Sub-THz IQ Impairment Compensation via Base Station Pre-compensation

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Solution Overview

Problem

Current wireless communication systems, particularly in sub-terahertz (sub-THz) communications, face significant power consumption issues due to the need for digital IQ imbalance compensation, which is exacerbated by high bandwidths, making it impractical for battery-operated devices like mobile phones.

Innovation Solution

The proposed solution involves the base station pre-compensating downlink transmissions to reduce or eliminate the need for digital filtering in user equipment (UE) by estimating and reporting IQ imbalances, allowing the UE to reduce its own filtering operations, thereby minimizing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If digital IQ imbalance compensation filtering is performed in the UE receiver, then IQ imbalance is corrected, but power consumption increases proportionally with bandwidth

Engineering Contradiction:

ImproveIQ imbalance compensationVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The base station performs IQ imbalance pre-compensation on downlink signals before transmission. The UE estimates its own IQ impairment characteristics and reports them to the base station, which then applies the corresponding pre-compensation filtering to the downlink signal, eliminating the need for power-consuming digital filtering in the UE receiver

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The IQ imbalance compensation function is extracted from the UE receiver and relocated to the base station transmitter. This transfers the computational burden and power consumption from the battery-operated UE to the grid-powered base station infrastructure

Inventive Principle:

Principle #2Taking out (Extraction)

2Speed

If high bandwidth operation is implemented in sub-THz communication, then data transfer speed increases, but power consumption increases making it impractical for battery-operated devices

Engineering Contradiction:

Improvedata transfer speedVSAvoidpower consumption

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The base station applies pre-compensation filtering to downlink signals before transmission at high bandwidths. This preliminary action at the base station eliminates the need for subsequent power-consuming filtering operations in the UE, enabling high bandwidth operation without proportionally increasing UE power consumption

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system changes the operating parameters by moving from conventional filtering at the UE to pre-compensation at the base station. This parameter change in the system architecture allows high bandwidth operation (10 GHz or more) while keeping UE power consumption manageable through more efficient analog or reduced-digital filtering

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11539571B2In-phase and quadrature-phase impairments compensation in sub-terahertz communication

Publication Date: 2022.12.27 QUALCOMM INC

AI summary

IQ impairments compensation in sub-terahertz (sub-THz) communication is disclosed. According to some aspects, a user equipment (UE) determines an estimated in-phase (I) and quadrature phase (Q) impairment of the UE, the IQ impairment of the UE comprising a mismatch of phase and/or amplitude, between an I path and a Q path within an analog receiver circuitry of the UE, and reports the estimated IQ impairment of the UE to a base station (BS). The BS determines a pre-compensation to compensate for the estimated IQ impairment of the UE and uses the determined pre-compensation when transmitting to the UE.