LTE Cell Search via P-SyS to Reference Signal Mapping
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Solution Overview
Problem
In LTE wireless communication networks, the large search space for determining reference symbol sequences and inaccuracies in channel estimation complicate the cell synchronization process, leading to inefficient cell identification.
Innovation Solution
A method that links Primary Synchronization Signals (P-SyS) sequences to reference signal sequences through a defined mapping, reducing the search space and facilitating cell identification by mapping detected P-SyS sequences to corresponding reference signal sequences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE performs correlation processing with all possible reference symbol sequences to determine cell ID, then the cell identification is comprehensive, but the search space becomes undesirably large and processing complexity increases
Solution Approach 1:
The patent segments the cell identification process into two stages: first identifying the cell group ID through S-SyS correlation with a reduced set of sequences, then determining the specific cell ID within the group. This segmentation divides the large search space into manageable subsets, reducing overall processing complexity while maintaining identification completeness
Solution Approach 2:
The patent performs preliminary channel estimation using P-SyS and S-SyS signals before the actual reference symbol sequence correlation. This preliminary action provides accurate channel compensation that enables reliable cell identification with fewer hypotheses, effectively reducing the search space while maintaining reliability
2Measurement precision
If the UE uses channel estimates based on P-SyS and S-SyS to mitigate propagation channel effects, then the reference symbol sequence reception is improved, but channel estimation inaccuracies still compromise cell search
Solution Approach 1:
The patent introduces P-SyS and S-SyS signals as intermediary elements that facilitate accurate channel estimation before reference symbol sequence detection. These intermediary signals serve as known references that enable precise channel compensation, improving the reliability of subsequent cell identification operations
Solution Approach 2:
The patent performs channel estimation and compensation as a preliminary action before correlating reference symbol sequences. By establishing accurate channel conditions in advance, the system ensures that subsequent cell identification operations are not compromised by propagation effects, maintaining high reliability
3Adaptability or versatility
If the network uses 510 unique reference symbol sequences to provide 510 unique cell identifications, then the cell identification capacity is sufficient, but the UE processing load and search time increase
Solution Approach 1:
The patent segments the 510 reference symbol sequences into multiple cell groups, where each group is associated with a specific S-SyS sequence. The UE first identifies the cell group through S-SyS detection, then only searches within that specific group for the final cell ID. This segmentation maintains the full 510-cell identification capacity while dramatically reducing the search time by limiting the correlation processing to a subset of sequences
Solution Approach 2:
The patent performs preliminary cell group identification through S-SyS detection before the actual cell ID search. This preliminary action narrows down the search space from 510 possible sequences to a much smaller subset, reducing cell search time while preserving the ability to identify all 510 unique cells
Data Source
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AI summary
For wireless networks that transmit synchronization signals allowing user equipment to synchronize to cells within the network and transmit reference signals allowing user equipment to determine cell identities, a method and apparatus taught herein advantageously link the synchronization signal sequences to the reference signal sequences according to a defined mapping. The linkingsimplifies the cell search process by allowing user equipment to determine cell identities based on mapping detected synchronization signal sequences to the corresponding reference signal or to the corresponding subset of referencesignals in embodiments where there are more reference signal sequences than synchronization signal sequences.In at least one embodiment, the network is a 3G LTE network and at least the Primary Synchronization Signal(P-SyS) sequences are linked to the Downlink (DL) reference symbol sequences according to a defined mapping, thereby allowing to user equipment to determine cell identities from detected P-SySsequences.