Patent ID: 8983289
Filing Date: 2015-03-17
Classification: H04B

Abstract:
1. A method of recovering frequency and phase associated with an optical carrier signal in an optical communication system, the method comprising: determining, using a processing device, an estimated frequency offset based on a starting training sequence, the estimated frequency offset being associated with the optical carrier signal; determining, using the processing device, a current frequency offset based on the estimated frequency offset and a current phase during steady-state operation of the optical communication system, the current frequency offset and the current phase being associated with the optical carrier signal; determining, using the processing device, a current frequency based on the current frequency offset, the current frequency being associated with the optical carrier signal; determining, using the processing device, an estimated phase using training symbols inserted into the optical carrier signal, the estimated phase being associated with the optical carrier signal; and determining, using the processing device, the current phase associated with the optical carrier signal based on the estimated phase and a constrained blind phase estimation algorithm, the current phase being associated with the optical carrier signal, the estimated frequency offset being determined using ▴ω representing the estimated frequency offset, x(n) representing a received training symbol received at an n th time slot, x ref (n) representing a transmitted training symbol transmitted at the n th time slot, x(n+1) representing a received training symbol received at an n+1 th time slot, x ref (n+1) representing a transmitted training symbol transmitted at the n+1 th time slot, T representing a symbol period, N representing a symbol length.