Synchronization Signal Mapping in OFDM Symbols
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Solution Overview
Problem
Current synchronization signal designs for Discovery Reference Signals (DRS) in LTE are insufficient for one-shot synchronization in low Signal-to-Noise Ratio (SNR) conditions, and they do not effectively map multiple synchronization sequences to an Orthogonal Frequency-Division Multiplexing (OFDM) symbol for improved detection performance and low complexity receiver implementations.
Innovation Solution
A processor is configured to map at least two synchronization signal sequences, such as Primary Synchronisation Signals (PSS) and Secondary Synchronisation Signals (SSS), to a respective set of resource elements of one OFDM symbol. This is achieved by introducing one or more intermediate resource elements between the synchronization signal sequences, ensuring frequency diversity and maintaining frequency and time symmetry, which simplifies receiver implementations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple synchronization sequences are mapped to one OFDM symbol, then synchronization performance is improved, but receiver implementation complexity increases
Solution Approach 1:
The patent divides the OFDM symbol into multiple resource element sets, with each set carrying a separate synchronization sequence. Intermediate resource elements are inserted between adjacent sets to provide separation. This segmentation allows the receiver to process each sequence independently, maintaining low complexity while improving synchronization reliability through frequency diversity.
Solution Approach 2:
Intermediate resource elements are introduced as mediators between adjacent synchronization sequence sets. These intermediate elements provide frequency diversity and separation, enabling the receiver to distinguish between multiple sequences more easily without increasing processing complexity, thus resolving the contradiction between performance improvement and complexity increase.
2Measurement precision
If synchronization sequences are repeated in the frequency domain, then detection performance is improved, but frequency diversity is reduced
Solution Approach 1:
The patent applies different mapping strategies to different parts of the frequency spectrum. Synchronization sequences are mapped to specific resource element sets with intermediate elements between them, creating local variations in the frequency domain. This local quality differentiation maintains detection performance while introducing frequency diversity through the intermediate resource elements.
Data Source
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AI summary
Processor (920) configured to map at least two synchronisation signal sequences (310-1, 310-2, 310-3, 310-4) to a respective set of resource elements (210-0, 210-1,..., 210-61 ) of an OFDM symbol (220), wherein there is at least one resource element (330) between each pair of adjacent sets of resource elements (210-0, 210-1,..., 210-61 ).