Access Control for Terminals in UTRAN FEMTO System

Abstract

The teachings herein provide authorization control enabling the co-existence of legacy mobile terminals ( 20 ) that do not support Closed Subscriber Groups (CSGs), and non-legacy mobile terminals ( 20 ) that do. New behaviors are defined for a CSG femtocell base station ( 10 ) (referred to as a Home NodeB or HNB), and for a base station gateway ( 14 ) (referred to as a HNB Gateway or HNB GW) that couples the HNB ( 10 ) to a Core Network (CN) ( 22 ). The HNB ( 10 ) and/or the HNB GW ( 14 ) determine whether a terminal ( 20 ) attempting to gain connection through the HNB ( 10 ) supports CSGs. If not, the HNB GW ( 14 ) performs access control and rejects the connection attempt if authorization fails. If the terminal ( 20 ) is recognized as supporting CSGs, the HNB GW ( 14 ) defers access control to the CN ( 22 ) by automatically accepting registration/connection requests from the HNB ( 10 ) for CSG-capable terminals ( 20 ). In such cases, the CN ( 22 ) is relied upon for access control, including any CSG authorization of the terminal ( 20 ). The HNB GW ( 14 ) indicates to the CN ( 22 ) whether or not access control was performed for the terminal ( 20 ).

1 . A network gateway configured to interface femtocells to a core network of a wireless communication system, to provide access to the core network for mobile terminals connecting through the femtocells, said network gateway comprising one or more processing circuits configured to operate as a registration controller, wherein the registration controller is configured to perform access control for mobile terminals that are not indicated as supporting closed subscriber groups, and defer access control to the core network, for mobile terminals that are indicated as supporting closed subscriber groups. 
     
     
         2 . The network gateway of  claim 1 , wherein the registration controller is configured to receive registration requests from given ones of the femtocells, for mobile terminals attempting to gain access through those femtocells, and is configured to determine whether a given mobile terminal supports closed subscriber groups based on one or more indicators included in the registration request received for the given mobile terminal. 
     
     
         3 . The network gateway of  claim 2 , wherein the one or more indicators included in the registration request received for the given mobile terminal comprise an Access stratum release indicator or a User Equipment capabilities indicator, and wherein the registration controller is configured to recognize from such an indicator whether the given mobile terminal supports closed subscriber groups. 
     
     
         4 . The network gateway of  claim 1 , wherein the registration controller is configured to interpret the receipt of a connect message from a given femtocell for a given mobile terminal without first receiving a registration request from the given femtocell for the given mobile terminal as an indication that the given mobile terminal supports closed subscriber groups. 
     
     
         5 . The network gateway of  claim 1 , wherein the registration controller is configured to perform access control for mobile terminals that are not indicated as supporting closed subscriber groups and defer access control for mobile terminals that are indicated as supporting closed subscriber groups, based on, for a given mobile terminal the registration controller being configured to:
 receive a registration request from a given femtocell for the given mobile terminal;   determine from the registration request whether the given mobile terminal is indicated as supporting closed subscriber groups;   if the given mobile terminal is indicated as supporting closed subscriber groups, return a registration acceptance to the given femtocell for the given mobile terminal without performing access control, receive a corresponding connect message from the given femtocell for the given mobile terminal, and send a connection request to the core network for the given mobile terminal in response to the connect message from the given femtocell; and   if the given mobile terminal is not indicated as supporting closed subscriber groups, perform closed subscriber group authorization of the given mobile terminal at the network gateway and, if closed subscriber group authorization is not successful, reject connection of the given mobile terminal, and, if closed subscriber authorization is successful, return a registration acceptance to the given femtocell for the given mobile terminal, receive a corresponding connect message from the given femtocell for the given mobile terminal, and send a connection request to the core network for the given mobile terminal in response to the connect message from the given femtocell.   
     
     
         6 . The network gateway of  claim 1 , wherein the network gateway is configured to indicate to the core network whether access control has or has not been performed at the network gateway for a given mobile terminal that is attempting to gain access to the core network through the network gateway. 
     
     
         7 . The network gateway of  claim 1 , wherein the network gateway is configured to provide a closed subscriber group ID to the core network, as an indication that access control was not performed at the network gateway. 
     
     
         8 . The network gateway of  claim 1 , wherein the network gateway comprises a Home NodeB Gateway, for interfacing Home NodeBs, providing said femtocells, to the core network. 
     
     
         9 . A method of interfacing femtocells through a network gateway to a core network of a wireless communication system, to provide access to the core network for mobile terminals connecting through the femtocells, said method comprising:
 performing closed subscriber group authorization in the network gateway, for mobile terminals that are not indicated as supporting closed subscriber groups; and   deferring closed subscriber group authorization to the core network, for mobile terminals that are indicated as supporting closed subscriber groups.   
     
     
         10 . The method of  claim 9 , wherein the network gateway receives registration requests from given ones of the femtocells, for mobile terminals attempting to gain access through those femtocells, and determines whether a given mobile terminal supports closed subscriber groups based on one or more indicators included in the registration request received for the given mobile terminal. 
     
     
         11 . The method of  claim 10 , wherein the one or more indicators included in the registration request received for the given mobile terminal comprise an Access stratum release indicator or a User Equipment capabilities indicator, and wherein the network gateway recognizes from such an indicator whether the given mobile terminal supports closed subscriber groups. 
     
     
         12 . The method of  claim 9 , wherein the network gateway interprets the receipt of a connect message from a given femtocell for a given mobile terminal without first receiving a registration request from the given femtocell for the given mobile terminal as an indication that the given mobile terminal supports closed subscriber groups. 
     
     
         13 . The method of  claim 9 , wherein the network gateway performs closed subscriber group authorization for mobile terminals that are not indicated as supporting closed subscriber groups and defers closed subscriber group authorization for mobile terminals that are indicated as supporting closed subscriber groups, based on, for a given mobile terminal:
 receiving a registration request from a given femtocell for the given mobile terminal;   determining from the registration request whether the given mobile terminal is indicated as supporting closed subscriber groups;   if the given mobile terminal is indicated as supporting closed subscriber groups, returning a registration acceptance to the given femtocell for the given mobile terminal without performing closed subscriber group authorization, and correspondingly receiving a corresponding connect message from the given femtocell for the given mobile terminal and sending a connection request to the core network for the given mobile terminal in response to the connect message from the given femtocell; and   if the given mobile terminal is not indicated as supporting closed subscriber groups, performing closed subscriber group authorization of the given mobile terminal at the network gateway and, if closed subscriber group authorization is not successful, rejecting connection of the given mobile terminal, and, if closed subscriber authorization is successful, returning a registration acceptance to the given femtocell for the given mobile terminal, receiving a corresponding connect message from the given femtocell for the given mobile terminal, and sending a connection request to the core network for the given mobile terminal in response to the connect message from the given femtocell.   
     
     
         14 . The method of  claim 9 , wherein the network gateway indicates to the core network whether closed subscriber group authorization has or has not been performed at the network gateway for a given mobile terminal that is attempting to gain access to the core network through the network gateway. 
     
     
         15 . The method of  claim 9 , wherein the network gateway comprises a Home NodeB Gateway, for interfacing Home NodeBs, providing said femtocells, to the core network.