Radio Channel Emulation Using Lookup Tables and Matrix Reduction
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Solution Overview
Problem
Existing methods for emulating radio channels between moving transmitters and receivers require significant computing time and may introduce artifacts due to phase jumps and attenuation variations, limiting precision and accuracy in simulating dynamic propagation paths.
Innovation Solution
A method that calculates the relative position and movement of antennas over time, determines attenuation and Doppler frequencies for each propagation path, and uses Kronecker products and lookup tables to create a transmission matrix, which is then processed in a programmable circuit to generate a time-varying impulse response, avoiding phase jumps by maintaining initial phase shifts across time segments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing emulation methods are used to simulate radio channels between moving transmitters and receivers, then the radio channel behavior can be emulated, but significant computing time is required and artifacts appear due to phase jumps and attenuation variations
Solution Approach 1:
The emulation method divides the continuous radio channel simulation into discrete propagation paths, each with separate parameter tables for delay and Doppler frequency. This segmentation allows independent processing of each path's characteristics, reducing overall computational complexity while maintaining precision.
Solution Approach 2:
The patent pre-calculates and stores delay and Doppler frequency values in separate lookup tables for each propagation path. During emulation, these pre-computed values are directly retrieved rather than calculated in real-time, significantly reducing computing time while preserving accuracy.
2Reliability
If existing emulation methods are used, then radio channel simulation can be performed, but artifacts appear due to phase jumps and attenuation variations
Solution Approach 1:
Initial phase shifts for each propagation path are calculated and stored in advance. During time interval transitions, these pre-calculated phase values are applied to prevent abrupt phase changes, thereby eliminating phase jump artifacts and improving simulation reliability.
Solution Approach 2:
The emulation method continuously monitors and maintains phase continuity across time intervals by using feedback from previous interval states. This ensures smooth transitions and prevents artifacts while maintaining high simulation accuracy.
3Measurement precision
If high precision emulation is achieved by detailed calculation of all propagation paths, then accuracy improves, but computing time increases significantly
Solution Approach 1:
The emulation system segments the complex radio channel into multiple independent propagation paths, each processed separately with dedicated parameter tables. This allows parallel processing and optimizes the balance between precision and computational efficiency.
Solution Approach 2:
The patent transforms continuous physical parameters (delay, Doppler frequency, phase) into discrete tabulated values for each propagation path. This parameter discretization enables efficient lookup-based processing while maintaining high accuracy in representing the physical phenomena.
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
This approach reduces computing time and enhances precision in emulating radio channels, accurately modeling dynamic propagation paths and avoiding artifacts, thereby improving the realism of radio channel simulations.
Implementation Method 1
for each propagation path, a damping factor, a delay, and a Doppler frequency are determined separately
Implementation Method 2
the time-varying impulse responses of the respective time interval are determined by multiplying the transfer matrix with the base matrix
Data Source
Figure 1~3
Figure 2
AI summary
The invention relates to the emulation of a radio channel between moving transmitters and receivers with antennas. The relative position and relative movement and also the environment are used to ascertain propagation paths (P0, P1,..., PP-1) running between the antennas, for which propagation paths a damping factor (ηp), a delay (θp) and a Doppler frequency (νp) are separately ascertained. For each propagation path (P0, P1,..., PP-1), table lookup for the delay and the Doppler frequency is used to produce a respective path matrix (Ψp) that is weighted with the respective damping (ηp) of the propagation path (P0, P1,..., PP-1), and all the path matrices are summed. The summed matrix (Ψ) produced in this way is taken as a starting point for using a linear transformation to ascertain a transfer matrix (Y), the transformation reducing the dimension of the transfer matrix (Y) in comparison with the summed matrix (Ψ), which corresponds to the coefficient vector (ε'p) of the delay. The transfer matrix (Y) is transferred to a programmable circuit (20). In the programmable circuit (20), a number of discrete base functions characterising the time variance of an impulse response is prescribed, as base matrix (U). The signal of the transmitter is convoluted with the time-variant impulse response (h) by the digital circuit and in this way a discrete output signal (y) is produced.