Modulated Retroreflector Uplink for Full-Duplex Optical Links

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Solution Overview

Problem

Existing wireless communication systems face challenges in achieving full duplex optical communications efficiently, particularly in reducing manufacturing costs and power consumption by eliminating the need for active lasers at user equipment (UE) devices.

Innovation Solution

Implementing a modulated retro reflector (MRR) at the UE, which modulates and reflects incoming laser beams using a controllable absorber or phase shifter, enabling full duplex optical wireless communications (OWC) by employing compatible downlink and uplink modulation schemes without an active laser at the UE.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If an active laser is used at the UE for uplink transmission, then transmission capability is improved, but manufacturing cost and power consumption increase

Engineering Contradiction:

Improvetransmission capabilityVSAvoidpower consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent extracts the laser function from the UE and relocates it to the network entity. The UE now uses a passive retro-reflective element that reflects incoming laser beams from the network entity back to the network entity, eliminating the need for an active laser at the UE while maintaining uplink transmission capability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The retro-reflective element acts as an intermediary between the network entity's laser and the uplink transmission. It modulates the reflected beam based on uplink data without requiring active laser generation at the UE, thus reducing power consumption and manufacturing cost

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If an active laser is used at the UE for uplink transmission, then transmission capability is improved, but manufacturing cost increases

Engineering Contradiction:

Improvetransmission capabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the expensive active laser component at the UE with a much cheaper passive retro-reflective element. This substitution dramatically reduces manufacturing cost while maintaining the essential uplink transmission functionality through optical wireless communication

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Productivity

If full duplex optical communication is implemented, then communication efficiency is improved, but system complexity increases

Engineering Contradiction:

Improvecommunication efficiencyVSAvoidsystem complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent merges the downlink and uplink optical communication channels into a single full-duplex system. The network entity transmits downlink data using an active laser while simultaneously receiving uplink data through the UE's retro-reflective element, enabling bidirectional communication without requiring separate hardware systems

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The optical communication system achieves multi-functionality by using the same optical path for both downlink transmission (network entity to UE) and uplink transmission (UE to network entity). The retro-reflective element enables the UE to participate in full-duplex communication without requiring active laser generation, simplifying the overall system architecture

Inventive Principle:

Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables high throughput and low latency full duplex OWC, reducing manufacturing costs and power consumption at the UE while maintaining effective communication.

Implementation Method 1

modulated retro reflector (MRR)

Methodology Applied

Scientific EffectRetro reflection: Retroreflector

Implementation Method 2

controllable absorber

Methodology Applied

Scientific EffectAbsorption: Absorption (EM radiation)

Implementation Method 3

phase shifter

Methodology Applied

Scientific EffectPhase shifting: Phase Modulation

Data Source

PatentUS12562814B2Full duplex optical communications with modulated retro reflector

Publication Date: 2026.02.24 QUALCOMM INC

AI summary

Methods, systems, and devices for wireless communications are described. Techniques described herein provide for a user equipment (UE) with a Modulated Retro Reflector (MRR) to support full duplex Optical Wireless Communications. To achieve full duplex communication, the UE and a network entity may use compatible modulation schemes for downlink communications and uplink communications. The UE and network entity may negotiate and agree upon compatible the uplink and downlink modulation schemes. The UE may receive a downlink OWC transmission using the downlink modulation scheme and transmit an uplink OWC transmission via modulating the downlink transmission in accordance with the uplink modulation scheme.