GCL Sequence Cell Search Reducing Processing Complexity
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Solution Overview
Problem
Current mobile communication systems face challenges in quickly identifying a service cell or sector during initial access or handover, due to the need for exhaustive searches of cell-specific reference signals, which increases processing complexity and power consumption.
Innovation Solution
A method and apparatus utilizing chirp reference signal transmission with Generalized Chirp-Like (GCL) sequences that have optimal cyclic cross-correlation properties, allowing for fast cell search by detecting class indices, thereby simplifying the identification process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If exhaustive search method is used to detect each reference signal, then cell identification reliability is improved, but processing complexity and power consumption increase
Solution Approach 1:
The patent changes the parameter of reference signal sequence selection by using Gold codes with specific autocorrelation and cross-correlation properties. This allows the mobile station to reduce the search space by pre-selecting sequences with optimal correlation characteristics, thereby maintaining identification reliability while reducing processing complexity.
Solution Approach 2:
The patent applies preliminary action by pre-configuring the mobile station with a set of candidate reference sequences that have optimal correlation properties. This preliminary preparation allows the station to perform faster search without exhaustively checking all possible sequences, thus reducing real-time processing complexity while maintaining reliability.
2Reliability
If exhaustive search method is used to detect each reference signal, then cell identification reliability is improved, but power consumption increases
Solution Approach 1:
The patent changes the parameter of reference signal sequence selection by using Gold codes with specific autocorrelation and cross-correlation properties. This allows the mobile station to reduce the search space by pre-selecting sequences with optimal correlation characteristics, thereby maintaining identification reliability while reducing processing complexity.
Solution Approach 2:
The patent applies preliminary action by pre-configuring the mobile station with a set of candidate reference sequences that have optimal correlation properties. This preliminary preparation allows the station to perform faster search without exhaustively checking all possible sequences, thus reducing real-time processing complexity while maintaining reliability.
3Measurement precision
If reference sequences with good cross-correlation are used, then channel estimation accuracy is improved, but sequence design complexity increases
Solution Approach 1:
The patent uses copying by deriving multiple reference sequences from a single base Gold code through cyclic shifts and phase rotations. This allows the system to generate multiple sequences with optimal cross-correlation properties without independently designing each one, thus maintaining channel estimation accuracy while reducing sequence design complexity.
Solution Approach 2:
The patent applies universality by using Gold codes that serve multiple functions: they provide good autocorrelation for timing estimation, good cross-correlation for cell identification, and can be generated through a unified mathematical framework. This multi-functionality reduces the overall complexity of sequence design while maintaining estimation accuracy.
Data Source
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AI summary
A method and apparatus for transmitting a primary and secondary synchronization channel is provided herein. During operation a transmitter will transmit a primary synchronization channel (P-SCH) in a subframe and a secondary synchronization channel (S-SCH) in the subframe. The S-SCH is modulated by a complex exponential wave and scrambled with a scrambling code. In certain embodiments of the present invention the P-SCH comprises a GCL sequence or a Zadoff-Chu sequence and the scrambling code is based on the GCL sequence index of the P-SCH.