Wireless Device Transmit Power Control for Tolling Interference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for coexistence between automatic tolling stations and intelligent traffic systems in Europe fail to adequately suppress interference, as the existing dynamic maximum power reduction (D-MPR) only modifies the lower limit of maximum configured transmit power, leaving the upper limit unchanged, leading to high interference levels.
Innovation Solution
A transmit power determining method that adjusts the maximum transmit power of a wireless communications device based on distance and frequency differences with another device, setting the transmit power to a preset threshold to suppress interference, using formulas to calculate the adjusted power considering various power losses and reductions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the upper limit of maximum configured transmit power is not modified, then the device can maintain higher transmit power for better communication performance, but interference to tolling stations increases and coexistence requirements are not met
Solution Approach 1:
The patent modifies the upper limit parameter of maximum configured transmit power by introducing a new parameter P_CMAX (absolute maximum transmit power) that is always less than or equal to the existing P_EMAX. This parameter change ensures that even when P_EMAX is high, the actual transmit power is capped at P_CMAX, which is calculated to meet ETSI coexistence requirements and prevent interference to tolling stations.
2Object-affected harmful factors
If the maximum transmit power is reduced to meet coexistence requirements, then interference to tolling stations is suppressed, but communication performance and coverage area deteriorate
Solution Approach 1:
The patent introduces dynamic power adjustment mechanisms where P_CMAX is not a fixed value but is determined based on multiple factors including frequency band, distance to tolling station, and environmental conditions. The device dynamically calculates and adjusts P_CMAX to achieve the minimum power level required to meet coexistence requirements while maintaining adequate communication performance.
3Ease of manufacture
If only the lower limit of maximum configured transmit power is modified, then implementation is simple, but coexistence requirements are not adequately met and interference remains high
Solution Approach 1:
The patent segments the power control mechanism into two distinct layers: P_EMAX (configured maximum power) and P_CMAX (absolute maximum power). This segmentation allows the system to maintain the existing P_EMAX configuration for backward compatibility while introducing P_CMAX as an additional constraint layer that specifically addresses coexistence requirements, making the implementation modular and manageable.
Data Source
Figure 1~3
Figure 4~5
AI summary
Embodiments of the present invention disclose a transmit power determining method. The method in the embodiments of the present invention includes: determining, by a first wireless communications device, a distance between the first wireless communications device and a second wireless communications device; determining, by the first wireless communications device, a working frequency of the second wireless communications device; and when the first wireless communications device determines that a first condition is met, if the first wireless communications device determines that a maximum transmit power corresponding to the first wireless communications device is greater than a preset threshold, adjusting the maximum transmit power, so that the adjusted maximum transmit power is equal to or less than the preset threshold, where the preset threshold is used to suppress, under the first condition, interference caused by the first wireless communications device to receiving performance of the second wireless communications device, where the first condition includes that the distance is less than or equal to a first threshold, and a difference between a working frequency of the first wireless communications device and the working frequency of the second wireless communications device is less than or equal to a second threshold.