Base Station Access Point Grouping for High Speed Mobility
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Solution Overview
Problem
In high-speed mobile environments, base stations face difficulties in obtaining channel information due to short coherence times, especially when access points move rapidly, leading to challenges in effective communication.
Innovation Solution
A communication method where a base station groups access points based on movement speed and line of sight (LOS) channel information to generate a transmission beamforming vector, reducing the need for channel information from high-speed access points and using linear beamforming to improve system capacity and reduce complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the base station requests channel information from high-speed access points, then the communication accuracy may be improved, but the coherence time is too short for the transmitting end to receive the channel information in time
Solution Approach 1:
The patent extracts and removes the requirement for channel information feedback from high-speed access points. By recognizing that the coherence time is too short for meaningful channel information acquisition, the system eliminates this requirement entirely for high-speed APs, focusing instead on location-based beamforming approaches that do not depend on channel state feedback.
Solution Approach 2:
The patent changes the parameter used for beamforming from channel state information to location information. Instead of relying on channel matrices that require feedback (which become obsolete due to short coherence time), the system uses geographic location and movement speed parameters to predict and optimize beamforming vectors, making the system adaptable to high-speed scenarios.
2Reliability
If the base station uses traditional beamforming methods requiring channel information, then the transmission quality may be improved, but the system complexity and overhead increase significantly in high-speed mobile environments
Solution Approach 1:
The patent removes the complex channel information feedback and processing mechanism from the system. By eliminating the requirement for channel state information (CSI) feedback from high-speed access points, the system reduces overhead and complexity while maintaining transmission quality through location-based beamforming prediction.
Solution Approach 2:
The patent uses location information as a proxy or copy substitute for channel state information. Instead of requiring actual channel measurements and feedback, the system creates a predictive model based on location and movement parameters that replicates the essential directional information needed for beamforming without the complexity of full channel characterization.
3Ease of operation
If the base station groups all access points together for beamforming, then the processing simplicity is improved, but the communication performance deteriorates due to different movement speeds affecting channel characteristics
Solution Approach 1:
The patent segments access points into different groups based on their movement speeds. High-speed access points are handled differently from low-speed or stationary access points, with each group receiving appropriate beamforming strategies. This segmentation allows the system to optimize performance for each group while maintaining overall system efficiency.
Solution Approach 2:
The patent applies different beamforming strategies to different groups of access points based on their specific characteristics. High-speed APs receive location-based predictive beamforming, while low-speed APs can utilize traditional channel information-based beamforming. This localized optimization ensures each group receives the most appropriate treatment for its movement characteristics.
Data Source
AI summary
Provided is an access point grouping method to be performed in a high speed mobile environment and a communication system using the access point grouping method. A system capacity may be improved by grouping users having different movement speeds with respect to various channel environments classified based on existence of an LOS channel, and by performing beamforming. Channel information with respect to a user moving at a high speed may not be required, and thus overhead may be reduced.