Adaptive Receiver Filtering for Interference and Current Drain
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Solution Overview
Problem
Conventional receiver architectures in cellular systems face performance degradation due to interference, as they require multiple narrow analog filters and high linearity RF stages, which increase current drain and distort the desired signal, and fail to adapt to varying interference conditions effectively.
Innovation Solution
The proposed receiver architecture employs estimation circuits with variable selectivity and a state machine to dynamically adjust gain and bias settings based on interference measurements, using progressively narrower filters to identify and mitigate interference, thereby optimizing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If multiple narrow analog filters are used to prevent clipping due to interference, then interference rejection is improved, but current drain increases and desired signal is distorted
Solution Approach 1:
The patent implements dynamic filter bandwidth adjustment where the baseband filter bandwidth is adaptively changed based on detected interference conditions. When interference is detected, the filter bandwidth is narrowed to reject interference; when no interference is present, the bandwidth is widened to pass more of the desired signal, thereby reducing unnecessary current consumption and signal distortion.
Solution Approach 2:
The system changes the bandwidth parameter of the baseband filter dynamically based on interference detection. The filter transitions between different bandwidth states (wide, narrow, very narrow) according to the presence and type of interference, optimizing the trade-off between interference rejection and current drain/signal quality.
2Reliability
If high linearity RF stages are designed to minimize distortion in the presence of interference, then signal quality is improved, but current drain increases due to high bias conditions
Solution Approach 1:
The patent implements dynamic bias adjustment in the LNA and mixer stages based on interference detection. When interference is detected, the bias conditions are increased to improve linearity and reduce distortion; when no interference is present, the bias is reduced to lower current consumption, thus dynamically optimizing the trade-off between signal quality and power consumption.
Solution Approach 2:
The system changes the bias current parameter of RF stages (LNA, mixer) dynamically based on interference conditions. The bias point is adjusted between high and low states depending on the presence of interference, allowing the system to maintain high signal quality when needed while reducing power consumption during normal operation.
3Object-affected harmful factors
If conventional receiver architecture uses fixed filter settings to remove interference completely, then interference rejection is improved, but receiver performance degrades when expected interference is absent
Solution Approach 1:
The patent implements a dynamic interference mitigation system that continuously monitors for interference and adjusts filter bandwidth and RF stage bias accordingly. The system transitions between different operational states (wideband/high-bias, narrowband/low-bias) based on real-time interference detection, ensuring optimal receiver performance whether interference is present or absent.
Solution Approach 2:
The system employs feedback from interference detection circuits to control filter bandwidth and bias settings. The detected interference level feeds back to the control logic, which adjusts the receiver parameters in response, creating a closed-loop system that adapts to changing interference conditions and maintains optimal performance.
4Difficulty of detecting and measuring
If wideband detection is used to detect high levels of interference, then interference detection capability is improved, but ability to distinguish out-of-band interference from adjacent channel interference is lost
Solution Approach 1:
The patent segments the interference detection process into multiple stages with different filter bandwidths. The system first uses a wideband detector to identify presence of any interference, then employs narrowband detectors tuned to specific frequency offsets to determine the precise location and type of interference. This segmented approach maintains both detection sensitivity and location precision.
Solution Approach 2:
The system adds a frequency offset dimension to interference detection by using multiple detectors tuned to different frequency offsets from the carrier. This allows the system to not only detect the presence of interference but also determine its precise frequency location, transforming a single-dimension detection problem into a multi-dimensional solution.
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
This approach allows for efficient adaptation to changing interference conditions, reducing unnecessary performance degradation and current consumption by dynamically adjusting filter settings and gain, leading to improved signal quality and reduced power usage.
Implementation Method 1
a first amplifier configured to amplify an input signal
Implementation Method 2
The mixer is configured to mix the amplified input signal outputted by the first amplifier with an oscillator signal, to provide a mixed signal
Implementation Method 3
A first filter is configured to filter the mixed signal to pass a first band of frequencies
Implementation Method 4
A second amplifier is configured to amplify an output of the first filter
Implementation Method 5
A second filter is configured to filter the output of the second amplifier to pass a second band of frequencies narrower than the first band
Data Source
AI summary
A novel receiver architecture optimizes receiver performance in the presence of interference. In various embodiments, power estimation circuits are used with variable selectivity to determine the exact nature of the interference and to optimize the performance correspondingly. The variable selectivity is achieved using stages of filtering with progressively narrower bandwidths. Also, the actual method of optimizing the receiver performance is novel compared to the prior art in that the gain settings and the baseband filter order (stages to be used) will be optimized based on the nature of the interference as determined by the power detector measurements. For a device such as a cellular phone that operates in a dynamic and changing environment where interference is variable, embodiments advantageously provide the capability to modify the receiver's operational state depending on the interference.