Random Access Preamble Transmission Using Flexible Time Resources
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Solution Overview
Problem
In 5G wireless communication systems, terminals at the cell edge face challenges in performing random access due to PRACH coverage limitations, as the time resource indicated by the base station is insufficient for transmitting random access preambles with larger subcarrier spacings, leading to incomplete random access capabilities.
Innovation Solution
The method involves configuring a wireless communication system with a combination of fixed and flexible time resources, allowing terminals to use part or all of the fixed uplink, fixed downlink, and flexible time resources to extend the time available for transmitting random access preambles, ensuring sufficient time resources are available for successful random access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a terminal uses a relatively large subcarrier spacing to achieve higher data rates, then the transmission speed improves, but the time length of the slot becomes relatively small, causing the time resource in PRACH resource to be insufficient for transmitting the random access preamble
Solution Approach 1:
The patent merges fixed uplink time resources with flexible time resources (originally intended for downlink or other purposes) to create an extended time resource pool for random access preamble transmission. This combination allows terminals with large subcarrier spacing to find sufficient time resources by utilizing both traditional uplink slots and previously unused flexible slots, thereby resolving the contradiction between high data rates and insufficient random access time resources.
2Device complexity
If the base station configures only fixed uplink time resources for random access, then the configuration is simple, but cell-edge terminals with larger subcarrier spacings cannot perform random access due to insufficient time resource length
Solution Approach 1:
The patent introduces flexible time resources that can be dynamically configured and adapted based on terminal requirements. Instead of a static fixed uplink time resource configuration, the system now includes flexible slots that can be allocated to random access purposes when needed, particularly benefiting cell-edge terminals with large subcarrier spacing while maintaining simple configuration for other terminals.
3Duration of action of moving object
If the time resource for random access preamble is extended to include fixed downlink time resource and flexible time resource, then the time resource available to random access preamble increases, but the system complexity increases due to multiple resource types
Solution Approach 1:
The patent makes flexible time resources universal by allowing them to serve multiple functions: downlink transmission when needed and random access preamble transmission when allocated to uplink purposes. This multi-functionality enables the same flexible time resources to extend random access capability without requiring separate dedicated resources, thereby increasing time resource availability while limiting the increase in system complexity.
Data Source
AI summary
This application provides a wireless communication method and an apparatus. The method includes: receiving higher layer signaling from a base station; receiving a broadcast message from the base station; and sending a random access preamble to the base station based on a random access configuration, where a time resource available to the random access preamble includes a part or all of a flexible time resource. Therefore, a random access requirement of a cell-edge terminal can be met, and a problem of PRACH coverage limitation can be resolved.