Sidelink Power Control Using Spatial Domain Reference Signals
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Solution Overview
Problem
The existing 5G V2X systems face challenges in accurately estimating sidelink transmission interference to the cellular network, leading to reduced sidelink performance due to overestimation of interference constraints, which affects transmit power and resource utilization.
Innovation Solution
A method is proposed where a node selects a downlink reference signal for sidelink power control based on spatial domain information, using a linear pathloss measurement to determine the appropriate transmit power, ensuring that the sidelink transmission interference is accurately estimated and managed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a node uses multiple downlink reference signals for pathloss estimation in sidelink power control, then the interference estimation accuracy should improve, but the complexity of selecting the appropriate reference signal increases
Solution Approach 1:
The patent applies local quality by associating each downlink reference signal with specific spatial domain information (beam directions). The node selects the reference signal whose spatial domain information matches the spatial domain filter used for sidelink transmission. This ensures that the pathloss estimation is performed using the reference signal that corresponds to the actual transmission direction, thereby improving interference estimation accuracy while maintaining manageable complexity through targeted association rather than exhaustive comparison.
2Device complexity
If a node uses a downlink reference signal that does not match the spatial domain information, then the device complexity is reduced, but the sidelink transmission interference is overestimated leading to performance reduction
Solution Approach 1:
The patent implements parameter changes by dynamically selecting different downlink reference signals based on the spatial domain information associated with the sidelink transmission. Instead of using a fixed or default reference signal, the node changes the selected reference signal parameter to match the current transmission's spatial domain filter. This ensures accurate pathloss estimation and prevents interference overestimation, thereby maintaining reliable sidelink transmission performance.
3Measurement precision
If the node uses beam-based power control in sidelink, then the transmit power accuracy is improved, but the difficulty of determining the appropriate reference signal increases
Solution Approach 1:
The patent applies preliminary action by pre-associating spatial domain information with each downlink reference signal before the actual sidelink transmission occurs. The network configures the node with multiple downlink reference signals, each linked to specific spatial domain information (beam directions). When sidelink transmission is needed, the node simply retrieves the pre-associated reference signal based on its spatial domain filter, avoiding the need for complex real-time analysis and reducing the difficulty of reference signal determination while maintaining beam-based power control accuracy.
Data Source
AI summary
A method and a device in a node used for wireless communications. A first node receives K first-type reference signals; and transmits a first signal. A transmit power for the first signal is a first power value, a first reference power value is used to determine the first power value, and the first reference power value is linear with a first pathloss. A measurement on a first reference signal is used to determine the first pathloss, the first reference signal being one of the K first-type reference signals; a first index is related to at least a transmission antenna port for the first signal, and is used for determining the first reference signal out of the K first-type reference signals. The method above ensures a more accurate estimation of the interference sidelink transmission has caused to the cellular networks, thus improving the sidelink transmission performance and resource utilization.