| 摘要 |
<p>A signal processing method, particularly in a MIMO wireless communications system, is capable of receiving a DATA frame and responding with transmission of an ACK frame, the ACK frame being of conventional structure in that it contains a reserved portion and an active portion, the ACK frame further containing, in the reserved portion, information defining a transmission mode selection message for interpretation by suitably configured communications apparatus. In such apparatus, the message is interpreted as an indication of the transmission mode, of a plurality available, to be used in future transmissions of frames of information. The transmission mode selection message could for example indicate a new data rate. The reserved portion used to transport the mode selection message could be the second part of a 16-bit Service field (see Figures 1 and 2), the first part of the service field containing initialisation values. Alternatively the mode selection message could be transported in place of one or more pad bits.</p> |
