MOBILE RADIO SYSTEM WITH TRANSLATION OF BCIE

Abstract: A method allowing a public land mobile network containing at least one mobile services switching center to offer a direct or dedicated data service to a public or private wide area and local area network (WAN and LAN), wherein the PLMN network is capable of using different information transfer capabilities to support the services. A communication request from a mobile station is received wherein the request contains condition parameters set in the mobile station. The received condition parameters are then modified so as to correspond to specified configurations of the network. The communication request is then routed using the modified parameters.

Description: MOBILE RADIO SYSTEM WITH TRANSLATION OF BCIE Field of the Invention The present invention relates to a method for setting up data calls to direct access services, and more particularly to a method for setting up such services regardless of the information transfer capability parameters. Background of the Disclosure One of the main concerns of a cellular communications system operator is that for mobile data services to be commercially viable, their customers must find them easy to use. Currently, to make a mobile originated call, in for example the Global System for Mobile Communications (GSM), a mobile data user must have a relatively high degree of knowledge of several parameters. First, the user needs to know the called party's data circuit equipment, i.e., whether a modem or terminal adapter, baud rate, etc. Secondly, the user needs some knowledge of the network call routing arrangements, i.e., Public Switched Telephone Network (PSTN), Integrated Services Digital Network (ISDN), dial- up Packet Assembly/Disassembly facility (PAD), bridge/router, etc. Finally, the called party's data applications and whether these applications require specific set-up arrangements across the public land mobile network (PLMN). To make the cellular system's bearer services easier for customers to use, the operators and their service providers need to take adequate steps to ensure that the set-up and network accessing procedure is as automated as possible for the user. One of the prime uses of cellular data services is dial-up access into the corporate packet switch data network. This may be via a public or private gateway into the network and could involve routing through the PSTN or ISDN. In the United Kingdom, the cellular operators offer a service on their analog TACS networks, by which customers can short code dial and directly route via a PAD into a Packet Switched Public Data Network PSPDN without using the public switch telephone network. A similar arrangement to access private corporate data networks is also supported. It is planned by these operators that a similar service, called direct access, from their GSM networks will be available. Figure 1 illustrates a practical realization of how a UK cellular operator can configure the mobile network infrastructure for both the TACS and GSM networks, using the current national UK signalling standards to support the direct access service. As illustrated in Figure 1, the TACS network 12 and the GSM network 14 are both tied into a transit switch 18. Transit switch 18 is connected to an ISDN private branch exchange PBX with analog line LF which is then connected to a modem 22. The modem 22 transmits data back and forth between the packet assembly/disassembly facility PAD 24 which is tied to private Public Data Networks PDNs 26 and public PSPDNs 28. From a GSM perspective, the service can be described as a hybrid of the basic and dedicated PAD services. The user is a customer of both the PLMN and the PDN, but the network access to PAD is solely via the GSM operator's infrastructure. The internetwork boundary between the PLMN and the PDN is the V24 interface. In order to make a call to a direct access PAD from the GSM network, the Called Party BCD number and Bearer Capability information elements (BCIE), carried in the "Set Up" message are needed to provide the routing and service information to the network. Using the example illustrated in Figure 1, a mobile user could dial a short code to provide the MSC with a "B number" for routing to the required PAD, and will also create the appropriate BCIE at the mobile station to set up the correct network interworking function, i.e., speed, word length, modem type, etc. If any changes or enhancements in direct access services are made by the PLMN administrator, i.e., changes in the network configuration, then details of these changes will need to be passed back to the service users, since a different BCIE and/or B number may be required. For example, Figure 1 illustrates a service based on modem access to the data network that can be accessed by both the GSM and TACS networks. Therefore, the most important parameters required from the GSM network to provide the correct interworking function, would be the correct selection of the modem type. If the network configuration is changed to use a different modem type, then the mobile station will have to create a different BCIE for the selected modem type. Figure 2 illustrates a GSM only direct access service. In Figure 2, the CME 20 is connected to a GSM interworking unit (GIWU) 32. The GIWU unit 32 has several main functions: to be a modem and/or fax adapter pool; to perform rate adaption; and protocol handling and conversion. The modem type would be set to a default autobauding type 1, which will allow the GIWU unit 32 modem flexibility in negotiating the baud rate with the PAD modem. The customers data terminal equipment DTE/MS may also be preconfigured to set the user rate, word length, stop bits, parity, and called destination. The user may select an icon on the DTE to set up the service. Therefore, the most important parameters required to provide the correct interworking function would be information transfer capability (ITC)= 3.1 Khz audio and modem type = auto bauding type 1. This example would allow the greatest flexibility since modem based enhancements could be made without requiring the changes be made at the mobile station. Any changes in routing arrangements would be carried out by translation of the B number to a new destination in the mobile services switching center MSC if required. Also, future services for GSM customers could evolve toward Unrestricted Digital Information (UDI) based access as is illustrated in Figure 3. Figure 3 illustrates two ways of how the CME20 MSC could be connected to provide a digital interface to the PAD. In the first example, the CME20 MSC is connected to a Transit Switch which has the ability to provide the ISDN "access" signalling means to an ISDN device, e.g., an I-series multiplexer (IMUX) or an ISDN protocol converter. The ISDN device will then provide the means for connecting the Terminal Adaptor (TA) via the Network Terminating Equipment (NTE) to the network. The terminal adaptor provides the V24 interface to the PAD. The second example illustrates possible future GIWU developments, which may also see "dedicated" line interfaces, so that PADs, MUXs, etc., can be connected directly to the GIWU. In these examples, three parameters in the BCIE would have to be changed. As a result, the mobile user will have to change these at the mobile station in order to correctly signal the appropriate interworking function. There may also be a need to use a new telephone number (short code) to access the service. However, the Public Land Mobile Network will have to inform customers that changes within the network have been made, so that the mobile station can reflect these changes in their set up. This could present the PLMN with a fairly complex administration problem plus may lead to confusion by the service users. As a result, there is a need for a method which allow reconfiguration of the network without placing too much of the burden upon the users. Summary of the Invention It is an object of the present invention to provide a method for overcoming the disadvantages cited in the prior art, by translating the BCIE's received from the mobile stations when services or systems have been changed. According to one embodiment of the present invention, a method for allowing a public land mobile network containing at least one mobile services switching center to offer a direct or dedicated data service to a public or private wide area and local area network (WAN & LAN), wherein the PLMN network is capable of using different information transfer capabilities to support the services. A communication request from a mobile station is received wherein the request contains condition parameters set in the mobile station. The received condition parameters are then modified so as to correspond to specified configurations of the network. The communication request is then routed using the modified parameters. According to another embodiment of the present invention, a call set up method is disclosed. A mobile station sends a service request to the cellular communications network, wherein the request contains the "called Party Number" and the "Bearer Capability." On receipt of the request, the network analyzes the "Called Party Number" and associates it with a particular routing. The network on identifying the routing, will equate it with a particular "Bearer Capability" requirement, and will modify the "Bearer Capability " sent by the mobile station, to match the requirements of the network routing. The modified "Bearer Capability" will then be sent to the network's interworking equipment, which will provide the appropriate interworking functionality as indicated by the bearer capability information received. Once this has been established, the call set-up will proceed with the rest of the call chain. Brief Description of the Drawings These and other features of the present invention will become apparent to one of ordinary skill in the art from the following description in conjunction with the figures, wherein Figure 1 illustrates the hardware that can be used in a direct access service to private and public packet data networks; Figure 2 illustrates an analog direct access service from GSM; Figure 3 illustrates an evolving direct access service for UDI interworking; Figure 4 illustrates the procedure for translating and analyzing bearer capability information elements at call set up according to one embodiment of the present invention; Figure 5 illustrates a flow chart according to one embodiment of the present invention; Figure 6 illustrates a B-number analysis according to one embodiment of the present invention; Figure 7 illustrates a called party BCD information element; and Figure 8 illustrates a bearer capability information element. Detailed Description of the Disclosure While the present invention will be described with reference to the GSM system, it will be understood by those skilled in the art that the present invention can also be used in other cellular systems and is not limited to just the GSM system. One embodiment of the present invention will now be described with reference to Figures 4 and 5 which illustrate the procedure for translating and analyzing bearer capability information elements at call set up. According to the present invention, a standard default mobile station configuration is used to provide the cellular communications network set up information for a particular service. The default information is configured on the mobile users terminal equipment when initial use of the service is required. If the PLMN administration changes the network configuration, such as from information transfer capability ITC = 3.1 Khz to unrestricted digital information UDI, the user should not need to make any changes to the BCIE parameter settings at the mobile station, since the default BCIE information should be accepted by the network. The network now has to ensure that the default information would still provide the user with the requested service, even though changes have been made to the network configuration. To do this, a translation facility will need to be provided by the PLMN. The required translation is achieved as an extension to the normal "B-number" or called party analyze process, which equates the digits dialled with not only routing instructions, but in addition causes a process to begin which examines the bearer capability information sent by the mobile station as well. This additional process replaces certain parameters, with a set of predefined values applicable for a particular route, e.g. the ITC requirements for the called number. In the case of a direct access service, during the B-number analysis phase of the call set-up, the MSC on seeing the B-number applicable for a direct access or similar service will replace the default BCIE received with one containing predefined parameters for the route. Then the MSC modifies the appropriate parameters in the received BCIE accordingly, and then passes the modified BCIE to the systems interworking unit for the appropriate interworking resources to be inserted into the call. It will be understood by those skilled in the art that the BCIE translation facility could be provided by various means. One possible solution could be based around adding additional software coding blocks to the MSC/VLR, to provide the required analysis tables, logic, etc., as for example illustrated in Figure 6. In this example, the B-number is analyzed in a B-number analyzer 60. The B-number analysis creates several pointers for routing and charging analysis as well as a pointer BSR (Bearer Service for Route) which is allocated a numeric value which equates to a position in a look-up table 62 containing the bearer capability parameters for the route called. The bearer capability parameters selected from the look-up table 62 are processed in the conventional manner by the mobile services switching center as if the bearer capability parameters had been forwarded from the mobile station. Another possible solution may employ the use of the intelligent network concepts, where external nodes will perform the various analysis and translation functions. However, the basic concept and principles of the BCIE translation functionality will remain the same regardless of the means for implementation. At call set up, the mobile station 72 transmits a set up signal to the base station 74. The set up signal contains a called party number and the bearer capability information elements. The called party BCD number information element is used to identify the called party and an example of a called party BCD number information element is illustrated in Figure 7. The called party BCD number is a type 4 information element with a minimum length of 3 octets and a maximum length of 13 octets. As noted above, the bearer capability information element is used to describe a bearer service. A bearer capability information element is illustrated in Figure 8. The bearer capability information element is a type 4 information element with a minimum length of 3 octets and a maximum length of 10 octets. For example, the BCIE values sent by the mobile station may be ITC = 3.1 Khz audio, rate adaption = none, and modem type = auto bauding type 1. It will be understood by one skilled in the art that the bearer capability information elements can set a wide range of system parameters and the present invention contemplates such parameters and is not limited to rate adaption, modem type, and information transfer capability. The received set up request is then transparently sent from the base station 74 to the mobile services switching center 76. First, the mobile service switching center 76 analyses the called party number to determine the service requested. After determining the service requested, the MSC determines whether or not the Bearer Capability information elements need to be modified for the requested service because of some new network configuration that was not in place when the BCIE numbers were originally set in the mobile station. The functionality of the BCIE modification process could be provided by various means. However, the basic functionality required would be to provide a means to analyze/compare each BCIE parameter against the pre-defined bearer capability characteristic for a particular service. If required, the mobile services switching center modifies the Bearer Capability information elements so as to correspond to the new configuration of the network. The modified or non-modified Bearer Capability information elements are then sent to the cellular system's interworking unit 78. The cellular system's interworking unit 78 selects the required modem, rate adaptation, and protocols necessary to perform the service requested. After this has been performed, the call set up is completed and the user is set up to the service requested. The present invention allows the PLMN a high degree of flexibility. Customers can continue to use the same configuration, independently of the changes to the ITC the PLMN administration to access the service. It also allows the PLMN the option of using both 3.1 Khz audio and UDI within the same network. Another benefit may be for roamers whose home PLMN may support a similar direct access to a PSPDN but through a different ITC setting. The roamer may be on a PLMN which uses a UDI connection while the BCIE elements specify a 3.1 Khz audio base service. By modifying the BCIE of the roaming mobile station at the MSC in accordance with the present invention, the roaming mobile station can use the system regardless of the BCIE stored in the mobile station. It will be appreciated by those of ordinary skill in the art that the present invention can be embodied in other specific forms without departing from the spirit or essential character thereof. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the appended claims rather than the foregoing description, and all changes which come within the meaning and range of equivalents thereof are intended to be embraced herein.

Claims: CLAIMS: 1. A method for allowing a public land mobile network containing at least one mobile services switching center to offer a direct or dedicated data service to a public/private wide or local area network, said network being capable of using different information transfer capabilities to support the service, comprising the steps of: receiving a communication request from a mobile station, said request containing condition parameters set in the mobile station; modifying the received condition parameters so as to correspond to specified configurations of the network; and routing the communication request using said modified parameters. 2. A method according to claim 1, wherein said condition parameters specify information transfer capability, rate adaption and modem type. 3. A method according to claim 1, wherein said condition parameters are modified using look-up tables. 4. A method for setting up a call in a cellular communications system, comprising the steps of: receiving a call set up request from a mobile station to said cellular system, said request containing a called party and bearer capability information elements; analyzing said called party information to decode a specific route or service; analyzing and modifying said bearer capability information elements so as to correspond to pre-defined parameters used by said system for the specific route or service specified by the called party information; completing said call set up using said modified bearer capability information elements. 5. A method for setting up a call in a cellular system according to claim 4, wherein said bearer capability information elements specify information transfer capability, rate adaption and modem type. 6. A method for setting up a call in a cellular system according to claim 4, wherein said condition parameters are modified using look-up tables. 7. A method for setting up a call in a cellular system according to claim 4, wherein external nodes analyze and modify the bearer capability information elements. 8. A system for setting up a call in a cellular communications system containing a plurality of mobile stations, a plurality of base stations, and at least one system controller, comprising: means for receiving a call set up request from a mobile station at said cellular system, said request containing a called party and bearer capability information elements; means for analyzing said called party information to decode a specific route or service; means for analyzing and modifying said bearer capability information elements so as to correspond to pre-defined parameters used by said system for the specific route or service specified by the called party information; means for completing said call set up using said modified bearer capability information elements. 9. A method for setting up a call in a cellular system according to claim 8, wherein said bearer capability information elements specify information transfer capability, rate adaption and modem type. 10. A method for setting up a call in a cellular system according to claim 8, wherein said condition parameters are modified using look-up tables. 11. A method for setting up a call in a cellular system according to claim 8, wherein external nodes analyze and modify the bearer capability information elements.

Inventors: BARKER KEITH, SHIRET PETER JOHN, BARKER, KEITH, SHIRET, PETER, JOHN
Applicants: ERICSSON TELEFON AB L M, TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
Application year: 1996
Main classification: H04Q7
IPC codes: H04W76, H04W88, H04W92