Random Access Resource Time Alignment in 5G NR
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Solution Overview
Problem
In New Radio (NR) technology, there is a conflict between the time the base station sends a downlink signal and the time the terminal sends an uplink random access preamble, due to the short period for sending downlink signals, which can lead to overlapping communication times.
Innovation Solution
A method where the terminal determines available random access resources based on time location information for both random access and downlink signals, ensuring non-overlapping times, and uses these resources to send a random access preamble, or punctures overlapping resources to avoid conflicts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the base station sends downlink signals in a short period (5ms window), then the downlink signal transmission efficiency is improved, but the time for sending downlink signals conflicts with the time for sending uplink random access preambles
Solution Approach 1:
The patent segments the time resources by dividing the 5ms window into distinct downlink signal transmission periods and uplink random access preamble periods. This segmentation allows downlink signals to be sent in specific slots while reserving other slots for uplink random access, preventing time conflicts between the two functions while maintaining high downlink transmission efficiency
Solution Approach 2:
The patent dynamically adjusts the time locations of downlink signals and random access resources based on actual transmission needs. The network device can flexibly configure which slots within the 5ms window are used for downlink signals versus random access, allowing adaptive optimization of both downlink efficiency and random access reliability under different traffic conditions
2Area of stationary object
If downlink signals are sent in nearly all slots in one system frame, then the downlink signal coverage is improved, but the conflict with uplink random access preamble time increases
Solution Approach 1:
The patent resolves the conflict by transitioning from a one-dimensional time conflict to a two-dimensional time-frequency resource allocation. By carefully selecting which slots within the 5ms window are used for downlink signals versus random access, the system achieves both wide downlink coverage and reliable random access without time conflicts
Data Source
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AI summary
This application provides a communication method, an apparatus, and a communications system. The communication method comprises: sending information for random access resources to a terminal; wherein a time location for at least one actually available random access resource in the random access resources does not precede a time location for the at least one SS/PBCH block, and the at least one actually available random access resource comprises a random access resource whose time location is after the time location for the at least one SS/PBCH block; and receiving a random access preamble from the terminal based on the at least one actually available random access resource.