out the ability of being contacted at any place and at any time. This advantage may become an inconvenience if the user loses the possibility of delaying the answer to telephone calls. Users must keep the freedom of whether or not answering a call without losing the benefit of the communication. It is therefore important, for the user comfort, to have the following functions available: • calling line identification, • call forwarding to mail box or fixed terminal, • the possibility of defining a certain number of authorized calling numbers. Terminal Uniqueness Current mobile networks do not allow to cover all user needs. This binds them to subscribe to different networks and leads them to acquire several different terminals. However, most users do not want to multiply cordless terminals. The development of an offer of terminals allowing access to several different networks is required, in particular: • access to a wireless corporate network and a public cellular network: for example, DECT/GSM, DECT/DCS1800, • access to different public cellular networks: for example DCS1800 and GSM, to take advantage from extended GSM radio coverage outside urban areas and from the DCS1800 greater traffic capacity within the urban areas. Numbering Preferably, the calling number of wireless subscribers will be integrated into the company numbering scheme in order to facilitate remembering and dialing of the wireless subscriberÕs number by callers. However, in the case of a subscriber to a public network such as GSM, the cost of the communication being higher than a call on the fixed network, certain callers want to be informed of the cost of the communication. Among the users who were interviewed, one said he would like to have a single mobile telephone number which would allow him to be reached via the private wireless system when he is in the company and via the public network when he is outside the company. Data Transmission Services Data transmission services seem interesting but may be seen mainly as a service that complements telephone functions. The purpose is mainly related to facsimile transmission and paging function (reception of alpha-numerical messages on the cordless terminal). In a more limited manner, the transfer of documents and the renewal of data bases in portable Pcs may be seen in a telworking perspective for nomadic people. Confidentiality of Communications Wireless networks must offer protection from undesired listeners. Some sensitive professions require the ciphering of communications.
  11. 11. Expectations of Telecommunications Managers and Heads of Purchasing Access Control and Protection against Theft Access to a private wireless system must not allow fraudulent utilization of the fixed corporate network: a non-authorised individual must not be able to have access to public networks via the wireless system and must not then be able to access the fixed corporate network. The terminal must be protected from theft: • it must be equipped with an access code, • rights to access must be able to be easily and quickly modified. Cost Control The cost control of communications is often necessary when in a public network context. The following functions are esteemed useful and must be able to be applied individually: • limitation of the duration of the communication, • call restriction for the cordless subscriber: on numbers or a list of numbers and for a defined time span. Also, when there is the acquisition of a private mobile system, the telecommunications manager wants to evaluate costs in investment of materials as well as in engineering. Billing Billing management must take the following needs into account: • integration into the existing billing system in the case of a private less11Wi network in order to avoid the multiplication of billing systems in the company, • breakdown of communication costs following several levels, for example, by extension/service/direction, • distinction between private and professional communications (notably for pre-sales staff). In addition, to facilitate management, some administrators want to be able to easily consolidate contracts taken out individually or one by one into a single contract. Alarm Management Preferably, the alarm management system of a private less11Wi telephony system should be integrated into the alarm management system of the private telephony network or at least should interwork with it. Interchangeability of Terminals When purchasing terminals, the manager wants the possibility of choice, whatever the private wireless system in place is, while preserving most of the service facilities. Control of Quality of Service It is necessary to have tools allowing to control the quality of service in terms of dimension and radio coverage. Network Interworking Needs Private Telephone Network/Private Wireless Telephone Network A minimum of interworking is necessary: • to have tools for management and billing that can interwork with existing tools, • to offer some interactivity of service between fixed posts and cordless posts (calling line identification, automatic callback, call forwarding ...).
  12. 12. Multi-site Wireless Corporate Telephony (the same PBX or different PBXs) In the case of a single area of communication and several radio controllers plugged into the same PABX, this technical constraint must be transparent for the subscriber. All the wireless communication areas served by different radio controllers must form a single one in the eyes of the user. Handover and roaming functions must be available throughout the area. In the case of several areas of communication, a wireless subscriber attached to site A in his company and visiting site B must be able to use the wireless infrastructure of the site he is visiting by a simple act of relocalisation. Administrative information concerning the subscriber must be transmitted to the site being visited. Corporate Telephony of proximity/ Public Cellular Telephony The introduction of multi-network terminals implies a certain level of interworking between mobile networks, that is, the passage of administrative and mobility information (handover, roaming) from one to another. The choice of a default network must be easily defined by the user.
  13. 13. PANORAMA of MOBILE SERVICES IN EUROPE Compared to traditional communication systems, mobile systems have several specific features that must be taken into account, namely: ¥ the mobile sector is much more open to competition, and this requires an adequate level of regulation and standardization, ¥ the use of the radio spectrum, which is a rare resource, has led to the development of complex technical systems in order to optimize its allocation and use, ¥ new technical factors such as propagation, confidentiality and mobility management affect quality, ¥ the life cycles of technology are becoming shorter and shorter; no sooner has one product appeared on the market, than others arrive before the former have reached their break- even point. The aim of this chapter is to present the different kinds of radio systems such as: ¥ analog and digital cellular systems, ¥ cordless systems, ¥ Professional radio systems: analog systems (trunked and dedicated channel) and digital systems, ¥ paging systems, ¥ data transmission systems, ¥ satellite based communication systems. A list of the European digital cellular (GSM, DCS1800) and cordless (CT2/DECT) networks/operators is given at the end of this chapter with a table that summarises the key features of GSM, DCS1800, CT2 and DECT solutions. Definitions and radio concepts Radio cell: Geographical area covered by means of one (or more) radio transmitter-receiver. Roaming: Automatic location of mobile terminals. Handover: Automatic procedure whereby an established call on a cellular radio system is passed from one channel to another or from one cell to another. Multiple Access: Multiplexing is a technique whereby several channels can be combined to share the same transmission medium without there being any mutual interference. There are three forms of multiple access to radio resources: Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA) and Code Division Multiple Access (CDMA). Time Division Multiple Access (TDMA): The use of time interlacing to provide multiple and apparently simultaneous transmission without mutual interference. This technique presents an important synchronisation constraint. Frequency Division Multiple Access (FDMA) : A high bandwidth transmission line is shared by sub-dividing it into a number of smaller bandwidths, each used to convey a different signal. Code Division Multiple Access (CDMA): A spread spectrum technique in which the baseband is itself spread before being applied to a carrier frequency.
  14. 14. Cellular systems The problem of the lack of spectrum has led to the cellular concept: cellular systems allow frequency re-use and provide more traffic capacity. Analog systems Two systems are currently being operated in France: Radiocom 2000 operated by France Télécom and ligne SFR NMT operated by SFR. Both networks are incompatible. Unlike SFR, France TŽlŽcom has a corporate network offering. One analog network is being operated in Germany, namely C-Netz (DeTeMobil). In Italy the analog network of Telecom Italia has 2 million subscribers. Two operators are offering analog services in the United Kingdom: Cellnet and Vodafone. In the United Kingdom and Italy, market penetration of analog cellular networks is still increasing. The GSM standard has therefore some difficulties in penetrating in these countries. GSM GSM (Global System for Mobile communications) is a digital radiocommunication European standard operating in the 900 MHz band. Advantages of GSM compared to analog systems The principal advantage of GSM is that the interfaces are standardised, and especially the radio interface between mobile terminals that allows terminals compatibility. It is precisely thanks to this that the major enhancement of European roaming is possible. Compared to the analog system, GSM networks present four specific features from the end userÕs point of view: • a better vocal quality, • conversation confidentiality, • international roaming (the possibility of fully benefiting from the service in a network other than the one where the subscribtion was taken out), • possibility of data and short message transmission. Services offered Today, great importance is given to the diversification of services for users on this stable, high quality network. GSM services are classified by three categories: • Teleservices (group 3 fax, voice mail, short message service, ...), • Bearer services (data transmission via RTCP, ...), • Supplementary services (call forwarding, calling line identification, ...). A vital element in the system is the SIM (Subscriber Identity Module), an intelligent card that not only identifies the subscriber but also activates the terminal. A subscriber is no longer ÇÊattachedÊÈ to a given terminal; there is consequently a clear distinction between the subscription as opposed to the terminal equipment. The risk of fraud is therefore reduced. The subscriber doesnÕt even need to take his own terminal with him to a foreign country but could choose a short hire solution thanks to his SIM card. Operators In France two networks are being operated: France TŽlŽcom (ITINERIS) and SFR. Both of them are obliged to cover 90% of the metropolitan population. In Germany, there are two GSM operators, which are DeTeMobil and Mannesmann. It can be pointed out that Germany has the most important GSM market in Europe. In Italy, Telecom Italia and Omnitel Pronto Italia are both operating GSM networks. In the United Kingdom there are two GSM operators namely, Cellnet and Vodafone.
  15. 15. Many other countries have adopted the GSM standard: Europe: Austria, Belgium, Bulgaria, Croatia, Denmark, Spain, Finland, Greece, the Netherlands, Hungary, Ireland, Luxembourg, Norway, Portugal, Sweden, Switzerland, Turkey, ... Asia/Oceania: Australia, China, Hong-Kong, India, Macao, Malaysia, New-Zealand, Singapore. Middle East: Saudi Arabia, Bahrain, United Arab Emirates, Iran, Israel, Oman, Qatar. Africa: South Africa, Marocco, Ouganda, Zaire. DCS 1800 DCS 1800 is a European standard elaborated by the ETSI technical committee responsible for GSM standardisation. In fact, DCS1800 is the GSM technological transposition on the 900 MHz band. Services offered to users are the same as for GSM. Compared to GSM, cells size are smaller in order to allow a higher traffic density. The first DCS1800 operators are British: • Mercury (a consortium made up of Cable & Wireless and US West) opened its ÇÊOne 2 OneÊÈ service in September 1993, • Hutchison (Hutchison Whampoa, British Aerospace et Barclays Bank) opened its "Orange" service at the end of April 94. These operators have no obligation regarding the density of the population that is covered. In Germany, the ÇÊE-PlusÊÈ consortium (Thyssen AG, Bell South, Vodafone and Caisse des Dépôts et Consignations) opened its DCS1800 service in May 1994. Its radio coverage commitment is very important (more than 75% of the population before 1997). There is only one French operator, namely Bouygues Telecom (Bouygues, Jean-Claude Decaux, Cable & Wireless, Veba, US West, Paribas et la BNP). Bouygues Telecom should be able to open its service in 1996. Cordless telephony The first standards related to cordless telephony (CT0, CT1) were analog systems. These standards, which constituted the cordless telephony of the first generation, were mostly used in the residential domain. Cordless telephony of the second generation is digital and is based on two standards, namely: CT2/CAI (Cordless Telephone Second Generation/Common Air Interface) and DECT (Digital European Cordless Telecommunications). CT2/CAI is a British standard and has become an interim ETSI standard whereas DECT is a standard defined by ETSI. These standards are related to the interface between cordless terminal and base stations which constitute the link with fixed networks. CT2 operates in the 800 MHz range. DECT operates on the 1800ÊMHz band. Public offering: Telepoint Telepoint is based on the concept of personal communications: a pocket-sized handset that you can take with you anywhere and that allows you to call any subscriber on national or international networks. The Telepoint service permits a subscriber to access PSTN by radio transmission via the public base stations, and one can say that the telepoint terminal is rather like a personal telephone booth. Telepoint offerings based on CT2 France Telecom has offered a Telepoint service called Bi-Bop since December 1991.
  16. 16. Compared to GSM, Telepoint has the following features: • mobility is reduced (the user has to stay in the area where he has initiated the call), • radio coverage is limited: only important towns are covered, • terminal and communications costs are lower than GSM. Another operator was awarded a Telepoint licence in April 1995 for the Southwest of France, namely: Prologos Aquitaine. Up to the present day, many telepoint networks based on CT2/CAI standards are being operated, particularly in South-East Asia (Singapour, Hong-Kong) and in the Netherlands with the Green-Point service, which has 40 000 subscribers. Deutsche Bundespost Telekom launched an experimental Telepoint Service named ÇBirdieÊÈ. This experiment was stopped due to financial reasons. Public offerings based on DECT Public offerings based on DECT are not widespread at all, but Compagnie Générale des Eaux was allowed to establish and operate a Telepoint network using this standard in France (in a town called Saint-Maur-des-Fossés) in March 1994. However fourteen mobile and fixed networks operators have set up the "DECT Operators Group" (DOG) in June 95. The aim of DOG is to promote cordless technology in public networks compatible with DECT standards and make GSM/DECT and DECT/ISDN inter-operability easier. DOG is made up of the following operators: TeleDenmark, Helsinki Telephone, Telecom Finland, CGRP (CGE subsidiary), DeTeMobil, Mannesmann et E-Plus, Telecom Italia, Telenor (Norway), Telia, British Telecom, Mercury Communications and Westel Radiotelephon (Hungary). Corporate Network offerings In the business sector, cordless telephony systems or cordless PBX allow an employee who has a cordless terminal to initiate or receive calls via base stations distributed on his company premises and connected to his corporate network. These systems provide an extension of the fixed telephoned connected to the corporate network of the company. Major features Cordless systems for business applications based on CT2/CAI and DECT standards have more or less the same features described below. Architecture: There are two kinds of architecture: 1- A radio controller integrated to the PBX: radio stations are directly connected to the PBX, which has mobility functions (fig. 1). Fixed and cordless subscribers can coexist on the same PBX. 2- A radio controller connected to the existing PBX of the company (fig. 2). Base Station PBX Base Station Base Station figure 1: integrated mobility
  17. 17. Base Station Radio Base PBX Controller Station Base Station figure 2: non integrated mobility Mobility management: DECT and CT2 systems for business applications provide roaming functions. Handover is available on all DECT systems and on certain CT2 systems. Due to capacity constraints (an important number of subscribers or base stations) or distance constraints (several km2 of coverage) it can be necessary to install several radio controllers on certain sites. So each radio controller will manage one part of the whole base station. Most systems available today have no networking facility: handover and roaming functions are limited to the coverage of each controller even if they are connected to the same PBX. Manufacturers are improving their products in order to provide networking facilities and to allow Handover and Roaming between several controllers. In addition to that, ETSI is elaborating standards in order to provide mobility on several sites. Cordless systems engineering: DECT and CT2/CAI system installations on company premises require the study of the location of the base stations in order to ensure radio coverage and to permit user traffic. Indeed, buildings are not always constructed with the same materials. A user will have to pay more if he has a building made of metallic structures because this type of material requires more base stations in order to ensure radio coverage. Manufacturers generally use a tool in order to evaluate the number of base stations required, their approximate location according to building size, structure, and traffic estimation for each site. Until now, these tools were often based on prediction models defined for cellular networks, but they were not really convenient for networks with small cells ("picocellular networks"). Now more suitable tools especially designed for picocellular networks are appearing on the market. The choice of a standard: Cohabitation of both standards is possible. Indeed CT2 is more convenient for small companies (few cells, low traffic) whereas DECT is more suitable for big companies requiring many cells and higher traffic.
  18. 18. Manufacturers offerings DECT systems CT2 systems ERICSSON: Freeset. ERICSSON: Tangara 16. ALCATEL: A4220 } integrated NORTHERN TELECOM: A4400 (fin 95) } solutions Companion 100/120. A4672 } Add-on A4674 } solutions. A4075 } Terminal. MATRACOM: MC 6220 (being developed MATRACOM: offers Companion for in collaboration with Philips) MC6500 and MC6501 PBX. SIEMENS, JS TELENORMA: offer Freeset. ASCOM Tateco: CTS 902. PHILIPS: SOPHOS 3000: integrated solution. ATT/Barphone: Domoline 16 and Generis. Residential application CT2 and DECT standards allow cordless telephony in the residential area via domestic base stations located in houses and apartments. In France, France Télécom sells domestic base stations operating on the CT2 standard. Siemens sells a domestic base station based on the DECT standard and called Gigaset. Radio Professional systems Radio professional systems or PMR (Private Mobile Radio) and PAMR (Public Access Mobile Radio) are used by organisations that need some means of communication between a base station and employees on the move. Most current professional systems are analog systems, but ETSI is elaborating a digital trunked system standard. Conventional networks Conventional networks are usually two-way analog radio systems using a dedicated radio channel. Users can communicate alternately, and the communication is half-way. These networks are based on proprietary systems. They are often used by emergency and police services. Trunked systems Trunked systems are based on a technique that allows radio frequency sharing between several individual users or groups of users. Users are allocated a frequency dynamically, as the communication need arises. Radio coverage of a trunked network is regional; it can cover a town and its suburb or several sites connected via fixed links. Communication is half-way, in accordance with private radio networks.
  19. 19. Trunked systems provide the following functions: ¥ individual calls, group calls, priority calls, calls via dispatcher, ¥ limitation of call duration, ¥ roaming, ¥ transmission of status messages, ¥ data transmission via the signalling channel. And depending on the manufacturer: ¥ calling line identification, ¥ billing, reports. It is necessary to draw a distinction between the two kinds of professional mobile radio systems, PMR or private mobile radio where the network is owned and run by a user for his own private needs, and PAMR where the network is run by an operator and opened to third parties. The kind of users that are targeted by the PAMR operators are the ones who use or are likely to use conventional networks. The advantage of PAMR networks is that they offer a better global quality and an easier extension. PMR networks are owned by companies that have many subscribers such as the RATP (Paris transport system) that supports 5000 users. Digital systems Digital trunked networks currently used are proprietary (MC9600 system of Matra Communication and ASTRO of Motorola). ETSI is defining a standard related to digital trunked systems called MDTRS (Mobile Digital Trunked Radio System) or TETRA. TETRA stands for Trans-European Trunked Radio. The radio frequency band will probably be [400, 500 MHz] (and then 1,7 GHz for data transmission). The 380 MHz band is allocated to public safety and security networks. The mode of communication is half duplex. Unlike DECT and GSM ETSI standards, handover is not provided with TETRA. TETRA networks will have to be easily interconnected, and a minimum level of inter-operability will be required in order to provide users with most functions whatever the network is used. Commercialisation of the first products is planned for 1996/1997. Radio Paging Radio paging is a simple concept: sending of a non-speech message to a pocket-sized handset via a radio channel. Messages can be sent from a telephone handset or a videotex terminal, and there are 3 kinds of messages: • alert (bip), • digital, • alphanumerical. There are more and more services in Europe, but they are often incompatible (Eurosignal, Alphapage and Operator in France; DeTeMobil, MiniRuf and DFR in Germany; BT, Mercury paging, Vodapage, Aircall, Digital, Intercity, Hutchinson in the UK ...). In order to avoid incompatible systems multiplication, ETSI specified a European standard for digital radio paging: ERMES (European Radio Message System). This system will provide inter-operability of terminals all around Europe and will eventually lead to lower prices. Until now three operators have launched an ERMES service: TDR (Tam-Tam), Bouygues (Kobby) and France TŽlŽcom. All of them are French operators. ERMES operates on the following frequency band: [169,4; 169,8 MHz].
  20. 20. Data Transmission radio networks Data transmission radio networks are based on proprietary systems. The most wide spread system in Europe is MOBITEX, which is based on Ericsson technology. In France two operators are using this technology on their network: France TŽlŽcom with MOBIPAC and TDR with "Service MOBITEX". In Germany, the MODACOM network is based on DATA TAC technology developed by Motorola. Satellite Communication systems Current mobile systems operate with geostationary satellites and require voluminous terminals. These systems, INMARSAT (voice and data) and EUTELTRACS (radio paging and radio location), are limited to professional use. Other systems are being developed and may be available by the end of the century: IRIDIUM, GLOBALSTAR and INMARSAT/project 21. These systems will allow the use of pocket-sized handsets, and they will offer world-wide radio coverage.
  21. 21. Digital Wireless Telephony offerings in Europe GSM DCS 1800 CT2 DECT - DeTe Mobile - E-Plus GERMANY - Mannesmann - Belgacom (Proximus) BELGIUM - TeleDenmark Mobil DENMARK - Telecom Finland FINLAND - Radiolinja - France Télécom (Itinéris) - Bouygues Télécom - France Télécom (Bi-bop) - CGE FRANCE - SFR - Cellnet - Mercury (One-to-One) UNITED - Vodafone - Hutchison (Orange) KINGDOM - PTT Telecom - Green-Point NETHERLANDS - Omnitel-Pronto Italia ITALY - Télécom Italia - Tele-Mobil - Norvegian Telecom NORWAY - Netcom - TMN PORTUGAL - Telecel - Comviq SWEDEN - Europolitan - Telia Mobitel ICELAND
  22. 22. Positioning of Digital Wireless Telephony offerings GSM DCS 1800 CT2 DECT Availability Standard yes yes yes yes Products yes yes (beginning of Ô96 in yes yes France) Mobility level all levels (pedestrian, car...) pedestrian only pedestrian pedestrian Handover in business field _ _ depends on the product yes in public domain yes yes yes yes Roaming in business field _ _ yes yes in public domain yes yes no yes Terminal handsets interchangeable proprietary solutions interchangeable interchangeable (European agreement being specified) Access Control access code + calling line authentification access code (+calling line access code + calling line authentication in business authentication domain) Confidentiality Communication coding is very complex Communication coding Communication coding + Ciphering on radio channel (not always implemented on + Ciphering on radio channel network operators) Maximum traffic capacity 500 E/km2 1000 E/km2 2 000 E/km2 10 000 E/km2 (estimation) Evolutivity high low high many supplementary services, data transmission Data transmission technical improvements interworking with GSM and ISDN
  23. 23. STANDARDISATION The increased mobility of radio telephone users in Europe, problems caused by incompatibility of analog standards in Europe, the technical evolution imposed by network saturation have pushed European operators to unite their efforts. They are uniting in order to develop a common solution in order to offer, private users single access to radio telephone services on one hand and to offer industrials on the other hand a large market to manufacture their products in large numbers and thereby diminish the number of versions of a product, and reduce fabrication and sales costs. ETSI The European Telecommunications Standards Institute ÐETSIÐ was founded in 1988 after the European Commission published its Green Paper on the Development of the Common Market for Telecommunications Services and Equipment. ETSI is an open forum bringing together the most highly qualified experts in Europe to work on common problems. Drawing on Administrations, public network operators, manufacturers, users, service providers and research bodies, the organisation involves all interested parties so that its output is technically correct and widely acceptable. ETSI provides: • ETS (European Telecommunications Standards), • I-ETS (Interim - European Telecommunications Standards), • TBR (Technical Basis for Regulation). These documents are sent out for public enquiry before their adoption. When standards are adopted, they become effective on a voluntary basis, but national governments may make them mandatory, or the EC may issue a directive thereby making them enforceable throughout Europe. GSM GSM standards fully specify a GSM network: the radio interface between mobiles and base stations, interfaces between the different parts of the GSM network, interfaces between GSM networks and fixed networks (PSTN, ISDN, X25, ...), services offered, etc. GSM history In 1982, the CEPT (Conférence Européenne des Postes et Télécommunications) set up the ÇÊGroupe Spécial MobileÊÈ called GSM. The task of the GSM was to specify a unique radiocommunication system for Europe on the 900 MHz band. The CEPT requirements for GSM were the following: • high number of subscribers, • international compatibility, • efficient radio spectrum use, • high availability, • adaptability to traffic density, • service quality comparable to that of fixed networks, • attractive costs for the end user, • access capabilities for portable and mobile handsets, • an ordinary telephone service and specific services like fleet management. In 1989, the work of the ÇÊGroupe SpŽcial MobileÊÈ was transferred to the SMG technical committee of ETSI. Then ÇÊGSMÊÈ changed its signification and became the "Global System for Mobile communications".
  24. 24. Five groups constitute the SMG. They define: • services offered, • the radio interface, • network aspects, • data transmission, • the Subscriber Identity Module (SIM). The SIM card is a smart card that contains information describing the subscription. The GSM system is completely defined by the GSM ETSI standards numbered 01 to 12. GSM Features The GSM frequency band The frequency band allocated to the GSM is: • the 890-915 MHz band for transmission from mobile stations, • the 935-960 MHz band for transmission from fixed stations. The key features of GSM The key features of this system are: • digital transmission, • time multiplexing of radio channels (TDMA), and frequency duplexing division (FDD) for the two directions of transmission, • ciphering of information on the radio channel, • a speech coding algorithm at reduced rate (13 kbps) compared to those that are currently being used by the fixed telecommunications system. This coding law ensures good spectral efficiency and good resistance to error conditions. The different steps of standardisation The process of GSM standardisation relies on several steps. In order to permit the commercial opening of the first GSM network as planned, in 1991, it was decided to set the specifications that were available at that time and to publish them under the name of "GSM phase 1" while continuing the work on specifications in order to publish a more complete version later under the name of "GSM phase 2". Phase 1 mainly includes speech services. GSM phase 2 technical specifications are currently being published. They are partially implemented in infrastructures. The change from phase 1 to phase 2 will really become effective when the first phase 2 mobile stations are approved and put on the market, that is to say by the first semester of 1996. Phase 2 is mainly an improved version of phase 1 and contains supplementary services. Phase 2 notably includes: - new services, - a complete fusion between the GSM and the DCS 1800, - provisions for future evolution, - integrated compatibility for the mobile stations of phase 1. After phase 2, it is planned to pursue the evolution of the system, but with total compatibility, which is the next step called "phase 2+". Total compatibility is possible, but it requires a reasonable increase in the complexity of mobile stations.
  25. 25. GSM phase 2+ introduces: ¥ new speech coding - half rate coding that has the same performance as full rate coding (that is to say, the same speech quality despite a complexity 4 times higher): this coding will allow an increase in GSM traffic capacity, - improved full rate coding with a quality comparable to that of fixed networks. ¥ multiple radio techniques The GSM network platform can be adapted to different radio techniques. So it is possible to envisage different forms of interworking and especially roaming by means of the subscriber identification module (SIM) or multimode terminals. This will be the case for public access point systems based on the DECT standard or personal communication systems based on satellite (Globalstar, Iridium and Inmarsat), ... ¥ new services: - packet data services on the radio channel, - private radio network services (Union Internationale des Chemins de fer Ð UIC) Services offered The GSM network offers its subscribers three kinds of services: ¥ bearer services, ¥ teleservices, ¥ supplementary services. Bearer services Bearer services provide end to end data transmission within the network. Technical attributes define services and the way a user perceives them from an access point. A particular bearer service is identified by means of its attributes. The standard defines three kinds of attributes: ¥ information transfer attributes: they characterise possibilities of the information transfer on a network from an originating point to one or more recipients, ¥ access attributes: they describe ways to access functions and supplementary services of a network, ¥ general attributes: they are related to the entire set of supplementary services. The access and general attributes identify a service and specify a bearer service in details. GSM offers bearer services without restriction concerning the type of the data used by the user; they carry end-to-end information without modification in circuit mode via the GSM network. This transmission mode ensures the chronology of exchanged information. Bearer services provided are used for various applications such as speech transmission, access to an X25 network, data multimedia transfer, messaging services, etc. GSM bearer services Data transmission in duplex asynchronous mode 300-9600 bps Data transmission in duplex synchronous mode 1200-9600 bps Synchronous access to a PAD 300-9600 bps Data transmission in duplex synchronous mode 2400-9600 bps Half way digital speech transmission 2400-9600 bps
  26. 26. Teleservices Teleservices are operational applications offered by the network to its subscribers. They use the possibilities offered by bearer services. They allow information transmission from one to another within the framework of an application. Telephony is the most important teleservice; it provides communication between two mobile stations or between a mobile station and a fixed terminal within any number of networks. For instance: ¥ emergency call: it automatically generates a call to an emergency service when the user pushes the button dedicated to this function. ¥ group 3 fax is possible thanks to an adaptator. ¥ short message service (140 car. maximum) transmission and reception (SMS). It can be implemented for transmission from any of the terminals capable of transmitting alphanumerical messages to a GSM terminal. There are two modes of operation: point-to- point and point-to-multipoint. GSM teleservices Kind of information Service offered Speech Telephony Speech Emergency calls (112) Point to point messages Data ¥ 300 bps access ¥ 1200 bps access Short messages Short alphanumerical messages transmission (max. 140 bytes) Graphic Group 3 fax Supplementary services Supplementary services improve other services. There are many supplementary services, and the following list is not complete: ¥ calling line identification, ¥ call forwarding (all calls, on busy, on no answer... ), ¥ call waiting, ¥ call queuing, ¥ charge advice, ¥ call barring (outgoing, incoming, international), ¥ voice messaging, ¥ three party service, ¥ 3-way teleconference, ¥ call transfer, ¥ speed dialling, ¥ closed user group ¥ automatic callback on busy. Security management Network security is based on very sophisticated mechanisms. The standard imposes the following points on the network:
  27. 27. ¥ subscriber identity confidentiality, ¥ identity of subscribers and mobile stations authentication, ¥ data and signalling on the radio interface confidentiality. These services are described in the ETSI GSM 03-20 recommendation. From the user point of view, confidentiality of user information is ensured thanks to the speech, data and signalling ciphering. From the user and the operator points of view, confidentiality of user identity is ensured by the dynamical allocation of a temporary identity transmitted in a ciphering mode. For the operator, the authentication of the subscriber is ensured by a secret key stored in the SIM card.
  28. 28. List of GSM services planned for each step and approximate date of publication for standards * Name of the service kind of Publication service Phase 1 Vocal telephony (3,1 Khz band) bearer yes Asynchronous data transmission in circuit mode bearer yes (at 300, 1200, 2400, 4800, 9600, 1200/75 bit/s) (except 9600 bit/s) Synchronous data transmission in circuit mode bearer yes (at 1200, 2400, 4800, 9600 bit/s) (except 9600 bit/s) Asynchronous PAD access to a packet switched bearer 1995 public data network (at 300, 1200, 2400, 4800, 9600, 1200/75 bit/s) Synchronous access to a packet switched public data bearer 1995 network (at 2400, 4800, 9600 bit/s) 12 kbit/s unrestricted digital bearer 1995 Speech followed by data bearer 1995 Alternate speech/unrestricted digital bearer 1995 Telephony teleservice yes Emergency calls teleservice yes DTMF teleservice yes Short message service from/to a mobile station teleservice 2nd term 1995 Short message service cell broadcast teleservice 2nd term 1995 Advanced MHS access (X400) teleservice 1995 Videotex access teleservice 1995 Teletex teleservice 1995 Alternate speech/fax group 3 teleservice 1995 Automatic fax group 3 teleservice 1995 Call barring supplementary since 1993 Call forwarding supplementary since 1993 Phase 2 Calling line identification (and restriction) supplementary 1996 Malicious calling line identification supplementary 1996 Call transfer supplementary 1996 hold supplementary 1996 call waiting supplementary 1996 Automatic callback supplementary 1996 3-way teleconference supplementary 1996 Charge advice supplementary 1996 User to user signalling supplementary 1996 Taxiphone supplementary 1996 Phase 2+ Closed user group (group calls, group broadcast calls, supplementary by 1995 priority, fast set up calls) Improved services of phase 1 or 2 teleservice 1997 ? New services related to packet oriented data bearer 1997 ? transmission (GPRS, higher rates, data compression) * The time between the publication of a standard and the commercialisation of services is more or less long. DCS 1800 DCS1800 standard is entirely based on the GSM Phase 2 standard. The frequency bands allocated to the DCS 1800 are: • 1710, 1785 MHz band for transmission from mobile stations,
  29. 29. • 1805, 1880 MHz band for transmission from fixed stations. The CT2/CAI standard Introduction CT2/CAI is a de facto standard of British origin. It was adopted by ETSI in October 1991 and became the interim standard I-ETS 300 131. A second version of this standard was published in 1993. This standard specifies the radio interface (CAI: Common Air Interface) and ensures in particular the interchangeability of terminals: any terminal that respect this standard can operate with any private or public network based on CT2/CAI. Features of the standard CT2/CAI operates on a frequency band of 4 MHz wide between 864,1 MHz and 868,1 MHz and is divided in 40 channels of 100 KHz wide. It is based on the following techniques: ¥ FDMA: allocation of a radio channel during the entire duration of the communication. ¥ TDD (Time Division Duplex): one way transmission (mobile to base station) then transmission in the other direction(base station to mobile). The choice of one frequency among the forty is random. A terminal that wants to establish a call, scans the 40 radio channels and chooses the radio channel that offers the best quality of reception. When the base station that manages this radio channel detects the call from the terminal, there is a connection between the base station and the mobile terminal.
  30. 30. The DECT standard Introduction The DECT was created for several applications: ¥ cellular networks extension, ¥ public networks extension, ¥ residential cordless telephony, ¥ business cordless telephony, ¥ Telepoint service, ¥ Local Area Network (LAN) access. The aims of this standard are: ¥ to support a high user density, ¥ to provide a good quality of traffic flow, ¥ to provide a cordless extension to an ISDN terminal, ¥ to provide supplementary services (fax, data transmission), ¥ flexibility in order to adapt to new needs, a new implementation. DECT is specified by standard ETS 300 175 (part 1 to 9) published in October 1992. This standard defines the common radio interface between mobile terminals and base stations. Part 01 Overview Part 02 Physical layer Part 03 Medium access control layer Part 04 Data link control layer Part 05 Network layer Part 06 Identities and addressing Part 07 Security features Part 08 Speech coding and transmission Part 09 Public access profile (PAP) Specifications of the approval tests are described in TBR 6 and 10 (Technical Basis for Regulation) that define respectively the tests for the radio interface and transmission quality. Even though DECT standard has been published, ETSI is continuing working on the DECT standardisation in order to define protocol subsets, called access profiles in order to guarantee interworking between products. Two access profiles are being defined: PAP (Public Access Profile, TAR 11) and GAP (Generic Access Profile, TAR 22). GAP will ensure interchangeability between DECT terminals.
  31. 31. Technical features of the DECT standard DECT operates on a frequency band of 20 MHz wide between 1880 MHz and 1900 MHz divided into 10 radio channels. It is based on the following techniques: ¥ MC (Multi Carrier): Frequency band divided in 10 radio channels, ¥ TDMA: on each radio channel, there is a frame divided in 12 communication channels. The radio frame is composed of 24 TS (Time Slot): 12 TS from the base station to the cordless terminals and 12 TS from the base station to the cordless terminals. ¥ TDD (Time Division Duplex). Standardisation EVOLUTION, Interworking Cordless terminal mobility in private networks BTC1 technical committee of ETSI is currently specifying standards and technical reports in order to provide cordless terminal mobility between different sites on the same private network. This is part of the work that ECMA and ETSI have done on QSIG for private networks. In fact, three groups of standards are being elaborated in order to facilitate mobility in private networks: ¥ The CTM: Cordless Terminal Mobility, ¥ The PUM: Personal User Mobility, ¥ The PSIG interface: interface between PBX radio controllers. PSIG applies to the interface between the radio controller and the PBX; this standard will be defined from one of the two potential interfaces that follow: ¥ The ISDN, proposed by operators, ¥ QSIG, proposed by PBX manufacturers. The aim of PSIG is to allow: ¥ definition of the interactive services between fixed terminals behind PBX and mobile terminals, ¥ management of several radio controllers connected to a PBX in extended areas. PSIG should allow circulation of supplementary information between radio controllers, handover and roaming functions between mobile terminals that are connected to different radio controllers. CTM functions are supplementary functions added to PBX network standards (QSIG) in order to provide all the configurations and potential on a new site that the mobile terminal had on a previous site. These standards are currently in a public enquiry state and may be available soon. Interworking standards being studied Several standards related to interworking are currently being defined at ETSI, in particular: ¥ DECT/GSM Interworking: in order to provide the interconnexion of DECT base stations to a GSM network. Certain parts of this standard are in public enquiry. ¥ DECT/RNIS Interworking: in order to consider a DECT subscriber as an ISDN subscriber. ¥ Bi-band operation (GSM/DCS) by a single operator.
  32. 32. The Status of regulations Regulations at the european level The European Commission published a report dealing with the harmonisation of regulation policies for mobile communication systems in Europe: Green Paper for Mobile communications. The aim of this report was to establish several proposals and orientations related to regulation, taking into account technological evolution and current diversity of the development in this sector in the various European countries. The aims of this document are: ¥ to make the development of mobile communications easier in Europe, ¥ to render the use of services democratic, ¥ to offer opportunities to European actors (industrials, operators...). Key proposals are summarised as follows: ¥ Abolition of exclusive and special rights in the mobile communications field. ¥ Liberalisation of conditions for the establishment of mobile network fixed infrastructures by allowing operators to build their infrastructures as they like. ¥ Liberalisation of economic conditions related to interconnection on public networks, interconnection between mobile networks and interconnection between mobile and fixed networks at the international level. ¥ Continuation of the European harmonisation plan for DCS1800 and TETRA, as was done with GSM, ERMES, DECT and TFTS: to save frequency bands in advance in order to integrate further services based on European standards. Frequency bands Due to three European Commission directives, the new radiocommunications systems such as GSM or DECT, are able to operate on harmonised frequency bands all around the European Union. A terminal can operate all around Europe, which contributes to the GSM and DECT markets. Frequency management Due to the rarity of spectrum resources, a new organisation, more efficient and prospective, has to be created. All changes that are noted in Europe today show that we are slowly moving toward a European management of the spectrum resources; notably through the increasing importance of European standards and ETSIÕs role. Concerning the use of the frequency spectrum, standardisation is very important, especially in the case of international services. Frequency cost The economic problem of the cost for use of the frequency has to be taken into account. Today in France, only the civil radiocommunications operators have to pay for frequency use (about £ 35 millions). In the United States, frequencies are put up for auction. The expected revenue between 1994 and 1998 is about $ 7 billion. In the United Kingdom, civilian frequencies have been managed by an agency of the Department of Trade and Industry (The Radiocommunications Agency) for 5 years. Its principal aim is to favour the development of industry and the emergence of new technologies.
  33. 33. The terminals Radiocommunications terminals have to be approved in order to be sold and connected to the network. Approval provides the guarantee that the terminal satisfies the following requirements: ¥ user security, ¥ electro-magnetic compatibility, ¥ public network protection against damages, ¥ efficient use of the spectrum resource (the terminal must not cause scrambling), ¥ interworking with the public network, and end-to-end inter-operability for voice telephony. Terminals are subject to severe controls. These controls are done by test laboratories on the basis of technical specifications in accordance with European requirements. In France, approval is granted by the DGPT (Direction Générale des Postes et Télécommunications). In the case of GSM and DECT terminals, there are Common Technical Regulations (CTR: TBR approved by the European Commission): ¥ CTR 5 and 9 for GSM phase 1 since 1st January 1994 (this will be CTR 19 and 20 for phase 2), ¥ CTR 6 and 10 for DECT since July 1994. As there is mutual recognition of GSM and DECT approval at the European level, an approved cordless GSM or DECT system, on the basis of its CTR, in any of one of the European Union countries, is automatically approved in the other countries of the EU. Therefore industrials can present their terminals in any of the EU country in order to make them approved. The delivered approval is valid in every other country without other formalities. So there is a competition between national regulation bodies and laboratories in charge of the realisation of tests for approval. This competition has some effects on the duration of the waiting period and on the costs of tests.
  34. 34. List of acronyms & ABBREVIATIONS CAI Common Air Interface CEPT Conférence Européenne des Postes et Télécommunications CDMA Code Division Multiple Access CTM Cordless Terminal Mobility CTR Common Technical Regulations CT2 Cordless Telephone 2nd generation DCS Digital Cellular System DECT Digital European Cordless Telecommunications DGPT Direction Générale des Postes et Télécommunications DOG DECT Operators Group E Erlang ERMES European Radio MEssaging System ETS European Telecommunications Standard ETSI European Telecommunication Standards Institute FDMA Frequency Division Multiple Access GAP Generic Access Profile GSM Global System for Mobile communication I-ETS Interim - European Telecommunications Standard ISDN Integrated Services Digital Networks MDTRS Mobile Digital Trunked Radio System NMT Nordic Mobile Telephone system PAP Public Access Profile PBX Private Automatic Branch Exchange PSTN Public Switched Telephone Network PUM Personal User Mobility SFR Société Française de Radiotéléphone SIM Subscriber Identity Module SMS Short Messages Service TETRA Trans European Trunked RAdio TBR Technical Basis for Regulation TDD Time Division Duplex TDMA Time Division Multiple Access

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