V2X Power Control for Unicast and Groupcast Reliability
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Solution Overview
Problem
In V2X communication systems, determining optimal transmitting power values for groupcast and unicast communications is challenging, especially when resources are limited, as existing methods fail to prioritize unicast transmission effectively, leading to potential deficiencies in implementation.
Innovation Solution
A method where separate power control mechanisms are employed for groupcast and unicast transmissions based on their respective pathlosses, ensuring that unicast transmissions are prioritized by guaranteeing their power values, even when resources are limited, and adjusting power allocation dynamically based on time window overlaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate power control mechanisms are employed for groupcast and unicast to match respective pathlosses, then the reliability of individual transmission modes is improved, but the device complexity increases and power management becomes more difficult when power is limited
Solution Approach 1:
The patent implements dynamic power control by adjusting the power of second control information based on whether the first and second time windows overlap. When overlap occurs, the power of second control information is scaled down proportionally to ensure unicast power requirements are met, while maintaining separate power control mechanisms for different transmission modes.
Solution Approach 2:
The patent changes the power parameter of control information dynamically based on time window overlap conditions. Specifically, when the first time window (unicast) and second time window (groupcast) overlap, the power of the second control information is adjusted according to the ratio of non-overlapping resources, transforming a static power control problem into a dynamic one that adapts to resource availability.
2Reliability
If power is allocated to guarantee unicast transmission performance, then unicast reliability is improved, but the power available for groupcast transmission is reduced
Solution Approach 1:
The patent applies partial action by allocating power to groupcast control information only for the non-overlapping portion of time resources. When unicast and groupcast time windows overlap, the groupcast power is scaled down to the ratio of non-overlapping resources, ensuring unicast gets full power while groupcast receives proportional power for its exclusive resources.
Solution Approach 2:
The patent segments the time resources into overlapping and non-overlapping portions between unicast and groupcast transmissions. By dividing the power allocation accordingly - full power for unicast during overlap and proportional power for groupcast during non-overlap - it resolves the power conflict between the two transmission modes.
3Loss of energy
If the power value on the V2X link is limited, then the loss of energy is reduced, but the transmission reliability deteriorates when the expected power value exceeds available power
Solution Approach 1:
The patent dynamically adjusts transmission power based on the ratio of non-overlapping time resources. When power is limited, the system calculates the available power ratio and scales down the expected power values proportionally, maintaining reliable transmission within the available power budget by adapting power allocation to actual resource availability.
Data Source
AI summary
The present disclosure discloses a method and a device in nodes used for wireless communications. A first node first receives a first radio signal and a second radio signal; and then determines that transmitting power of first control information in a first time window is a first power value and transmitting power of second control information in a second time window is a second power value; and transmits the first control information in the first time window with the first power value; the first power value is unrelated to the second power value, and the second power value is relevant to whether the first time window overlaps with the second time window. The present disclosure designs power allocation priorities of first control information and second control information to optimize both transmission performance and efficiency of a feedback channel in sidelink.