On-Demand Tracking Reference Signal for 5G NR Synchronization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing LTE wireless communication standard's cell-specific reference signals (CRS) are inefficient for the next-generation 5G New Radio (NR) system due to their periodic and load-agnostic transmission over wideband, which leads to inefficiencies in bandwidth usage and increased overhead, limiting flexibility and adaptability.
Innovation Solution
The introduction of a Tracking Reference Signal (TRS) that is transmitted on-demand by the gNB in response to a UE's request, allowing for flexible bandwidth usage and reduced overhead, tailored for specific functions rather than being periodic and wideband like CRS, enabling improved synchronization and channel estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cell-specific reference signals (CRS) are transmitted periodically over wideband, then synchronization and channel estimation can be maintained, but bandwidth usage efficiency decreases and overhead increases
Solution Approach 1:
The patent extracts the essential tracking function from the comprehensive CRS signal. Instead of transmitting full CRS periodically, the system transmits only the necessary tracking reference signals (TRS) with reduced density and bandwidth, containing just enough information for synchronization and channel estimation while removing redundant components.
Solution Approach 2:
The patent transforms the continuous periodic CRS transmission into on-demand TRS transmission triggered by specific events (e.g., random access channel detection, scheduling decisions). This converts a fixed periodic action into a conditional periodic action, reducing overall transmission frequency while maintaining necessary tracking capability.
2Reliability
If cell-specific reference signals (CRS) are transmitted periodically over wideband, then synchronization and channel estimation can be maintained, but system overhead increases
Solution Approach 1:
The patent extracts only the essential tracking functionality from the CRS signal structure. The TRS contains minimal necessary elements for time and frequency tracking, eliminating overhead associated with full CRS transmission including pilot symbols, reference signals for demodulation, and associated control information.
Solution Approach 2:
The patent introduces dynamic TRS transmission where the presence, bandwidth, and timing of reference signals adapt based on current system conditions, traffic load, and UE requirements. This dynamic approach reduces overhead during low-activity periods while maintaining reliability when needed.
3Loss of energy
If tracking reference signals are transmitted on-demand based on UE requests, then bandwidth usage efficiency improves and overhead reduces, but system complexity increases
Solution Approach 1:
The patent implements self-service mechanisms where UEs autonomously determine when TRS transmission is needed based on their synchronization status and channel conditions. The network side uses simple trigger conditions (e.g., detection of random access preamble, scheduling decisions) rather than complex centralized control, reducing overall system complexity.
Solution Approach 2:
The patent employs feedback mechanisms where UEs report their tracking status and channel conditions, enabling the network to make informed decisions about TRS transmission. This feedback loop simplifies the on-demand triggering logic by providing explicit information about when reference signals are actually needed.
Data Source
AI summary
Embodiments include apparatuses, methods, and systems that may be used in a UE in a mobile communication network to communicate with a gNB. An apparatus may include a memory and processing circuitry coupled with the memory. The processing in circuitry may cause coarse time and frequency synchronization information, obtained from primary and secondary synchronization signals (PSS/SSS), to be stored in the memory. Based on the coarse time and frequency synchronization information, the processing circuitry may decode a physical broadcast channel to obtain a first system information, and may acquire a second system information based on the first system information. Based on the first and second system information, the processing circuitry may cause a transmission of a PRACH, to trigger a transmission of a TRS by the gNB. Other embodiments may also be described and claimed.