Interference reduction method for downhole telemetry systems

An apparatus for reducing interference in a received downhole telemetry signal, the apparatus comprising:

• a receiver configured to receive a downhole telemetry signal in a time domain;
• and
• a processor coupled to the receiver and configured to implement a method comprising:
• segmenting the received signal into a plurality of signal segments;
• windowing each signal segment in the plurality of signal segments to generate a plurality of windowed signal segments;
• transforming each windowed signal segment in the plurality of windowed signal segments into a complex variable domain to generate a plurality of complex variable domain segments, each complex variable domain segment having an in-phase component vector I and a quadrature component vector Q;
• calculating a real amplitude vector A from the in-phase component vector I and the quadrature component vector Q for each complex variable domain segment;
• filtering interferers in the amplitude vector A for each complex variable domain segment to generate a filtered amplitude vector à for each complex variable domain segment;
• recalculating an amplitude of the amplitude vector A using the filtered amplitude vector à for each complex variable domain segment to generate an output amplitude vector  for each complex variable domain segment;
• scaling the in-phase component vector I and the quadrature component vector Q by a factor Â/A for each complex variable domain segment to generate an output in-phase component vector I′ and an output quadrature component vector Q′ for each complex variable domain segment;
• and
• transforming I′ and Q′ for each complex variable domain segment into the time domain to provide an interference-reduced output signal in the time domain.

A non-transitory computer readable medium comprising computer executable instructions for reducing interference in a received downhole telemetry signal by implementing a method comprising:

• segmenting a received downhole telemetry signal in a time domain into a plurality of signal segments;
• windowing each signal segment in the plurality of signal segments to generate a plurality of windowed signal segments;
• transforming each windowed signal segment in the plurality of windowed signal segments into a complex variable domain to generate a plurality of complex variable domain segments, each complex variable domain segment having an in-phase component vector I and a quadrature component vector Q;
• calculating a real amplitude vector A from the in-phase component vector I and the quadrature component vector Q for each complex variable domain segment;
• filtering interferers in the amplitude vector A for each complex variable domain segment to generate a filtered amplitude vector à for each complex variable domain segment;
• recalculating an amplitude of the amplitude vector A using the filtered amplitude vector à for each complex variable domain segment to generate an output amplitude vector  for each complex variable domain segment;
• scaling the in-phase component vector I and the quadrature component vector Q by a factor Â/A for each complex variable domain segment to generate an output in-phase component vector I′ and an output quadrature component vector Q′ for each complex variable domain segment;
• and
• transforming I′ and Q′ for each complex variable domain segment into the time domain to provide an interference-reduced output signal in the time domain;
• wherein the segmenting, windowing, transforming each windowed signal segment, calculating a real amplitude vector A, filtering, recalculating, scaling I and Q, and transforming I′ and Q′ are performed using a processor.