Radio communication system and transmission mode selecting method

A transmission mode selection method performed in a radio communication system comprising first and second radio communication apparatuses which can communicate with each other by radio, wherein the method comprises:

• the first step, performed by the first radio communication apparatus, of estimating propagation path environment information indicating an environment of a propagation path to the second radio communication apparatus on the basis of a signal from the second radio communication apparatus;
• the second step, performed by the first radio communication apparatus, of estimating propagation path quality information indicating quality of the propagation path to the second radio communication apparatus on the basis of the signal from the second radio communication apparatus;
• the third step, performed by the first radio communication apparatus, of transmitting the propagation path environment information and propagation path quality information together with a data signal to the second radio communication apparatus;
• and
• the fourth step, performed by the second radio communication apparatus, of selecting, in accordance with the propagation path environment information, one of a plurality of tables in each of which a plurality of transmission modes each having a threshold value corresponding to a value of the propagation path quality information are registered, and selecting, as a mode for transmission to the first radio communication apparatus, one of the transmission modes registered in the selected table in accordance with the propagation path quality information.

A transmission mode selection method performed in a radio communication system comprising first and second radio communication apparatuses which can communicate with each other by radio, wherein the method comprises:

• the first step, performed by the first radio communication apparatus, of estimating propagation path environment information indicating an environment of a propagation path to the second radio communication apparatus on the basis of a signal from the second radio communication apparatus;
• the second step, performed by the first radio communication apparatus, of estimating propagation path quality information indicating quality of the propagation path to the second radio communication apparatus on the basis of the signal from the second radio communication apparatus;
• the third step, performed by the first radio communication apparatus, of obtaining an error detection result indicating an error in the signal from the second radio communication apparatus;
• the fourth step, performed by the first radio communication apparatus, of transmitting the propagation path environment information, propagation path quality information, and error detection result together with a data signal to the second radio communication apparatus;
• and
• the fifth step, performed by the second radio communication apparatus, of selecting, in accordance with the propagation path environment information, one of a plurality of tables in each of which a plurality of transmission modes each having a threshold value corresponding to a value of the propagation path quality information are registered, selecting, as a mode for transmission to the first radio communication apparatus, one of the transmission modes registered in the selected table in accordance with the propagation path quality information, and rewriting, in accordance with the error detection result, a threshold value registered in the table to correspond to the selected transmission mode.