LTE UE Synchronization via System Clock Sample Counting
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Solution Overview
Problem
In LTE/E-UTRA communication systems, mobile devices face challenges in accurately synchronizing with base stations to determine cell-specific parameters such as symbol timing, frame timing, and cell ID, which affects initial cell search and handover processes due to complexity in resolving timing and frequency offset issues.
Innovation Solution
A method and system that utilize system clock-aligned Primary Synchronization Signal (PSS) and Secondary Synchronization Signal (SSS) hypothesis timings to generate timed events in a radio frame, allowing mobile devices to synchronize with base stations and determine cell-specific parameters by counting samples of the common system clock and aligning them based on operating bandwidths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mobile devices use conventional synchronization methods to determine cell-specific parameters, then they can establish basic connectivity, but the complexity of resolving timing and frequency offset issues increases significantly
Solution Approach 1:
The patent applies preliminary action by pre-defining the relationship between PSS timing and system clock cycles. The mobile device counts system clock cycles from a known reference point (PSS timing) to predetermined values that correspond to SSS timing and other cell-specific parameters. This pre-established relationship eliminates the need for complex real-time timing and frequency offset resolution, as the timing information is derived directly from the counted clock cycles rather than through complex synchronization algorithms.
2Measurement precision
If mobile devices perform comprehensive timing analysis to accurately determine all cell-specific parameters, then parameter determination accuracy improves, but the initial cell search and handover processes become more complex
Solution Approach 1:
The patent segments the cell search process into distinct timing intervals based on system clock cycle counts. Each cell-specific parameter (SSS timing, frame timing, subframe timing) corresponds to a specific counted value of the system clock. This segmentation allows the mobile device to determine multiple parameters through simple counting operations rather than comprehensive complex analysis, reducing processing complexity while maintaining accuracy.
3Ease of operation
If mobile devices use system clock-aligned PSS hypothesis timings to generate timed events, then the synchronization process is simplified, but the requirement for precise system clock alignment increases
Solution Approach 1:
The patent applies self-service by using the mobile device's own system clock as the reference for counting timing intervals. The system clock is already present in the device and runs continuously, so no external high-precision timing reference needs to be introduced. The mobile device simply counts its own system clock cycles from the PSS timing reference to determine other parameters, eliminating the need for complex inter-device clock synchronization while maintaining sufficient precision for cell search and handover operations.
Data Source
AI summary
A mobile device coupled to a common system clock receives a signal comprising a primary synchronization sequence (PSS) and a secondary synchronization sequence (SSS) in a radio frame. Sample counts are generated for timed events based on corresponding operating bandwidths. The timed events are detected at modulo sample counts of the generated sample counts according to corresponding operating bandwidths. PSS symbol timing determined via the PSS synchronization is aligned to the generated sample counts based on corresponding operating bandwidth. The generated sample counts are bit-shifted relative to the aligned PSS symbol timing for other timed events based on corresponding operating bandwidths. The one or more timed events are determined via performing modulo counting after the bit-shifting. Timing operations are performed at the determined timed events and the determined one or more timed events are refined, accordingly.