5G Terminal Channel Occupancy Detection on Unlicensed Bands
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Solution Overview
Problem
In the 5G system, there is no downlink transmission that is always transmitted, making it difficult for terminals to detect channel occupation by base stations on unlicensed frequency bands, which affects power consumption and channel occupancy detection.
Innovation Solution
A terminal obtains configuration information to determine detection parameters for downlink transmission on unlicensed frequency bands, allowing it to dynamically detect downlink transmissions and channel occupancy, using mechanisms like LBT Cat.4 with variable contention window sizes and frame-based equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the base station transmits CRS on each subframe in traditional LTE, then the terminal can easily detect channel occupation, but in 5G there is no downlink transmission that is always transmitted, making channel occupation detection difficult
Solution Approach 1:
The base station performs preliminary actions by transmitting indication information (such as PDCCH or PDSCH) before actual downlink data transmission. The terminal detects these indication signals to determine whether the base station will occupy the channel, enabling proactive channel occupation detection without requiring continuous reference signal transmission.
Solution Approach 2:
The patent extracts the channel occupation indication function from continuous reference signal transmission and implements it through sporadic downlink indication information. Instead of using dedicated reference signals for channel detection, the system reuses existing downlink control or data signals to carry channel occupation indication, simplifying the detection mechanism.
2Measurement precision
If the terminal continuously monitors for downlink transmission to detect channel occupation, then detection accuracy improves, but power consumption increases
Solution Approach 1:
Instead of continuous monitoring, the terminal performs periodic detection by monitoring for downlink indication information (PDCCH/PDSCH) at specific intervals. The terminal wakes up to check for indication signals and remains in low-power state when no transmission is detected, achieving a balance between detection accuracy and power consumption through periodic rather than continuous operation.
Solution Approach 2:
The downlink indication information serves dual purposes: it both conveys scheduling information for actual data transmission and simultaneously indicates channel occupation status. This self-service mechanism eliminates the need for separate reference signals dedicated solely to channel detection, reducing overall signal overhead and terminal processing requirements.
3Adaptability or versatility
If the base station uses LBT mechanism to ensure coexistence on unlicensed bands, then fair channel access is achieved, but channel occupation detection becomes more complex
Solution Approach 1:
The downlink indication information (PDCCH/PDSCH) serves multiple functions simultaneously: it provides scheduling information for data transmission, indicates channel occupation status, and works within the LBT framework for fair unlicensed band access. This multi-functionality eliminates the need for separate detection mechanisms, simplifying the overall system while maintaining adaptability to LBT requirements.
Data Source
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AI summary
Embodiments of the present disclosure provide a detection method, device and apparatus for downlink transmission and a storage medium, which belong to the field of communications. In the method, a terminal obtains first configuration information, determines a detection parameter for downlink transmission according to the first configuration information, and detects the downlink transmission on an unlicensed frequency band according to the detection parameter. According to the embodiments, the terminal may dynamically detect the downlink transmissions according to the first configuration information, which solves the problem of that there is no downlink transmission that is always transmitted in the 5G system and thus the terminal cannot detect the channel occupation of the base station on the unlicensed frequency band, therefore the terminal can detect the occupancy of the base station on the unlicensed frequency band in time, and the power consumption of the terminal is saved.