Digital Phased Array Polar Modulation for Efficient mmWave Power
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Solution Overview
Problem
Designing highly efficient and linear power amplifiers for mmWave frequencies is challenging, and the power back-off required for modulation further reduces efficiency, leading to increased power consumption when multiple power amplifiers are enabled.
Innovation Solution
Implementing a polar modulation scheme with constant amplitude phase modulation and varying numbers of antenna elements, optimizing power amplifiers for gain without linearity constraints, and using out-phasing techniques to achieve efficient power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If power amplifiers are enabled to achieve good gain, then transmit power is improved, but power consumption increases and efficiency decreases
Solution Approach 1:
The patent implements dynamic control of power amplifier enablement based on instantaneous signal requirements. The system dynamically enables or disables specific power amplifiers in the array depending on the current transmit power level and modulation requirements, rather than keeping all amplifiers continuously enabled. This dynamic adaptation allows the system to achieve good transmit power when needed while minimizing power consumption during lower power operations.
2Reliability
If power back-off is applied for modulation, then linearity is improved, but efficiency decreases
Solution Approach 1:
The patent segments the transmit function across multiple power amplifiers in an array, where each amplifier operates independently. By distributing the total transmit power across multiple amplifiers, the system can achieve the required linearity for modulation without requiring excessive power back-off from each individual amplifier. The combined output of multiple amplifiers provides the necessary linearity while maintaining better overall efficiency compared to using a single amplifier with large back-off.
3Power
If multiple power amplifiers are enabled, then transmit power is improved, but power consumption increases
Solution Approach 1:
The patent applies partial action by enabling only the necessary number of power amplifiers based on current transmit requirements rather than enabling all available amplifiers continuously. The system determines the minimum number of amplifiers needed to achieve the desired transmit power level and enables only that subset, leaving other amplifiers disabled to conserve power. This partial utilization strategy maintains adequate transmit power while significantly reducing power consumption compared to having all amplifiers enabled.
Data Source
AI summary
A wireless communication device includes an antenna array with multiple antenna elements, an array of power amplifiers, and an array of phase shifters. Each antenna element is coupled to a power amplifier and a phase shifter. The device also includes transmitter circuitry coupled to the antenna array to encode a constant amplitude signal, which includes a power amplifier enable code to indicate which power amplifiers are to run in a subsequent data sample and a beam direction code to control beam direction of each phase shifter of the array of phase shifters in the subsequent data sample. The constant amplitude signal is then provided to the array of antenna elements and amplitude and phase modulation is combined over an air interface into a composite modulated signal.