WLAN Packet Length Adaptation for High-Speed Vehicular Doppler Disturbance
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Solution Overview
Problem
WLAN communication in high-speed vehicles faces disturbances such as Doppler Spread due to the mismatch between channel characteristics developed for indoor environments and the high velocities encountered on highways, leading to packet errors and reduced performance.
Innovation Solution
A device equipped with directional antennas that adapt packet length based on estimated Doppler Spread severity, using geometric parameters and signal strength to optimize signal power and reduce interference, ensuring robust communication by adjusting packet length according to the severity of the disturbance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If WLAN communication uses standard packet lengths designed for indoor environments, then communication simplicity is maintained, but communication reliability deteriorates due to Doppler spread at high speeds
Solution Approach 1:
The patent implements dynamic packet length adjustment based on the estimated Doppler spread. The system continuously monitors channel conditions and adapts packet length accordingly - using shorter packets when Doppler spread is high (at high speeds) and standard packets when conditions are favorable. This dynamic adaptation resolves the contradiction by making the communication protocol flexible rather than static, improving reliability without requiring a completely new complex protocol suite.
Solution Approach 2:
The patent changes the packet length parameter based on estimated Doppler spread values. By adjusting this key communication parameter in response to channel conditions, the system optimizes communication reliability for high-speed scenarios while maintaining compatibility with standard WLAN protocols when conditions permit, thus resolving the reliability-complexity contradiction.
2Reliability
If packet length is shortened to combat Doppler spread effects, then communication reliability improves, but transmission efficiency deteriorates due to increased overhead
Solution Approach 1:
The system dynamically adjusts packet length based on real-time Doppler spread estimation rather than using a fixed short packet length. When Doppler spread is low, longer packets are used to maintain high transmission efficiency. When Doppler spread increases, packet length is reduced to improve reliability. This conditional approach resolves the contradiction by optimizing both reliability and efficiency based on actual channel conditions.
Solution Approach 2:
The patent implements conditional parameter change of packet length based on Doppler spread thresholds. By changing the packet length parameter adaptively rather than uniformly, the system maintains high transmission efficiency when channel conditions allow while ensuring reliability when Doppler spread becomes problematic, thus resolving the efficiency-reliability trade-off.
3Reliability
If directional antennas are used to focus signal power, then signal strength improves, but device complexity increases due to antenna array requirements
Solution Approach 1:
The patent applies directional antennas to focus signal power in specific directions where stations are located, particularly along highway corridors. By concentrating energy in the directions of interest rather than radiating uniformly in all directions, the system improves signal strength and reliability for vehicular applications. This localized quality enhancement resolves the contradiction by providing targeted signal reinforcement without requiring complex omnidirectional antenna arrays.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces packet error rates and improves WLAN communication performance by accurately determining disturbances and adapting packet lengths, maintaining communication quality even at high speeds.
Implementation Method 1
the device comprises at least one directional antenna. This provides the effect that the data transmitted is emitted and/or received with greater power in specific directions
Implementation Method 2
The term 'Doppler spread' as used in the present invention may be defined as a quantity or a measure of the spectral broadening of any frequency transmitted based on the time rate of a change of a mobile radio channel
Data Source
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AI summary
The present invention relates to a device (100) for Wireless-Local-Area-Network (WLAN), -communication to a station, in particular to a vehicle, wherein the device is configured to, determine a disturbance of the WLAN-communication, in particular a Doppler spread; and define a packet-length of the WLAN-communication based on the disturbance.