Sidelink Beam Pathloss Compensation for Accurate Transmit Power Control
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Solution Overview
Problem
In wireless communications systems using high-frequency frequencies, beamforming complicates communications due to directional beams, leading to incorrect pathloss estimation when using cellular beams for sidelink transmissions, which results in improper interference management and power control.
Innovation Solution
A transmitting UE estimates pathloss using sidelink beams and compensates for antenna gain differences between sidelink and cellular beams, reducing the need for repeated measurements and improving power control accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If cellular beams are used for pathloss estimation in sidelink transmissions, then measurements can be reused from cellular communications, but pathloss estimation becomes incorrect due to directional beam differences
Solution Approach 1:
The patent applies local quality by introducing beam-specific pathloss estimation. Instead of using a general cellular beam pathloss for all sidelink transmissions, the system estimates pathloss specifically for each sidelink beam direction. This localized approach accounts for the directional characteristics of different beams, ensuring accurate pathloss estimation tailored to each specific beam's propagation conditions.
Solution Approach 2:
The patent inverts the conventional approach by not reusing cellular beam measurements for sidelink pathloss estimation. Instead of assuming cellular beam pathloss applies to sidelink beams, the system performs dedicated pathloss estimation for sidelink beams by measuring reference signals transmitted in sidelink beam directions. This inversion resolves the accuracy issue by treating sidelink beam pathloss as a distinct measurement requirement.
2Measurement precision
If sidelink beam pathloss estimation is performed separately from cellular beam measurements, then pathloss accuracy improves, but power control overhead and device complexity increase
Solution Approach 1:
The patent applies universality by designing a pathloss estimation mechanism that serves multiple purposes. The same reference signal measurements used for sidelink pathloss estimation also provide information for beam management and link quality assessment. This multi-functional approach allows the system to achieve accurate pathloss estimation without proportionally increasing measurement overhead, as the measurements serve multiple communication functions simultaneously.
Solution Approach 2:
The patent implements preliminary action by performing pathloss estimation for sidelink beams during initial beam establishment and configuration phases. By pre-establishing pathloss values for different sidelink beam directions before actual data transmission begins, the system avoids the need for continuous real-time measurements during active communication, thereby reducing ongoing power control complexity while maintaining accuracy.
3Reliability
If directional sidelink beams are used for D2D transmission, then communication reliability improves in high-frequency systems, but interference management becomes more difficult due to beam misalignment
Solution Approach 1:
The patent applies feedback by implementing a mechanism where receiving devices measure reference signals from transmitting devices using directional beams and report channel quality information back to the transmitting side. This feedback loop enables the system to monitor beam alignment status and link quality in real-time, allowing for dynamic adjustment of beam directions and power levels to maintain reliable communication while managing interference caused by beam misalignment.
Data Source
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AI summary
A method implemented by a first device includes estimating a first pathloss between the first device and a serving access node with respect to a sidelink beam between the first device and a second device, the sidelink beam being used by the first device to make a device-to-device (D2D) transmission to the second device, determining a sidelink transmit power for a sidelink transmission between the first device and the second device in accordance with the first pathloss, and transmitting, to the second device, the sidelink transmission in accordance with the sidelink transmit power.