Showing papers on "Roaming published in 1992"

Wireless telephone/satellite roaming system

Abstract: A wireless telephone system capable of servicing a roaming wireless telephone user includes a satellite communications system consisting of one or more orbiting satellites, each carrying a database of users, destination codes and call codes, within a satellite service area, a satellite control center, and a plurality of terrestrial communications links. The system operates by effecting communication between a terrestrial wireless telephone end user transceiver apparatus and a terrestrial communications link via a single relay through a single satellite or a succession of satellites wherein the relay station may be in motion relative to the end user transceiver apparatus and the terrestrial communications link, wherein the orbiting relay station effects the ultimate decision on linking based on stored on-board information and on-board processing, and wherein the end user transceiver apparatus, the orbiting satellite and the terrestrial communications link are operative in cooperation with the on-board database to effect hand-off from a first orbiting satellite to a second orbiting satellite. The satellite system is a single satellite or preferably a constellation of satellites orbiting near the earth, all of which are capable receiving requests for calls and participating in the call routing and call setup on an autonomous basis. The satellites are capable of decoding the calls, switching, handing off of calls to other satellites, and updating databases of users based on information provided by network control.

Subscriber interrogation point

Abstract: In a cellular radio communications network a plurality of mobile switching centers have data access to a subscriber interrogation point which maintains a database identifying the home exchange of a plurality of mobile stations, the home exchanges of which are within a given region. When a roaming mobile subscriber seeks to register with a visited exchange, that exchange contacts a subscriber interrogation point identified in its own database as being associated with the roaming mobile in order to locate within the database of the subscriber interrogation point the home exchange of the mobile seeking to register. Maintenance of the home exchange identification information in the database of a subscriber interrogation point, rather than in the database of each potentially visited exchange, greatly simplifies database maintenance when the home exchange of a mobile station is changed.

Satellite/wireless telephone roaming system with link to network database management system

Abstract: A wireless telephone system capable of servicing a roaming wireless telephone user includes a satellite communications system consisting of at least one orbiting satellite; at least one terrestrial-based gateway having access to a database of users, destination codes (telephone numbers); a network coordinating gateway within a satellite service area; a network control center; and a plurality of terrestrial communications links. The system operates by effecting communication between a terrestrial wireless telephone end user transceiver apparatus and a terrestrial communications link via a single relay through a single satellite or a succession of single relay satellites wherein the relay station may be in motion relative to the end user transceiver apparatus and the terrestrial communications link. The ground-based gateway effects the ultimate decision on linking in cooperation with the network database to effect hand-off from a first orbiting satellite to a second orbiting satellite. The single satellite or preferably a constellation of satellites orbiting near the earth need only translate signals from the gateways to the users and from the users to the gateways without satellite-based control. The gateways are capable of decoding the calls, switching, processing call requests from the end users, processing call requests to the end users, processing call set-ups, handing off of calls to other satellites, and updating databases of users based on information provided by network control and requests from end users.

Security in mobile and cordless telecommunications

Abstract: Second generation mobile and cordless telephone systems, like GSM and DECT, provide for intersystem roaming and have integrated security features. These security features and the role played by smart cards in the implementation and management are discussed. The focus is on the security features provided in DECT because these are more comprehensive, and probably less widely known, then those provided in GSM. The method of authentication is identical to that used for authenticating subscribers accessing a GSM network. However, the DECT authentication mechanism includes an additional feature which is not provided within GSM. This feature provides for greater flexibility in the way authentication keys and authentication data may be managed. >

Service mobility/transparency for personal communications

Abstract: Personal communications services require that subscriber services be made available to users independent of their physical location. Services can be separated into their components of feature construct, common data, and user-specific data. Mobility can also be separated into local roaming, within the network provider's common control area, across control areas, and across providers. The author discusses the pros and cons of several approaches to providing service mobility/transparency: using an advanced intelligent network (AIN) to bring service profile data to the mobile user; using an intelligent loop distribution arrangement to bring the user's connection always back to their 'home' service logic area; and using an AIN to provide a limited, but ubiquitous, set of call processing features to users. >

Performance evaluation of a hierarchical location registration and call routing for personal communications

Abstract: A new hierarchical location registration is presented for personal communications, and its related call routing through broadband-ISDN is described. The call routing utilizes signaling packets to directly access the lowest registration unit (HLRUO) of portable stations, so that centralized accesses as in GSM systems are avoided. After a description of the model of hierarchical location registration, the average number of registrations at each layer is statistically analyzed. The registration time interval vs. roaming range is derived. Thus, the average time interval for updating location information in the HLRUO is obtained. The performance evaluation of the proposed scheme and a comparison with GSM are outlined. >

Certifying method for mobile communication system

Abstract: PURPOSE:To secure the privacy of a certification key shared with a mobile subscriber by performing certification corresponding to a signal receiving and ciphering a temporary certification key from a second mobile communication network in the case of subscriber certification for roaming. CONSTITUTION:When a mobile subscriber 30 moves from a first mobile communication network to a second mobile communication network 20, an identification number ID is transmitted for getting subscriber certification. The second network sends this ID and a set certification key K12 to the first network 10, and the first network returns a certification key K13 ciphered by the K12 to the second network in place of directly sending the certification key K12 shared with the subscriber 30. The second network 20 stores the K13, sends a random value to the subscriber 30, collates the random number value provided by restoring a certification response signal ciphered by the K13 by using the K12 and certifies the identity of the subscriber by the coincidence. Thus, since the certification key K13 is used only for ciphering, the privacy can be secured.

Error rate prediction for high data rate short range systems

Abstract: Present mobile radio services offer primarily voice communication to customers roaming within large cell topographies. Typically these systems do not require large bandwidths and offer little or nothing in the way of data based services with the result that they operate with bit error rates as high as one in one thousand. However, in recent years there has been a trend towards more spectrally efficient, small cell, high data rate systems and a growing demand for a new type of service offering very high data rates for indoor wireless LAN applications. In this paper we present a model which predicts propagation characteristics for given small cell environments and subsequently uses the propagation data to analyse the radio link performance for a variety of system designs. In order to achieve very accurate high data rate transmission the benefits of linear modulation combined with techniques such as diversity, frequency hopping and pulse shaping are investigated.

Mobile data communications: the future is in networks

Abstract: As mobile data communications moves away from specialized markets towards a more integrated role with established data communications networks, the service features and quality that are supported must address the expectations of the experienced network user. These services include: provisioning for coverage and capacity; network management; billing; network administration; network access; authentication, reliable data transfer (connection-oriented), unreliable data transfer (connectionless or datagram) and transparent inter- and intra-network roaming. The paper describes the service requirements and the services facilities of a wireless data network. An existing mobile data network offering: the Motorola DataT.A.C network is discussed as an example. >

Service control system during roaming

Abstract: PURPOSE: To provide the control system receiving the same service when a roaming subscriber is resident in its own network. CONSTITUTION: A common representative specific number is provided between enterprises and when a mobile body exchange VMSC of other network processes a call signal SETUP from a roaming mobile set MS and detects the representative specific number from a called number field, the exchange indexes a home network of the mobile set based on the caller number and makes call connection to a mobile set exchange HMSC. Or the mobile set detects a dial entry of the representative specific number to set information of a roaming service request to a field of a call signal and sends the call, and when the mobile body exchange of the other network detects the information representing the roaming service request, the exchange makes call connection to the mobile body exchange HMSC. Then the mobile body exchange of the home network subjected to setup provides a relevant additional service to call connection to a destination based on a dial number other than the representative specific number. COPYRIGHT: (C)1993,JPO&Japio

Autonomous registered overload control method and device to cell moving type radio system

Abstract: PURPOSE: To avoid overloading by transmitting a message for instructing the inhibition of current registration in a specific mobile radio telephone when overloading is near. CONSTITUTION: When a mobile radio telephone 202 separates from an area covered with a cell site 201 and enters into an area covered with a cell site 204, a roaming person loses the set-up and reverse control channel of the cell site 201. The roaming person is requested to execute registration in a new cell based on new identification information related to a set-up channel corresponding to the cell site 204. The number of requested autonomous registration messages is monitored, and when overloading is near, a message instructing the inhibition of current registration is transmitted to the specific mobile ratio telephone 202.

Networking requirements in a wireless system

Abstract: Cordless systems together with cellular telephony will be the most important personal communication techniques in the future. Focusing on indoor applications, it will be necessary to implement closely spaced grid of micro-cells so as to use the limited radio spectrum more efficiently and to meet the expected capacity requirements. Among them, one could single out the growing demand for data services. Such reduced cell size makes the control tasks much more complex, demanding a broadband network and a distributed architecture. In order to design a network able to accommodate wireless services, the traffic generated must be modelled, particularly signalling traffic. Protocols for signalling must deal with roaming, call set-up and handover procedures. The authors present the results of computer simulations of an indoor wireless PABX system conforming to the digital European cordless telecommunications (DECT) standard. >

Incoming regulating system for mobile communication system

Abstract: PURPOSE:To prevent a routining component from being charged even in the case of roaming-out during incoming regulation and to originate a call by a moving object subscriber itself by displaying a caller number. CONSTITUTION:An inquiry is executed to a common data base 7 to manage routining information according to phone numbers uniquely applied to moving object subscrivers 1, 2 and 3 and when the call is generated, it is identified whether the phone number is the object of incoming regulation or not. During the incoming regulation, call routining related to roaming is not executed but only the caller number of this call is informed of the moving object subscriber.

Changing control system for traveling object communication system

Abstract: PURPOSE:To operate a charge by the same format with a conventional charge record by preparing the charge record corresponding to the execution of a routining generated by operating an automatic roaming by a radio subscriber from calling information CONSTITUTION:When a radio subscriber 3 dials the subscriber's number 05488-2003 of a radio subscriber 5 who seems to be present in an area 9, an automatic communication of the radio subscriber 3 with the radio subscriber 5a can be realized by an automatic roaming function At the time of the completion of the communication of this calling, this system is equipped with a function which transfers the charge information from a master exchange 1 to a register HLR 7, so that the master exchange 1 can prepare the charge record from the radio subscriber 3 to the radio subscriber 5, and from the radio subscriber 5 to the radio subscriber 5a The charge record is that corresponding to the execution of the routining generated by the automatic roaming by the radio subscriber 5, and the charge can be exactly operated even when the automatic roaming is operated