HARQ-ACK Consolidation for Multi-TRP Uplink Control
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Solution Overview
Problem
In 5G communication systems, multi-TRP (multiple transmission and reception points) scenarios face challenges in handling HARQ-ACK feedback efficiently, leading to robustness issues and increased latency due to blockage and non-ideal backhaul links, particularly in scenarios requiring ultra-low latencies like URLLC.
Innovation Solution
A user equipment (UE) with a transceiver and circuitry that receives data on multiple downlink shared channels, decodes the data, and generates a common indicator for successful decoding, transmitting this indicator on uplink control channels associated with the downlink shared channels, allowing for robust HARQ-ACK feedback even in blockage conditions and reducing backhaul latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ-ACK feedback is transmitted separately on each uplink control channel in multi-TRP scenarios, then each TRP can independently receive feedback, but the system complexity increases and latency increases due to non-ideal backhaul links
Solution Approach 1:
The patent combines multiple separate HARQ-ACK feedback transmissions into a single unified feedback message that is transmitted once and shared across multiple TRPs. Instead of each TRP receiving separate feedback on dedicated uplink control channels, the UE generates one common HARQ-ACK feedback that contains decoding results for all received downlink data, regardless of which TRP transmitted it. This single feedback message is transmitted on a single uplink control channel, eliminating the need for multiple separate feedback paths and reducing system complexity while maintaining reliability through the use of spatial diversity in the forward link.
Solution Approach 2:
The patent creates a universal HARQ-ACK feedback mechanism that serves multiple TRPs simultaneously with a single feedback message. The feedback structure is designed to be multi-functional, providing acknowledgment information for downlink data from any TRP in the multi-TRP configuration. This universal feedback approach allows the system to handle multiple TRPs without requiring TRP-specific feedback channels, thereby reducing overall system complexity while maintaining the ability to provide reliable feedback to all participating TRPs.
2Measurement precision
If separate HARQ-ACK feedback is used for each downlink shared channel, then feedback accuracy is maintained, but latency increases due to non-ideal backhaul links between TRPs
Solution Approach 1:
The patent merges multiple separate HARQ-ACK feedback messages into a single consolidated feedback transmission. Instead of generating and transmitting separate feedback for each downlink shared channel from each TRP, the UE consolidates all decoding results into one unified HARQ-ACK feedback message. This single feedback message is transmitted once on an uplink control channel, eliminating the need for multiple feedback transmissions and the associated backhaul latency that would result from separate feedback paths between TRPs.
Solution Approach 2:
The patent implements preliminary consolidation of HARQ-ACK feedback information at the UE before transmission. The UE collects decoding results for all downlink data from multiple TRPs and prepares a single unified feedback message in advance, rather than generating separate feedback messages that would need to be transmitted and coordinated through the backhaul. This preliminary action of consolidating feedback information eliminates the need for subsequent backhaul communication to coordinate separate feedback messages, thereby reducing latency.
3Reliability
If multiple uplink control channels are used for HARQ-ACK feedback in multi-TRP, then feedback robustness against blockage is improved, but system complexity and resource overhead increase
Solution Approach 1:
The patent merges multiple uplink control channel transmissions into a single uplink control channel transmission for HARQ-ACK feedback. Instead of transmitting feedback on multiple separate uplink control channels to provide redundancy against blockage, the system transmits one consolidated HARQ-ACK feedback message on a single uplink control channel. This approach eliminates the resource overhead associated with multiple parallel feedback transmissions while maintaining efficiency through the unified feedback structure that serves multiple TRPs simultaneously.
Data Source
AI summary
The present disclosure relates to a user equipment, a network node and respective communication methods for a user equipment and a network node. A according to some embodiments, a user equipment comprises a transceiver which, in operation, receives data on a plurality of downlink shared channels, the data received on the plurality of downlink shared channels being respectively the same data, and circuitry which, in operation, decodes the data, generates an indicator which indicates whether or not the data has been successfully decoded using the plurality of downlink shared channels. The transceiver, in operation, transmits the indicator on at least one of a plurality of uplink control channels associated respectively with the plurality of downlink shared channels.