Enhancing channel estimates made in digital communications receivers

A method of refining a channel estimate for an OFDM sub-carrier, the method comprising:

• calculating a first channel estimate for an OFDM sub-carrier for a first OFDM frame received at a receiver from a transmitter;
• calculating a second channel estimate for the OFDM sub-carrier for a second OFDM frame received at the receiver from the transmitter at a time later than the first OFDM frame is received;
• adjusting the first channel estimate to ameliorate a difference between the first and second channel estimates that arises from a shift in an operating state of the transmitter and the receiver between the times of reception of the first and second OFDM frames;
• measuring a discrepancy between the second channel estimate and the adjusted first channel estimate;
• modifying the second channel estimate by averaging the second channel estimate with the adjusted first channel estimate if the discrepancy is smaller than a predetermined amount;
• and
• demodulating data from the second OFDM frame using the modified second channel estimate.