P-SCH Subcarrier Mapping for Timing Synchronization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional wireless communication systems, such as IEEE 802.16e and 802.16m, face challenges in timing synchronization due to incomplete repetition patterns and increased Peak to Average Power Ratio (PAPR) caused by the number of sequences required for multiple cell IDs and supplementary information transmission, leading to interference and decreased detection performance.
Innovation Solution
The proposed solution involves generating a Primary Synchronization Channel (P-SCH) with a two-time repetition pattern by mapping sequences to odd-numbered or even-numbered subcarriers in the frequency domain, ensuring a complete repetition pattern and low PAPR, thereby improving timing synchronization and enabling efficient transmission of supplementary information like BS type and system parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If sequences are mapped to all subcarriers to support multiple cell IDs, then the number of distinguishable cell IDs increases, but the Peak to Average Power Ratio (PAPR) increases and correlation characteristic deteriorates
Solution Approach 1:
The patent segments the subcarriers into two groups: odd-numbered subcarriers and even-numbered subcarriers. By mapping sequences only to odd-numbered subcarriers, the system creates a structured subset that maintains good correlation properties while supporting multiple cell IDs. This segmentation resolves the contradiction by organizing the frequency resources in a way that preserves signal quality.
Solution Approach 2:
The patent applies local quality by concentrating sequence energy on specific subcarriers (odd-numbered ones) rather than distributing it uniformly across all subcarriers. This localized mapping approach improves the correlation characteristic and reduces PAPR while still providing sufficient diversity to support multiple cell IDs through the selected subset of subcarriers.
2Reliability
If a three-time repetition pattern is used in time domain, then timing synchronization can be achieved, but incomplete repetition pattern causes interference at cell boundaries
Solution Approach 1:
The patent extracts the harmful incomplete repetition pattern from the synchronization signal design and replaces it with a two-time repetition pattern. By removing the problematic three-time repetition structure that causes boundary interference, the system maintains timing synchronization capability while eliminating the interference issue at cell boundaries.
Solution Approach 2:
The patent implements periodic action through the two-time repetition pattern in the time domain. This periodic structure ensures that the synchronization signal repeats itself in a controlled manner, providing reliable timing synchronization while the specific period (two repetitions) is chosen to avoid the interference problems associated with other repetition counts at cell boundaries.
3Adaptability or versatility
If the number of sequences is increased to support more cell IDs, then more BSs can be distinguished, but the detection performance degrades
Solution Approach 1:
The patent transitions from considering only the time-domain repetition structure to incorporating frequency-domain subcarrier selection as an additional dimension for optimization. By mapping sequences to odd-numbered subcarriers in the frequency domain, the system creates a two-dimensional optimization approach (time repetition + frequency selection) that maintains detection performance while supporting more cell IDs.
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A Synchronization CHannel (SCH) transmission method includes generating a Primary SCH (P-SCH) sequence according to supplementary information, the supplementary information comprising at least one of Base Station (BS) type information, Fast Fourier Transform (FFT) size information, BandWidth (BW) information, group information, sector information, and carrier type information, modulating the P-SCH sequence, mapping the modulated P-SCH sequence to subcarriers within a predefined subcarrier set, the subcarriers included in the subcarrier set being spaced one subcarrier interval apart, generating a P-SCH symbol by Orthogonal Frequency Division Multiplexing (OFDM)-modulating the P-SCH sequence mapped to the subcarriers, and transmitting the P-SCH symbol.