SRS Delay Shift Reporting for Accurate UE Positioning
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Solution Overview
Problem
Existing 5G wireless communication systems face challenges in accurately determining the position of user equipment (UE) due to the lack of efficient methods for reporting and processing sounding reference signal (SRS) delay shifts, which affect signal decoding and positioning accuracy.
Innovation Solution
A user equipment (UE) sends multiple SRSs with controlled delay shifts to a network entity, reporting delay shift information based on subcarrier spacing, enabling the network to process these signals for improved positioning. The UE determines and reports the delay shift value, which is within the cyclic prefix duration, using signaling methods like MAC-CE or LPP/RRC, to facilitate accurate positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If SRS delay shift reporting is not implemented, then the system maintains simple signaling procedures, but positioning accuracy deteriorates due to inability to compensate for transmission delays
Solution Approach 1:
The patent introduces delay shift information as an intermediary parameter that mediates between the transmitted SRS signals and the positioning calculation. The network entity uses this intermediate information to compensate for transmission delays without requiring complex retransmission protocols or iterative positioning algorithms, thus improving positioning accuracy while maintaining signaling simplicity.
Solution Approach 2:
The delay shift information is reported in advance before the positioning calculation is performed. By preliminarily providing the delay characteristics of the SRS signals, the network entity can pre-compensate for transmission delays in the positioning computation, improving accuracy without adding complexity to the actual positioning procedure.
2Reliability
If multiple SRS signals are transmitted with delay shifts, then transmit diversity and positioning accuracy improve, but signal processing complexity increases
Solution Approach 1:
The network entity provides feedback in the form of delay shift information that enables the UE to adjust subsequent SRS transmissions. This feedback mechanism allows the system to iteratively improve signal decoding reliability by compensating for delay variations while maintaining a manageable processing complexity through standardized feedback procedures.
Solution Approach 2:
The patent changes the temporal parameter (delay shift) of the SRS signals to achieve transmit diversity. By systematically varying the delay parameter across multiple transmissions, the system improves signal reliability through diversity gains while keeping the processing complexity manageable through parameter-based control rather than structural complexity.
3Measurement precision
If delay shift information is reported frequently, then positioning accuracy is maintained in dynamic environments, but signaling overhead increases
Solution Approach 1:
The patent applies partial action by reporting delay shift information only when necessary - specifically when the delay shift exceeds a threshold or when positioning updates are required. This partial reporting approach maintains positioning accuracy in dynamic environments while avoiding the excessive signaling overhead that would result from continuous reporting, thus resolving the contradiction between accuracy and overhead.
Data Source
AI summary
A method of sending sounding reference signals includes: reporting delay shift information from a user equipment to a network entity, the delay shift information indicative of a second sounding reference signal having a delay shift relative to a first sounding reference signal; sending the first sounding reference signal from a first antenna of a plurality of antennas of the user equipment to the network entity; and sending the second sounding reference signal from a second antenna of the plurality of antennas of the user equipment to the network entity with the delay shift relative to the first sounding reference signal.