Multiplexing Radar Beat Signals for MPE Compliance
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Solution Overview
Problem
High-frequency wireless communications face challenges in maintaining performance while adhering to the Federal Communications Commission's maximum permitted exposure limit, particularly due to higher path loss and the need for resource-constrained interface circuitry that limits the propagation of radar signals.
Innovation Solution
A wireless transceiver that multiplexes radar beat signals using techniques like analog or digital frequency-division multiplexing, code-division multiplexing, or digital time-division multiplexing, allowing the generation of composite radar beat signals with narrower bandwidths that can be propagated across constrained interface circuitry, enabling object detection and adjustment of transmission parameters to meet MPE guidelines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If transmit power levels are increased to compensate for higher path loss, then signal propagation distance is improved, but power density increases and may exceed MPE limits
Solution Approach 1:
The patent segments the radar signal processing into multiple receive chains, each processing a portion of the signal spectrum. This allows the system to achieve long propagation distance through coherent integration of multiple lower-power signals while distributing the processing load and maintaining compliance with MPE limits through controlled power density at each chain.
2Measurement precision
If multiple receive chains are used to improve signal detection, then object detection capability is improved, but interface circuitry bandwidth requirements increase
Solution Approach 1:
The patent combines multiple radar beat signals from different receive chains into a single composite beat signal through multiplexing circuitry. This merging approach maintains object detection capability by preserving the spectral content of all receive chains while reducing the interface bandwidth requirement from multiple high-bandwidth channels to a single lower-bandwidth channel.
Solution Approach 2:
The patent introduces a multiplexing circuit as an intermediary between the multiple receive chains and the processor. This intermediary component combines the multiple beat signals into a composite signal, allowing the processor to receive comprehensive detection data through a single interface channel, thereby reducing interface complexity while maintaining detection precision.
3Productivity
If radar beat signals are processed in parallel to improve detection speed, then processing throughput is improved, but interface bandwidth requirements increase
Solution Approach 1:
The patent merges multiple parallel radar beat signals into a single composite signal that contains the spectral information from all input channels. This combining process maintains the throughput benefit of parallel processing at the RF front end while reducing the digital interface bandwidth requirement, as the composite signal can be processed sequentially without loss of detection capability.
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 enhances wireless communication performance by allowing longer signal propagation while ensuring compliance with exposure limits, enabling more efficient power management and beam steering to optimize signal density.
Implementation Method 1
a downconversion mixer configured to generate a radar beat signal by mixing a radar receive signal with the radar transmit signal
Implementation Method 2
an amplifier configured to amplify the radar beat signal to generate an amplified radar beat signal
Data Source
AI summary
An apparatus is disclosed for multiplexing radar beat signals. In an example aspect, the apparatus includes an antenna array and a wireless transceiver jointly configured to transmit a radar transmit signal and receive two or more radar receive signals. The two or more radar receive signals represent portions of the radar transmit signal that are reflected by an object. The wireless transceiver comprises a radio-frequency integrated circuit with two or more receive chains and a multiplexing circuit. Each one of the two or more receive chains is configured to generate a radar beat signal by downconverting a respective radar receive signal of the two or more radar receive signals using the radar transmit signal. The multiplexing circuit is coupled to the two or more receive chains and is configured to multiplex the two or more radar beat signals together to generate a composite radar beat signal.