FDM Random Access Configuration for NR-U Interference Mitigation
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Solution Overview
Problem
Current wireless communication systems face interference and congestion issues due to increased demand for mobile broadband access, particularly in shared unlicensed frequency bands, leading to inefficiencies in channel access and communication latency.
Innovation Solution
A method and apparatus for user equipment (UE) to detect random access configuration messages across multiple frequency bands, select appropriate random access occasions, and transmit random access requests and connection requests to base stations, optimizing channel access by prioritizing frequency bands with better signal strength and resource availability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple frequency bands are used for random access, then channel access success rate is improved, but device complexity increases
Solution Approach 1:
The patent segments the random access procedure by dividing frequency bands into two distinct groups: first frequency bands used for initial random access request transmission, and second frequency bands used for random access response reception. This segmentation allows the UE to systematically manage multiple frequency bands without overwhelming complexity, improving channel access success rate by providing diverse access opportunities while maintaining manageable device complexity through structured band utilization.
Solution Approach 2:
The patent introduces a frequency dimension to the random access procedure by utilizing multiple frequency bands simultaneously for different stages of access. Instead of relying solely on time or spatial dimensions, the system expands into the frequency domain, allowing UEs to transmit requests on one frequency band while monitoring responses on another, thereby improving access reliability without proportionally increasing processing complexity.
2Loss of time
If random access occasions are distributed across multiple frequency bands, then communication latency is reduced, but signal detection difficulty increases
Solution Approach 1:
The patent applies local quality by assigning different functional characteristics to different frequency bands. First frequency bands are optimized for random access request transmission with appropriate signal characteristics, while second frequency bands are optimized for random access response reception. This localized optimization allows the system to reduce communication latency through parallel frequency utilization while simplifying signal detection within each band by tailoring detection parameters to the specific function and signal type expected in that frequency region.
Solution Approach 2:
The patent introduces frequency band selection as an intermediary mechanism between the UE and the random access procedure. The UE selects appropriate frequency bands based on configuration information and current channel conditions, acting as an intermediary that simplifies the detection process by narrowing the search space and focusing detection efforts on specific frequency regions where signals are expected, thereby reducing overall detection difficulty despite multi-band operation.
Data Source
AI summary
Frequency division multiplex (FDM) random access configuration and selection is disclosed for new radio (NR) unlicensed (NR-U) operations. For idle mode user equipment (UEs), the network may configured multiple frequency bands for random access. The UE may then select different frequencies for random access when default frequencies experience interference. For connected mode UEs, the network may configured which of multiple configured frequency bands the connected UE may use for autonomous random access transmissions. The UE may then select any of the allowed frequency bands for autonomous random access. Contention-free random access resources may be configured on one or more of the multiple configured frequency bands. When contention-free resources are available, the UEs may initially attempt access of the contention-free resources on the default frequency band before attempting random access on other configured bands or the UE is provided a priority of bands for access by the network.