Group Delay Calibration for Carrier Aggregation
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Solution Overview
Problem
In wireless communication systems, particularly in 5G networks operating at high frequencies like millimeter wave (mmW) bands, propagation loss and multipath propagation issues lead to delayed RF signals, which can affect precise timing measurements and data communication efficiency, especially when beamforming is used to enhance signal strength but introduces longer propagation delays.
Innovation Solution
A method involving network nodes and user equipment (UE) that transmit and receive measurement signals on different frequencies and/or via different radio access technologies (RATs) to determine group delays and round-trip times (RTT), allowing for accurate calibration of RF front-end group delays and improved timing measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If beamforming is used to enhance signal strength in high-frequency bands, then signal strength is improved, but propagation delay increases
Solution Approach 1:
The system performs preliminary group delay calibration by measuring and storing delay values for different beam directions before actual communication occurs. This allows the receiver to compensate for propagation delays in advance, resolving the contradiction between beamforming's signal enhancement and its associated time loss.
2Measurement precision
If measurement signals are transmitted on multiple frequencies and via multiple RATs to determine group delays, then timing measurement accuracy is improved, but system complexity increases
Solution Approach 1:
The calibration procedure uses universal measurement signals that can be transmitted across multiple frequencies and radio access technologies (RATs) through a single unified process. This multi-functional approach enables accurate timing measurements across diverse network configurations without requiring separate calibration procedures for each frequency band or RAT, thereby managing system complexity while improving measurement precision.
Data Source
AI summary
Disclosed are techniques for handling of radio frequency (RF) front-end group delays for roundtrip time (RTT) estimation. In an aspect, a network node transmits first and second RTT measurement (RTTM) signals to a user equipment (UE) and receives first and second RTT response (RTTR) signals from the UE. The network node measures the transmission times of the RTTM signals and the reception times of the RTTR signals, and the UE measures the transmission times the RTTM signals and the transmission times of the RTTR signals. The group delays of the transmit/receive chains of the network node and the UE are determined for one set of transmit/receive chains based on the first RTTM signal and first RTTR signal. The group delays of the transmit/receive chain used for the second RTTM signal and the second RTTR signal are determined relative to the group delay of the one set of transmit/receive chains.