Wireless Node Transmission Power Control via Channel Sensing
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Solution Overview
Problem
Existing listen-before-talk (LBT) procedures in wireless communication often result in inefficient channel capacity utilization due to inappropriate selection of transmission power levels, leading to unnecessary deferrals and collisions, as the maximum transmission power may not be optimized for instantaneous channel conditions.
Innovation Solution
A method for wireless communication nodes that involves performing channel sensing to determine interference levels, selecting a maximum transmission power level based on these levels, and choosing an appropriate coding rate and modulation for transmissions, allowing for more efficient power control and channel utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fixed maximum transmission power is used in LBT procedures, then the transmission power control is simple, but the channel capacity utilization becomes inefficient due to inappropriate power levels causing unnecessary deferrals and collisions
Solution Approach 1:
The patent implements dynamic transmission power control by adjusting the maximum transmission power based on instantaneous channel conditions detected through channel sensing. The system transitions from a static power level to a dynamic adaptation mechanism where the maximum transmission power varies according to the measured interference level, thereby optimizing channel capacity utilization while maintaining manageable complexity through standardized adjustment procedures
Solution Approach 2:
The patent changes the transmission power parameter dynamically by selecting from multiple predefined maximum transmission power levels based on channel conditions. The system measures the interference level and maps it to an appropriate power level, effectively changing the power parameter to match instantaneous channel state, thus resolving the contradiction between simple control and efficient utilization
2Speed
If the maximum transmission power is increased to improve data rate, then the data transmission speed increases, but the probability of causing collisions increases
Solution Approach 1:
The patent implements a feedback mechanism where the system performs channel sensing to measure the interference level, then uses this measured information to adjust the maximum transmission power accordingly. This closed-loop feedback allows the system to increase power when the channel is clear (improving speed) while reducing power when interference is detected (maintaining reliability), thus resolving the contradiction between data transmission speed and collision probability
Solution Approach 2:
The system dynamically adjusts the maximum transmission power based on real-time channel conditions rather than using a fixed power level. By making the power level adaptive to instantaneous interference measurements, the system can achieve high data rates when possible while automatically reducing collision probability when channel conditions deteriorate
3Reliability
If the maximum transmission power is decreased to reduce collision probability, then the collision probability decreases, but the data rate is reduced
Solution Approach 1:
The patent uses channel sensing feedback to determine the appropriate maximum transmission power level. When the measured interference level is low, the system selects a higher power level to maximize data rate while maintaining low collision probability. When interference is high, it selects a lower power level to preserve reliability. This feedback-driven adaptation resolves the contradiction by making power selection conditional on channel state rather than fixed
4Measurement precision
If a threshold value for channel sensing is set low to detect ongoing transmissions, then the collision detection accuracy improves, but the probability of unnecessary deferrals increases
Solution Approach 1:
The patent changes the sensing threshold parameter dynamically by selecting from multiple threshold levels based on the determined maximum transmission power. When a lower transmission power is selected, a higher sensing threshold is applied, reducing unnecessary deferrals. When higher transmission power is selected, a lower sensing threshold is applied to ensure accurate collision detection. This parameter adaptation resolves the contradiction between detection accuracy and deferral probability
Solution Approach 2:
The system implements dynamic threshold adjustment where the sensing threshold adapts to the selected maximum transmission power level and instantaneous channel conditions. Rather than using a fixed threshold, the system makes the threshold dynamic to match the transmission strategy, thereby optimizing the balance between accurate collision detection and minimizing unnecessary deferrals
Data Source
AI summary
A method is disclosed for a wireless communication node configured for operation in accordance with a listen-before-talk (LBT) procedure. The method comprises—for an upcoming transmission—performing channel sensing to determine an interference level experienced by the wireless communication node, determining a maximum transmission power level for the upcoming transmission responsive to the determined interference level, and selecting at least one of a coding rate and a modulation to be used for the upcoming transmission responsive to the determined maximum transmission power level. According to some embodiments, the method further comprises preparing a plurality of transmission packet variants before performing the channel sensing, wherein each transmission packet variant is associated with a respective transmission power level. Then, selecting at least one of the coding rate and the modulation may comprise selecting one transmission packet variant of the plurality of transmission packet variants responsive to the determined maximum transmission power level and the respective transmission power levels of the plurality of transmission packet variants. Corresponding arrangement, wireless communication node and computer program product are also disclosed.