Wireless Receiver Gain State Recall for Faster Idle Wake-Up
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Solution Overview
Problem
Wireless receivers in mobile stations face challenges in optimizing front end gain during wake-up periods in idle mode, leading to uncertain and potentially random gain states, which can result in higher noise figures and intermodulation distortion, due to the trade-off between noise figure and dynamic range requirements.
Innovation Solution
A method and apparatus that store and reuse the optimal gain control state value from the previous wake-up period to initialize the low noise amplifier during the warm-up period of the next wake-up cycle, allowing the front end gain controller to adjust based on the current signal level once it reaches a steady state, thereby minimizing settling time and optimizing gain settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the receiver is turned off most of the time to save battery power in idle mode, then energy consumption is reduced, but the gain control state becomes uncertain and may result in higher noise figures and intermodulation distortion upon wake-up
Solution Approach 1:
The patent stores the gain control state value from the previous wake-up period in memory before the receiver enters sleep mode. Upon waking, this pre-stored value is retrieved and applied during the warm-up period, eliminating the need for the gain control loop to settle from an uncertain state. This preliminary action of saving and restoring the gain state ensures reliable performance while allowing the receiver to remain off during idle periods.
2Reliability
If a longer warm-up period is provided for the receiver to settle to steady state upon wake-up, then gain control stability is improved, but the time required to return to operational state increases
Solution Approach 1:
By storing the gain control state value before sleep and retrieving it upon wake-up, the system eliminates the need for a long settling period. The pre-restored gain state allows the receiver to become operational quickly without compromising stability, reducing the warm-up period from potentially seconds to merely the time required to retrieve and apply the stored value.
Solution Approach 2:
The patent creates a copy of the gain control state value from the previous operational period and restores it during wake-up. This copying approach allows the receiver to jump directly to a known good state rather than settling from an uncertain condition, dramatically reducing the time required to reach operational status while maintaining reliability.
3Reliability
If the front end gain controller continuously adjusts gain based on feedback during wake-up period, then noise figure and dynamic range optimization is improved, but the settling time and time to reach steady state increases
Solution Approach 1:
The patent applies the pre-stored gain control state value during the warm-up period to provide an immediate, optimized gain setting. This preliminary application of the correct gain value allows the feedback-based continuous adjustment to start from an already-optimized state rather than from scratch, significantly reducing the time required to achieve optimal noise figure and dynamic range performance.
Data Source
AI summary
The settling time of a wireless receiver is reduced by providing a previously utilized gain control state value to a low noise amplifier (LNA) of a receiver front end during a warm-up portion of a wake-up period of the wireless receiver which follows a sleep period. One illustrative method includes the steps of receiving a notification signal which indicates that the wireless receiver is to be placed in a sleep mode, reading a gain control state value from a gain controller based on receiving the notification signal, storing the gain control state value in memory, providing the stored gain control state value from the memory to the wireless receiver during a warm-up period of a second wake-up period following the first wake-up period, and providing a gain control state value from the gain controller to the wireless receiver based on a signal level of a currently received signal of the wireless receiver after the warm-up period.