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Analog self-interference cancellation systems for CMTS

  • US 10,382,085 B2
  • Filed: 12/21/2018
  • Issued: 08/13/2019
  • Est. Priority Date: 08/01/2017
  • Status: Active Grant
First Claim
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1. A system for wired analog self-interference cancellation comprising:

  • a transmit coupler, communicatively coupled to a radio frequency (RF) transmit signal of a wired communication system, that samples the RF transmit signal to create a sampled RF transmit signal having an RF carrier frequency;

    an analog-self-interference canceller comprising;

    a frequency downconverter, comprising a mixer, a local oscillator, and an intermediate frequency (IF) filter, wherein the frequency downconverter converts, by heterodyning, the sampled RF transmit signal to a sampled IF transmit signal having an IF carrier frequency, wherein the IF carrier frequency is less than the RF carrier frequency;

    a first coarse delayer that delays the sampled IF transmit signal by a first delay amount, resulting in a delayed sampled IF transmit signal;

    wherein the first coarse delayer delays the sampled IF transmit signal after frequency downconversion; and

    a first canceller tap group comprising a first per-tap-group delayer, a first sampling coupler, a first per-tap delayer, first and second analog vector modulators, and a first combining coupler;

    wherein the first per-tap-group delayer further delays the delayed sampled IF transmit signal;

    wherein the first sampling coupler splits the delayed sampled IF transmit signal, after the first per-tap-group delayer, into first and second IF transmit signal components;

    wherein the first analog vector modulator generates a first IF self-interference cancellation signal component from the first IF transmit signal component;

    wherein the first per-tap delayer delays the second IF transmit signal component, resulting in a delayed second IF transmit signal component;

    wherein the second analog vector modulator generates a second IF self-interference cancellation signal component from the delayed second IF transmit signal component;

    wherein the first combining coupler combines the first and second IF self-interference cancellation signal components to generate an IF self-interference cancellation signal;

    a frequency upconverter comprising a mixer, a local oscillator, and an RF filter, wherein the frequency upconverter converts, by heterodyning, the IF self-interference cancellation signal to an RF self-interference cancellation signal having the RF carrier frequency; and

    a receive coupler, communicatively coupled to an RF receive signal of the wired communication system, that combines the RF self-interference cancellation signal with the RF receive signal, resulting in an RF composite receive signal;

    wherein the RF composite receive signal contains less self-interference than the RF receive signal.

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