Radio communication system, radio base station, and mobile terminal

A radio communication system comprising multiple mobile terminals and multiple radio base stations communicating with the mobile terminals by radio,

• each of the multiple mobile terminals comprising:
• multiple reception antennas for receiving radio waves;
• an interference rejection combining processor adapted for giving weights to multiple signals obtained by the multiple reception antennas so as to suppress interference with a desired radio wave beam from a desired base station caused by interfering radio wave beams from interfering base stations;
• a signal separator adapted for separating a signal destined for the mobile terminal from signals destined for other mobile terminals among signals derived from radio waves received at the multiple receiving antennas with the use of the reception weights calculated at the interference rejection combining processor;
• channel estimator adapted for calculating downlink channel characteristics from the multiple radio base stations to the mobile terminal;
• a channel characteristics transmitter adapted for imparting channel characteristic information that indicates the channel characteristics calculated by the channel estimator;
• and
• an interference-suppression-capability-information transmitter adapted for imparting interference-suppression-capability information on the number of interfering radio wave beams of which interference can be suppressed by the interference rejection combining processor,
• each of the radio base stations comprising:
• multiple transmission antennas for transmitting radio waves on which signals destined for mobile terminals are carried;
• a channel characteristics receiver adapted for receiving, from a mobile terminal for which a desired radio base station is the radio base station, channel characteristic information that indicates the channel characteristics;
• an interference-suppression-capability-information receiver adapted for receiving interference-suppression-capability information from the mobile terminal for which a desired radio base station is the radio base station;
• an inter-base-station transmitter adapted for transmitting the channel characteristic information received at the channel characteristics receiver to other multiple radio base stations;
• an inter-base-station receiver adapted for receiving, from other multiple radio base stations, channel characteristic information for mobile terminals for which desired radio base stations are said other multiple radio base stations;
• an inter-base-station collaborator adapted for giving weights to the radio waves to be transmitted from the multiple transmission antennas, on the basis of channel characteristic information that indicates channel characteristics for multiple mobile terminals received at the channel characteristics receiver and at the inter-base-station receiver, so as to adjust a desired radio wave beam to a mobile terminal for which a desired radio base station is the radio base station and an interfering radio wave beam to another mobile terminal for which a desired radio base station is another radio base station;
• and
• a channel-characteristics-adjustment instructor adapted for, on the basis of the interference-suppression-capability information received at the interference-suppression-capability-information receiver, instructing each of the mobile terminals to adjust an amount of the channel characteristic information to be transmitted from the mobile terminal.

A radio base station communicating with mobile terminals by radio and communicating with other multiple radio base stations, comprising:

• multiple transmission antennas for transmitting radio waves on which signals destined for mobile terminals are carried;
• a channel characteristics receiver adapted for receiving, from a mobile terminal for which a desired radio base station is the radio base station, channel characteristic information that indicates downlink channel characteristics from the radio base station and other radio base stations;
• an interference-suppression-capability-information receiver adapted for receiving interference-suppression-capability information from the mobile terminal for which a desired radio base station is the radio base station, the interference-suppression-capability information being related to the number of interfering radio wave beams of which interference can be suppressed by the mobile terminal;
• an inter-base-station transmitter adapted for transmitting the channel characteristic information received at the channel characteristics receiver to other multiple radio base stations;
• an inter-base-station receiver adapted for receiving, from other multiple radio base stations, channel characteristic information for mobile terminals for which desired radio base stations are said other multiple radio base stations;
• and
• an inter-base-station collaborator adapted for giving weights to the radio waves to be transmitted from the multiple transmission antennas, on the basis of channel characteristic information that indicates channel characteristics for multiple mobile terminals received at the channel characteristics receiver and the inter-base-station receiver, so as to perform in-phase addition of an interfering radio wave beam directed to a mobile terminal for which the desired radio base station is another radio base station to an interfering radio wave beam transmitted from yet another radio base station for limiting the number of interfering radio wave beams that arrive at the mobile terminal,
• wherein the inter-base-station collaborator is adapted for giving weights to the radio waves to be transmitted from the multiple transmission antennas, depending on the number of interfering radio wave beams of which interference can be suppressed by the mobile terminal for which the desired radio base station is said another radio base station.

A radio base station communicating with mobile terminals by radio and communicating with other multiple radio base stations, comprising:

• multiple transmission antennas for transmitting radio waves on which signals destined for mobile terminals are carried;
• a channel characteristics receiver adapted for receiving, from a mobile terminal for which a desired radio base station is the radio base station, channel characteristic information that indicates downlink channel characteristics from the radio base station and other radio base stations;
• an interference-suppression-capability-information receiver adapted for receiving interference-suppression-capability information from the mobile terminal for which a desired radio base station is the radio base station, the interference-suppression-capability information being related to the number of interfering radio wave beams of which interference can be suppressed by the mobile terminal;
• an inter-base-station transmitter adapted for transmitting the channel characteristic information received at the channel characteristics receiver to other multiple radio base stations;
• an inter-base-station receiver adapted for receiving, from other multiple radio base stations, channel characteristic information for mobile terminals for which desired radio base stations are said other multiple radio base stations;
• and
• an inter-base-station collaborator adapted for giving weights to the radio waves to be transmitted from the multiple transmission antennas, on the basis of channel characteristic information that indicates channel characteristics for multiple mobile terminals received at the channel characteristics receiver and at the inter-base-station receiver, so as to adjust a desired radio wave beam to a mobile terminal for which a desired radio base station is the radio base station and an interfering radio wave beam to another mobile terminal for which a desired radio base station is another radio base station;
• and
• a channel-characteristics-adjustment instructor adapted for, on the basis of the interference-suppression-capability information received at the interference-suppression-capability-information receiver, instructing each of the mobile terminals to adjust an amount of the channel characteristic information to be transmitted from the mobile terminal.

A mobile terminal comprising:

• multiple reception antennas for receiving radio waves;
• an interference rejection combining processor adapted for giving weights to multiple signals obtained by the multiple reception antennas so as to suppress interference with a desired radio wave beam from a desired base station caused by interfering radio wave beams from interfering base stations;
• a signal separator adapted for separating a signal destined for the mobile terminal from signals destined for other mobile terminals among signals derived from radio waves received at the multiple receiving antennas with the use of the reception weights calculated at the interference rejection combining processor;
• channel estimator adapted for calculating downlink channel characteristics from multiple radio base stations to the mobile terminal;
• a channel characteristics transmitter adapted for imparting channel characteristic information that indicates the channel characteristics calculated by the channel estimator;
• and
• an interference-suppression-capability-information transmitter adapted for imparting interference-suppression-capability information on the number of interfering radio wave beams of which interference can be suppressed by the interference rejection combining processor.