Carrier phase offset correction for a QAM system

A method for correcting carrier phase offset in a quadrature amplitude modulated signal in a receiver, the method comprising:

• equalizing the signal;
• slicing the equalized signal, thereby obtaining real and imaginary sequences from the equalized signal;
• identifying a frame synchronization sequence in the real and imaginary sequences, wherein identifying the frame synchronization sequence includes correlating a stored pseudo-random sequence with the real and imaginary sequences, and determining a start of a frame from maximum correlation values associated with the real and imaginary sequences;
• and
• correcting a phase error in the equalized signal based on the maximum correlation values,
• wherein the correlating step includes performing continuous cross-correlation on a stored copy of the frame synchronization sequence separately with the real and imaginary sequences, and
• wherein real and imaginary parts of frame sync symbols in the frame synchronization sequence have the same sign.

A method for correcting carrier phase offset in a quadrature amplitude modulated signal, wherein the method is implemented in a system comprising one or more processors configured to execute instructions, the method comprising:

• executing, on the one or more processors, instructions configured to equalize the signal;
• executing, on the one or more processors, instructions configured to slice the equalized signal, thereby obtaining real and imaginary sequences from the equalized signal;
• executing, on the one or more processors, instructions configured to identify a frame synchronization sequence in the real and imaginary sequences, wherein identifying the frame synchronization sequence includes performing continuous cross-correlation on a stored copy of the frame synchronization sequence separately with the real and imaginary sequences, and determining a start of a frame from maximum correlation values associated with the real and imaginary sequences;
• and
• executing, on the one or more processors, instructions configured to correct a phase error in the equalized signal based on the maximum correlation values, wherein the real and imaginary parts of the frame sync symbols of the frame synchronization sequence have the same sign, and wherein correcting a phase error includes determining phase rotation in the equalized signal based on the signs of the maximum correlation values.

A non-transitory computer-readable medium comprising code for:

• equalizing the signal;
• slicing the equalized signal, thereby obtaining real and imaginary sequences from the equalized signal;
• identifying a frame synchronization sequence in the real and imaginary sequences, wherein identifying the frame synchronization sequence includes performing continuous cross-correlation on a stored copy of the frame synchronization sequence separately with the real and imaginary sequences, and determining a start of a frame from maximum correlation values associated with the real and imaginary sequences;
• and
• correcting a phase error in the equalized signal based on the maximum correlation values, wherein the real and imaginary parts of the frame sync symbols of the frame synchronization sequence have the same sign, and wherein correcting a phase error includes determining phase rotation in the equalized signal based on the signs of the maximum correlation values.