Bandwidth Part Configuration for Random Access in NR-U
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Solution Overview
Problem
Current bandwidth configuration methods for User Equipment (UE) in NR-U systems are inadequate for handling multiple LBT sub-bands, leading to inefficiencies in Random Access (RA) procedures and resource utilization.
Innovation Solution
The proposed method involves configuring Bandwidth Parts (BWP) with multiple LBT sub-bands, allowing the UE to select an available sub-band for RA, and defining parameters like sub-band offset and PRACH transmission occasions to optimize RA procedures across different sub-bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a single BWP configuration is used for Random Access in NR-U, then the configuration is simple, but it cannot efficiently handle multiple LBT sub-bands leading to increased RA latency
Solution Approach 1:
The patent divides the bandwidth part into multiple LBT sub-bands, each with its own PRACH configuration. This segmentation allows the UE to perform LBT on individual sub-bands and select an available sub-band for random access, thereby reducing RA latency caused by LBT failures on the entire BWP while maintaining manageable configuration complexity through structured sub-band organization.
Solution Approach 2:
The patent introduces frequency domain segmentation by creating multiple LBT sub-bands within the BWP. This dimensional division allows parallel random access opportunities across different frequency sub-bands, transforming a single-point failure scenario into a multi-point redundancy scenario, thus reducing overall RA latency without proportionally increasing complexity.
2Productivity
If LBT is performed on the entire BWP before Random Access, then channel access is ensured, but it increases the time required for channel access and reduces RA efficiency
Solution Approach 1:
The patent segments the BWP into multiple LBT sub-bands, allowing the UE to perform LBT on individual sub-bands rather than the entire BWP. This enables faster channel access by identifying available sub-bands more quickly and allows parallel LBT operations on multiple sub-bands, thereby improving RA efficiency while reducing the effective channel access time.
Solution Approach 2:
The patent applies LBT only to necessary portions of the spectrum by dividing the BWP into sub-bands. The UE can perform LBT on a subset of sub-bands and select from available ones, performing partial LBT action rather than exhaustive LBT on the entire BWP, thus reducing channel access time while maintaining sufficient channel access control for efficient RA.
Data Source
AI summary
The present disclosure relates to telecommunications. In one of its aspects, the disclosure concerns a method performed by a User Equipment (UE) in a communications system. The method comprises receiving information indicating a Bandwidth Part (BWP) configuration from a network node. The BWP configuration comprises at least one initial BWP and at least one non-initial BWP. The method further comprises transmitting, to the network node, a Random Access (RA) preamble message according to the received BWP configuration to initiate a RA procedure with the network node.