IAB Uplink Preemption Signaling for Full-Duplex URLLC Puncturing
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Solution Overview
Problem
Current mmW 5G NR systems face challenges with self-interference due to urgent ultra-reliable-low latency communications (URLLC) packets during ongoing uplink transmissions in integrated access and backhaul (IAB) nodes, particularly in full-duplex operations, where existing downlink preemption indications are not available for uplink communications.
Innovation Solution
The IAB node transmits uplink preemption indications by puncturing specific resources or symbols in ongoing PUSCH transmissions to accommodate urgent URLLC traffic, using techniques such as PUCCH resource indication, reserved resource elements in PUSCH, subsequent PUSCH retransmissions, and MAC-CE messages, to minimize self-interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the IAB node transmits uplink traffic to the parent backhaul node during a first time slot, then the uplink transmission can proceed normally, but self-interference occurs when urgent URLLC traffic needs to be received from a child node or UE during the same time slot
Solution Approach 1:
The uplink transmission resources are segmented by puncturing specific symbols or resource elements within the PUSCH transmission. This allows the IAB node to selectively remove affected resources while maintaining the rest of the uplink transmission, thereby resolving self-interference without completely abandoning the original uplink communication.
Solution Approach 2:
The patent extracts and removes the interfering symbols or resource elements from the PUSCH transmission. By identifying and taking out the specific resources that cause self-interference (where URLLC traffic is received), the system eliminates the harmful effect while preserving the non-interfering portions of the uplink transmission.
2Object-affected harmful factors
If the IAB node punctures resources in ongoing PUSCH transmissions to accommodate urgent URLLC traffic, then self-interference is minimized, but the uplink transmission resources are reduced
Solution Approach 1:
Instead of completely interrupting the uplink transmission, the patent applies partial action by puncturing only the specific symbols or resource elements that cause self-interference. This partial puncturing approach minimizes the impact on overall uplink throughput while still effectively addressing the self-interference problem.
Solution Approach 2:
The patent discards the punctured resources temporarily to accommodate URLLC traffic, but the uplink transmission is recovered and continued in the remaining non-punctured resources. This allows the system to recover from the resource reduction by maintaining transmission in unaffected resource elements.
3Adaptability or versatility
If downlink preemption indications are used for uplink communications, then the existing mechanism can be leveraged, but the indication direction is incorrect since preemption indications are designed for downlink only
Solution Approach 1:
The patent inverts the traditional downlink preemption indication approach by implementing an uplink preemption indication mechanism. Instead of the network indicating preemption to the UE for downlink, the IAB node generates and transmits preemption indications to the parent node for uplink communications, effectively reversing the indication direction to suit the uplink scenario.
Solution Approach 2:
The patent adapts the preemption indication mechanism to serve multiple functions: it can indicate both downlink preemption (traditional function) and uplink preemption (new function). By making the preemption indication system universal, the same basic mechanism can handle both uplink and downlink preemption scenarios despite the directional differences.
Data Source
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AI summary
Aspects of the present disclosure provide techniques for transmitting an uplink preemption indication in an integrated access and backhaul (IAB) system identifying the resources or symbols that may be punctured by the IAB in order to minimize self-interference at an IAB node when an ultra-reliable-low latency communications (URLLC) packet is received at the IAB node from one of a child IAB node or a user equipment (UE) during an on-going uplink transmission from an IAB node to a parent backhaul node.