Millimeter-Wave Modulation with Constant Envelope PA Efficiency
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Solution Overview
Problem
Conventional millimeter-wave modulation systems face inefficiencies in power amplifiers due to high Peak to Average Power Ratio (PAPR), leading to reduced transmission efficiency and increased power consumption as heat, especially in the millimeter wave band, where frequency efficiency is not maximized and systems are vulnerable to noise.
Innovation Solution
A millimeter-wave modulation apparatus employing a constant envelope modulation mode with a phase shifter, power amplifier, and antenna array configuration, utilizing a first local oscillator and phase locked loop to enable MSK modulation, which maximizes power amplifier efficiency and combines high-order modulation outputs in air space for enhanced data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-order modulation methods (QPSK, 64QAM) are used to increase frequency efficiency, then data transmission capacity is improved, but PAPR increases causing power amplifier efficiency to deteriorate
Solution Approach 1:
The transmitter is divided into multiple independent transmitter units, each performing simple OOK modulation. By segmenting the high-order modulation into multiple simple modulations performed in parallel, the system achieves high data transmission capacity while maintaining low PAPR in each unit.
Solution Approach 2:
The patent transitions from temporal modulation (single stream high-order modulation) to spatial modulation (multiple streams parallel transmission). By adding the spatial dimension with multiple transmitter units transmitting simultaneously, the system achieves high data capacity without increasing PAPR.
2Reliability
If high back-off power is applied to power amplifier to handle high PAPR, then modulation capability is maintained, but power consumption increases and heat generation worsens
Solution Approach 1:
The patent extracts the complex modulation function from the power amplifier stage and relocates it to the signal generation stage. Each transmitter unit performs only simple OOK modulation, allowing the power amplifier to operate at maximum efficiency without back-off power requirements.
Solution Approach 2:
The system changes the modulation parameter from high-order complex modulation to simple binary OOK modulation at each transmitter unit. This parameter change enables the power amplifier to operate without back-off power while maintaining overall system modulation capability through spatial multiplexing.
3Loss of energy
If OOK modulation is used to minimize PAPR and improve power efficiency, then power consumption is reduced, but frequency efficiency deteriorates
Solution Approach 1:
Multiple transmitter units performing simple OOK modulation are merged in the spatial domain. By combining multiple low-complexity modulations simultaneously transmitted through different antennas, the system achieves high frequency efficiency equivalent to high-order modulation while maintaining low power consumption characteristics of OOK.
Solution Approach 2:
The high-order modulation stream is segmented into multiple parallel OOK streams. Each segment is transmitted independently through a separate transmitter unit, allowing the system to achieve the data capacity of high-order modulation using only simple binary modulation schemes.
4Device complexity
If single power amplifier is used to simplify system structure, then device complexity is reduced, but output power is insufficient for millimeter wave transmission
Solution Approach 1:
The single power amplifier is segmented into multiple distributed power amplifiers, each located in separate transmitter units. This segmentation allows the system to achieve high total output power through parallel operation while keeping each individual amplifier simple and manageable.
Solution Approach 2:
The system adds the spatial dimension by deploying multiple transmitter units with their own power amplifiers. This dimensional expansion allows the system to achieve high output power without increasing the complexity of individual amplifier stages, as each unit remains structurally simple.
Data Source
AI summary
Provided is a lower power and high efficiency millimeter-wave modulation apparatus capable of modulating digital data into transmitting signals in a millimeter frequency band, the millimeter-wave modulation apparatus including; a modulation part, which carries out a modulation of a constant envelope attribute, and to which a first local oscillation signal is fixed according to a rate of input data; a phase shifter adopted to shift a phase of an output of the modulation part; a power amplifier adopted to amplify an output of the phase shifter; and an antenna connected to an output of the power amplifier.