Radio Communications Apparatus Dynamic LO Power Control
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Solution Overview
Problem
Conventional radio communication systems face challenges in adapting the local oscillation (LO) output power to match varying communication environments, leading to suboptimal modulation schemes and back-off amounts, which affect communication quality and carrier-to-noise ratio.
Innovation Solution
A radio communications apparatus and method that includes control means to dynamically adjust the LO output power and modulation scheme based on the quality of communication, using a mixer that can change the LO output power in accordance with the communication environment, allowing for optimal modulation methods by controlling the back-off amount.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the IF input power is set at point A where RF output power matches LO output power, then the carrier-to-noise ratio is optimized, but the back-off amount from P1 dB is fixed and cannot be adjusted for varying communication environments
Solution Approach 1:
The patent introduces a variable back-off amount that can be dynamically adjusted based on communication environment quality. The control unit changes the back-off amount according to modulation scheme requirements, transforming the fixed power setting into a dynamic parameter that adapts to different conditions while maintaining optimal carrier-to-noise ratio performance
Solution Approach 2:
The patent changes the operational parameter of back-off amount from a fixed value to a variable parameter. By controlling the back-off amount as a changeable parameter based on communication quality and modulation scheme requirements, the system can optimize both carrier-to-noise ratio and adaptability to varying environments
2Productivity
If the back-off amount is reduced to increase transmission power, then productivity improves, but the RF signal enters nonlinear region causing output distortions
Solution Approach 1:
The patent makes the back-off amount a dynamic parameter that can be adjusted based on communication conditions. By dynamically controlling the back-off amount, the system can operate at higher transmission powers when conditions permit while maintaining signal quality, thus improving productivity without causing nonlinear distortions
Solution Approach 2:
The control unit monitors communication environment quality and adjusts the back-off amount accordingly. This feedback mechanism ensures that transmission power is optimized while preventing the RF signal from entering the nonlinear region, thereby maintaining output signal quality
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
Enables flexible adjustment of LO output power and modulation schemes to match changing communication conditions, improving communication quality and carrier-to-noise ratio by optimizing the back-off amount, thereby ensuring effective radio communication.
Implementation Method 1
an intermediate frequency band signal is converted to the radio frequency band signal by a mixer
Data Source
AI summary
A bit error rate of the reception signal is detected on the reception side, such that an n optimal modulation method and LO output power are determined in accordance with this bit error rate, and an LO output changing instruction is sent to an image signal rejection mixer on the transmission side. The image signal rejection mixer changes the phase X=α+γ in response to the LO output changing instruction when power splitter (201) splits the LO into two components with equal amplitude and phase difference α, power splitter (202) splits the IF signal into two components with equal amplitude and phase difference β, and power combiner (205) combines RF signals with equal amplitude and phase difference γ. By changing the X, the LO output power is controlled and the back-off amount of a transmission amplifier is changed in accordance with an optimal modulation scheme. In this event, α−β+γ=2nπ (n is an integer) is set so as to maximize the image signal rejection amount.