Patent ID: 8811515

Claim:
A receiver for issuing a request for changing a transmission parameter for a transmission bit string to a transmitter to adapt to a state of one communication link, the receiver comprising: a high-frequency carrier receiver configured to receive a transmission bit string from the transmitter; a preamble detector configured to detect a preamble from the transmission bit string; an error correction decoder configured to obtain a total sum of a number of modified bits in a range of a payload following the detected preamble, the number of modified bits including a number of bits of error corrected in decoding; a reception state detector configured to determine whether or not the total sum of the number of modified bits exceeds a threshold; and a low-frequency carrier transmitter configured to issue, if it is determined that the total sum of the number of modified bits exceeds the threshold, a request for changing a transmission parameter for the transmission bit string to the transmitter, using a communication link provided in parallel with the one communication link and serving as a relatively-low-frequency carrier.