Scrambling Codes for Secondary Synchronization in Wireless Systems

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Solution Overview

Problem

Wireless communication systems face challenges in optimizing peak-to-average power ratios and minimizing cross-correlation of secondary synchronization codes, which affect signal transmission efficiency and interference avoidance.

Innovation Solution

The use of scrambling codes indexed by primary synchronization codes, designed to minimize peak-to-average power ratios and cross-correlation, is employed to scramble and descramble secondary synchronization codes, optimizing their transmission and reception in wireless communication environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If secondary synchronization codes are transmitted without scrambling, then transmission simplicity is maintained, but peak-to-average power ratio optimization and cross-correlation minimization are compromised

Engineering Contradiction:
Improvetransmission simplicityVSAvoidsignal transmission efficiency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

A scrambling code is introduced as an intermediary element between the secondary synchronization code and the transmission channel. The scrambling code, selected based on the primary synchronization code index, modifies the SSC to optimize peak-to-average power ratio and minimize cross-correlation, thereby resolving the contradiction between transmission simplicity and signal efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If scrambling codes are applied to secondary synchronization codes, then peak-to-average power ratio and cross-correlation are optimized, but system complexity increases

Engineering Contradiction:
Improvesignal transmission efficiencyVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system optimizes signal properties by changing parameters of the scrambling codes. Different scrambling codes are selected based on the primary synchronization code index, with each scrambling code having specific properties optimized for particular transmission conditions. This allows optimization of peak-to-average power ratio and cross-correlation through parameter selection rather than structural complexity.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If multiple scrambling codes are used to minimize cross-correlation, then interference avoidance is improved, but code selection and management complexity increases

Engineering Contradiction:
Improveinterference avoidanceVSAvoidcode selection complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

Different scrambling codes with locally optimized properties are applied to different secondary synchronization codes based on the primary synchronization code index. Each scrambling code is specifically designed or selected to minimize cross-correlation with particular other codes in the set, providing localized optimization of interference avoidance without requiring global system complexity.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2213028B1Scrambling codes for secondary synchronization codes in wireless communication systems
Publication Date: 2016.12.21 QUALCOMM INC
  • EP2213028B1 patent drawing
  • EP2213028B1 patent drawing
  • EP2213028B1 patent drawing

AI summary

Systems and methodologies are described that facilitate employing a scrambling code from a set of scrambling codes, which is indexed by primary synchronization codes (PSCs), to scramble or descramble a secondary synchronization code (SSC). The scrambling codes in the set can be designed to optimize peak-to-average power ratios and/or mitigate cross correlation. For example, the scrambling codes can be based on different M-sequences generated from disparate polynomials. In accordance with another example, the scrambling codes can be based on different cyclic shifts of the same M-sequence. According to another example, the scrambling codes can be based upon binary approximations of possible primary synchronization codes utilized in a wireless communication environment. Pursuant to a further example, the scrambling codes can be based on different Golay complementary sequences.