Controllable Filter for Concurrent SPS and Communication Operation
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Solution Overview
Problem
Mobile devices face interference from high-power wireless communication signals, which disrupt the reception of Satellite Positioning System (SPS) signals, leading to degraded positioning performance due to the inability to effectively reject interfering signals without using high-cost, high-selectivity filters.
Innovation Solution
A controllable filter, such as a tunable notch or lowpass filter, is used to attenuate aggressor transmission signals only when active, allowing SPS signals to be received in interfered frequency bands, and turning off or tuning away from SPS frequencies when not active to maintain full signal access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-power wireless communication signals are transmitted, then communication operation is enabled, but SPS signal reception is interfered with and positioning performance degrades
Solution Approach 1:
The filter is made dynamically controllable, switching between different states (active/inactive) based on whether wireless communication is ongoing. This allows the system to adapt its filtering characteristics in real-time, enabling communication when needed while preserving SPS reception when communication is not active.
Solution Approach 2:
The filter's frequency response parameters are changed based on operational mode. When wireless communication is active, the filter parameters are adjusted to attenuate communication signals and protect SPS reception. When communication is inactive, filter parameters are adjusted to pass SPS signals without attenuation.
2Object-affected harmful factors
If a controllable filter is used to attenuate aggressor transmission signals, then interference is reduced and SPS signal reception is maintained, but some SPS signal frequencies are also attenuated
Solution Approach 1:
The filter is dynamically controlled to be active only during wireless communication transmissions. During SPS-only operation, the filter is inactive or tuned away from SPS frequencies, ensuring complete SPS signal access. This temporal differentiation resolves the contradiction between interference rejection and signal reception reliability.
Solution Approach 2:
The filter operates periodically based on communication transmission cycles. It is activated during communication periods to reject interference and deactivated during SPS reception periods to ensure full signal access, creating a periodic on-off pattern that balances both requirements.
3Object-affected harmful factors
If the controllable filter is turned on to reject aggressor signals, then interference is attenuated, but complete access to SPS signal frequencies is lost
Solution Approach 1:
The filter's operational state is dynamically adjusted based on real-time detection of communication signal presence. When communication signals are detected, the filter is activated to attenuate aggressor signals. When no communication signals are present, the filter is deactivated or tuned away, preserving complete SPS signal access.
Solution Approach 2:
The controllable filter acts as an intermediary element that is selectively engaged based on operational context. It mediates between the conflicting requirements of interference rejection and signal preservation by being activated only when communication signals are present, thus preventing information loss while providing necessary attenuation.
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 solution enables concurrent SPS and communication operations by reducing interference, maintaining SPS signal reception while minimizing the need for expensive filters, thus improving positioning accuracy and availability without saturating the SPS front end.
Implementation Method 1
controlling a controllable filter based on the control signal to attenuate the aggressor carrier frequency
Data Source
AI summary
A mobile device may be configured to perform concurrent Satellite Positioning System and communication system operation, e.g. enabling an SPS receiver to continue to receive SPS signals in frequency bands that are interfered with due to aggressor transmission signals. A controllable filter, such as a selectable and/or tunable notch or lowpass filter is used to reject the aggressor transmission signals. The controllable filter may also attenuate some, but not all, frequencies in the SPS L1 band. To avoid losing complete access to these filtered SPS signal frequencies, the controllable filter is controlled, e.g., selected or tuned to these frequencies only when the aggressor transmission signal is active, and is otherwise turned off or tuned away from the SPS signal frequencies.