Patent ID: 8503357

Claim:
A radio system, comprising a first radio terminal, a second radio terminal and a radio base station, in which the first radio terminal and the second radio terminal transmit radio signals to the radio base station under a space multiplexing scheme, the first radio terminal comprising a first transmitting unit configured to transmit a request signal to the radio base station for requesting an access right to transmit radio signals to the radio base station, the request signal describing a first period during which the first radio terminal and the second radio terminal continuously transmit radio signals without relinquishing the access right and a second period which is a transmission period of radio signals under the space multiplexing scheme, the second period being shorter than the first period and the second period being included in the first period, the second radio terminal comprising a prevention unit configured to prevent transmission of radio signals for a predetermined duration when receiving radio signals other than those directed to the second radio terminal, the radio base station comprising: a receiving unit configured to receive the request signal from the first radio terminal; a storage configured to store an identifier of a radio terminal which transmits radio signals to the radio base station under the space multiplexing scheme in association with the first radio terminal; and a second transmitting unit configured to transmit an assignment signal for assigning an access right to transmit radio signals to the radio base station to not only the first radio terminal which is a sender of the request signal, but also the second radio terminal when an identifier of the second radio terminal is stored in association with the first radio terminal in the storage, the first period and the second period being described in the assignment signal, wherein the first radio terminal transmits radio signals according to the assignment signal, the second radio terminal cancels the prevention of transmission of radio signals and transmits radio signals according to the assignment signal even when transmission of radio signals is prevented according to receiving of the request signal directed to the radio base station, and during the first period, transmission of radio signals by the first radio terminal and the second radio terminal is performed without the access right being relinquished, and transmission of the radio signals by the first radio terminal and the second radio terminal under the space multiplexing scheme completes within the second period.