Uplink SRS Frequency Shifting for PUCCH-Free Resource Scheduling

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Solution Overview

Problem

In LTE Rel-10 systems, the removal of Physical Uplink Control Channel (PUCCH) in non-backwards compatible Secondary Cells (non-backwards compatible SCells) leads to inefficient SRS scheduling due to the absence of PUCCH, resulting in suboptimal resource scheduling and loss of orthogonality among SRSs.

Innovation Solution

The method involves configuring, transmitting, and receiving SRSs with shifted frequency domain positions to create an extended SRS region, allowing SRS transmission on additional RBs not previously used for PUCCH, thereby increasing the UL carrier's efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If PUCCH is removed in non-backwards compatible SCells to improve resource efficiency, then more RBs are available for data transmission, but SRS scheduling becomes inefficient and orthogonality is lost

Engineering Contradiction:
Improveresource efficiencyVSAvoidSRS scheduling efficiency
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies parameter changes by shifting the frequency domain position of SRS from its predefined position to a new position that accounts for the removed PUCCH resources. This parameter modification allows SRS to be properly scheduled in the remaining RBs without PUCCH, resolving the scheduling inefficiency while maintaining resource efficiency gains.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces dynamic adjustment of SRS frequency domain position based on whether PUCCH is present or removed. The system dynamically adapts the SRS configuration to match the actual resource availability, enabling efficient SRS scheduling in both backwards compatible and non-backwards compatible SCells.

Inventive Principle:
Principle #15Dynamics

2Productivity

If SRS frequency domain position is shifted to create extended SRS region, then more RBs can be sounded for proper scheduling, but orthogonality among SRSs is lost

Engineering Contradiction:
Improvescheduling efficiencyVSAvoidorthogonality
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent modifies the frequency domain position parameter of SRS to create an extended SRS region that covers additional RBs. This parameter change enables sounding of previously unused RBs, improving scheduling efficiency while the system manages orthogonality through coordinated configuration.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If predefined SRS configuration is used in non-backwards compatible SCells, then implementation is simpler, but resource utilization is suboptimal due to PUCCH removal

Engineering Contradiction:
Improveimplementation simplicityVSAvoidresource utilization
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent changes the frequency domain position parameter of SRS from the predefined value to a shifted value that accommodates the removed PUCCH resources. This parameter modification enables proper resource utilization in non-backwards compatible SCells while maintaining a relatively simple implementation based on existing SRS mechanisms.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2764749B1Sounding reference signal transmission
Publication Date: 2025.12.10 HUAWEI TECH CO LTD
  • EP2764749B1 patent drawingFigure 1~2
  • EP2764749B1 patent drawingFigure 3
  • EP2764749B1 patent drawingFigure 4

AI summary

An improved method for transmission of Sounding Reference Signals (SRSs) on an uplink carrier of a telecommunication system is disclosed. In the system a set of SRSs is predefined, each predefined SRS being configured as having a bandwidth and a frequency domain position, and a predefined SRS region includes a set of all Resource Blocks (RBs) being usable for transmission of said predefined SRSs on said uplink carrier, said set of RBs being smaller than a total set of RBs being available on said uplink carrier. According to the invention, the following steps are performed: - creating at least one shifted SRS by shifting said predefined frequency domain position for at least one of said predefined SRSs, thereby creating an extended SRS region including at least one additional RB being separate from said predefined SRS region; and - transmitting said at least one shifted SRS on said uplink carrier.