TDMA Symbol Clock Correction for Intermittent Reception
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Solution Overview
Problem
In wireless communication terminals performing intermittent reception, existing techniques face challenges in synchronizing the symbol clock with the base station's symbol clock due to inappropriate reception period lengths, leading to difficulties in demodulating data during synchronization deviation detection.
Innovation Solution
A receiving apparatus and method for a TDMA system that performs intermittent reception by adjusting the symbol clock frequency based on the number of time slots and symbol count values during reception and non-reception periods, allowing for synchronization and correction of the reception termination timing after detecting a synchronous word.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the reception period length is set according to existing techniques, then power consumption is reduced, but synchronization accuracy deteriorates
Solution Approach 1:
The patent applies preliminary action by detecting the synchronous word in advance during the reception period, measuring the symbol clock frequency deviation, and preparing correction values before the non-reception period begins. This allows the system to maintain accurate synchronization without extending the reception period, thereby reducing power consumption while preserving synchronization accuracy.
Solution Approach 2:
The patent implements feedback by continuously measuring the symbol clock frequency using the detected synchronous word, comparing it with the expected frequency, and adjusting the reception period timing based on the measured deviation. This closed-loop feedback mechanism ensures accurate synchronization without requiring longer reception periods, thus maintaining low power consumption.
2Measurement precision
If the reception period is extended to improve synchronization, then synchronization accuracy is improved, but power consumption increases
Solution Approach 1:
The patent changes the parameter of symbol clock frequency measurement by utilizing the known synchronous word pattern to accurately measure frequency deviation within a short reception period. This parameter change approach allows achieving high synchronization accuracy without extending the reception period duration, thereby avoiding increased power consumption.
Solution Approach 2:
The system performs preliminary measurement of symbol clock frequency during the reception period using the synchronous word, and applies correction in advance before entering the non-reception period. This preliminary action enables accurate synchronization without requiring extended reception time, thus maintaining low power consumption.
3Device complexity
If symbol clock frequency is not corrected, then device complexity is reduced, but data demodulation reliability deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the symbol clock frequency is measured using the detected synchronous word, and the reception period timing is adjusted based on the measured frequency deviation. This feedback-based correction ensures reliable data demodulation without requiring complex synchronization circuits, thus maintaining simple device architecture while improving reliability.
Solution Approach 2:
The system uses the synchronous word, which is already present in the received signal, to measure and correct the symbol clock frequency deviation. This self-service approach allows the system to perform its own synchronization without external assistance or complex additional hardware, maintaining device simplicity while ensuring demodulation reliability.
Data Source
AI summary
A reception apparatus of a time division multiple access (TDMA) system for performing intermittent reception by a reception period of a time slot and a non-reception period of a predetermined number of time slots which follow the reception period and in which reception is suspended includes a symbol clock controller configured to perform symbol synchronization at a timing at which a synchronous word included in the reception period after the non-reception period, and correct a symbol clock frequency of a symbol clock based on a number of time slots and a symbol count value during a previous reception period and the non-reception period following the previous reception period; and a reception period controller configured to correct, after detection of the synchronous word, a reception termination timing of the reception period in which the synchronous word is detected based on the symbol clock with the corrected symbol clock frequency.