Cell Search Frequency Shifts in Orthogonal Wireless Systems
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Solution Overview
Problem
Wireless communication systems face challenges in efficiently and reliably constructing synchronization and reference signals due to features like cyclic prefix in 3G LTE and E-UTRA systems, which complicate cell acquisition procedures, necessitating improved methods for maximizing system speed and reliability while minimizing resource usage.
Innovation Solution
A method and apparatus for coordinating transmission of signals in wireless communication systems by creating a frequency reuse pattern, applying frequency shifts to base frequencies, and linking cells to respective frequency sets based on identifiers, enabling efficient generation and transmission of reference signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cyclic prefix is added to mitigate inter-symbol interference in OFDM systems, then system reliability is improved, but device complexity and signal construction difficulty increase
Solution Approach 1:
The patent segments the frequency spectrum into multiple groups or sets of subcarriers. Each group is assigned to different cells with specific frequency shifts, allowing reference signals to be constructed in a modular and organized manner that reduces complexity while maintaining reliability in OFDM systems with cyclic prefix
2Adaptability or versatility
If downlink system bandwidth versatility is increased, then system adaptability is improved, but cell acquisition procedure complexity increases
Solution Approach 1:
The patent employs frequency shifts as a key parameter to differentiate cells across different bandwidth configurations. By applying cell-specific frequency shifts to reference signals, the system achieves bandwidth versatility while maintaining a standardized and simplified cell acquisition procedure that does not become more complex with increased bandwidth options
3Reliability
If frequency shifts are applied to differentiate cells, then cell identification reliability is improved, but frequency resource usage increases
Solution Approach 1:
The frequency spectrum is segmented into multiple groups, with each group serving specific cells. This segmentation allows frequency shifts to be applied in an organized manner where each cell is assigned to a specific group, improving cell identification reliability while efficiently utilizing frequency resources without unnecessary overlap or waste
Data Source
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AI summary
Systems and methodologies are described that provide techniques for efficient cell search in a wireless communication system. In one aspect, a frequency reuse pattern can be generated by applying frequency shifts to reference signals transmitted from cells that provide coverage for a NodeB based on cell IDs or cell group IDs for the cells. The frequency shifts applied to reference signals can then be utilized as a basis for multiplexing reference signals from different cells using frequency division multiplexing (FDM) or a combination of FDM and other multiplexing techniques. Other adjustments to reference signals transmitted from respective cells, such as transmit power adjustments, can further be made to improve detection performance.