Relay station apparatus, mobile communication system, base station apparatus, and method for controlling relay station

Abstract

A mobile communication system includes at least one upper radio station ( 1 ) and a relay station ( 2 ). The relay station ( 2 ) performs a radio relay between a lower radio station ( 3 ) and the upper radio station ( 1 ). The relay station ( 2 ) is configured to attach, when an attaching to a first upper radio station included in attaching configuration information indicating an upper radio station to which the relay station ( 2 ) should attach is unsuccessful, to a second upper radio station different from the first upper radio station, and to notify a network ( 4 and 5 ) of notification information via the second upper radio station, the notification information indicating that the attaching to the first upper radio station is unsuccessful.

1 . A relay station apparatus that is wirelessly connectable to an upper radio station, comprising:
 a lower radio link communication unit configured to perform radio communication with at least one lower radio station;   an upper radio link communication unit configured to perform radio communication with at least one upper radio station; and   a control unit configured to attach, when an attaching to a first upper radio station included in attaching configuration information indicating an upper radio station to which the relay station apparatus should attach is unsuccessful, to a second upper radio station different from the first upper radio station, and to notify a network of notification information indicating that the attaching to the first upper radio station is unsuccessful.   
     
     
         2 . The relay station apparatus according to  claim 1 , wherein the control unit receives updated attaching setting information sent from the network in response to the notification information, and controls to attach to an upper radio station designated by the updated attaching setting information. 
     
     
         3 . The relay station apparatus according to  claim 1 , wherein
 when the relay station apparatus attaches to the second upper radio station, the control unit controls the relay station apparatus to connect to the second upper radio station by using a first connection mode to operate as a mobile station, and   when the relay station apparatus attaches to the first upper radio station, the control unit controls the relay station apparatus to connect to the first upper radio station by using the first connection mode or a second connection mode to operate as a relay station.   
     
     
         4 . The relay station apparatus according to  claim 3 , wherein
 when the relay station apparatus attaches to the first upper radio station, the control unit notifies the first upper radio station of a first indication indicating that the second connection mode is supported, and   when the relay station apparatus attaches to the second upper radio station, the control unit notifies the second upper radio station of a second indication indicating that the second connection mode is not supported.   
     
     
         5 . The relay station apparatus according to  claim 3 , wherein
 when the relay station apparatus attaches to the first upper radio station, the control unit notifies the first upper radio station of a first indication indicating that the second connection mode is supported, and   when the relay station apparatus attaches to the second upper radio station, the control unit does not notify the first upper radio station of the first indication.   
     
     
         6 . The relay station apparatus according to  claim 1 , wherein the relay station apparatus preliminarily stores the attaching configuration information. 
     
     
         7 . The relay station apparatus according to  claim 1 , wherein the notification information includes information capable of determining whether the first upper radio station matches the upper radio station to which the relay station apparatus should attach. 
     
     
         8 . The relay station apparatus according to  claim 1 , wherein
 the upper radio station is a base station or an upper relay station, and   the lower radio station is a mobile station or a lower relay station.   
     
     
         9 . A mobile communication system comprising:
 at least one upper radio station; and   a relay station that performs a radio relay between a lower radio station and an upper radio station,   wherein the relay station is configured to attach, when an attaching to a first upper radio station included in attaching configuration information indicating an upper radio station to which the relay station should attach is unsuccessful, to a second upper radio station different from the first upper radio station, and to notify a network of notification information via the second upper radio station, the notification information indicating that the attaching to the first upper radio station is unsuccessful.   
     
     
         10 . The mobile communication system according to  claim 9 , wherein the relay station receives updated attaching configuration information sent from the network in response to the notification information, and tries to attach to an upper radio station designated by the updated attaching configuration information. 
     
     
         11 . The mobile communication system according to  claim 9 , wherein
 when the relay station attaches to the second upper radio station, the relay station connects to the second upper radio station by using a first connection mode to operate as a mobile station, and   when the relay station attaches to the first upper radio station, the relay station connects to the first upper radio station by using the first connection mode or a second connection mode to operate as a relay station.   
     
     
         12 . The mobile communication system according to  claim 11 , wherein
 when the relay station attaches to the first upper radio station, the relay station notifies the first upper radio station of a first indication indicating that the second connection mode is supported, and   when the relay station attaches to the second upper radio station, the relay station notifies the second upper radio station of a second indication indicating that the second connection mode is not supported.   
     
     
         13 . The mobile communication system according to  claim 11 , wherein
 when the relay station attaches to the first upper radio station, the relay station notifies the first upper radio station of a first indication indicating that the second connection mode is supported, and   when the relay station attaches to the second upper radio station, the relay station does not notify the second upper radio station of the first indication.   
     
     
         14 . The mobile communication system according to  claim 11 , wherein each of the first and second upper radio stations is configured to be connectable to the relay station in both the first and second connection modes. 
     
     
         15 . The mobile communication system according to  claim 12 , wherein
 each of the first and second upper radio stations is configured to set, upon receiving the first indication, a radio interface with the relay station so as to correspond to the second connection mode, and   each of the first and second upper radio stations is configured to set, upon receiving the second indication or upon not receiving the first indication, the radio interface with the relay station so as to correspond to the first connection mode.   
     
     
         16 . The mobile communication system according to  claim 9 , wherein the network updates the attaching configuration information upon receiving the notification information. 
     
     
         17 . A base station apparatus comprising:
 a radio communication unit configured to perform radio communication with a mobile station and a relay station; and   a control unit that controls communication with the relay station, wherein   when the base station apparatus does not correspond to an upper station preliminarily determined as a destination to which the relay station attaches, the control unit controls the radio communication unit to connect to the relay station by using a first connection mode in which the relay station operates as a mobile station, and   when the base station apparatus corresponds to the upper station, the control unit controls the radio communication unit to connect to the relay station by using a second connection mode in which the relay station operates as a relay station.   
     
     
         18 . A method for controlling a relay station that is wirelessly connectable to an upper radio station, comprising:
 attaching, when an attaching to a first upper radio station included in attaching configuration information indicating an upper radio station to which the relay station should attach is unsuccessful, to a second upper radio station different from the first upper radio station; and   notifying a network of notification information via the second upper radio station, the notification information indicating that the attaching to the first upper radio station is unsuccessful.   
     
     
         19 . The method according to  claim 18 , further comprising:
 receiving updated attaching configuration information sent from the network in response to the notification information; and   controlling to attach to an upper radio station designated by the updated attaching configuration information.   
     
     
         20 . The method according to  claim 18 , further comprising:
 controlling, when the relay station attaches to the second upper radio station, the relay station to connect to the second upper radio station by using a first connecting mode to operate as a mobile station; and   controlling, when the relay station attaches to the first upper radio station, the relay station to connect to the first upper radio station by using the first connection mode or a second connection mode to operate as a relay station.   
     
     
         21 . A relay station apparatus that is wirelessly connectable to an upper radio station, comprising:
 a lower radio link communication unit configured to perform radio communication with at least one lower radio station;   an upper radio link communication unit configured to perform radio communication with at least one upper radio station; and   a control unit configured to determine whether attaching configuration information indicating an upper radio station to which the relay station apparatus should attach is held or not, and to attach to an upper radio station included in the attaching configuration information acquired from a network according to a result of the determination.   
     
     
         22 . A mobile communication system comprising:
 at least one upper radio station; and   a relay station that performs a radio relay between a lower radio station and an upper radio station,   wherein the relay station is configured to determine whether attaching configuration information indicating an upper radio station to which the relay station should attach is held or not, and to attach to an upper radio station included in the attaching configuration information acquired from a network according to a result of the determination.   
     
     
         23 . A method for controlling a relay station that is wirelessly connectable to an upper radio station, the method comprising:
 determining whether attaching configuration information indicating an upper radio station to which the relay station should attach is held or not; and   attaching to an upper radio station included in the attaching configuration information acquired from a network according to a result of the determination.