Analog self-interference cancellation systems for CMTS

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 generates a first delayed sampled IF transmit signal by delaying the sampled IF transmit signal by a first delay amount and generates a second delayed sampled IF transmit signal by delaying the sampled IF transmit signal by a second delay amount;
• wherein the second delay amount is greater than the first delay amount;
• wherein the first coarse delayer generates delayed sampled IF transmit signals after frequency downconversion;
• a first canceller tap group comprising a first per-tap-group delayer, a first sampling coupler, a first per-tap delayer, and first and second analog vector modulators;
• wherein the first per-tap-group delayer further delays the first delayed sampled IF transmit signal;
• wherein the first sampling coupler splits the first 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;
• a second canceller tap group comprising a second per-tap-group delayer, a second sampling coupler, a second per-tap delayer, and third and fourth analog vector modulators;
• wherein the second per-tap-group delayer further delays the second delayed sampled IF transmit signal;
• wherein the second sampling coupler splits the second delayed sampled IF transmit signal, after the second per-tap-group delayer, into third and fourth IF transmit signal components;
• wherein the third analog vector modulator generates a third IF self-interference cancellation signal component from the third IF transmit signal component;
• wherein the second per-tap delayer delays the fourth IF transmit signal component, resulting in a delayed fourth IF transmit signal component;
• wherein the fourth analog vector modulator generates a fourth IF self-interference cancellation signal component from the delayed fourth IF transmit signal component;
• and
• a combining coupler that combines the first, second, third, and fourth 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.

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 sampling coupler that splits the sampled IF transmit signal into first and second sampled IF transmit signals;
• 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 coupling combiner;
• wherein the first per-tap-group delayer delays the first sampled IF transmit signal;
• wherein the first sampling coupler splits the first 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 a first IF self-interference cancellation signal super-component;
• a second canceller tap group comprising a second per-tap-group delayer, a second sampling coupler, a second per-tap delayer, third and fourth analog vector modulators, and a second combining coupler;
• wherein the second per-tap-group delayer delays the second sampled IF transmit signal;
• wherein the second sampling coupler splits the second sampled IF transmit signal, after the second per-tap-group delayer, into third and fourth IF transmit signal components;
• wherein the third analog vector modulator generates a third IF self-interference cancellation signal component from the third IF transmit signal component;
• wherein the second per-tap delayer delays the fourth IF transmit signal component, resulting in a delayed fourth IF transmit signal component;
• wherein the fourth analog vector modulator generates a fourth IF self-interference cancellation signal component from the delayed fourth IF transmit signal component;
• wherein the second combining coupler combines the third and fourth IF self-interference cancellation signal components to generate a second IF self-interference cancellation signal super-component;
• a first coarse delayer that delays the first IF self-interference cancellation signal super-component by a first delay amount, delays the second IF self-interference cancellation signal super-component by a second delay amount, and combines the first and second IF self-interference cancellation signal super-components to generate an IF self-interference cancellation signal;
• wherein the second delay amount is greater than the first delay amount;
• 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.