5G PRACH Time and Frequency Shifts for Preamble Success
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Solution Overview
Problem
Existing 5G PRACH configurations face interference and preamble collision issues due to the use of the same root sequence index across sectors, leading to decreased preamble success rates and increased latency.
Innovation Solution
Implementing a PRACH configuration system that utilizes the same root sequence index across sectors but shifts preambles in time or frequency domains to avoid collisions and interference, using different time slots or frequency resources for each sector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the same root sequence index is used across sectors, then configuration simplicity is improved, but PRACH interference increases causing preamble success rate degradation
Solution Approach 1:
The patent applies dimensionality change by introducing time domain shifts (different time slots) and frequency domain shifts (different frequency resources) to separate preambles from different sectors. Instead of using different root sequence indices (one-dimensional solution), the patent multiplies the separation dimensions by adding time and frequency offsets, allowing the same root sequence index to be reused across sectors without interference.
2Reliability
If time shifting is applied to separate preambles, then interference is reduced, but processing complexity increases
Solution Approach 1:
The patent changes physical parameters (time slot indices and frequency resource indices) to achieve preamble separation. By modifying the time domain parameter (prach-TimeSlotIndex) and frequency domain parameter (prach-FrequencyStart) for different sectors, the system enables the same root sequence index to be reused while maintaining orthogonality and reducing interference.
3Reliability
If frequency shifting is applied to separate preambles, then interference is reduced, but spectral efficiency may be affected
Solution Approach 1:
The patent segments the frequency resources by allocating different frequency starts (msg1-FrequencyStart) to different sectors. This segmentation allows simultaneous reuse of the same root sequence index across sectors in different frequency regions, reducing interference while maintaining overall spectral efficiency through resource division.
Data Source
AI summary
Systems and methods for enhanced PRACH 5G configuration by preventing interference with signal transmission. One such method includes: implementing a PRACH configuration in which the same root sequence index (RSI) is utilized across the sectors of the site, implementing the PRACH configuration in which a time shift is utilized for each preamble that provides each preamble with its own time slot, enabling multiple UEs to each send a preamble that is time shifted to arrive at the gNB at different times and avoid a RAPID (Random Access Preamble Identifier) mismatch, and receiving preambles that are frequency shifted and reducing PRACH interference among different sectors that causes a degradation of PRACH performance using shifts in time domain.