Interworking between radio access networks

Abstract

The present invention discloses a method of interworking between different radio access networks. A radio transceiver device is capable of operating with the first radio access network and the second radio access network is attached to the first radio access network. The method comprises the steps of detecting a service request is requested. Information is accessed on conditions for the first and the second radio access network for giving sufficient support for a service requested by the service request. It is analyzed whether or not the first radio access network and the second radio access network meets the conditions, and a handover of the radio transceiver device from the first radio access network to the second radio access network is initiated if the second radio access network meets the conditions but the first radio access network does not. Thus, the present invention serves to support dual mode mobile stations and networks in such a way that the correct radio access which sufficiently supports a requested service is automatically obtained.

1 . A method, comprising: 
 detecting a service request, wherein said service request is received from a network side;    accessing information on conditions for a first and a second radio access network for giving sufficient support for a service requested by said service request,    analysing whether or not said first radio access network and said second radio access network meets said conditions; and    initiating a handover of a radio transceiver device from said first radio access network to said second radio access network if the second radio access network meets the conditions but the first radio access network does not.    
     
     
         2 . A method according to  claim 1 , wherein said conditions comprise a condition whether said requested service exists in the radio access network.  
     
     
         3 . A method according to  claim 1 , wherein said conditions depend on each other.  
     
     
         4 . A method according to  claim 3 , wherein one of said conditions for the first radio access network is a given amount lower than the corresponding condition for the second radio access network.  
     
     
         5 . A method according to  claim 1 , wherein said method is performed in said radio transceiver device.  
     
     
         6 . A method according to  claim 1 , wherein said method is performed in a network control device.  
     
     
         7 . A method according to  claim 6 , further comprising the step of informing said radio transceiver device of the fact that a handover to said second radio access network is to be initiated.  
     
     
         8 . A method according to  claim 1 , wherein said radio transceiver device is a dual mode phone which is adapted to be operated in said first radio access network and said second radio access network.  
     
     
         9 . A method according to  claim 1 , wherein either said first or said second radio access network is a GSM network.  
     
     
         10 . A method according to  claim 1 , wherein either said second or said first radio access network is a UMTS network.  
     
     
         11 . A method according to  claim 1 , wherein said requested service is a circuit-switched service.  
     
     
         12 . A method according to  claim 1 , wherein said requested service is a packet service.  
     
     
         13 . A method according to  claim 1 , wherein an error procedure is initiated, when it is detected in said analysing step that said requested service is not available in any of said networks.  
     
     
         14 . A method according to  claim 13 , in which said error procedure is a notification of the user.  
     
     
         15 . A method according to  claim 1 , wherein said radio transceiver device is attached to said first radio access network such that it is located in a cell of said first radio access network and connected by air with said first radio access network.  
     
     
         16 . A method according to  claim 15 , wherein said radio transceiver device is also located in a cell of said second radio access network.  
     
     
         17 . A method according to  claim 1 , wherein said analysing step also analyses whether a subscriber using said radio transceiver device is entitled to use said requested service.  
     
     
         18 . A network interworking device, comprising: 
 a detecting unit configured to detect a service request, wherein said service request is received from a network side,    an analyzing unit responsive to said detecting unit and wherein the analyzing unit is configured to, 
 access information on conditions for a first and a second radio access networks for giving sufficient support for a service requested by said service request, and  
 analyse whether or not said first radio access network and said second radio access network meet the conditions, and  
   initiating unit responsive to said analysing unit, the initiating being configured to initiate a handover of said radio transceiver device from said first radio access network to said second radio access network if the respective conditions are not met by said first radio access network but by said second radio access network.    
     
     
         19 . A network interworking device according to  claim 18 , wherein said interworking device is configured in said radio transceiver device.  
     
     
         20 . A network interworking device according to  claim 18 , wherein said interworking device is configured in a network control device.  
     
     
         21 . A network interworking device according to  claim 18 , wherein said analysing unit is connected to a database to obtain information regarding said conditions of said requested service.