NR Uplink Carrier Selection Using Measurement Signals for Coverage
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Solution Overview
Problem
In 5G new radio (NR) communication systems, uplink transmit power is limited, leading to insufficient received signal strength and spectrum, making it difficult to ensure coverage performance, especially when using high frequency bands like 4.9 GHz, where current supplementary uplink access rules are not applicable.
Innovation Solution
A method and apparatus for determining an active carrier by sending a first uplink signal and receiving feedback information, which includes signal strength and timing advance values, to improve communication reliability and efficiency, particularly for high frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If uplink transmit power is limited in 5G NR system, then device power consumption is controlled, but received signal strength becomes insufficient leading to poor coverage performance
Solution Approach 1:
The patent introduces a low frequency carrier as an intermediary medium to improve uplink coverage. The terminal device performs uplink transmission on the low frequency carrier which has better propagation characteristics, thereby indirectly improving the received signal strength at the base station without increasing transmit power.
Solution Approach 2:
The patent changes the frequency parameter of the uplink transmission carrier from high frequency to low frequency. By selecting a low frequency carrier with frequency less than a threshold frequency, the system exploits the better propagation characteristics of low frequency signals to improve coverage performance while maintaining limited transmit power.
2Reliability
If supplementary uplink uses low frequency band for better coverage, then uplink coverage is improved, but spectrum resources become insufficient
Solution Approach 1:
The patent segments the uplink transmission into two parts: coverage-sensitive transmissions (such as random access preamble, scheduling request) are performed on the low frequency carrier for reliable delivery, while data transmissions are performed on the high frequency carrier for efficient spectrum utilization. This segmentation allows each carrier to be optimized for its specific function.
Solution Approach 2:
The low frequency carrier serves multiple functions: it provides both coverage extension and serves as a control channel for uplink grant reception. The high frequency carrier simultaneously provides data transmission and can also carry uplink grants. This multi-functionality allows the system to achieve both good coverage and sufficient spectrum resources.
3Ease of operation
If current SUL access rule is applied to high frequency band, then access mechanism remains simple, but signal strength cannot consistently meet acceptable threshold
Solution Approach 1:
The patent introduces dynamic carrier selection based on measured signal quality. The terminal device measures the signal quality of the high frequency carrier, and when it determines that the signal quality is below a threshold, it dynamically switches to use the low frequency carrier for uplink transmission. This dynamic adaptation ensures consistent signal strength while maintaining relatively simple access procedures.
Solution Approach 2:
The patent implements a feedback mechanism where the terminal device measures the signal quality of the high frequency carrier and provides this information to determine whether to switch carriers. The base station also provides feedback through downlink messages indicating whether the terminal should use the low frequency carrier, creating a closed-loop system that maintains reliable signal strength.
4Reliability
If multiple uplink carriers are configured in one cell for SUL, then uplink coverage is expanded, but device complexity increases
Solution Approach 1:
The patent extracts the coverage-critical functions (random access, scheduling request, uplink grant reception) and assigns them specifically to the low frequency carrier. This extraction simplifies carrier management by clearly defining which carrier handles which function, reducing the complexity of managing multiple carriers while maintaining expanded coverage capability.
Data Source
AI summary
Embodiments of this application disclose a communication method and apparatus. The method includes that a terminal device sends a first uplink signal to a first network device on at least one first carrier. The method further includes that the first network device detects the first uplink signal on the at least one first carrier, determines an active carrier based on determined signal strength of the first uplink signal on the at least one first carrier, and sends first feedback information to the terminal device. The first feedback information includes information about the active carrier in the at least one first carrier. A corresponding apparatus is further provided. In this way, the signal strength of the first uplink signal sent by the terminal device on the at least one first carrier is determined, to accurately determine the information about the active carrier in the at least one first carrier.