User apparatus, base station, and communication method

Abstract

A user apparatus communicating with a base station in a radio communication system including the base station and the user apparatus includes a first receiving unit to receive multiple first reference signals transmitted from the base station; a detection unit to detect a specific antenna port via which the plurality of first reference signals is received, or a specific directivity pattern, among a plurality of directivity patterns generated by a plurality of antenna ports, in which the plurality of first reference signals are received; a measuring unit to measure reception power of each of the first reference signals; and a transmission unit to group the reception power of each of the first reference signals into one of groups of the specific antenna port and the specific directivity pattern via which the first reference signals are received to transmit the groups of the reception power to the base station.

1 . A user apparatus communicating with a base station in a radio communication system, the radio communication system including the base station and the user apparatus, the user apparatus comprising:
 a first receiving unit configured to receive a plurality of first reference signals transmitted from the base station;   a detection unit configured to detect a specific antenna port via which the plurality of first reference signals is received, or a specific directivity pattern, among a plurality of directivity patterns generated by a plurality of antenna ports, in which the plurality of first reference signals are received;   a measuring unit configured to measure reception power of each of the plurality of first reference signals; and   a transmission unit configured to group the reception power of each of the plurality of first reference signals into one of groups of the specific antenna port and the specific directivity pattern via which the plurality of first reference signals are received to transmit the groups of the reception power to the base station.   
     
     
         2 . The user apparatus according to  claim 1 , wherein
 the transmission unit transmits, to the base station, header information indicating a number corresponding to the plurality of first reference signals belonging to a corresponding one of the groups.   
     
     
         3 . The user apparatus according to  claim 1 , wherein
 the transmission unit may group the reception power of each of the plurality of first reference signals satisfying a predetermined condition into the groups and transmit the groups to the base station.   
     
     
         4 . The user apparatus according to  claim 1 , further comprising:
 a second receiving unit configured to receive one or more of second reference signals transmitted from the base station; and   a generating unit configured to measure a reception quality of the one or more second reference signals to generate feedback information based on the reception quality, wherein   the transmission unit transmits the reception power of each of the plurality of first reference signals and the feedback information simultaneously to the base station.   
     
     
         5 . The user apparatus according to  claim 1 , wherein
 the transmission unit receives, from the base station, header information indicating the number of the plurality of first reference signals belonging to the corresponding groups, and groups the reception power of each of the plurality of first reference signals into the groups based on the received header information to transmit the groups of the reception power to the base station.   
     
     
         6 . The user apparatus according to  claim 1 , wherein
 the first receiving unit receives the plurality of frequency hopped first reference signals from the base station.   
     
     
         7 . The user apparatus according to  claim 1 , wherein
 the measuring unit calculates the reception power of each of the plurality of first reference signals to be transmitted to the base station by measuring the reception power of a corresponding one of the plurality of first reference signals a plurality of times.   
     
     
         8 . A base station communicating with a user apparatus in a radio communication system, the radio communication system including the base station and the user apparatus, the base station comprising:
 a first transmission unit configured to transmit a plurality of first reference signals;   a first receiving unit configured to receive, from the user apparatus, the reception power of each of the plurality of first reference signals grouped into a plurality of groups;   a selection unit configured to select one of antenna ports for transmitting one or more second reference signals based on the reception power of each of the plurality of first reference signals grouped into the plurality of groups;   a second transmission unit configured to transmit the one or more second reference signals from the antenna port selected by the selecting unit;   a second receiving unit configured to receive, from the user apparatus, feedback information based on reception quality of each of the one or more second reference signals; and   a control unit configured to control the antenna port based on the feedback information.   
     
     
         9 . A communication method executed by a user apparatus communicating with a base station in a radio communication system, the radio communication system including the base station and the user apparatus, the communication method comprising:
 receiving a plurality of first reference signals transmitted from the base station;   detecting a specific antenna port via which the plurality of first reference signals is received, or a specific directivity pattern, among a plurality of directivity patterns generated by a plurality of antenna ports, in which the plurality of first reference signals are received;   measuring reception power of each of the plurality of first reference signals; and   grouping the reception power of each of the plurality of first reference signals into one of groups of the specific antenna port and the specific directivity pattern via which the plurality of first reference signals are received to transmit the groups of the reception power to the base station.   
     
     
         10 . A communication method executed by a base station communicating with a user apparatus in a radio communication system, the radio communication system including the base station and the user apparatus, the communication method comprising:
 transmitting a plurality of first reference signals;   receiving, from the user apparatus, the reception power of each of the plurality of first reference signals grouped into a plurality of groups;   selecting one of antenna ports for transmitting one or more second reference signals based on the reception power of each of the plurality of first reference signals grouped into the plurality of groups;   transmitting the one or more second reference signals from the antenna port selected in the selecting;   receiving, from the user apparatus, feedback information based on reception quality of each of the one or more second reference signals; and   controlling the antenna port based on the feedback information.