Secondary Synchronization Signal Shift Index Scaling
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Solution Overview
Problem
In wireless communication systems, particularly in LTE and LTE-A, there is a challenge in accurately detecting cell IDs due to frequency offset errors during the transmission of synchronization signals, which affects the synchronization and frame boundary detection of user equipment (UE) with base stations.
Innovation Solution
The method involves determining shift indexes for generating secondary synchronization signal (SSS) sequences based on cell identifiers, where the first shift index is scaled by an integer value greater than or equal to 3, and the sequences are cyclically shifted and mapped to specific resource elements, ensuring robustness against frequency offsets by using a combination of M-sequences and cyclic shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional SSS sequence generation is used, then device complexity is reduced, but measurement precision of cell ID detection deteriorates due to frequency offset errors
Solution Approach 1:
The patent applies parameter changes by scaling the first shift index by an integer value K≥3 and using different shift indexing methods for the first and second M-sequences. This modifies the sequence generation parameters to create frequency offset robustness, improving cell ID detection accuracy while maintaining manageable complexity through systematic parameter adjustment
Solution Approach 2:
The patent segments the SSS generation process into two independent M-sequences with different shift indexing strategies. The first M-sequence uses scaled shift indexing (K×shift) while the second uses conventional indexing, allowing each sequence to be optimized independently for frequency offset robustness and detection accuracy
2Reliability
If frequency offset robustness is enhanced through scaled shift indexing, then reliability of synchronization improves, but device complexity increases due to additional processing steps
Solution Approach 1:
The patent introduces a scaling parameter K≥3 for the first shift index to enhance frequency offset robustness. This parameter change improves synchronization reliability by making the sequence less sensitive to frequency offsets, while the systematic nature of the scaling keeps processing complexity manageable
Solution Approach 2:
The patent applies preliminary action by pre-determining the shift indexes based on cell ID before sequence generation. The scaled shift index for the first M-sequence is calculated in advance, allowing the sequence generation to proceed efficiently without requiring complex real-time adjustments during synchronization
Data Source
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AI summary
The present invention discloses a method of transmitting an SSS (secondary synchronization signal), which is transmitted by a base station, in a wireless communication system. The method includes the steps of determining a first shift based on a first and a second cell identifiers for identifying a cell, and determining a second shift index based on the first cell identifier and transmitting the SSS using a first sequence which is generated based on the first shift index and a second sequence which is generated based on the second shift index. In this case, the first shift index can be determined as K times a value determined based on the first and second cell identifiers, where K is an integer equal to or greater than 3.