Multi-TRP Sidelink Feedback for Selective SDM Retransmissions

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Solution Overview

Problem

Existing wireless communication systems face challenges in efficiently handling sidelink transmissions with spatial division multiplexing (SDM) configurations, particularly in decoding failures and retransmissions, without effective feedback mechanisms for multiple transmit-receive points (TRPs).

Innovation Solution

Implementing feedback mechanisms for sidelink transmissions that indicate decoding failures and specify the affected layers, allowing for selective retransmissions based on the SDM configuration, enhancing communication efficiency in multi-TRP environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If spatial division multiplexing (SDM) configuration is used for sidelink transmissions, then communication capacity and spectral efficiency are improved, but decoding complexity and reliability deteriorate due to difficulty in identifying failed transmissions

Engineering Contradiction:

Improvecommunication capacityVSAvoiddecoding reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent segments the feedback information by associating each sidelink transmission with a specific demodulation reference signal (DMRS) port. This segmentation allows the receiving device to identify which specific transmission failed by detecting which DMRS port failed to decode, thereby resolving the reliability issue while maintaining SDM capacity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements a feedback mechanism where the receiving device sends HARQ-ACK information back to the transmitting device. This feedback includes explicit indication of which DMRS port (and thus which transmission) failed, enabling targeted retransmissions and improving overall decoding reliability in SDM configurations

Inventive Principle:

Principle #23Feedback

2Reliability

If feedback is transmitted for each sidelink transmission, then decoding reliability is improved, but feedback overhead and system complexity increase

Engineering Contradiction:

Improvedecoding reliabilityVSAvoidfeedback mechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple feedback responses into a single HARQ-ACK message. Instead of transmitting separate feedback for each sidelink transmission, the receiving device combines feedback for multiple transmissions (associated with different DMRS ports) into one consolidated feedback message, reducing overhead and simplifying the feedback mechanism

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a universal feedback mechanism that handles both successful and failed transmissions uniformly. The same HARQ-ACK message structure and transmission procedure is used regardless of which specific DMRS ports failed, simplifying the system while maintaining comprehensive feedback coverage

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12452007B2Sidelink feedback for multiple transmit-receive points

Publication Date: 2025.10.21 QUALCOMM INC

AI summary

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive a plurality of sidelink transmissions associated with a spatial division multiplexing (SDM) configuration. The UE may fail to decode at least one sidelink transmission of the plurality of sidelink transmissions. The UE may transmit feedback indicating the failure to decode the at least one sidelink transmission, wherein the feedback includes an indication of at least one layer of the SDM configuration associated with the at least one sidelink transmission. Numerous other aspects are described.