Composite Code Sequence Generation for Multi-Path Robustness
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Solution Overview
Problem
The existing mobile communication systems face limitations in the number of code sequence types available for initial synchronization, cell detection, and channel estimation, particularly due to the restricted length of code sequences which affects bandwidth efficiency and the ability to handle multi-path effects in radio channels.
Innovation Solution
A method is introduced to generate new code sequences by combining at least two different code sequences, such as CAZAC sequences, through addition or concatenation, and converting them into time domain signals, which allows for increased code diversity and robustness against multi-path interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the code sequence length is increased to generate more code types, then the number of available code sequence types increases, but the bandwidth efficiency decreases and the system becomes more complex
Solution Approach 1:
The patent combines multiple code sequences (e.g., two CAZAC sequences) through addition or concatenation to generate new code sequences. This merging approach allows the system to create a larger variety of code types without increasing the length of individual sequences, thereby resolving the contradiction between code diversity and system complexity
Solution Approach 2:
The patent creates composite code sequences by combining base code sequences (such as CAZAC sequences) into new composite structures. These composite sequences maintain the desirable properties of the original sequences while providing increased code diversity, effectively solving the problem of limited code types without proportionally increasing system complexity
2Reliability
If the code sequence length is increased to handle multi-path effects, then the robustness against multi-path interference improves, but the bandwidth efficiency decreases
Solution Approach 1:
By combining multiple shorter code sequences through addition or concatenation, the patent achieves the equivalent of longer sequences in terms of robustness, while maintaining better bandwidth efficiency. The combined sequences provide sufficient length to handle multi-path effects without the inefficiency of simply using one very long sequence
3Adaptability or versatility
If the number of orthogonal codes is increased, then the code diversity increases, but the orthogonality is lost and cross-correlation increases
Solution Approach 1:
The patent generates new code sequences by combining existing orthogonal codes through addition or concatenation operations. This parameter change approach creates new sequences that maintain good correlation properties and low cross-correlation, achieving high code diversity while preserving the essential orthogonality characteristics needed for reliable communication
Data Source
AI summary
A method for transmitting a signal by a transmitting side device, the method including combining a first sequence and a second sequence to generate a third sequence in a frequency domain. The second sequence is obtained by cyclic shifting the first sequence. The method further includes transforming the third sequence into a time domain signal; and transmitting the time domain signal to a receiving side device. The third sequence includes information to identify a cell and is periodically transmitted.