Non-CAZAC Pilot Sequences for Wireless Receiver Identification
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Solution Overview
Problem
In wireless communication systems, particularly in WLANs, the efficient transmission of pilot sequences is hindered by the limitations of existing channel access mechanisms, leading to increased power consumption and interference, especially in scenarios with a large number of apparatuses, such as in M2M communication.
Innovation Solution
The use of non-CAZAC sequences for pilot transmission, which minimizes correlation between pilot sequences and considers hardware performance to improve receiver identification and reduce EVM, thereby enhancing channel access efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CAZAC sequences are used for pilot transmission, then orthogonality between pilot sequences is improved, but receiver identification performance deteriorates when hardware imperfections are present
Solution Approach 1:
The patent changes the fundamental parameter of the pilot sequence from CAZAC to non-CAZAC sequences. This parameter change allows the system to prioritize receiver identification performance over perfect orthogonality, as non-CAZAC sequences are more robust to hardware imperfections like phase noise and frequency offsets, even though they sacrifice some orthogonality properties
Solution Approach 2:
The patent employs quantized non-CAZAC sequences that are computationally simpler and more tolerant of hardware imperfections. These sequences can be generated and processed with lower precision hardware, effectively using 'cheaper' signal processing that is more resilient to real-world hardware limitations
2Measurement precision
If non-CAZAC sequences are used for pilot transmission, then receiver identification performance is improved, but correlation between pilot sequences increases
Solution Approach 1:
The patent applies local quality by designing non-CAZAC sequences with specific local properties that minimize correlation in certain domains while maintaining robustness in others. The sequences are engineered to have controlled correlation characteristics that prioritize identification performance while managing interference through careful sequence design
Solution Approach 2:
The patent changes the sequence type parameter from CAZAC to non-CAZAC, fundamentally altering the correlation properties. This parameter change accepts increased correlation as a trade-off for significantly improved receiver identification performance in the presence of hardware imperfections
3Device complexity
If channel access mechanism is not improved, then system simplicity is maintained, but power consumption increases and interference occurs in M2M communication scenarios
Solution Approach 1:
The patent changes the pilot sequence parameter to non-CAZAC sequences, which enables more efficient channel access in M2M scenarios. This parameter change improves the ability to distinguish between multiple transmitters, thereby reducing interference and enabling more efficient medium access without requiring complex protocol changes
Data Source
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AI summary
Disclosed is a method for transmitting a pilot sequence, the method comprising: generating a sequence set on the basis of a baseline sequence having non-CAZAC properties; and selecting any one pilot sequence form among sequence sets corresponding to different additional information, and transmitting same to a receiver.