Tracking Reference Signal for Wireless Time Frequency Synchronization
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Solution Overview
Problem
Proposed standards for modifying downlink carriers in wireless networks reduce bandwidth consumption but lack sufficient signals for user equipment (UE) to achieve time and/or frequency lock, as existing reference signals like CSI-RS are not designed for effective timing and frequency tracking.
Innovation Solution
Incorporating a tracking reference signal (TRS) in downlink subframes with a frequency density of at least one resource element per six, transmitted periodically among other subframes, to enable UE to maintain timing and frequency synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If downlink carriers are modified to reduce bandwidth consumption, then bandwidth efficiency is improved, but the availability of reference signals for time and frequency tracking deteriorates
Solution Approach 1:
The patent segments the downlink carrier structure by introducing a dedicated tracking reference signal (TRS) component that is separately configured from other reference signals like CRS and CSI-RS. This segmentation allows the TRS to be optimized specifically for time and frequency tracking purposes while other signals can be reduced or removed to save bandwidth, thereby resolving the contradiction between bandwidth efficiency and tracking capability
Solution Approach 2:
The patent applies local quality by configuring TRS with specific properties tailored for tracking functionality - including particular frequency densities (e.g., one resource element per six resource elements), specific periodicities, and dedicated time-frequency positions. This localized optimization ensures that the tracking function receives dedicated signal quality while overall bandwidth consumption is reduced through selective reference signal configuration
2Quantity of substance
If existing reference signals like CSI-RS are used for tracking, then signal availability is maintained, but tracking effectiveness deteriorates
Solution Approach 1:
The patent introduces TRS as an intermediary signal specifically designed to bridge the gap between available reference signals and effective time-frequency tracking. The TRS acts as a dedicated mediator that provides the precise tracking functionality that existing signals like CSI-RS cannot deliver, while maintaining compatibility with the overall reference signal structure
Solution Approach 2:
The patent changes key parameters of the reference signal by configuring TRS with specific frequency densities (at least one resource element per six resource elements), periodicities among subframes, and time-frequency positions that are optimized for tracking precision. These parameter changes distinguish TRS from existing signals and enable superior tracking effectiveness
Data Source
AI summary
A method and an apparatus in a base station are capable of including a tracking reference signal (TRS) in a downlink subframe. The method includes generating a TRS subframe by including the TRS in the downlink subframe at a frequency density of at least one resource element per six resource elements in the TRS subframe. Additionally, the method includes transmitting the TRS subframe at a periodicity among other subframes not including the TRS.