D2D Transmit Power Adaptation via Timing Measurements
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Solution Overview
Problem
Current device-to-device (D2D) communication technologies face challenges in adapting transmit power efficiently between wireless communication devices, leading to excessive interference with other devices and network nodes, as existing methods rely on path loss estimation which is difficult and slow to adapt, especially when devices are in different cells.
Innovation Solution
The method involves adapting the transmit configuration of one UE based on timing measurements, such as timing advance and propagation delay, to determine the optimal transmit power level for direct communication with another UE, without requiring knowledge of path loss, thereby constraining initial power levels to avoid interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If full power transmission is used in D2D communication, then communication reliability is improved, but interference to other devices and network nodes increases
Solution Approach 1:
The patent changes the transmit power parameter from fixed full power to dynamically adjusted power levels based on timing measurements. The source UE determines propagation delay and round trip time, then adapts transmit power accordingly to maintain reliable communication while reducing interference to other devices and network nodes.
Solution Approach 2:
The patent implements feedback mechanisms where the source UE measures timing parameters (propagation delay, round trip time) from signals received from the target UE and network node, then uses this feedback information to adjust transmit power levels. This closed-loop approach ensures reliable communication while minimizing harmful interference.
2Object-generated harmful factors
If iterative path loss measurement approaches are used to adapt transmit power, then interference is reduced, but adaptation speed is slow
Solution Approach 1:
The patent performs preliminary timing measurements using existing signaling messages (RACH, SRS, uplink data) before D2D communication begins. By obtaining propagation delay and round trip time measurements in advance through these preliminary actions, the system avoids slow iterative adaptation during actual D2D communication, quickly constraining transmit power to appropriate levels.
Solution Approach 2:
The patent uses timing measurements (propagation delay, round trip time) as intermediary parameters to infer path loss characteristics without directly measuring path loss. These timing measurements serve as mediators that provide rapid information about distance and signal conditions, enabling fast transmit power adaptation without the slowness of traditional iterative path loss measurement approaches.
3Adaptability or versatility
If path loss-based power control is used, then transmit power adaptation is achieved, but accuracy is poor when devices are in different cells
Solution Approach 1:
The patent uses timing measurements (propagation delay, round trip time) as intermediary parameters that are independent of cell boundaries and antenna configurations. These timing-based measurements provide accurate distance and signal condition information even when source and target UEs are in different cells, overcoming the limitations of path loss-based methods that rely on eNodeB-specific measurements.
Solution Approach 2:
The patent substitutes path loss-based power control (which relies on signal strength measurements affected by antenna gains and cell-specific factors) with timing measurement-based power control. By replacing the mechanical/electrical measurement approach with time-based measurements, the system achieves more accurate and consistent power adaptation across different cell boundaries and antenna configurations.
Data Source
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AI summary
A method by a first network node (eNB1) is disclosed for adapting transmit configuration of a first user equipment (UE1) for communications directly to a second UE (UE2). The method includes obtaining (1000) a first timing measurement between thefirst UE (UE1) and the first network node (eNB1). A second timing measurement between the second UE (UE2) and a second network node (eNB2) is obtained (1002). A transmit configuration of a wireless communication from the first UE (UE1) directly to the second UE (UE2) is adapted (1004) based on the first timing measurement and the second timing measurement. Related network nodes, methods by user equipment, and user equipments are disclosed.