PRACH Preamble Access Slot Segmentation for Collision Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In existing communication technologies, the repeated sending of PRACH preambles by user equipment (UE) increases the probability of access failures due to collisions when multiple UEs use the same signature sequence, leading to inefficient coverage and access failures.
Innovation Solution
A method where a controller determines and sends access slot information to UEs, specifying the start access slot and quantity of repetitions for each RACH sub-channel, allowing UEs to repeatedly send PRACH preambles in specific access slots, thereby reducing collision probabilities and improving access success rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If UE repeatedly sends a same PRACH preamble in multiple access slots to improve coverage, then coverage capability is improved, but the probability of access failure increases due to higher collision probability with other UEs using the same signature sequence
Solution Approach 1:
The invention segments the access slot resources by introducing a start access slot parameter that divides the available access slots into multiple groups. Each UE is assigned to specific groups based on its coverage enhancement level, so that UEs at different coverage levels use different access slot groups. This segmentation reduces the probability of collision between UEs while maintaining the repetition benefit for coverage enhancement.
Solution Approach 2:
The invention applies local quality by providing different access slot configurations to different UEs based on their specific coverage requirements. The start access slot parameter is configured differently for different UEs or different coverage enhancement levels, allowing each UE to use optimal access slots tailored to its coverage needs while reducing overall system collision probability.
2Device complexity
If UE randomly selects an access slot from available slots to send PRACH preamble, then the system maintains simplicity in resource allocation, but collision probability increases when multiple UEs select the same slot
Solution Approach 1:
The invention implements preliminary action by pre-configuring start access slot parameters to UEs before the random access procedure. This pre-configuration guides UEs to select from specific access slot groups rather than all available slots, reducing collision probability while maintaining the randomness and simplicity of the selection process within each group.
3Temperature
If the base station performs combined processing on repeated PRACH preambles from the same UE, then coverage is improved through combined gain, but the probability of collision with other UEs increases
Solution Approach 1:
The invention segments the access slot resources into different groups using the start access slot parameter, where each group is assigned to UEs with specific coverage enhancement requirements. This segmentation ensures that repeated preambles from the same UE remain within a dedicated group, allowing the base station to perform combined processing for coverage improvement while preventing collisions with UEs in other groups.
Data Source
Figure 1
Figure 2~4
Figure 5
AI summary
Embodiments of the present invention provide a PRACH preamble sending method, a device, and a system. A controller determines access slot information according to at least one PRACH preamble repetition. The access slot information includes a start AS corresponding to each RACH sub-channel. ASs that start from the start AS and whose quantity is the quantity of PRACH preamble repetitions are used by same UE to send a same PRACH preamble. The controller sends the access slot information to each UE, so that each UE repeatedly sends a PRACH preamble to a base station according to the access slot information, and the ASs that start from the start AS and whose quantity is the quantity of PRACH preamble repetitions are all used by the same UE to repeatedly send the PRACH preamble to the base station. This resolves a problem that a possibility of a collision is increased due to repeatedly sending the PRACH preamble, thereby reducing a probability of an access failure.