Điện thoại di động mạng lưới Radio P15

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Điện thoại di động mạng lưới Radio P15

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UPT—Universal Personal Telecommunication∗ People are becoming more mobile. At the same time they have a greater need to be reachable and to be able to reach others. A variety of different systems that address all the different categories of mobility already exist: • Employees can be reached through a DECT terminal anywhere in their company. • Tradesmen can be called over a Digital Communication System (DCS) within a city. • Business people can be reached over the same telephone number via GSM anywhere in Europe, wherever they are located. ...

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  1. Mobile Radio Networks: Networking and Protocols. Bernhard H. Walke Copyright©1999 John Wiley & Sons Ltd ISBNs: 0-471-97595-8 (Hardback); 0-470-84193-1 (Electronic) 15 UPT—Universal Personal Telecommunication∗ People are becoming more mobile. At the same time they have a greater need to be reachable and to be able to reach others. A variety of different systems that address all the different categories of mobility already exist: • Employees can be reached through a DECT terminal anywhere in their company. • Tradesmen can be called over a Digital Communication System (DCS) within a city. • Business people can be reached over the same telephone number via GSM anywhere in Europe, wherever they are located. • Adventurous types are linked to civilization through the INMARSAT satellite system. For each of these communications systems, the user requires a special terminal. In contrast to these radio-based systems, wireline telecommunications sys- tems capable of reaching almost every household in the industrialized countries are available. Fixed networks do not offer users mobility. To be reached at another terminal, the user has to inform the caller of his new location area in the form of a telephone number. With Universal Personal Telecommunication (UPT) the telecommunications network assumes responsibility for establish- ing a user’s location through an interrogation of databases based on a personal telephone number. This provides mobility in telecommunications networks to a larger number of users without the need for special new terminals. 15.1 Classification of Telecommunications Services The services of a telecommunications network first allow users to exchange information over the network in order to communicate. A service is what is ∗ With the collaboration of Matthias Fr¨hlich o
  2. 774 15 UPT—Universal Personal Telecommunication IpV0hi¨gvy5`55vx g T X e X g X s g I!0hw5I5!5gv€ g p T X g U g  IVT0w5veu0h t#5s`5gYdrq g p h X g g T W p X W IVT0iX5f5cVTY$5!`XY#VTRS g p h g e d W b a T W U #D I!5R8¨$¥ 5 4P  H § E ( Q 6  ¨¥ $¦¤¨#!¡¨¥ ¨¦¤¢  ¡    ¡ " §    © § ¥ £ ¡ % ¤¨¤'   ( ¥ & 5!¤5423¨10) 6 ¥ § ¡ ¥ § " #D I!5R$!5¢E  H § E Q  § ¥  ¨¥ $¦¤¨#!¡¨¥ ¨¦¤¢  ¡    ¡ " §    © § ¥ £ ¡ 1D I!¨GF9¨1#¤B@ 9542  H § E 66  D @ C A 66  ¨$8$( § 7 ¡ 5!¤5423¨10) 6 ¥ § ¡ ¥ § " Figure 15.1: Classification of telecommunications services made available to users by telecommunications authorities and private service providers for communication over public and private networks. The ITU-T distinguishes [20] between two types of service: Bearer services, also called communications services, are used to transfer data between precisely defined user–network interfaces. According to the ISO/OSI reference model, a bearer service is provided by layers 1–3 (the Open Systems Interconnection reference model (OSI-RM, [6, 25]) of the ISO (International Organization for Standardization) describes communication between open systems as seven interrelated layers). An example of this is the socalled B-channel in ISDN with 64 kbit/s of transmission capacity. Teleservices offer users the possibility of communicating with one another over network terminals, and are provided by layers 1–7 of the OSI-RM. This also specifies the communications functions of the terminals. An example of this is the telephone service in ISDN. With both services a separate distinction is made between interactive ser- vices and distribution services, which are subdivided further as shown in Fig- ure 15.1. Services are described according to the service features offered to the user. A differentiation is made between general connection features, basic service features and extended service features (see Figure 15.2). Extended service features are only available in connection with a bearer or teleservice, and can be provided either outside of the network or within the network. Within the network they are subject to standardization and are specifically referred to as supplementary services (see Figure 15.3). Value-added services (VAS) are extended service features that are provided by service nodes outside the network in OSI layers 4–7. These services usually contain storage, call-up or conversion functions for interfaces, protocols and
  3. 15.2 Extended Service Features in ISDN and GSM 775 General connection features Service- specific Fast connection setup Special call completion Barring Subscriber Supplementary Connection- Special lines service features service features specific Charge display Information- Supplementary information Basic specific Operations advice and dictionary service features Number identification Figure 15.2: Breakdown of the service features of telecommunications services Supplementary service features Available only together with bearer services or teleservices Additional services Value-added services Provision inside Provision outside the network defined the network by standards non-standardized Figure 15.3: Separation of supplementary service features into additional and value-added services bit-rate adaptation. They require an interface to a bearer or teleservice of the network. Figure 15.4 presents a breakdown of the bearer services, teleservices, sup- plementary services and value-added services in a telecommunications net- work, with S representing the access interface of the user between terminal and network and Q the interface between value-added service and network. 15.2 Extended Service Features in ISDN and GSM The current worldwide success of GSM is due to a great extent to the sup- plementary and value-added services offered. Owing to the harmonization between ISDN and GSM, most of the extended service features of ISDN are also available in GSM. The following section describes the most important supplementary and value-added services of ISDN. The service features offered additionally by GSM will be described in Section 15.2.2.
  4. 776 15 UPT—Universal Personal Telecommunication Service Module Q Value-added Service Transport Network, Ter- e.g., ISDN Ter- Supplementary minal Function for minal Service S Supplementary S Service Bearer Service Teleservice Figure 15.4: Breakdown of bearer services, teleservices, supplementary services and value-added services 15.2.1 Supplementary and Value-Added Services in ISDN Because of full digitalization of its network, ISDN offers a variety of supple- mentary services compared with the analogue telephone network, the most important of which can be summarized into seven groups: Number identification displays the telephone number of the party calling or of the party being called. The latter is of interest, for example, when call diversion is being activated. There are ways of keeping these supplementary services secret. In addition, more than one telephone number can be supported on one connection. Call diversion allows an incoming call to be diverted immediately to another number after a brief wait or if a number is busy. Special call completion includes supplementary service features such as call holding for enquiries as well as automatic callback or call-waiting if the number called is busy. Group connections include conference and three-party calls as well as calls for closed user groups. Charge functions allow to bill all or some incoming calls to the called sub- scribers account and to display the charges for these calls. Supplementary information can be exchanged between the terminals using transparent user signalling. Barring functions can be used for suppressing unwanted incoming calls, as well as for restricting specific or all outgoing calls. For the first time, some of the supplementary and value-added services of ISDN are supporting the mobility of users, or, in other words, a person- alization of the services is offered. Thus, for example, call diversion allows
  5. 15.2 Extended Service Features in ISDN and GSM 777 incoming calls to be routed to another location, thereby supporting the user’s mobility. Personalization is provided to a limited degree through the exclusive assignment of multiple-access telephone numbers to specific groups of people or the barring of certain telephone numbers for incoming calls. 15.2.2 Supplementary and Value-Added Services in GSM Depending on the system, GSM offers several extended service features that are not supported by ISDN. In particular, these are services that support mobility and personalization directly through the system. The main ones include the following: Device mobility, i.e., the ability to move freely within the radio coverage area of a base station during a call. Because the radio connection is switched automatically (handover ), it is even possible to change between any number of adjacent base stations without causing an existing connection to be broken off. Authentication of the user, i.e., establishing and checking the identity in- dependently of the terminal used. A Personal Identification Module (PIM), usually in the form of a smart card, is used along with a Per- sonal Identification Number (PIN). Localization describes the automatic identification and storage of a user’s location area in the network. This allows the user to be reached under his GSM telephone number irrespective of his location. Registration means making available the services subscribed to within the framework of the contract agreed between operator and user (service profile). The costs that are incurred are charged at the same time to the user in accordance with the terms of the agreement. The subscriber’s identity must be clearly established through the authentication process in order to prevent fraudulent use. Personalization of the service profile allows the user to configure certain ser- vice features individually within the framework of the agreed service agreement. Thus, for example, the user could activate or deactivate a voice mail service (automatic answering service in the network) or re- strict his own accessibility by blocking incoming calls because of the extra cost these would occur or to avoid being disturbed. The large number of users subscribing to the GSM network underline the demand for these extended service features, so an effort is being made to support them also in the fixed network—wherever this would be technically feasible. The first step in this direction is the service referred to as Universal Personal Telecommunication (UPT), which is introduced below.
  6. 778 15 UPT—Universal Personal Telecommunication 15.3 The UPT Service for Universal Personal Telecommunication The UPT service has been under development since the early 1990s, and was standardized in its outline form through international recommendations [21, 24] of the ITU in 1993. The introduction of the UPT service will take place in several stages, and to date only the first (Capability Set 1 ) has been standardized [26]. In wireline telecommunications networks such as ISDN the telephone num- ber of a user is firmly linked to the network connection of the terminal. All services of the network accessed from this network connection are charged to the user. This fixed relationship between network connection and telephone number of the user will be eliminated with the UPT service. Identification of UPT users is carried out independently of the terminal addressing and the access points of the network. A unique UPT number allows a user to make and receive calls at any access point and from any terminal in the network. A telecommunications network must offer different supplementary services in order to support the UPT service: Personal mobility, which allows a UPT user to make and receive calls us- ing different terminals in accordance with his service agreement (UPT User’s Service Profile). Identification of UPT users on the basis of network-independent UPT num- bers. Charging and billing, which is based on the UPT number independently of the terminal. Uniform access and authentication functions for UPT services in different networks. Security functions for protecting the personal data of UPT users. Configuration functions, which are used by the UPT user and the UPT sub- scriber to tailor the subscribed services to meet individual requirements. The UPT service of the first phase offers these supplementary services in a lim- ited form, and only supports the telephone service in the analogue telephone network, in ISDN and in mobile radio networks. Other restrictions affect the scope of the security functions as well as the access and authentication functions. These supplementary services will be available during the second phase in a less restricted form and, e.g., data services will be supported. However, this phase has not yet been standardized.
  7. 15.3 The UPT Service for Universal Personal Telecommunication 779 15.3.1 Existing Studies of the UPT Service The mobile radio system UMTS (Universal Mobile Telecommunications Sys- tem) [2, 29] is being designed to support standardized personalized worldwide user telephone numbers and supplementary services similar to those of the UPT service. Concepts for user administration in UMTS using a distributed database are being developed [28] and quantitively evaluated on the basis of models. Flat directory hierarchies used in connection with the interrogation technique passing are proving to be particularly favourable. The extended service features of ISDN such as call diversion and num- ber identification enable services similar to those of UPT to be implemented through a PC connected to the network access interface of the user. This kind of system is being developed [27] and evaluated on a simulated basis. For comparison purposes, several alternatives to UPT implementations are being simulated and studied in the Deutsche Telekom network. The imple- mentation with a PC at the network access interface of the user is showing clear advantages in terms of waiting times for requested services. However, this does not offer a complete UPT service, because the system does not sup- port UPT calls from non-UPT terminals. 15.3.2 Further Development of UPT The introduction of UPT into existing telecommunications networks is a dy- namic development process. The fundamental objectives mentioned in Sec- tion 15.3 are to be seen as guidelines that should be considered in any further development of UPT [30]. Figure 15.5 shows the phases projected in the development of UPT. These show a differentiation between essential and optional service features. Es- sential service features must be available at the outset of the corresponding development phase, whereas the offering of optional service features depends on the decisions made by the UPT provider. A certain proportion of the ser- vice features in both groups have already been standardized. The others have already been developed to a degree and are awaiting future standardization. 15.3.3 Phase 1—Scenario with Limited UPT Functionality During the introductory phase, UPT is limiting itself to PSTN (Public Switched Telephone Network ), ISDN (Integrated Services Digital Network ) and possibly the Public Mobile Telephone Service. Only voice telephone ser- vices are being offered. UPT phase 1 does offer limited service features for security and user-friendliness. According to the projected plan, the first phase has been completed at the end of 1993. UPT phase 1 functions are already available in the IN operating tests being conducted worldwide. Phase 1 is to be carried out without any intervention in existing networks, if possible.
  8. 780 15 UPT—Universal Personal Telecommunication )I¤W"¡ $ 4 7   ¤¤ ¤¨¦¤¢    ©  © §¥ £ ¡ 8I¤(¡ X 4 7W %9F¤(¡ ' 4 7 W  A@¤¤98¤ H¨6F2G   © 4  7 # 4 @ 7 4  A¤¤97E 9"U @  © 4   7   A¤¤98#¤¤¤¤¨6! @  © 4  7 4 # © 4 5 ¤ ¨¤I6!  © 4 77 ¤ F¤9!  © 4 7 7 ¤ 9!  © 4 7 7 ¤4 ¥ 94 (P #   D ¤%2£ 4B  SF¤(Q © R© #¤4 ¨¥ I4 D 7   ¤%2£ 4B  #¤4 ¨¥ 9F4 D 7   )¤¤¤   P © R©T©§  ¤¤¤ ¨ DEC ©  ¤¤©¤  VC   D ¤4 ¥ 94 (P #   D ¤%2£ 4B  ¤¤©¤  EC   D ¤4 ¨¥ I4 D 7 #   ¤%2£ 4B  SF¤(Q © R© #¤4 ¨¥ 9F4 D 7   )¤¤¤   P © R©T©§  %3 2£ 4  ¤&¤¤%¤"! ' &$ #© ¤¤)(! 0&&$ #© ¤&¤)#¤"! 1 &$ © Figure 15.5: Timetable for the development and standardization of UPT service features 15.3.4 Phase 2—Scenario with UPT Basic Functionality Phase 2 does offer UPT subscribers additional service features and supports a larger number of networks. During this phase, UPT also linked up with GSM networks and connection-oriented data networks. Smart cards and card read- ers offer users improved security against fraudulent use by outsiders. Phase 2, which was completed in 1995, is using the technology of intelligent networks. 15.3.5 Phase 3—Scenario with Extended UPT Functionality Phase 3 is offering extended UPT functionality. This phase was not specified in detail, but only regarded as a target for UPT to allow a more effective integration of new technological developments and an opportunity to respond to the economic developments of UPT services. Phase 3 results were projected for late 1997, and are available since then. 15.3.6 Service Features of UPT in Phase 1 of its Introduction As already explained, the ITU-T is considering some of the service features are being essential and others as being optional. Four service features in phase 1 are essential for the implementation of UPT [21]:
  9. 15.4 Business Relationship between UPT Users and Providers 781 $¤ §"¤ §© ¤¢ # !   ¤ §¨¤¦¡© §¨¦¤¢  £ ¡ ¥ £  ¥£ ¡ ¤4¦¤¡  75¦¤14¤¡ 2 £ ! £ 6 £  3! ¤¨1)0'(¤& ¦£¨$¤%¢  £ ¡$ £ ¡ § © & 4!¤¤E¤ ¡ 7¦¤14¤¡F47$©¨¤FED "! C ¡ B $ # ¡ D ¡ 5£  3! # ! $ ¡ © ¡ § $  ¤¤ "¤  @¦¤4!¤ §#  4!¦4¤98 § A $ # §! ¡££ ¡ % © £! #  Figure 15.6: Business relationshipment between conventional telephone subscriber and system provider • Authentication of a UPT user’s identity protects both the UPT provider and the user from unauthorized use of the UPT service. • In-call registration enables a UPT user to notify the network of the location area where he can be reached through a terminal. This regis- tration can be restricted to a specific period of time or revoked through an explicit deregistration or new registration. It is possible for several subscribers to be registered at the same terminal. • An outgoing UPT call allows a UPT user to use a terminal and have the call charged to his bill. So long as no follow-on service feature is avail- able, an authentication must be carried out for each UPT call in order to prevent fraudulent use. The service feature follow indicates to the network that other calls are following the outcalls. New authentication is then not necessary. • In-call delivery refers to the call forwarding service. The UPT subscriber makes his location known to the network beforehand through an in-call registration. The incoming call is then forwarded to this terminal. The subscriber to the network connection must be able to prevent registra- tion and call forwarding at his terminal. Access to UPT functions using registration is shown in Section 15.4.2. 15.4 Business Relationship between UPT Users and Providers To be able to use the telecommunications services, users must enter into a business relationship with the provider. Three different market participants can be identified in the conventional monopolistic telecommunications market. Figure 15.6 identifies these three business partners as:
  10. 782 15 UPT—Universal Personal Telecommunication Service Provider (Tele-, Supplementary, Value-added Services) UPT Service Provider Network Operator Subscriber (UPT + Framework Service) (Bearer Services) User Access Provider Figure 15.7: UPT business relationships • The network operator who provides network access and the communi- cations network • The subscriber to the service • The service provider of the applications who contributes to the value- added service in the network The user has a direct business relationship with the network operator. With UPT there is a complicated situation from the view of the user (see Figure 15.7). In addition to • a network operator, a user and an applications service provider, there are also • a UPT service provider, a network access provider and a subscriber to the UPT services who are involved in the UPT service arrangements. A business relationship no longer exists between subscriber and network operator. Instead, a subscriber can order the UPT services from a UPT service provider. In the case of private individuals, this subscriber will be the user himself. With companies, the organization appears as the subscriber to the UPT services that it makes available to its employees through proper registration in the user service profile. Since users usually do not use their own terminals (mobility), it is important that a relationship exists with a network access provider who can provide access to the network. A deregulation of the telecommunications market is necessary in order to enable the relationship between user and network operator to be split up. A similar situation was observed with the mobile radio networks in Europe, where users acquire mobile radio services from a service provider. The service provider is not automatically also the network operator.
  11. 15.4 Business Relationship between UPT Users and Providers 783 15.4.1 Charging—New Concepts in the Introduction of UPT In conventional telecommunications networks the person placing a call is charged for the duration of a successfully completed call, depending on time of day and distance between user A and user B. With UPT, users do not have to be registered at their home locations, and instead may be linked to the network at location C. Users placing a call are not aware of the distance between home location B and visitor location C. There- fore they have no way of estimating how much a call will cost unless additional information is provided. The following scenarios are therefore possible • User A absorbs all the costs of the call, in other words connections A–B as well as B–C. • User A pays the cost of the connection A–B. User B pays the cost for his mobility and consequently the cost of connection B–C. • User B absorbs all the costs. The second solution is the one that would appear to be ideal, because the costs of the extended connection are charged to the person who is responsible for the higher cost. Other solutions are conceivable for determining the charges; however, cost transparency is important for the acceptance of new services so that users have an easy way of estimating the costs of the calls they initiate. With UPT it may be necessary also to charge the UPT user for calls that were not switched successfully. The reason for this is the running costs and investment in processors and databases in the network. This measure could be justified at least for outgoing calls, where UPT calls have to be checked for approval. 15.4.2 Example of Registration of a UPT Subscriber Figure 15.8 presents an example of what a communication between UPT sub- scriber and UPT service provider could look like with a dialogue control over the telephone. This UPT function can also be carried out over analogue connections for terminals, e.g., using DTMF signalling. First the user dials the access code, which can be in the form of a previously unused dialling code (in the example #0185). After he has authenticated him- self by entering his own UPT number and his personal identification number, he dials the menu for registration. He then requests registration for incoming calls. Now he can notify the UPT service to which terminal the calls should be directed and for how long. This completes the access procedure to the UPT service. In man–machine communication, especially acoustic communication, it is particularly important to allow a person a chance to return to the previously
  12. 784 15 UPT—Universal Personal Telecommunication Access procedure to UPT service 0185 (Access code for UPT service) Welcome to your UPT service provider Please enter your UPT number followed by #: 24569039# Please enter your PIN followed by #: ____# You are currently still registered to receive InCalls during the next 2 hours for terminal 0241880099 Main menu Please select an entry from the following list: To finish UPT access please enter * To register please enter 1 To change your service profile please enter 2 For an outgoing call please enter 3 To redirect calls from another terminal please enter 4 For Outcall-follow-on please enter 5 For operator assistance please enter 6 To repeat the menu please enter # 1 Registrations You want to register, please select an item from the following list: To finish UPT access please enter * For InCall please enter 1 For OutCall please enter 2 For AllCall please enter 3 For Linked please enter 4 To return to main menu please enter 0 To repeat the menu please enter # 1 InCall Registration Please enter the local terminal identification number for InCall registration followed by #: 0241909090# Please enter the time span during which the InCall registration is valid at calling identification number 0241909090: 0200# You have successfully registered for InCall under number 0241909090 for the next 2 hours. Do you want: To finish UPT access please enter * To cancel the InCall registration please enter 1 To return to the main menu please enter 0 * Thank you for using the UPT service. Goodbye. Figure 15.8: Example of an in-call registration with a UPT service provider
  13. 15.5 UPT Service Profile 785 processed dialogue levels to enable errors to be corrected. In addition, the user should be able to have personal contact with an operator if assistance is needed. 15.4.3 Options for Authentication For security reasons a UPT user must be authenticated before UPT resources are accessed. This can be done in different ways. • The easiest way, which requires no intervention in terminals or the net- work, is authentication using a DTMF transmitter or by dialling certain numbers at a terminal. These signals are picked up by an appropriate functional unit and forwarded for evaluation. This type of authentica- tion is regarded as weak, because it does not provide any special security. However, this approach can be implemented in every network and at ev- ery terminal, which is also a requirement of the ITU-T [21]. With this model the authentication data travels over the traffic channel, which has already been switched and puts no strain on the signalling network. • A variation of the above option involves using an intelligent terminal for an automatic execution of the authentication. The terminal is then responsible for transmitting the DTMF signals. This option does not require signalling functions either. • Card readers and smart cards offer a higher level of security and are easier to use. As soon as authentication is required, the card-reading device reads the inserted smart card and carries out the authentication. The signalling can be implemented over traffic channels or over signalling channels. Thus different versions/variations, which are also able to offer different levels of user comfort, are possible, depending on the terminal intelligence or authentication security required. 15.5 UPT Service Profile One of the elements that determines the functionality of UPT is the Flexible Service Profile (FSP). This is part of a database, and is used to supply the data associated with UPT users to the Service Control Functions (SCFs). One of the most important entries in the service profile is the terminal identification that a user has registered for incoming calls for a specific period of time. With each call, irrespective of whether it is an incoming or an outgoing call, the FSP must be interrograted for certain data relating to the call. A differentiation is made between permanent and variable entries in the structure of the FSP. Permanent entries relate to data that is fixed when the UPT identification is
  14. 786 15 UPT—Universal Personal Telecommunication established and seldom needs to be changed. Variable entries concern data with values that change owing to actions of the user, such as change of location. Permanent entries that can be changed only by the service provider include: • UPT number • Identification of the home local terminal connection • Basic services contracted by the subscriber • Supplementary services contracted • Number of maximum possible authentication attempts • Type of authentication procedures • Security options • Barred destination numbers (e.g., police, speaking clock) Permanent entries that can be changed by the subscriber include: • Approved payment options (e.g.,credit card calls) • Maximum ceiling on calls • Maximum number of accesses from other terminals • Released user functions The following variable entries relate to service control: • Type of active authentication • Active option for charging • Active security mode • Status of supplementary services The following variable entries are used for mobility control and supervision: • Relevant terminal number • Fallback terminal for incoming calls • Relevant terminal for incoming calls • Standard number of outgoing calls per registration • Destination for call forwarding—absolute • Destination for call forwarding—when terminal is busy • Destination for call forwarding—when there is no answer • Destination for call forwarding—if called party cannot be reached
  15. 15.6 Requests to UPT-Supported Networks 787 ¥¤" §!¥#(£#H¤¥¤HA$ 342 £ ©£ ¡ I ¡E&£ & G ¥¤" !8(F¡(#¡E D§ ¤C¡(B£A$ 42 £ § ©£ ©£ D @ 3 (#" !¥©898© 0'7¤¡6$ 42 £ § ©£ ¡ ©  ¡ § ¦ 5 3 (#" !¥#1¦#¥)0(#'&%¢© ¨¤¥£¤¢   £ § © £   "  £ ¦ $ §¦ ¡ ¡ ¥£#" !¥©¢© ¨¤¥£¤¢   § © £     ¡ ©  §¦ ¡ ¡ Figure 15.9: Functional grouping of UPT ¨¡ © ¨ £¥¦ ¤¢   § £¡ 0¨!¨ ¥ £¥ ¤¨¡ © ¢  & ¥% ¡ §¤ £¥¦ ¨!¤¤! $ ¤¢¤¨¦ £  ¦ # !   £ ¥¤! ©  $ 4¤)2¨1 0 ¥ 3  &  ¨ £¥¦ ¤¢  § £¡ ¤¦ ¥¤¤¦ ¤§  §  ¡ ¥ ¥ ¨! ¥¤¨¦ ¥)¤ ( ¦ ¡ & ¤ £ ¤¢  ' £¡ ¤¡ ©  ¨" ¤¤¦ # !  #¤¢¤¨¦ !   ¤¡ ©  &¨ ¥ £¥ ¨¤¡ © ¡ $ ¥% &¤ ¥ £¥ ¤¤¡ © ¡ $ ¥% ¨!¨ ¥ £¥ ¤¨¡ © ¢  0 & ¥% ¡ ¤ £¥¦ ¨!¤¤! $ ¤¢¤¨¦ § £  ¦ # !   £ ¥¤! ©  $ 4¤)2¨1 0 ¥ 3  &  ¤¡ © ¤ £ ¤¢   ' £¡ Figure 15.10: Reference model for UPT calls 15.6 Requests to UPT-Supported Networks A model for the functional architecture of UPT was developed in I.373 [14] to enable the formulation of requests to the UPT-supporting network. Fig- ure 15.9 illustrates this model, which consists of five layers hierarchically po- sitioned underneath each other, which will later be related to the network. This abstraction is desirable to avoid the need of having to specifiy any spe- cific form of network. UPT can thus be implemented in fixed as well as in mobile networks. A UPT call can cross different networks on its route from the person plac- ing the call to the person receiving the call. These networks have different capabilities for supporting UPT. Connections for traffic channels and for sig- nalling exist between the different network components such as the network and service profiles. I.373 provides a reference model for UPT calls to present an overview of the dependences between the individual components (see Fig- ure 15.10). For each UPT call a different sequence of communication between
  16. 788 15 UPT—Universal Personal Telecommunication ¤¡ © ¤ £¥¦ ¨¢   § £ ¡ ¤¤ ¥ £¥ ¤¤¡ © ¢  ( $ ¥# ¡ §¤ £¥¦ ¤¤¤ " ¨¢¤¤¦ £  ¦ !   9CB7 A £ ¥¨ ©  " 1¤10¤) ( ¥ 2  $  ¤7 9E ¨ £¥¦ ¤¢  § £¡ ¤¦ ¥¤¤¦ ¤§  §  ¡ ¥ ¥ ¨7 98 ¤ ¥¤¤¦ ¥'$¨ & ¦ ¡  ¨ £ ¨¢  % £¡ ¤¡ ©  ¤¢¨¤¦ !  ¨¢¤¤¦ !   ¨¡ ©  $¤ ¥ £¥ ¤¨¡ © ¡ " ¥# ¤ ¥ £¥ ¥¨¤¡ © ¡ " $ # ¤7 9D ¤7 9@ ¤¤ ¥ £¥ ¤¤¡ © ¢  ( $ ¥# ¡ ¤ ¥¨¡ " ¥¤¦¤¨)¤6CPI§ HIG¤0¨¦¤F9CB7 ¦     R Q H  9 E7 % ¡ A §¤ £¥¦ ¤¤¤ " ¨¢¤¤¦ £  ¦ !   ¤¦ ¥¨¤T¤PI £ ¥¨ ©  " 1¤6CPI§ HIG¤0¨¦¤F¤7 § R S ( ¥ 2  5 H  9 D7 % ¡ 9 @ £ ¥¨ ©  " 1¤10¤) ( ¥ 2  $  ¤¤¨¤¤) 4" ¥(¤ 3 £¦¦¡ " (¡ ¤ ¥ " ¤¤¤ " ¨¤¦¤¨¤) " ¥((¤ 3 ¦ ¦¦ £ ¦¡ " ¡ ¤7 98 ¤¡ © ¤ £ ¤¢   % £ ¡ £¤¤¦¤¨¤) " ¤ £¥¦ £¨¤¤§ 65 ¦¡ § ¡¦ ¥ Figure 15.11: Example of a UPT call: call between two UPT users ¨¤¢¦¤'¦£ %¨¤¡¦¤¤#¨¥ §  ¡   £ &  $ $ " ! © ) ¨¤¢¤¦'¤£ %¨¤¤$¦¤#¨¥ §  ¡   £ &  ¡ $ " !  © ( ( ¨¤¢¦¤§¨¦¤¢   ¡   £  © ¥ £ ¡ Figure 15.12: Interfaces in a heterogeneous network configuration the network components and the service profile is conceivable. Only an ex- ample of a call between two UPT users is shown here (see Figure 15.11). When UPT is offered in heterogeneous network configurations, conflicts can occur because networks have different capabilities for supporting UPT. Figure 15.12 shows where interfaces occur between networks supporting UPT and non-supporting UPT. Two possibilities for handling UPT connec- tions across network boundaries are to be considered. For networks that do not support UPT, either no UPT service or only a limited UPT service can be offered. The same options apply to UPT connections that are to be routed over non-UPT-supporting networks. The first option is very unsatisfactory, which is why the second option should be taken into consideration even if additional costs are involved. 15.7 PSCS as a Further Development of UPT Personal Services Communication Space (PSCS) is a service concept that was developed within the framework of the EU research programme RACE by the Mobilise project partners [5]. PSCS represents a further development of UPT phase 1, and is serving as the basis for projecting the services and functions of UPT phases 2 and 3. It enhances the UPT service in the following ways:
  17. 15.8 Numbering and Dialling 789 • User-friendliness during access • Use of services beyond telephony, such as fax, e-mail and data services • Easier access procedures to the service profile • Flexible routing schemes, such as e-mail forwarding to a fax device To achieve a certain level of user-friendliness, PSCS requires special termi- nals that have at least an alphanumeric display and a card reader for smart cards. Consequently, demands that UPT allow access from any terminal can- not be met, but what is gained is a far more flexible man–machine interface. 15.8 Numbering and Dialling In telecommunications networks users are addressed by sequences of digits. By entering the telephone number of the party being called (user B), the calling party (user A) is instructing the network to set up a connection. For technical reasons, direct dialling was previously used to route a call across the network elements. On the basis of how it is structured, the telephone number can provide a direct indication of where user B is located with a direct dialling system. A telephone number therefore has a direct relationship to the location of user B, and also determines how a call is routed through the network. Because of the individual numbers that make up the telephone number, the switching centre is able to route the call to user B. In addition to addressing users, the telephone number is used for the billing of telecommunications services. This gives the telephone number economic significance along with its technical importance. This direct control has now been replaced by indirect dialling systems, which is why it is necessary to establish an association between telephone number and location of user B. In an indirect dialling system the routing of a call is largely separate from the telephone number. A path established from the routing tables filed in the switching centres is switched between the two users. In this case the telephone number only serves for the addressing, and does not contain any information about a subscriber’s location. However, users of telecommunications services have the knowledge to de- termine from the telephone number the calling area of user B, the charges and type of telecommunications services required. It is therefore important to retain this information function for the acceptance of new numbering systems. Current and future numbering systems are explained in the following sec- tions. 15.8.1 ISDN, PSTN Telephone numbers in public telecommunications networks as well as in ISDN for a long time period consisted of 12 digits. Since the end of 1996, this
  18. 790 15 UPT—Universal Personal Telecommunication F EF FGEC D C IH   ¡  ¦&©%"#¥ !¦¤ ¥ ¤¤¤¤¡©¨¤¦¤¡  (' $     ¢    §¥£¢   B) 2 ¤¦¢¡!¤¢ ©§ 0 ¥ ©5¤ 3¦0 ¤ ¢ § ¡)    ¥ §4 2 1 ¥ 0 ) 6 ¤¤A¤£ ) ¦¤7 59¦¤%6 ¨  7 @ ¨  ¨ 8 4 7 £ Figure 15.13: Structure of an ISDN telephone number number has been extended to 15 digits [10]. The telephone number structure is provided in ITU Recommendation E.163 [7]; see Figure 15.13. The country code for Germany is 49. In their structure, national destina- tion codes indicate the direct dialling control of the network that existed until about 1977. Like the network, they are arranged hierarchically, with • position 1 for the central switching centre • position 2 for the home location switching centre • position 3 for the customer switching centre • position 4 for the subscriber switching centre The national destination code is different for each local network, and typi- cally unique for a whole country. It consists of two to four digits, depending on the size of the local network. A user within the same local network can be reached through his respective telephone number. Parties in Germany beyond one’s own local network can be reached through dialling the prefix 0 followed by the national destination code and the respective telephone number. Users outside Germany can be reached through dialling the international prefix 00, the country code and the respective telephone number. The length of the telephone number to be dialled therefore depends on the distance between the two communicating parties. Special services can be selected by dialling special prefixes before the actual telephone number of the person being called. A 1 is reserved as the first digit for this purpose. For example, the GSM networks in Germany are accessed from the fixed network through dialling a 17x. Telecommunications connections are charged based on the national des- tination code. Knowledge of the structure of the national destination codes provides the user with an information source for determining the cost of a call. According to newer tariffing models there will be probably only two national tarif zones in the future: local and long distance. Then there will be no more advantage for the user to differentiate from the destination code where the long-distance call party is located, and the acceptance of the indirect dialling system will grow.
  19. 15.8 Numbering and Dialling 791 QHB E E FDB E C CPGHB I ¤¢  £ £ "¤!2 ¤£(5'4¤32 1¨¤¢  ¢   ¨ £ 0)¨ ¡  &%#"¨ £ 0) £ ©¨ ¤¢  £ ¡ ¤£! ¤¤(¢&'#$¤! ¤¤¢  ¢  "¨ ¨  ¡ ¡   % "¨ £ ¨  ¡ ©¨ ¡ ¦§¢  ¥ ©¢¤@ 9 1" 8¨ 76¢  ¢   A) ¡ 0 ¦ 0   ¥ ©¨ Figure 15.14: Numbering structure in GSM 15.8.2 Public Mobile Telephone Network—GSM The numbering used in the public mobile telephone network is similar to that of PSTN. ITU Recs. E.212 [8] and E.213 [9] provide the relevant structures. The GSM numbering scheme is based on these recommendations. Figure 15.14 shows how a public mobile telephone number is structured. It consists of the respective country code, the network code and the terminal identification number. A complete integration into the ISDN/PSTN num- bering plan could have been possible, but was not implemented. Instead, as mentioned above, GSM networks are differentiated from the PSTN through separate dialling codes which function as a traffic discrimination feature. 15.8.3 UPT The ITU presents proposals for UPT numbering in Rec. E.168 [13]. In these proposals a UPT number is defined as a user’s unique identification, and is dialled by a caller to reach the user. The UPT indicator is the part of the UPT number that identifies the call as a UPT call, e.g., in Germany 0700 is used as the prefix. From the standpoint of the user, the UPT number must meet the following requirements [12]: • A UPT number must be recognizable as such by users, so that they have the opportunity to determine that a call is a UPT call and therefore will be handled and charged in a special way. • A UPT number must be as short as possible to minimize the number of digits to be dialled. • It must be possible to dial the UPT number from any terminal in the PSTN. Therefore digits have already been reserved (digits 0. . . 9 and possibly the characters # and *). • UPT users should be able to retain their UPT numbers if they change service provider. • In the future the UPT number should be valid in all networks, at all terminals and for the use of any service.
  20. 792 15 UPT—Universal Personal Telecommunication £ ¢£ ¤¢  £ ¡   ¦¥ Figure 15.15: Subscriber-based UPT telephone number • Any further developments and changes to the UPT numbering plan should have as little an effect as possible on existing UPT numbers. Network operators have other requirements of UPT numbers: • It must be easy for a network to recognize a UPT call. • The numbering capacity must be protected even when UPT is intro- duced. • UPT numbers should have no influence on routing. • The administration of UPT numbers must be kept simple. • UPT numbers must fit into existing numbering plans (see E.164) [11]. Recommendation E.168 differentiates between three scenarios that all com- ply with E.164 and therefore are aimed at meeting the requirements of both user and network operator. 15.8.3.1 Scenario 1—Subscriber-Based Concept The subscriber-based concept gives no indication to the subscriber that a call is a UPT call (see Figure 15.15). All information concerning the UPT subscriber is administered by the Flexible Service Profile (FSP) at his home location. In scenario 1, CC remains the country code, NDC the national desti- nation code and SN the subscriber’s telephone number. NDC and SN together produce a unique telephone number for a country. Owing to the lack of other criteria, the entire number has to be evaluated and searched in a database to determine whether the call is to be recognized as a UPT call. 15.8.3.2 Scenario 2—Country-Based Concept In the country-based concept, CC retains its significance as the country code (see Figure 15.16). Unlike scenario 1, however, NDC identifies a call as a UPT call. This applies to the party making the call as well as to the network. Special codes can be used to select UPT services or a UPT service provider instead of the local network. This concept has already be applied in the integration of GSM mobile radio networks. For example, the first NDC digit can select the UPT service while the other digits would be responsible for the selection of the UPT service provider.
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