High Dimensional Radio Environment Characterization via Angle Domain Processing
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Solution Overview
Problem
Current methods for obtaining radio environment maps in cellular networks are costly and provide one-dimensional representations that fail to capture the uniqueness of radio characteristics at specific locations, limiting the effectiveness of base station performance in managing user handover, radio resource management, and channel estimation.
Innovation Solution
A device comprising processors that calculate complex channel values in the angle domain for received signals from multiple antenna elements, applying frequency and time-offset estimations to transform these values into high-dimensional radio environment representations, including power angle delay profiles, spatial-time, and spatial-frequency correlations, which are stored for geographical locations to improve base station performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If drive tests are used to obtain radio environment maps, then radio environment data can be collected, but the cost becomes high
Solution Approach 1:
The patent uses signal processing to create virtual radio environment maps by processing existing cellular signals from user equipment. Instead of physical drive tests, the system copies and analyzes channel state information from multiple antennas to reconstruct radio environment characteristics, significantly reducing cost while maintaining measurement quality.
Solution Approach 2:
The system utilizes signals already present in the network (uplink signals from user equipment) to automatically generate radio environment maps. The base station processes these self-generated signals through angle domain transformation and correlation analysis, eliminating the need for external drive test equipment and personnel.
2Loss of information
If one-dimensional scalar representations are used for radio environment maps, then data storage is simple, but the uniqueness of radio characteristics at particular locations cannot be captured
Solution Approach 1:
The patent transforms the radio environment representation from one-dimensional scalars to two-dimensional power angle delay profiles by introducing the angle domain dimension. This is achieved through discrete Fourier transformation of channel state information from multiple antennas, creating a dimensional expansion that captures spatial characteristics while maintaining manageable data structure.
Solution Approach 2:
The system changes the representation parameters from simple power values to complex channel values in the angle domain, then to power angle delay profiles with multiple dimensions (power, angle, delay). This parameter transformation enables unique identification of locations based on their specific radio characteristic patterns without excessive complexity.
3Measurement precision
If complex channel values in angle domain are calculated with frequency and time-offset estimations, then detection accuracy improves above 90%, but processing complexity increases
Solution Approach 1:
The patent performs frequency offset estimation and time offset estimation as preliminary steps before calculating the final power angle delay profiles. By correcting these offsets in advance, the system ensures high detection accuracy in the subsequent correlation analysis without adding complexity to the core location identification algorithm.
Solution Approach 2:
The system uses correlation analysis of power angle delay profiles at different locations to provide feedback for detecting unique radio characteristics. This feedback mechanism enables the base station to iteratively refine location identification accuracy, achieving above 90% detection accuracy through adaptive processing.
Data Source
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AI summary
A device comprises a memory that stores instructions executed by one or more processors to obtain a plurality of received signals transmitted by a user equipment from a plurality of antenna elements in a cellular network. A plurality of complex channel values are calculated in an angle domain for a horizontal arrival angle and a vertical arrival angle per a received ray in a plurality of received rays in response to the plurality of received signals. A frequency-offset estimation is calculated and applied to the plurality of complex channel values. The plurality of offset complex channel values are transformed to a plurality of channel values in a time domain. A time-offset estimation is calculated and applied to the plurality of channel values. An expected value of the plurality of channel values is obtained to obtain a power angle delay profile for the geographical location of the user equipment.