Patent ID: 7936727

Claim:
A transmission apparatus that performs transmission to a reception apparatus, the transmission apparatus comprising: a control unit operable to select one transmission rate of a physical layer (PHY rate) from among a plurality of PHY rates of a protocol stack; a communication unit operable to perform transmission at the PHY rate selected by the control unit; and a storage unit that stores therein first information and second information for each of the plurality of PHY rates, the first information showing a plurality of possible reception power values respectively corresponding to packet error rates (PERs), the second information showing a plurality of possible PERs respectively corresponding to retransmission ratios, wherein the control unit includes a retransmission ratio acquisition subunit operable to acquire a retransmission ratio that corresponds to a reception power value for each of the PHY rates, based on the first information and the second information, the control unit performs the selection by calculating one or more effective values of transmission rates of an upper layer of the protocol stack with respect to one or more PHY rates of the plurality of PHY rates respectively, and making a comparison with use of the calculated one or more effective values, the communication unit performs transmission in units of packets, the control unit further includes: a PER calculation subunit operable to calculate a PER that corresponds to a PHY rate used for the transmission, using a number of retransmissions for each transmitted packet and a number of packets that have been completely transmitted; a comparison subunit operable to compare the PER calculated by the PER calculation subunit with a PER that corresponds to the used PHY rate shown by the first information; and a correction subunit operable to correct the first information if the calculated PER differs from the PER shown by the first information by no less than a predetermined value, and each of the one or more effective values is calculated based on (i) an ideal value of corresponding one of the transmission rates and (ii) a retransmission ratio via the physical layer that corresponds to a reception power value detected in the reception apparatus, said transmission apparatus further comprising; an accumulation unit operable to acquire a reception power value, and accumulate therein the acquired reception power value, wherein the correction subunit includes: a generation subunit operable to generate corrected first information showing a plurality of possible reception power values respectively corresponding to PERs, based on the PER calculated by the PER calculation subunit, the PER shown by the first information, and a reception power value accumulated in the accumulation unit that corresponds to the calculated PER; and an update subunit operable to update the first information stored in the storage unit with the corrected first information generated by the generation unit.