Patent ID: 7257408

Claim:
A radio communication system comprising first and second radio communication apparatuses which can communicate with each other by radio, wherein said first radio communication apparatus comprises: a propagation path environment estimator which outputs, as propagation path environment information, a result of estimation of an environment of a propagation path to said second radio communication apparatus on the basis of a signal from said second radio communication apparatus; a propagation path quality estimator which outputs, as propagation path quality information, a result of estimation of quality of the propagation path to said second radio communication apparatus on the basis of the signal from said second radio communication apparatus; an error detector which detects an error in the signal from said second radio communication apparatus and outputs the error as an error detection result; and transmitting means for transmitting the propagation path environment information, propagation path quality information, and error detection result together with a data signal to said second radio communication apparatus, wherein said second radio communication apparatus comprises: a transmission mode selector which includes a plurality of tables in which a plurality of transmission modes each having a threshold value corresponding to a value of the propagation path quality information are registered, selects one of said plurality of tables in accordance with the propagation path environment information, and selects, as a mode for transmission to said first radio communication apparatus, one of the transmission modes registered in the selected table in accordance with the propagation path quality information, wherein said transmission mode selector of said second radio communication apparatus rewrites, in accordance with the error detection result, a threshold value registered in the table to correspond to the selected transmission mode.