Wireless Receiver Sensitivity Threshold Adjustment
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Solution Overview
Problem
Wireless communication devices (WCDs) face challenges in processing forward-link signals when the signal power level is below their sensitivity threshold, and base stations may not be able to further increase power levels, leading to difficulties in maintaining adequate signal-to-noise ratios (SNR) for reliable communication.
Innovation Solution
The WCD adjusts its sensitivity threshold by measuring signal and noise power levels, determining if the signal power is below the current threshold and the SNR is above a certain threshold, and then reducing the sensitivity threshold to a level equal to or less than the signal power, which can be achieved by reducing the receiver's bandwidth or changing the output SNR threshold, allowing it to detect weaker signals and improve the calculated SNR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the base station increases the forward-link signal power level, then the as-received signal power level and SNR improve, but the base station may reach the maximum allowed power level and be unable to further increase power
Solution Approach 1:
The patent changes the receiver sensitivity threshold parameter from a fixed value to a dynamically adjustable value. When the base station reaches maximum power levels, the WCD adjusts its sensitivity threshold based on measured signal and noise power levels, allowing it to detect and decode signals that would otherwise be below the original threshold. This resolves the contradiction by enabling reliable signal reception without requiring additional transmit power.
2Reliability
If the WCD maintains a fixed sensitivity threshold, then the receiver operates with consistent performance characteristics, but the WCD cannot process signals received at power levels below the sensitivity threshold
Solution Approach 1:
The patent transforms the static sensitivity threshold into a dynamic parameter that adapts to current signal and noise conditions. The WCD continuously measures signal power level and noise power level, then adjusts the sensitivity threshold accordingly. This allows the receiver to maintain reliable operation across varying signal conditions, resolving the contradiction between consistent performance and adaptive capability.
3Reliability
If the WCD reduces the sensitivity threshold to detect weaker signals, then the WCD can process signals below the original threshold, but the receiver bandwidth or output SNR threshold must be adjusted which increases device complexity
Solution Approach 1:
The patent implements a feedback mechanism where the WCD measures its received signal power level and noise power level, compares these measurements against thresholds, and uses the results to adjust its sensitivity threshold. This closed-loop control system automatically adapts the receiver parameters based on actual operating conditions, enabling weak signal detection while managing complexity through algorithmic control rather than hardware complexity.
Data Source
AI summary
Disclosed herein are systems and methods for adjusting a sensitivity threshold of a wireless communication device (WCD). In an embodiment, a WCD measures both a signal power level of a received signal and a noise power level. The WCD also makes a sensitivity-adjustment determination, which includes (i) a determination that the signal power level is less than a current sensitivity threshold of the receiver of the WCD and (ii) a determination that a signal-to-noise ratio (SNR) of the signal power level to the noise power level is greater than an SNR threshold. Responsive to making the sensitivity-adjustment determination, the WCD adjusts its receiver from having the current sensitivity threshold to having an adjusted sensitivity threshold that is less than or equal to the signal power level.