Reference Signal Beamforming Under eCCA in 60 GHz Unlicensed Bands
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently managing channel access and beam training in unlicensed frequency bands above 52.6 GHz, particularly due to regulatory requirements and interference, which complicate the transmission of reference signals like DRS, CSI-RS, and SRS.
Innovation Solution
Implementing an extended clear channel assessment (eCCA) mechanism that allows for short control signaling and reference signal transmissions without listen before talk (LBT) under certain conditions, ensuring compliance with regulatory thresholds and reducing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional listen before talk (LBT) mechanism is used for channel access in unlicensed bands, then regulatory compliance is achieved, but channel access efficiency deteriorates and beam training is blocked
Solution Approach 1:
The patent segments the channel access mechanism by separating beamforming reference signal transmissions from data transmissions. The eCCA mechanism allows DRS, CSI-RS, and SRS to be transmitted without full LBT, while data transmissions still require LBT. This segmentation enables efficient beam training while maintaining regulatory compliance for data communication.
Solution Approach 2:
The patent extracts the beamforming reference signal transmission requirement from the traditional LBT framework. By identifying that beam training is critical for mmWave operation and can be performed independently of data transmission, the patent extracts this function to allow transmission without full LBT procedure, thus resolving the efficiency constraint.
2Manufacturing precision
If beam training is performed using DRS, CSI-RS, and SRS signals, then beamforming accuracy is improved, but transmission interference increases in unlicensed bands
Solution Approach 1:
The patent applies preliminary action by transmitting beamforming reference signals (DRS, CSI-RS, SRS) before data transmission. This allows the gNB to perform beam training and determine optimal beam directions in advance, enabling subsequent data transmissions to use these pre-configured beams with reduced interference, as the critical beamforming parameters are established beforehand.
3Productivity
If regular transmission of reference signals is allowed without LBT, then channel access efficiency is enhanced, but regulatory compliance may be compromised
Solution Approach 1:
The patent applies local quality by differentiating the channel access requirements for different signal types. Beamforming reference signals (DRS, CSI-RS, SRS) are allowed to transmit without full LBT to ensure efficient beam training, while data transmissions maintain traditional LBT requirements. This localized differentiation of access rules enables both regulatory compliance and operational efficiency.
Data Source
AI summary
Techniques of beamforming in reference signal (RS) transmissions, applicable to frequency ranges including frequencies between 52.6 GHz and 71 GHz, are described. Such techniques may include determining a communication channel is unoccupied for an initial duration, determining a number of communication slots of the communication channel to defer for transmission, and counting one or more communication slots of the communication channel that are not in use. The techniques may include determining the number of counted one or more communication slots is not equal to the determined number of communication slots of the communication channel to defer, and transmitting one or more data units based on the determination that the number of the counted one or more communication slots is not equal to the determined number of communication slots of the communication channel to defer.