Sidelink Resource Reservation With Flexible Frequency Allocation
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Solution Overview
Problem
Existing sidelink communication systems in 5G NR lack flexibility in frequency-domain resource reservations, leading to suboptimal performance, especially in scenarios involving hybrid automatic repeat request (HARQ) feedback-based retransmissions.
Innovation Solution
Implement flexible frequency resource reservations in sidelink communications, allowing for varying frequency allocations within a single sidelink control information (SCI) to adapt to channel conditions, enabling efficient spectral usage and improved decoding performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed frequency resource allocations are used in sidelink communications, then resource reservation is simplified, but spectral efficiency deteriorates due to inability to adapt to channel conditions
Solution Approach 1:
The patent implements dynamic frequency resource allocation where the frequency domain resources for retransmissions can differ from initial transmissions. The transmitting UE selects frequency resources adaptively based on HARQ feedback and channel conditions, allowing the system to transition from static to dynamic resource allocation. This resolves the contradiction by enabling spectral efficiency improvement through adaptability while maintaining manageable complexity through standardized procedures.
Solution Approach 2:
The patent changes the frequency domain parameters (resource block allocations, subchannel assignments) based on channel conditions and HARQ feedback. Different frequency resources are allocated for initial transmissions versus retransmissions, and resources can vary across different retransmission occasions. This parameter adaptation enables spectral efficiency improvement while the changes are governed by standardized protocols that control complexity.
2Loss of energy
If flexible frequency resource allocations are implemented in sidelink communications, then spectral efficiency improves through adaptation to channel conditions, but resource allocation complexity increases
Solution Approach 1:
The patent utilizes HARQ feedback mechanisms where receiving UEs send acknowledgment information about successful data reception. The transmitting UE uses this feedback to determine whether retransmissions are needed and selects appropriate frequency resources based on the feedback and channel conditions. This feedback-driven approach enables flexible resource allocation that improves spectral efficiency while the decision-making process remains structured and manageable.
Solution Approach 2:
The transmitting UE autonomously selects frequency resources for retransmissions based on HARQ feedback and channel conditions without requiring centralized scheduling. The UE serves itself by making intelligent resource allocation decisions, which improves spectral efficiency through adaptability while avoiding the complexity of centralized resource management. This self-service mechanism operates within standardized protocols that bound the complexity.
3Device complexity
If same frequency resources are used for all resource reservations, then resource allocation is simplified, but data transmission reliability deteriorates due to lack of diversity
Solution Approach 1:
The patent applies different frequency resource allocations to different transmission occasions (initial transmission versus retransmissions, different retransmission events). Each transmission receives locally optimized frequency resources based on its specific channel conditions and HARQ feedback status. This local quality differentiation improves reliability through frequency diversity while the allocation rules for each location remain standardized and manageable.
Solution Approach 2:
The patent implements dynamic frequency resource selection where the frequency allocation for retransmissions is determined adaptively based on channel conditions and HARQ feedback received between transmissions. This dynamic approach creates frequency diversity across transmission occasions, improving reliability while the dynamic selection follows standardized procedures that control complexity.
Data Source
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Figure 3A~3B
AI summary
Certain aspects of the present disclosure provide techniques for flexible resource reservations in sidelink communications. An example method that may be executed by a first user equipment (UE) includes determining, for sidelink communications with a second UE, one or more first resource reservations and one or more second resource reservations. The second resource reservations may have a different frequency resource allocation than the first resource reservations. The method also includes transmitting, to the second UE, control information having an indication of the first resource reservations and the second resource reservations. The method further includes communicating with the second UE based on the first resource reservations and the second resource reservations.