Cell Synchronization Code Assignment Permutations
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Wireless communication systems face challenges in efficiently assigning primary and secondary synchronization codes to cells, leading to suboptimal cell detection performance for user equipment (UEs), particularly due to phase mismatch issues and increased detection complexity.
Innovation Solution
Assigning unique primary synchronization code (PSC) and secondary synchronization code (SSC) sequences to cells based on their identity, with different permutations of SSC sequences used across Node Bs to prevent phase mismatch and ensure unambiguous channel estimation, allowing UEs to efficiently detect cells and demodulate downlink channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the same SSC sequences are used across multiple Node Bs, then device complexity is reduced, but phase mismatch occurs leading to degraded measurement precision
Solution Approach 1:
The patent applies local quality by assigning different permutations of SSC sequences to different Node Bs based on their local identifiers. Each Node B uses a specific permutation (e.g., Node B 1 uses SSC(G1), SSC(G2), SSC(G3) while Node B 2 uses SSC(G2), SSC(G3), SSC(G1)), ensuring that local channel characteristics are uniquely identified without requiring complex system-wide coordination. This resolves the contradiction by maintaining simple sequence structures locally while preventing phase mismatch through localized differentiation.
2Measurement precision
If different permutations of SSC sequences are assigned to different Node Bs, then measurement precision is improved by preventing phase mismatch, but device complexity increases due to permutation management
Solution Approach 1:
The patent implements universality by using a single set of base SSC sequences (G1, G2, G3) that serve multiple functions through different permutations. The same base sequences are reused across all Node Bs, but their assignment order varies by Node B identity. This universal approach allows the system to maintain a limited sequence pool while achieving differentiation, thus improving measurement precision without proportionally increasing complexity.
Solution Approach 2:
The patent applies parameter changes by modifying the assignment parameters (permutation indices) of SSC sequences based on Node B identifiers rather than changing the sequences themselves. Each Node B is assigned a specific permutation pattern (e.g., cyclic shifts of the base sequences), which changes the effective parameter configuration locally. This allows precise channel estimation through parameter differentiation while keeping the underlying sequence structure simple and manageable.
3Measurement precision
If more SSC sequences are used to differentiate cells, then measurement precision is improved, but the quantity of substance increases leading to higher overhead
Solution Approach 1:
The patent applies segmentation by dividing the cell identification function into two parts: PSC sequences for primary cell detection and SSC sequences for secondary identification. Within the SSC layer, further segmentation occurs through permutation groups assigned to different Node Bs. This segmentation allows the system to differentiate multiple cells using a limited set of base sequences by varying their assignment patterns, thus improving cell detection accuracy without proportionally increasing the total number of sequences required.
Data Source
AI summary
Techniques for assigning primary synchronization code (PSC) sequences and secondary synchronization code (SSC) sequences to cells in a wireless communication system are described. At least one PSC sequence and multiple SSC sequences may be used for multiple cells in a Node B. In one design, the available SSC sequences in the system may be arranged into groups, with each group including M different SSC sequences. Additional groups of M SSC sequences may be formed with different permutations (e.g., different cyclic shifts) of each group of M SSC sequences. In one design, three SSC sequences SSC(G1), SSC(G2) and SSC(G3) may be used for three cells in one Node B. A first permutation including SSC(G3), SSC(G1) and SSC(G2) may be used for three cells in another Node B. A second permutation including SSC(G2), SSC(G3) and SSC(G1) may be used for three cells in yet another Node B.