SRS Transmission Collision Avoidance in RRC Inactive State

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Solution Overview

Problem

In wireless communication networks, especially in unconnected states like RRC Idle or DRX, collisions occur between Sounding Reference Signal (SRS) instances and other signals due to the use of different bandwidth parts, leading to transmission conflicts and inefficiencies.

Innovation Solution

Implementing a method to cancel scheduled SRS transmissions by determining time gaps and center frequency differences between SRS and downlink/uplink bandwidth parts, ensuring sufficient time gaps to avoid collisions, particularly in unconnected states where SRS uses a different bandwidth part than the initial UL BWP.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If SRS instances are transmitted using a different UL BWP than the initial UL BWP in unconnected state, then positioning accuracy is improved, but transmission collisions occur between SRS instances and other signals

Engineering Contradiction:

Improvepositioning accuracyVSAvoidtransmission reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The UE determines time gaps between SRS transmissions and other signals in advance, and proactively cancels SRS transmissions that would collide with other signals. This preliminary determination and cancellation prevents transmission conflicts before they occur, resolving the contradiction between positioning accuracy and transmission reliability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces time gap parameters (first threshold time gap, SRS switching time) and frequency parameters (center frequency differences) to control SRS transmission timing. By adjusting these parameters, the system balances positioning accuracy requirements with transmission reliability constraints

Inventive Principle:

Principle #35Parameter changes

2Productivity

If SRS transmissions are scheduled without considering time gaps, then transmission efficiency is high, but collisions with other signals occur

Engineering Contradiction:

Improvetransmission efficiencyVSAvoidsignal collision

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The UE performs preliminary checks to identify potential SRS transmissions that would collide with other signals, and cancels them in advance. This preliminary anti-action prevents harmful signal collisions while maintaining efficient transmission scheduling for non-colliding SRS instances

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The UE autonomously determines time gaps, identifies collisions, and cancels its own SRS transmissions without external intervention. This self-service mechanism efficiently prevents signal collisions while maintaining high transmission efficiency for valid SRS transmissions

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS20250008500A1Transmission of SRS for positioning configured outside an initial UL BWP in an unconnected state

Publication Date: 2025.01.02 QUALCOMM INC

AI summary

The reduction of a timing collision between the Sounding Reference Signal (SRS) instances when a user equipment (UE) is in a Radio Resource Control (RRC) inactive state and SRS is configured to use an uplink (UL) bandwidth part (BWP) different than a UL BWP of messages transmitted by the UE in the RRC inactive state. More particularly, embodiments may implement collision-reduction techniques and establish action times for canceling the transmission of one or more SRS instances.