Adaptive Amplifier Biasing for LTE Harmonic Distortion Control
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Solution Overview
Problem
Conventional methods to reduce peak power harmonic distortions in LTE modulation, such as using lossy filters, increase circuit footprint, power consumption, and interfere with GPS functionality, especially during low activity conditions when few resource blocks are active.
Innovation Solution
Adaptive biasing of amplifiers based on the number of active resource blocks, switching to a higher bias during low activity conditions to reduce harmonic distortion and power consumption, and reverting to standard bias during high activity conditions to minimize power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If lossy filters are placed in the transmission path to filter out harmonic distortions, then harmonic distortion is reduced, but circuit footprint increases, circuit cost increases, and power consumption increases
Solution Approach 1:
The amplifier bias is dynamically adjusted based on the number of active resource blocks. During low activity conditions (few active RBs), the bias is increased to improve linearity and reduce harmonic distortion. During high activity conditions (many active RBs), the bias returns to standard levels to optimize power consumption. This dynamic adaptation eliminates the need for constant power consumption associated with traditional filters.
Solution Approach 2:
The invention changes the operating parameter (bias level) of the amplifier based on transmission conditions. By varying the bias current as a function of active resource blocks, the system achieves low harmonic distortion when needed without the continuous power penalty of fixed filter solutions. The bias parameter is adjusted adaptively rather than remaining static.
2Object-generated harmful factors
If lossy filters are placed in the transmission path to filter out harmonic distortions, then harmonic distortion is reduced, but circuit footprint increases and circuit cost increases
Solution Approach 1:
The invention extracts the harmonic distortion control function from separate physical filter components and integrates it into the amplifier's operating characteristics through adaptive biasing. By controlling the amplifier's bias point, the system achieves harmonic suppression without adding external filter circuits, thereby reducing circuit footprint and complexity.
Solution Approach 2:
The amplifier serves multiple functions: signal amplification and harmonic distortion control. By adjusting the bias point, the same amplifier component performs both amplification and linearity optimization, eliminating the need for separate filter components and reducing overall circuit complexity.
3Object-generated harmful factors
If lossy filters are placed in the transmission path to filter out harmonic distortions, then harmonic distortion is reduced, but power consumption increases thus decreasing maximum talk time
Solution Approach 1:
The adaptive biasing operates periodically or event-driven based on changes in active resource block configuration. The system monitors transmission conditions and adjusts bias only when necessary (during low activity conditions), rather than maintaining elevated bias continuously. This periodic or conditional action reduces average power consumption while still addressing harmonic distortion when needed.
4Use of energy by stationary object
If the amplifier is biased at standard bias during low activity conditions, then power consumption is reduced, but peak power of harmonic distortion becomes undesirably high
Solution Approach 1:
The system implements feedback by monitoring the number of active resource blocks and using this information to adjust the amplifier bias. When the feedback indicates low activity conditions (few active RBs), the bias is increased to reduce harmonic distortion. This closed-loop control ensures optimal performance without excessive power consumption during high activity conditions.
Data Source
AI summary
This disclosure relates to adaptively reducing the peak power of harmonic distortions as a function of the operating conditions for transmission communications. Specifically, the bias of the amplifier is adaptively increased to reduce harmonic distortions when a small fraction of the resource blocks are active.