Harmonic Interference Cancellation Using IQ LUT Multiplication

Solution Overview

Problem

Conventional methods for harmonic interference cancellation in wireless communication systems, such as complex polynomial modeling and polar-based LUTs, consume excessive power and increase the silicon footprint, leading to reduced battery life and inaccurate interference estimation due to sensitivity to model order selection and linearity of the RFPA.

Innovation Solution

The proposed solution employs an IQ LUT architecture that uses embedded AMAM and AMPM LUTs for estimating harmonic interference through complex multiplication, minimizing silicon resources and power consumption by correlating harmonic signal gain and phase nonlinearity with TX envelope, and truncating models for lower power levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If complex polynomial modeling or polar-based LUTs are used for harmonic interference cancellation, then interference estimation accuracy is improved, but power consumption and silicon footprint increase excessively

Engineering Contradiction:

Improveinterference estimation accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent segments the interference cancellation function into two separate LUTs: one for amplitude modeling (AMAM) and one for phase modeling (AMPM). This segmentation allows each LUT to be optimized independently for its specific function, reducing the overall memory requirements and computational complexity compared to a single comprehensive polynomial model or polar-based LUT system.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the modeling parameters from complex polynomial coefficients or polar coordinates to separate amplitude and phase parameters stored in LUTs. This parameter transformation enables more efficient memory access patterns and reduces the computational burden during real-time interference cancellation, thereby lowering power consumption while maintaining accuracy.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If complex polynomial modeling or polar-based LUTs are used for harmonic interference cancellation, then interference estimation accuracy is improved, but silicon footprint increases excessively

Engineering Contradiction:

Improveinterference estimation accuracyVSAvoidsilicon footprint

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent segments the interference cancellation function into two separate LUTs: one for amplitude modeling (AMAM) and one for phase modeling (AMPM). This segmentation allows each LUT to be optimized independently for its specific function, reducing the overall memory requirements and computational complexity compared to a single comprehensive polynomial model or polar-based LUT system.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses lookup tables that store pre-computed amplitude and phase values, effectively creating simplified copies of the complex interference model. Instead of computing complex polynomials or polar transformations in real-time, the system retrieves pre-calculated values from LUTs, dramatically reducing the silicon footprint required for the processing logic while maintaining estimation accuracy.

Inventive Principle:

Principle #26Copying

3Measurement precision

If multiple LUTs and interpolators are used for harmonic interference cancellation, then modeling accuracy is improved, but power consumption and device complexity increase

Engineering Contradiction:

Improvemodeling accuracyVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the interference cancellation function into two separate LUTs: one for amplitude modeling (AMAM) and one for phase modeling (AMPM). This segmentation allows each LUT to be optimized independently for its specific function, reducing the overall memory requirements and computational complexity compared to a single comprehensive polynomial model or polar-based LUT system.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the modeling parameters from complex polynomial coefficients or polar coordinates to separate amplitude and phase parameters stored in LUTs. This parameter transformation enables more efficient memory access patterns and reduces the computational burden during real-time interference cancellation, thereby lowering power consumption while maintaining accuracy.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12095490B2Apparatus and method of harmonic interference cancellation

Publication Date: 2024.09.17 GREATER SHINE LTD

AI summary

A baseband chip may include a transmitter configured to transmit a first signal. The baseband chip may also include a receiver configured to receive a second signal that includes a receive signal portion and a harmonic interference portion leaked from the transmitter. The baseband chip may further include a harmonic model block configured to multiply a first output from a first harmonic model associated with an amplitude modulation phase modulation (AMPM) look-up table (LUT) and a second output of a second harmonic model associated with an AMAM LUT to generate a third output. The harmonic model block may be further configured to estimate the harmonic interference portion based at least in part on the third output. The baseband chip may also include an interference cancellation block configured to cancel the harmonic interference portion from the second signal to obtain the receive signal portion.