Base Station RACH Resource Allocation for 5G Initial Access
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Solution Overview
Problem
In the 5G NR wireless communication system, there is a challenge in appropriately arranging RACH resources within a radio frame for initial access, which is essential for efficient random access channel operations, especially considering the increased propagation loss at higher frequency bands.
Innovation Solution
The solution involves arranging RACH resources based on the locations of SS blocks within the radio frame, using specific subcarrier spacings and preamble formats, and specifying the association between SS blocks and RACH resources to optimize their placement and usage for initial access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If beamforming with narrow beam width is applied to compensate for propagation loss in high frequency bands, then signal quality is improved, but the complexity of arranging RACH resources in radio frame increases
Solution Approach 1:
The patent segments the RACH resources by associating them with specific SS blocks (synchronization signal blocks) transmitted in different beams. Each SS block is linked to dedicated RACH resources, allowing the system to handle multiple beams and frequency hops systematically. This segmentation resolves the complexity by breaking down the resource arrangement into manageable units tied to specific transmission beams and time slots.
Solution Approach 2:
The patent performs preliminary actions by pre-configuring the association between SS blocks and RACH resources in the system information. The base station prepares and transmits system information that specifies which RACH resources correspond to which SS blocks before the actual random access procedure. This preliminary configuration simplifies the user equipment's task of determining correct resource allocation.
2Reliability
If multiple SS blocks are transmitted in different beams for initial access, then coverage and signal quality are improved, but the difficulty of detecting and measuring RACH resource locations increases
Solution Approach 1:
The patent introduces SS blocks as intermediary elements that carry system information including RACH resource configuration. The SS blocks act as mediators between the base station's beamforming transmission and the user equipment's resource selection. By embedding RACH resource location and configuration information within the SS blocks themselves, the system enables reliable detection without requiring separate signaling mechanisms.
Solution Approach 2:
The SS blocks serve multiple functions: they provide synchronization signals, transmit system information, and carry RACH resource configuration. This multi-functionality eliminates the need for separate dedicated channels for resource announcement, simplifying the overall system structure and reducing the difficulty of detecting RACH resource locations while maintaining reliable initial access across multiple beams.
Data Source
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AI summary
A base station apparatus that communicates with a user apparatus is provided. The base station apparatus includes: a setting unit configured to arrange in a radio frame one or more blocks and information, the one or more blocks including information used for initial access, the information specifying resources that are associated with the blocks and are used for transmitting preambles; a transmission unit configured to transmit the radio frame to the user apparatus; and a reception unit configured to receive the preambles from the user apparatus via the resources. The information specifying the resource is set based on locations of the blocks arranged in the radio frame.