Switchable DPD Measurement Paths for mmWave Phased Arrays
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Solution Overview
Problem
Existing phased array systems face challenges in obtaining accurate non-linearity measurements due to long, static measurement paths that result in attenuation and phase changes, especially at millimeter-wave frequencies, leading to inaccurate results.
Innovation Solution
The implementation of a switchable circuitry that selectively couples transmitter outputs to processing hardware, allowing for multiple, electrically short measurement paths to be used for digital pre-distortion processing, thereby reducing attenuation and phase changes across the transceiver array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a static measurement path is used to obtain distortion measurements from multiple transmitters, then the system structure is simple, but the measurement accuracy deteriorates due to long transmission paths causing attenuation and phase changes at millimeter-wave frequencies
Solution Approach 1:
The patent divides the measurement path into multiple segments by introducing a switch network that can selectively connect different transmitters to the processor. Instead of having all transmitters connected through a single long static path, the measurement path is segmented into multiple shorter paths that are activated sequentially. This segmentation reduces attenuation and phase changes in each individual measurement path while maintaining system functionality.
Solution Approach 2:
The patent transforms the static measurement path into a dynamic one by incorporating a switch network that can change connections based on which transmitter is being measured. The switch network dynamically reconfigures the measurement path to connect the processor to the currently active transmitter, ensuring that each measurement occurs through a short, optimized path rather than a long static path.
2Productivity
If multiple transmitters are connected to the processor simultaneously through a long path, then the system can obtain measurements from all transmitters, but signal attenuation and phase changes increase at millimeter-wave frequencies
Solution Approach 1:
The measurement system is segmented into multiple independent paths, each connecting the processor to a specific transmitter through the switch network. This allows the system to maintain the capability to measure all transmitters while ensuring that each individual measurement path remains short, thereby reducing signal attenuation and energy loss at millimeter-wave frequencies.
Solution Approach 2:
The switch network operates periodically to sequentially connect different transmitters to the processor for measurement. Instead of having all transmitters connected simultaneously through a long path, the system periodically switches between transmitters, activating one at a time through short dedicated paths. This periodic switching maintains measurement productivity while minimizing signal loss in each path.
3Measurement precision
If a long static measurement path is used, then the system structure is straightforward, but phase changes occur that reduce measurement accuracy at millimeter-wave frequencies
Solution Approach 1:
The patent introduces dynamic reconfigurability to the measurement system through the switch network. The switch network dynamically connects the processor to different transmitters based on measurement requirements, ensuring that each measurement occurs through a short path with minimal phase changes. This dynamic approach replaces the static long path architecture, accepting increased device complexity as a trade-off for significantly improved measurement precision.
Solution Approach 2:
The switch network acts as an intermediary between the transmitters and the processor. Instead of having transmitters directly connected to the processor through long static paths, the switch network mediates the connection by selectively routing signals through short paths. This intermediary component enables precise measurements while managing the complexity of connecting multiple transmitters to a single processor.
Data Source
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AI summary
Described herein are systems with switchable circuitry configured to selectively couple transmitter outputs to processing hardware, which may selectively route subsets of distortion measurements from transmitters for DPD processing that compensates for the measured distortion. The switchable nature of the distortion measurement propagation paths permits the paths to be made substantially shorter than static paths, resulting in improved (e.g., reduced and/or more uniform) attenuation and/or phase change across a transceiver array. In one example, measurement propagation paths may be no longer than a row or column of the array. In some embodiments, systems described herein may be suitable for implementation at mmW transmit and/or receive frequencies, where the length of measurement paths may have a significant impact on attenuation and phase changes.