Synchronization Sequence Pairing for Cell Group Detection
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Solution Overview
Problem
Current cell search schemes for 3G LTE systems require complex sequence designs for synchronization signals to uniquely identify cell groups and frame timing, while also needing to minimize interruption time during inter-frequency and inter-Radio Access Technology measurements.
Innovation Solution
The use of pairs of synchronization sequences, S1 and S2, arranged in different orderings within specific time slots of a radio frame, where each sequence is selected from a group of NSeq=ceil(1+1+8M²) unique sequences, allowing detection of cell group and frame timing using either sequence alone, and employing look-up tables for identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex sequence designs are used for synchronization signals to uniquely identify cell groups and frame timing, then measurement precision and reliability are improved, but device complexity increases
Solution Approach 1:
The cell group identification process is segmented into two stages: first detecting the primary synchronization signal (PSS) to identify the cell group, then detecting the secondary synchronization signal (SSS) to identify the specific cell within the group. This segmentation allows each synchronization signal to have a simplified design while collectively providing unique identification capability.
Solution Approach 2:
The cell group identification function is extracted from the overall cell search process and assigned specifically to the PSS detection stage. This extraction allows the PSS to be designed with simpler sequence structures while still providing sufficient information for cell group identification, reducing the complexity burden on the overall system.
2Measurement precision
If traditional cell search schemes are used to ensure accurate cell group detection, then measurement precision is improved, but loss of time increases due to interruptions during inter-frequency and inter-RAT measurements
Solution Approach 1:
The PSS is designed to contain cell group identification information that can be detected before the UE needs to perform inter-frequency or inter-RAT measurements. This preliminary detection allows the UE to prepare for measurements with knowledge of the cell group, reducing the need for interruptions during the actual measurement process.
Solution Approach 2:
The synchronization signal detection process is made dynamic by allowing the UE to adaptively adjust its measurement schedule based on the cell group information obtained from PSS detection. This dynamic approach enables the UE to minimize interruptions by planning measurements more efficiently around the synchronization information already acquired.
3Measurement precision
If synchronization signals are designed to provide complete cell identification information, then measurement precision is improved, but the complexity of processing and detecting these signals increases
Solution Approach 1:
The cell identification process is segmented into two distinct detection stages: PSS detection for cell group identification and SSS detection for specific cell identification within the group. This segmentation divides the complex processing task into two simpler, more manageable stages, reducing the processing complexity at each individual stage while maintaining complete identification capability.
Solution Approach 2:
The PSS is designed to provide partial cell identification information (cell group level) rather than complete cell identification. This partial action approach is sufficient for initial synchronization and measurement scheduling, allowing the system to proceed with reduced processing complexity while the SSS provides the remaining identification details when needed.
Data Source
AI summary
Timing parameters and an identity of a particular one of a number of cell groups are indicated in a signal transmitted in a cellular communication system having a radio frame in a physical layer, the radio frame comprising a number of time slots. In a known one of the time slots, a synchronization signal, S1, is transmitted that comprises a pair of sequences, Si%,Sj% (Si%≠Sj% arranged in a first ordering. In another known one of the time slots, a synchronization signal, S2 is transmitted that comprises the pair of sequences, Si%,Sj% arranged in a second ordering. The selected pair of sequences is uniquely identified with the particular cell group, and the first ordering of the sequences is used only for transmission in the known one of the time slots, and the second ordering of the sequences is used only for transmission in said another known one of the time slots.