Random Access Preamble Grouping for Larger Cell Coverage
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Solution Overview
Problem
The limited capacity of preambles in existing random access procedures in wireless communication systems, particularly in new radio systems, restricts the number of available preambles due to the constraints imposed by cell radius and transmission delay, leading to insufficient preamble capacity.
Innovation Solution
The method involves increasing the number of available preambles by dividing them into groups based on historical timing advance (TA) information or geographical location information, allowing for a larger number of cyclic shifts and total preambles, thereby enhancing preamble capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the cell radius is increased to cover larger areas, then the coverage area is improved, but the transmission delay increases, which reduces the quantity of preamble cyclic shifts and decreases preamble capacity
Solution Approach 1:
The patent divides the preambles into multiple groups (first group, second group, third group, etc.) based on different TA value ranges. Each group contains preambles with cyclic shifts suitable for specific distance ranges from the network device. This segmentation allows the system to support both large coverage areas and maintain adequate preamble capacity by matching appropriate preamble groups to different cell regions.
2Length of moving object
If the step of cyclic shift values is increased to accommodate larger cell radius, then the cell radius coverage is improved, but the quantity of preamble cyclic shifts decreases, reducing total preamble capacity
Solution Approach 1:
The patent dynamically selects different preamble groups based on the terminal device's TA value or geographical location information. Instead of using a fixed cyclic shift step for all devices, the system adapts the cyclic shift parameters by selecting from multiple preamble groups, each optimized for different distance ranges. This dynamic adaptation maintains sufficient preamble capacity while supporting larger cell radii.
3Device complexity
If the quantity of preambles is limited by the ZC sequence length and root combinations, then the system complexity is reduced, but the preamble capacity becomes insufficient for large scale random access
Solution Approach 1:
The patent introduces a new dimension for preamble differentiation by organizing preambles into multiple groups based on TA value ranges or geographical locations. Instead of relying solely on the traditional single-dimension approach of root and cyclic shift combinations within one ZC sequence, the system adds the group dimension, effectively expanding the preamble space from N preambles to M×N preambles (where M is the number of groups), thereby increasing capacity without significantly increasing system complexity.
Data Source
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AI summary
Embodiments of this application provide a preamble transmission method, an apparatus, and a system, to increase a quantity of available preambles. The method includes: A terminal device obtains first information. The first information includes at least one of the following: historical timing advance TA information, geographical location information, or power information of the terminal device. The terminal device determines one group of preambles from KG groups of preambles based on the first information. KG is an integer greater than 1, a total quantity of preambles in the KG groups of preambles is positively correlated with a quantity of preamble cyclic shifts, and the quantity of preamble cyclic shifts is positively correlated with the quantity KG of groups of preambles. The terminal device sends a first preamble in the one group of preambles to a network device.