Terminal, base station, wireless communication system and channel state information acquisition method

A channel state information acquisition method in a base station capable of wireless communication with a plurality of terminals, the method comprising:

• a step of holding information on P (P:
• an integer of 3 or more) terminals currently connected to the base station;
• a step of determining L (L:
• an integer satisfying 2≤L<P) terminals that are to report channel state information indicating a state of a propagation path to the base station from among the P terminals based on the information on the P terminals, at every data transmission cycle;
• a step of selecting M (M:
• an integer satisfying 2≤M≤L) terminals capable of spatial multiplex communication in the data transmission cycle based on the reporting of the channel state information from the L terminals;
• and
• a step of transmitting data to and from the M terminals via a plurality of antennas using the spatial multiplex communication.

A wireless communication system capable of wireless communication between a plurality of terminals and a base station,

• wherein the base station
• holds information on P (P:
• an integer of 3 or more) terminals currently connected to the base station, and
• determines L (L:
• an integer satisfying 2≤L<P) terminals that are to report channel state information indicating a state of a propagation path to the base station from among the P terminals based on the information on the P terminals and further transmits an instruction for reporting the channel state information to the P terminals, at every data transmission cycle,
• the terminal measures the channel state information based on the instruction for reporting the channel state information transmitted from the base station and further reports a measurement result of the channel state information to the base station, and
• the base station
• selects M (M:
• an integer satisfying 2≤M≤L) terminals capable of spatial multiplex communication in the data transmission cycle based on the reporting of the measurement result of the channel state information from the L terminals, and
• transmits data to and from the M terminals via a plurality of antennas using the spatial multiplex communication.

A terminal that is capable of communicating with a base station, the terminal comprising:

• a memory that holds information on the terminal itself;
• a determination unit that determines necessity of reporting channel state information indicating a state of a propagation path to the base station based on the information on the terminal itself, at every data transmission cycle;
• a measurement unit that measures the channel state information based on the determination to report the channel state information;
• and
• a communicator that reports a measurement result of the channel state information to the base station,
• wherein the communicator receives data transmitted from the base station in a case where M (M:
• 2 or more preset values) terminals capable of spatial multiplex communication with the base station in the data transmission cycle are selected based on the measurement result of the channel state information.

A channel state information acquisition method in a terminal capable of communicating with a base station, the method comprising:

• a step of holding information on the terminal itself;
• a step of determining necessity of reporting channel state information indicating a state of a propagation path to the base station based on the information on the terminal itself, at every data transmission cycle;
• a step of measuring the channel state information based on the determination to report the channel state information;
• a step of reporting a measurement result of the channel state information to the base station;
• and
• a step of receiving data transmitted from the base station in a case where M (M:
• 2 or more preset values) terminals capable of spatial multiplex communication with the base station in the data transmission cycle are selected based on the measurement result of the channel state information.

A wireless communication system capable of wireless communication between a plurality of terminals and a base station,

• wherein the terminal
• holds information on the terminal itself,
• determines necessity of reporting channel state information indicating a state of a propagation path to the base station based on the information on the terminal itself, at every data transmission cycle,
• measures the channel state information based on the determination to report the channel state information, and
• reports a measurement result of the channel state information to the base station,
• the base station
• selects M (M:
• an integer satisfying 2≤M≤L) terminals capable of spatial multiplex communication in the data transmission cycle based on the reporting of the measurement result of the channel state information from the terminals and
• transmits data to and from the M terminals via a plurality of antennas using the spatial multiplex communication, and
• the terminal
• receives the data transmitted from the base station by using the spatial multiplex communication in a case where M (M:
• a preset value of 2 or more) terminals capable of spatial multiplex communication with the base station in the data transmission cycle are selected based on the measurement result of the channel state information.