Multi-carrier Receiver Dynamic Power Adjustment for ICI
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Solution Overview
Problem
Mobile OFDM systems face performance degradation due to Doppler shifts and time-varying channels, leading to inter-carrier interference (ICI), which is compensated by power-consuming ICI cancellation and error correction methods, posing a challenge in balancing system performance and power consumption in handheld devices.
Innovation Solution
A multi-carrier receiver with dynamic power adjustment, comprising a demodulator, ICI detector, system performance detector, determination circuit, ICI canceller, channel estimator, and equalizer, that selectively activates ICI cancellation based on ICI strength and system performance thresholds to optimize power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ICI cancellation and error correction methods are applied to compensate for Doppler shifts and time-varying channels, then system performance is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic power adjustment by making the ICI canceller operable in two states: first operational mode when ICI strength exceeds threshold, and second operational mode (low power or off) when ICI strength is below threshold. The determination circuit dynamically switches between these modes based on real-time ICI strength detection, resolving the contradiction between maintaining system performance and reducing power consumption in handheld devices
Solution Approach 2:
The patent changes the operational parameter of the ICI canceller based on ICI strength conditions. When ICI strength is high, the canceller operates fully; when ICI strength is low, it switches to a lower power state or turns off. This parameter change approach allows the system to adapt power consumption to actual channel conditions, maintaining performance when needed while saving power when ICI is not a significant issue
2Reliability
If ICI canceller is continuously activated to handle mobile reception conditions, then system performance is maintained, but power consumption is excessive for handheld devices
Solution Approach 1:
Instead of continuously activating the ICI canceller (excessive action), the patent applies partial action by activating it only when ICI strength exceeds a determined threshold. The determination circuit assesses whether ICI cancellation is actually needed based on current channel conditions, applying the correction function partially rather than continuously, thus reducing power consumption while maintaining performance when necessary
Solution Approach 2:
The patent implements a feedback mechanism where the ICI detector continuously monitors ICI strength and provides this information to the determination circuit, which then controls the ICI canceller operation. This closed-loop feedback system ensures the ICI canceller is activated only when the monitored ICI strength warrants intervention, optimizing the balance between performance and power consumption
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
The solution effectively reduces power consumption while maintaining system performance by only activating ICI cancellation when necessary, thereby improving the tolerance to Doppler effects in mobile channels and reducing overall power usage.
Implementation Method 1
inter-carrier interference (ICI), which is compensated by power-consuming ICI cancellation
Data Source
AI summary
A method for dynamically adjusting the power consumption of a multi-carrier receiver and a multi-carrier receiver with dynamically power adjustment. The method includes receiving a multi-carrier signal, wherein the multi-carrier signal comprises a plurality of sub-carriers. Channel characteristics of each sub-carrier are estimated according to the demodulated multi-carrier signal. ICI strength is estimated from the demodulated multi-carrier signal. A system performance is detected. The estimated ICI is subtracted when the ICI strength exceeds an ICI threshold and the system performance is less than a system performance threshold. The demodulated multi-carrier signal is then equalized is based on the estimated channel characteristics, and the system performance is updated according to the equalized multi-carrier signal.