Sidelink Feedback Interlacing for OCB-Compliant Unlicensed Channels
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Solution Overview
Problem
Existing wireless communication systems face challenges in ensuring that sidelink feedback signaling on unlicensed channels meets the occupied channel bandwidth (OCB) condition, particularly due to varying numbers of sidelink transmissions and cast types, leading to potential interference and non-compliance with regulatory thresholds.
Innovation Solution
An adaptive interlacing scheme is employed where receiving UEs map sidelink feedback resources to initial and replica interlaces based on an interlace mapping rule, replicating feedback messages across available resources to satisfy the OCB condition, thereby minimizing interference and ensuring compliance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If receiving UEs transmit sidelink feedback on a single interlace, then device complexity is reduced, but the occupied channel bandwidth condition cannot be satisfied when multiple sidelink transmissions are detected
Solution Approach 1:
The feedback resources are segmented into multiple interlaces (first interlace and second interlace) instead of using a single interlace. Each interlace carries a portion of the feedback signals, allowing the system to distribute feedback transmissions across multiple frequency resources to satisfy the OCB condition while maintaining manageable complexity through structured segmentation
Solution Approach 2:
The patent introduces a frequency domain dimension by utilizing multiple interlaces (different frequency resources) for feedback transmission. Instead of relying solely on time domain resources, the system expands into the frequency dimension by mapping feedback to multiple interlaces, thereby increasing the occupied channel bandwidth and satisfying regulatory requirements
2Reliability
If receiving UEs map feedback to multiple interlaces to satisfy OCB condition, then regulatory compliance is achieved, but interference increases due to overlapping frequency resources
Solution Approach 1:
Different receiving UEs are assigned different local frequency resources (different interlaces or different portions of interlaces) for feedback transmission. This local quality differentiation ensures that each UE transmits on non-overlapping or minimally overlapping frequency resources, reducing mutual interference while collectively satisfying the OCB condition across the channel
Solution Approach 2:
The patent employs replica interlaces where feedback signals are copied to multiple frequency locations. By transmitting identical feedback content across multiple interlaces or interlace portions, the system ensures reliable delivery while distributing the transmission energy across non-conflicting frequency resources, thereby maintaining compliance without excessive interference
3Adaptability or versatility
If receiving UEs use fixed interlace mapping, then device complexity is reduced, but the system cannot adapt to varying numbers of sidelink transmissions and cast types
Solution Approach 1:
The interlace mapping is made dynamic rather than fixed. The system adapts the number of interlaces, the portion of interlaces used, and the specific frequency resources allocated based on the detected number of sidelink transmissions and their cast types. This dynamic adaptation allows the system to optimize resource usage and maintain OCB compliance across varying transmission scenarios
Solution Approach 2:
The patent changes key parameters of the feedback resource allocation based on transmission conditions: the number of interlaces used, the starting frequency position, the number of subcarriers allocated, and the interlace pattern itself. These parameter changes enable the system to adapt to different numbers of sidelink transmissions and cast types while maintaining manageable complexity through standardized adaptation rules
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. Multiple transmitting user equipments (UEs) may send sidelink data transmissions. Receiving sidelink UEs may map sidelink feedback interlaces corresponding to detected sidelink data transmissions to sidelink feedback resources of a common sidelink feedback symbol according to an interlace mapping rule (e.g., defining which contiguous or non-contiguous frequency resources the UE is to use for transmitting sidelink feedback for the received sidelink data messages). The receiving UEs may map one or more replicas of initial interlaces of sidelink feedback resources to additional available resources of the sidelink feedback resources in the common feedback symbol.