Signal transmission parameter control using channel sounding

An apparatus comprising:

• a transmitter configured to process signals for a downlink to a client station over a wireless transmission medium;
• a receiver configured to receive at least a sounding signal from an uplink from the client station over the wireless transmission medium;
• and
• a control circuit in communication with the transmitter and the receiver, wherein the control circuit is configured:
• to cause the transmitter to request in a downlink the client station to transmit the sounding signal over a wireless transmission medium;
• to determine channel characteristics associated with the sounding signal;
• to determine one or more signal transmission correction parameters for at least one of timing adjustment, power adjustment, or frequency adjustment based at least partly on the determined channel characteristics;
• and
• to cause the transmitter to transmit in a downlink a ranging response message including the one or more correction parameters wherein requesting the client station to transmit a sounding signal further comprises:
• requesting the client station to periodically repeat the sounding signal;
• and correspondingly receiving the repeated sounding signals, re-determining channel characteristics, re-determining one or more correction parameters, and retransmitting messages to the client station to correct transmission parameters.

An apparatus for correcting transmission parameters, the apparatus comprising:

• means for wirelessly communicating with a client station;
• means for requesting the client station to transmit a sounding signal;
• means for receiving in an uplink the sounding signal from the client station;
• means for determining channel characteristics based at least partly on the sounding signal;
• means for determining one or more signal transmission correction parameters for at least one of timing adjustment, power adjustment, or frequency adjustment based at least partly on the determined channel characteristics;
• and
• means for transmitting in a downlink a ranging response message including the one or more correction parameters wherein means for requesting the client station to transmit a sounding signal further comprises:
• means for requesting the client station to periodically repeat the sounding signal;
• means for correspondingly receiving the repeated sounding signals, re-determining channel characteristics, re-determining one or more correction parameters, and means for retransmitting messages to the client station to correct transmission parameters.

A computer readable medium which stores a computer program executed by a processor that embodies a method of correcting transmission parameters, the method comprising:

• wirelessly communicating with a client station;
• requesting the client station to transmit a sounding signal;
• receiving in an uplink the sounding signal from the client station;
• determining channel characteristics based at least partly on the sounding signal;
• determining one or more signal transmission correction parameters for at least one of timing adjustment, power adjustment, or frequency adjustment based at least partly on the determined channel characteristics;
• and
• transmitting in a downlink a ranging response message including the one or more correction parameters wherein requesting the client station to transmit a sounding signal further comprises:
• requesting the client station to periodically repeat the sounding signal;
• and correspondingly receiving the repeated sounding signals, re-determining channel characteristics, re-determining one or more correction parameters, and retransmitting messages to the client station to correct transmission parameters.