Distributed RF Channel Emulator Reducing Path Losses
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Solution Overview
Problem
Current RF channel emulators face limitations in scalability due to physical constraints, such as the need for a larger antenna array and increased amplifier and channel emulator resources, which lead to significant RF path losses and high costs, especially as the number of antennas and test frequency increase, resulting in degraded signal-to-noise ratios and system performance issues.
Innovation Solution
A distributed channel emulation system is implemented, where the functions of a spatial channel emulator are split between a central location and a remote location within the test chamber, using low-loss intermediate frequency or baseband signals to reduce cable losses, and moving power amplification and receive amplification closer to the antennas to improve signal strength and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of antennas and test frequency are increased to improve testing capability, then the testing versatility and precision are improved, but the RF path losses increase and system cost increases
Solution Approach 1:
The system segments the channel emulation functionality into distributed nodes, each handling specific antenna channels. This allows independent optimization of each node's RF path length and amplifier placement, reducing overall RF path losses while maintaining high-frequency testing capability across multiple antennas
Solution Approach 2:
The patent transitions from a centralized channel emulator to a distributed architecture where emulation functions are distributed across multiple spatial locations. This dimensional change allows shorter RF cable runs from each antenna to its dedicated amplifier and emulator node, reducing RF path losses while maintaining the ability to test multiple antennas simultaneously
2Power
If a larger antenna array and more amplifiers are used to improve signal strength, then the signal coverage is improved, but the system size and cost increase
Solution Approach 1:
The system applies local quality by placing low-noise amplifiers and channel emulator nodes in close proximity to each antenna element. This local placement ensures that each antenna channel receives optimized signal amplification without requiring excessive system-wide power, reducing the need for high-power amplifiers while maintaining adequate signal strength
Solution Approach 2:
The patent replaces the need for mechanically large high-power amplifier systems with distributed low-power amplifier nodes. By distributing the amplification function across multiple low-power units rather than using fewer high-power units, the overall system footprint is reduced while maintaining adequate signal strength for testing
3Reliability
If high-power amplifiers are used to overcome RF path losses, then the signal-to-noise ratio is improved, but the system cost and power consumption increase
Solution Approach 1:
The system performs preliminary amplification of RF signals at the antenna nodes before signals traverse long cable runs to the central emulator. This preliminary action at the source maintains signal strength throughout the transmission path, achieving adequate signal-to-noise ratio without requiring high-power amplifiers at the central location
Solution Approach 2:
The patent introduces intermediate frequency (IF) or baseband signal distribution as an intermediary approach. Instead of transmitting high-power RF signals through long cables, the system converts signals to lower frequencies for distribution, then reconverts to RF at remote nodes. This intermediary conversion allows use of lower-power amplifiers while maintaining signal integrity and reducing power consumption
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 RF path losses, improves signal-to-noise ratios, and allows for higher frequency testing beyond traditional limits, while minimizing the need for high-power amplifiers and reducing system size and cost, enabling more efficient and effective over-the-air testing.
Implementation Method 1
an up-converter configured to mix a local oscillator, LO, signal with an impaired signal of the emulated channel to up-convert it to a radio frequency, RF, signal
Implementation Method 2
a down-converter configured to mix a local oscillator, LO, signal with an RF signal to down-convert it to an intermediate frequency, IF, signal
Data Source
AI summary
In some embodiments, an electromagnetic measurement system to test a device under test, DUT, in a chamber is provided. Within the chamber, for each of at least one emulated channel, a first emulator core is configured to introduce an impairment in each of at least one transmit signal to produce an impaired signal, and a transmitter is configured to convert the impaired signal to a radio frequency, RF, signal to be transmitted by an antenna.