Random Access Preamble Transmission via Circular Shift
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Solution Overview
Problem
Current methods for transmitting messages in mobile communication systems using code sequences face challenges in data transmission efficiency, robustness to channel characteristics, and the need for unequal protection of information, particularly in the context of random access channels (RACH) where the length of sequences is limited and the degradation of CAZAC correlation characteristics affects performance.
Innovation Solution
Applying circular shift to code sequences to represent information and allocating sequences of different lengths based on error characteristics, allowing for increased data transmission efficiency and robustness while maintaining peak-to-average power ratio (PAPR) characteristics, and implementing unequal protection functions by determining sequence lengths according to the importance of information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the length of code sequence is increased to transmit more information, then data transmission capacity is improved, but the CAZAC correlation characteristics are degraded
Solution Approach 1:
The code sequence is divided into multiple segments or parts. Instead of using a single long code sequence that degrades correlation characteristics, the transmission system uses multiple shorter code sequences that are transmitted in sequence. Each segment maintains good CAZAC correlation properties while collectively they convey the required amount of information through their combination and ordering.
2Productivity
If circular shift is applied to code sequence to represent information, then data transmission efficiency is improved, but the peak-to-average power ratio characteristics are degraded
Solution Approach 1:
The system dynamically adjusts parameters such as the circular shift amount and code sequence length based on channel conditions and information importance. By changing these parameters adaptively, the system can represent more information through circular shifts while controlling the degradation of PAPR characteristics through selective parameter combination and optimization.
3Reliability
If unequal protection function is implemented by determining sequence lengths according to information importance, then information reliability is improved, but device complexity is increased
Solution Approach 1:
Different code sequences are allocated with different lengths and protection levels according to the local importance of each information element. Critical information uses longer sequences with higher protection, while less critical information uses shorter sequences. This localized quality differentiation achieves unequal protection without requiring complete reconfiguration of the entire system.
Data Source
AI summary
A method for transmitting a random access preamble from a user equipment is presented. The method includes generating the random access preamble by applying a circular shift to a code sequence having a sequence identifier, allocating the random access preamble to consecutive resource blocks, applying subcarrier spacing for the random access preamble to the consecutive resource blocks, and transmitting, via a transmitter of the user equipment, the random access preamble.