Sounding Reference Signal Transmission with Channel Sensing
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Solution Overview
Problem
In wireless communication systems, particularly in the new radio (NR) communication system using higher frequency bands, there is a challenge in transmitting sounding reference signals (SRS) without colliding with physical uplink shared channels (PUSCH), especially when time-domain resources are limited, which affects channel estimation performance at the base station.
Innovation Solution
The method involves receiving a higher layer message and trigger signal from the base station to determine the position of the SRS resource, performing channel sensing, and transmitting the SRS based on the result, allowing the SRS to be mapped contiguously with PUSCH and PUCCH, thereby preventing collisions and optimizing channel estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the SRS is transmitted in the same time-domain resources as PUSCH, then the channel estimation performance is improved, but collision between SRS and PUSCH occurs
Solution Approach 1:
The patent segments the time-domain resources by dividing them into multiple time slots, with SRS and PUSCH assigned to different time slots within the same subband. This temporal segmentation prevents collision while maintaining channel estimation functionality.
Solution Approach 2:
The patent implements dynamic resource allocation where the time slot for SRS transmission is flexibly determined based on channel sensing results and LBT outcomes. This dynamic approach allows the system to adaptively select transmission opportunities that avoid PUSCH collisions.
2Productivity
If the number of UL symbols is limited for DL traffic support, then DL traffic efficiency is improved, but time-domain resources for SRS transmission are reduced
Solution Approach 1:
The patent transitions from frequency-domain resource allocation to time-domain resource allocation by utilizing different time slots within the same subband. This dimensional shift allows SRS transmission without consuming additional frequency resources that would conflict with limited UL symbols.
Solution Approach 2:
The patent performs channel sensing and LBT procedures in advance before SRS transmission. This preliminary action identifies available time slots that do not conflict with PUSCH, ensuring successful SRS transmission within the limited time-domain resources.
3Reliability
If channel sensing and LBT procedures are performed before SRS transmission, then collision with PUSCH is prevented, but transmission delay increases
Solution Approach 1:
The patent performs channel sensing on a subset of candidate time slots rather than all possible slots. This partial action approach finds a suitable transmission opportunity quickly, preventing collision while minimizing the time loss from sensing procedures.
Solution Approach 2:
The terminal autonomously determines the SRS transmission time slot based on channel sensing results and LBT outcomes without requiring additional base station coordination. This self-service mechanism reduces signaling overhead and accelerates the resource allocation process.
Data Source
AI summary
An operation method of a terminal for transmitting a sounding reference signal (SRS) to a base station in a wireless communication system may comprise receiving a higher layer message including information on a position of an SRS resource for transmission of the SRS from the base station; receiving a trigger signal from the base station, the trigger signal triggering the transmission of the SRS and including index information of the position of the SRS resource; performing a channel sensing operation on a radio resource indicated by the information on the positions of the SRS resource and the index information; and transmitting the SRS to the base station based on a result of the channel sensing.