Multi-Mode Time Base Synchronization With Single Calibration
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Solution Overview
Problem
Multi-mode mobile phones and receiving stations face challenges in maintaining accurate time bases across different cellular standards while minimizing power consumption, especially during sleep modes, requiring complex interactions between hardware and software components for synchronization.
Innovation Solution
A method where a single calibrated time base unit is used to synchronize other time base units through software, reducing the need for hardware components and allowing the system controller to manage the synchronization process, with the wake-up signal generated by the time base unit with the highest clock rate for improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple high accuracy crystal clock sources are used to maintain time bases for different systems, then synchronization accuracy across multiple standards is improved, but power consumption increases significantly
Solution Approach 1:
The patent segments the time base maintenance function by using separate low accuracy oscillators for each time base unit during sleep mode, allowing independent operation with minimal power consumption. Each oscillator can be independently controlled and calibrated when needed, rather than running all high accuracy clocks continuously.
Solution Approach 2:
The patent performs preliminary calibration of low accuracy oscillators before entering sleep mode, storing calibration data that allows quick re-synchronization upon wake-up. This preliminary action eliminates the need for continuous high accuracy operation, as the system can rapidly re-calibrate using stored reference information when activated.
2Use of energy by moving object
If low accuracy oscillators are used during sleep mode to reduce power consumption, then power consumption is reduced, but synchronization accuracy deteriorates
Solution Approach 1:
The patent introduces a calibration unit as an intermediary that periodically calibrates the low accuracy oscillators against a reference time base. This calibration unit acts as a mediator between the low accuracy oscillators and the reference, transferring timing information to maintain synchronization accuracy without requiring continuous high accuracy operation.
Solution Approach 2:
The patent replaces continuous mechanical/high-frequency oscillation with low-frequency oscillation during sleep mode, using software-based calibration and synchronization mechanisms instead of continuous hardware-based high accuracy time keeping. This substitution allows the system to maintain functionality with minimal power consumption.
3Measurement precision
If complex hardware components are used for calibration and synchronization of multiple time base units, then synchronization accuracy is maintained, but device complexity increases
Solution Approach 1:
The patent implements a universal calibration unit that can calibrate multiple time base units using a single reference, rather than requiring separate calibration hardware for each time base. This multi-functional approach reduces hardware complexity while maintaining synchronization accuracy across all time bases.
Solution Approach 2:
The patent uses software to copy calibration data and synchronization information between time base units, replacing complex hardware synchronization circuits. By copying timing information through software rather than using dedicated hardware synchronization paths, the system achieves synchronization with reduced hardware complexity.
Data Source
AI summary
Due to emerging cellular standards, such as UMTS, TDMA and WLAN, there is more and more need for so-called multi-mode mobile phones, i.e. phones which support not only one air interface but at least two. According to an exemplary embodiment of the present invention, a simplified synchronization of a plurality of time base units in a receiving station, such as a multi-mode mobile phone, is provided, in which the plurality of time base units is synchronized by performing a calibration of one first time base unit only and then using the calibration for synchronizing the other time base units with the calibrated first time base unit. Since the synchronization of the various time base units can be performed by software, the number of hardware components for synchronization may be significantly reduced.