Patent ID: 8107993

Claim:
A radio communication apparatus comprising: a receiving unit configured to receive a first radio signal indicating a state in which transmission by a Space Division Multiple Access (SDMA) scheme is allowed; a first determination unit configured to determine, upon receiving the first radio signal, whether a transmission state is a first state in which transmission by the SDMA scheme is possible, or a second state in which the transmission by the SDMA scheme is impossible; a second determination unit configured to determine whether the first state continues for a first time period; a first transmission unit configured to transmit a radio signal using the SDMA scheme, when the second determination unit determines that the first state continues for the first time period; and a first setting unit configured to set a third time period instead of the first time period, when the second determination unit determines that the first state fails to continue for the first time period, the third time period being obtained by subtracting, from the first time period, a second time period ranging from when the carrier sense is started to when the transmission state is determined to be the second state, wherein when the receiving unit receives the first radio signal after the third time period is set, the second determination unit determines whether the first state continues for the third time period.