Wireless Synchronization via Two-Way Signal Timing Feedback
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Solution Overview
Problem
Current wireless synchronization methods for mobile devices in time division multiple access (TDMA) systems face challenges in achieving precise synchronization, leading to latency and potential collisions due to uncertainties in signal delay, which affects the efficiency of radio connections.
Innovation Solution
A method where a mobile device transmits a first synchronization signal to a base station, measuring the reception time, and then receives a second synchronization signal to calculate an average value for correcting its time base to match the base station's time base, minimizing signal transit time dependencies and allowing for autonomous synchronization without interfering with other connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional synchronization methods using predefined sequences are used, then synchronization can be established, but synchronization accuracy is limited to microsecond level due to signal latency
Solution Approach 1:
The patent implements a feedback mechanism where the base station measures the arrival time of the uplink synchronization signal, calculates the timing advance based on this measurement, and feeds back the timing advance value to the mobile device. The mobile device then applies this feedback to adjust its transmission timing, achieving precise synchronization that compensates for signal latency.
Solution Approach 2:
The patent replaces the traditional mechanical/clock-based synchronization approach with an electronic measurement and calculation system. Instead of relying on predefined sequences and autocorrelation properties, the system uses electronic timing measurements of actual signal transmission and reception, combined with computational calculation of timing advance, to achieve more accurate synchronization.
2Productivity
If time slots are shortened to improve efficiency, then system throughput increases, but synchronization accuracy requirements become more stringent
Solution Approach 1:
The feedback mechanism provides continuous timing adjustment information that enables the mobile device to maintain precise synchronization even as time slots are shortened. The timing advance value is calculated based on actual signal propagation conditions and fed back to the mobile device, allowing it to adjust its transmission timing with high precision.
Solution Approach 2:
The patent changes the synchronization approach from using fixed predefined sequences to using dynamically calculated timing advance values. This parameter change allows the system to adapt to varying signal conditions and maintain high synchronization accuracy regardless of time slot duration, enabling shorter time slots and improved system efficiency.
3Reliability
If guard times are increased to compensate for synchronization uncertainty, then collisions are avoided, but time division multiple access efficiency decreases
Solution Approach 1:
The feedback mechanism provides accurate timing advance information that reduces synchronization uncertainty to negligible levels. With this precise timing control, the system can minimize or eliminate guard times while maintaining reliable collision avoidance, thereby improving TDMA efficiency.
Solution Approach 2:
The patent changes the approach from using large fixed guard times to using precisely calculated timing advance values. This parameter change allows the system to reduce guard time duration while maintaining collision avoidance reliability, thus improving overall system efficiency by increasing the proportion of time available for actual data transmission.
Data Source
AI summary
The wireless communication between a base station and a mobile device is frequently based on time division multiple access methods with time slots, some of which are provided for control information. A common time base must be used for this. Since each mobile device has its own time base, it must first of all detect and correct deviations from the time base of the base station. However, the radio signals have unknown and variable transit times. In order to improve the synchronisation of a mobile device with the base station, a mobile device transmits a first synchronisation signal to the base station at a time which, according to its time base, lies in a time slot for control information. The base station measures the time of reception of the first synchronisation signal according to its own time base as a first measurement value and in the next control time slot transmits a second synchronisation signal to the mobile device, which measures the reception time according to its time base as a second measurement value. The base station also transmits the first measurement value to the mobile device. From the first and second measurement values, the mobile device determines the signal transit time and the deviation of its time base and corrects them.