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 method for a relay node (RN), wherein the method comprising:
 in a first case where the RN has first information indicating at least a cell of a first donor base station to access from the RN,   sending second information related to a first RRC (Radio Resource Control) connection to the first donor base station, wherein the second information includes a first RN indication which makes the first donor base station perform a first relay configuration; and   starting an operation of a relay cell with the first donor base station after the first relay configuration is performed by the first donor base station;   
       in a second case where the RN does not have the second information,
 sending third information related to a second RRC connection to a base station, wherein the third information does not include a second RN indication; 
 receiving, from the base station, a forth information indicating at least a cell of a second donor base station to access from the RN; 
 sending fifth information related to a third RRC connection to the second donor base station wherein the fifth information includes the second RN indication which makes the second donor base station perform a second relay configuration; and 
 starting an operation of the relay cell with the second donor base station after the second relay configuration is performed by the second donor base station. 
 
     
     
         2 . The method according to  claim 1 , wherein in a third case where the RN is preconfigured to access the first donor base station but receives a negative response from the first DeNB, the method further comprising:
 sending the third information to the base station;   receiving the fourth information from the base station,   sending the fifth information; and   starting the operation of the relay cell with the second donor base station after the second relay configuration is performed by the second donor base station.   
     
     
         3 . The method according to  claim 1 , wherein in the first case, the RN switches from a UE mode to an RN mode in response to the first donor base station performing the first relay configuration. 
     
     
         4 . The method according to  claim 1 , wherein in the second case, the RN does not have access information of a donor base station and the RN detects the base station to which the RN can attach. 
     
     
         5 . The RN apparatus according to  claim 1 , wherein in the second case, the RN temporarily attaches to the base station and the RN does not notify the base station that an RN mode is supported. 
     
     
         6 . A relay node (RN) comprising:
 a memory storing instructions; and   at least one hardware processor configured to process the instruction to:   in a first case where the RN has first information indicating at least a cell of a first donor base station to access from the RN,   send second information related to a first RRC (Radio Resource Control) connection to the first donor base station, wherein the second information includes a first RN indication which makes the first donor base station perform a first relay configuration; and   start an operation of a relay cell with the first donor base station after the first relay configuration is performed by the first donor base station;   
       in a second case where the RN does not have the second information,
 send third information related to a second RRC connection to a base station, wherein the third information does not include a second RN indication; 
 receive, from the base station, a forth information indicating at least a cell of a second donor base station to access from the RN; 
 send fifth information related to a third RRC connection to the second donor base station wherein the fifth information includes the second RN indication which makes the second donor base station perform a second relay configuration; and 
 start an operation of the relay cell with the second donor base station after the second relay configuration is performed by the second donor base station. 
 
     
     
         7 . A method for a base station comprising:
 connecting to a first relay node (RN) using a first connection mode in which the first RN operates as a user equipment (UE) when the base station receives, from the first RN, first information related to a first RRC (Radio Resource Control) connection, wherein the first information does not include an RN indication which makes a donor base station perform a relay configuration;   connecting to a second RN using a second connection mode in which the second RN operates as a relay when the base station receives, from the second RN, second information related to a second RRC connection, wherein the second information includes the RN indication; and   transmitting, to the first RN, third information indicating at least one cell of a donor base station to access from the first RN when the base station receives, from the first RN, the first information.   
     
     
         8 . The method according to  claim 7 , further comprising:
 setting up at least one bearer between the second RN and the base station, wherein the at least one bearer is used for relaying when the base station receives, from the second RN, the second information.   
     
     
         9 . The method according to  claim 7 , further comprising:
 the second RN selecting the base station from third information indicating the at least one cell of donor base station to access from the second RN.   
     
     
         10 . The method according to  claim 9 , wherein the third information is preconfigured. 
     
     
         11 . The method according to  claim 9 , wherein the third information is received from a base station as a first connection mode in which the second RN operates as a UE. 
     
     
         12 . The method according to  claim 7 , wherein the base station is a donor base station when the base station receives the second information. 
     
     
         13 . The method according to  claim 12 , wherein the base station is a donor base station included in third information indicating the at least one cell of donor base station to access from the first RN. 
     
     
         14 . The method according to  claim 7 , further comprising:
 the base station sending, to the second RN, an RRC signaling for relaying configuration, after the base station receiving the second information from the second RN.   
     
     
         15 . A base station comprising:
 a memory storing instructions; and   at least one hardware processor configured to process the instruction to:   perform radio communication with a user equipment (UE), a first relay node (RN), and a second RN;   connect to a first RN using a first connection mode in which the first RN operates as a UE when the base station receives, from the first RN, first information related to a first RRC (Radio Resource Control) connection, wherein the first information does not include an RN indication which makes a donor base station perform a relay communication;   connect to a second RN using a second connection mode in which the second RN operates as a relay when the base station receives, from the second RN, second information related to a second RRC connection, wherein the second information includes the RN indication; and   transmit, to the first RN, third information indicating at least a cell of a donor base station to access from the first RN when the base station receives, from the first RN, the first information.