Cell-Free Random Access Preamble Selection Across Multiple APs
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Solution Overview
Problem
The existing RACH procedure is not applicable to cell-free networks where the concept of a cell is obsolete, and user equipment (UE) communicates with multiple access points (APs, leading to challenges in random access management.
Innovation Solution
A random access method that involves determining a preamble based on information from multiple target signals, transmitting and receiving corresponding information to facilitate communication in a cell-free communications system, including a four-step RACH procedure with MSG1-MSG4 interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the existing RACH procedure is used in cell-free networks, then the terminal can perform random access, but the procedure becomes inapplicable due to the absence of cell concepts and identifiers
Solution Approach 1:
The patent applies universality by designing a random access procedure that works across multiple access points without requiring cell-specific identifiers. The terminal determines preambles based on target signal information from multiple APs, making the RACH procedure universally applicable to cell-free network architecture where traditional cell concepts are obsolete.
Solution Approach 2:
The patent changes the fundamental parameters of the RACH procedure by replacing cell ID-based preamble determination with target signal information-based preamble determination. This parameter change adapts the procedure to cell-free networks where multiple APs serve terminals without traditional cell boundaries, resolving the inapplicability issue.
2Reliability
If a terminal communicates with multiple access points in a cell-free network, then communication reliability improves, but the random access management becomes more complex
Solution Approach 1:
The patent segments the random access management by having the terminal determine preambles independently for each target signal from different access points. This segmentation allows the terminal to handle multiple APs through separate preamble determination processes, managing complexity while maintaining communication with multiple reliable APs.
Solution Approach 2:
The patent applies preliminary action by having the terminal determine preambles based on target signal information before the actual random access transmission. This preliminary determination of preambles for multiple APs simplifies the subsequent random access procedure, reducing management complexity while ensuring reliable communication setup.
3Ease of operation
If the preamble is determined based on a single cell's SSB index, then the RACH procedure is simple, but it cannot be applied to cell-free networks with multiple access points
Solution Approach 1:
The patent merges the preamble determination process with target signal information from multiple access points. Instead of using a single cell's SSB index, the terminal combines information from multiple target signals to determine preambles, maintaining operational simplicity while achieving compatibility with cell-free network architecture.
Solution Approach 2:
The patent makes the preamble determination mechanism universal by designing it to work with target signal information from any number of access points. This multi-functional approach allows the same procedure to serve both traditional and cell-free networks, enhancing adaptability without sacrificing ease of operation.
Data Source
AI summary
A random access method, a terminal device, and a network device are provided. The method includes: transmitting first information used for random access, where a preamble carried in the first information is determined based on information of a plurality of target signals; receiving second information transmitted by a network device, where the second information is a random access response to the first information; transmitting third information based on the second information; and receiving fourth information transmitted by the network device, where the fourth information is response information to the third information.