Sidelink Resource Allocation via HARQ Feedback
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Solution Overview
Problem
In wireless communication systems, especially in NR V2X transmission, the existing retransmission mechanism for sidelink communication wastes resources due to always reserving retransmission resources, even when initial transmissions are successful, leading to inefficiency and increased resource waste.
Innovation Solution
A method for conditionally reserving retransmission resources based on Hybrid Automatic Repeat Request (HARQ) feedback, channel status, distance/coupling loss, and Channel Busy Ratio (CBR), allowing for dynamic allocation and reuse of resources, reducing unnecessary reservations and improving utilization efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If retransmission resources are always reserved in LTE V2X transmission scheme, then reliability of data transmission is improved, but resource utilization efficiency deteriorates due to unnecessary reservations
Solution Approach 1:
The patent applies dynamics by transitioning from static blind retransmission to dynamic HARQ feedback-based retransmission. The transmitting UE adjusts retransmission behavior based on real-time HARQ feedback (ACK/NACK) from the receiving UE, making the resource reservation dynamic rather than always reserved. This resolves the contradiction by maintaining reliability through feedback-driven retransmission while improving resource efficiency by avoiding unnecessary retransmissions when ACK is received.
Solution Approach 2:
The patent introduces HARQ feedback mechanism where the receiving UE sends ACK or NACK to the transmitting UE. This feedback enables the transmitting UE to make informed decisions about whether to perform retransmission and whether to reserve retransmission resources. The feedback principle directly resolves the technical contradiction by providing the information needed to balance reliability (retransmit when NACK) with resource efficiency (don't reserve when ACK).
2Reliability
If blind retransmission is performed in LTE V2X, then transmission reliability is improved, but transmission power consumption increases
Solution Approach 1:
The patent uses HARQ feedback (ACK/NACK) from the receiving UE to control retransmission decisions. When ACK is received, the transmitting UE knows the transmission was successful and avoids unnecessary retransmissions, thereby saving power. When NACK is received, retransmission is triggered to maintain reliability. This feedback-based approach resolves the contradiction between reliability and power consumption.
Solution Approach 2:
The patent changes the retransmission parameter from fixed (blind retransmission always on) to variable (conditional on HARQ feedback). The transmitting UE dynamically adjusts whether to retransmit based on the received feedback, changing the transmission behavior parameter to optimize the balance between reliability and power consumption.
3Reliability
If retransmission resources are always reserved, then data transmission reliability is improved, but interference on sidelink increases
Solution Approach 1:
The patent employs HARQ feedback to control retransmission resource reservation. When the receiving UE sends ACK, the transmitting UE releases reserved retransmission resources, reducing sidelink interference. When NACK is sent, resources are retained for retransmission to ensure reliability. This feedback mechanism resolves the contradiction by dynamically adjusting resource reservation based on actual transmission outcomes.
Solution Approach 2:
The patent applies discarding and recovering by releasing (discarding) reserved retransmission resources when they are not needed (ACK received), and recovering (retaining) them when needed (NACK received). This dynamic resource management reduces unnecessary resource occupation and sidelink interference while maintaining reliability when required.
Data Source
AI summary
Embodiments of the present application are directed to a method and apparatus for sidelink resource allocation. In an embodiment of the present application, the method includes determining a plurality of initial transmission resources, wherein each of the plurality of initial transmission resources is associated with a packet to be transmitted on a sidelink channel between a transmitting user equipment (UE) and a receiving UE; determining whether one or more retransmission resources are to be reserved for at least one of the packets associated with the plurality of initial transmission resources; and reserving the one or more retransmission resources for at least one of the packets in response to that the one or more retransmission resources are determined to be reserved.