Wireless communication apparatus and transmission control method

A wireless communication apparatus comprising:

• a transmitter;
• a receiver;
• a generation unit configured to generate an aggregated frame including a plurality of frames and being transmitted by the transmitter;
• an estimation unit configured to estimate a degree of channel variation;
• a transmission control unit configured to control the transmitter so as to transmit a first frame for requesting response information necessary to select a modulation scheme and an error correction coding scheme used by the transmitter;
• a measurement unit configured to measure a response time between an instant when the transmitter transmits the first frame and an instant when the receiver receives a second frame including the response information;
• a threshold determination unit configured to determine a threshold value of the response time for determining reliability of the response information, based on the degree of channel variation;
• and
• a control unit configured to control the generation unit so as (a) to maintain a current number of frames in the aggregated frame if the response time measured by the measuring unit is shorter than the threshold value, and so as (b) to decrease the current number of frames in the aggregated frame if the response time is longer than or equal to the threshold value.

A wireless communication apparatus comprising:

• a transmitter;
• a receiver;
• and
• a first control unit configured to determine a modulation scheme and an error correction coding scheme used by the transmitter;
• wherein the first control unit includes
• a transmission control unit configured to control the transmitter so as to transmit a first frame for requesting response information necessary to select the modulation scheme and the error correction coding scheme;
• a measurement unit configured to measure a response time between an instant when the transmitter transmits the first frame and an instant when the receiver receives a second frame including the response information;
• a calculation unit configured to calculate a correlation value between reception powers or reception envelopes at two time points separated from each other by the response time;
• and
• a determination unit configured to determine the modulation scheme and the error correction coding scheme selected based on the response information included in the second frame received by the receiver, if the correlation value is larger than a predetermined threshold value for determining reliability of the response information in the second frame.

A transmission control method for a wireless communication apparatus including a transmitter and a receiver, and determining a modulation scheme and an error correction coding scheme used by the transmitter, the method comprising:

• estimating a degree of channel variation;
• transmitting, by the transmitter, a first frame for requesting response information necessary to select the modulation scheme and the error correction coding scheme;
• measuring a response time between an instant when the transmitter transmits the first frame and an instant when the receiver receives a second frame including the response information;
• determining a threshold value of the response time for determining reliability of the information, based on the degree of channel variation;
• and
• determining a first set of the modulation scheme and the error correction coding scheme selected based on the response information included in the second frame received by the receiver in the response time shorter than the threshold value.

A transmission control method for a wireless communication apparatus including a transmitter and a receiver, the method comprising:

• generating an aggregated frame including a plurality of frames and being transmitted by the transmitter;
• estimating a degree of channel variation;
• transmitting, by the transmitter, a first frame for requesting response information necessary to select a modulation scheme and an error correction coding scheme used by the transmitter;
• measuring a response time between an instant when the transmitter transmits the first frame and an instant when the receiver receives a second frame including the response information;
• determining a threshold value of the response time for determining reliability of the information, based on the degree of channel variation;
• maintaining a current number of frames in the aggregated frame if the response time measured by the measuring unit is shorter than the threshold value;
• and
• decreasing the current number of frames in the aggregated frame if the response time is longer than or equal to the threshold value.