Systems and methods for polarization control using blind source separation

A blind source separation (BSS)-based analog polarization and carrier phase control system, the control system comprising:

• a polarization controller in a receiver;
• ADC circuits coupled to the polarization controller;
• sample-and-hold circuits coupled to the ADC circuits, the sample-and-hold and ADC circuits concurrently acquire a number of samples from XI, XQ, YI, and YQ branches of the receiver;
• a set of memory buffers coupled to the sample-and-hold circuits to accumulate samples, the polarization controller performing steps comprising:
• initializing a set of polarization control state variables and a set of carrier phase state variables;
• applying to the samples in the set of memory buffers complex ICA such as to perform BSS;
• factorizing a demixing matrix obtain incremental angles;
• adding the incremental angles to the set of polarization control state variables to obtain updated polarization control state variables;
• and
• using the updated polarization control state variables to perform polarization control.

A method for coherent combining of two receiver branches with initially unknown relative phase, the method comprising:

• vertically concatenating four row vectors representing XI, XQ, YI, and YQ receiver branch signals to form a 4×N matrix;
• performing a real-valued blind source separation (BSS) to obtain a 4×4 demixing matrix;
• reversing row permutations that separate complex variables into non-adjacent rows;
• and
• obtaining a first estimate of a 2×2 complex demixing matrix.