Multi-User PDSCH Packet Scheduling for URLLC Reliability
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Solution Overview
Problem
Current wireless communication technologies, such as 5G NR, face challenges in achieving high reliability and low latency for ultra-reliable low-latency communications (URLLC) due to limited retransmissions and high reliability requirements for physical downlink control channels (PDCCH) carrying downlink grants.
Innovation Solution
Implementing a multi-user data packet transmission method that schedules multiple user equipment (UEs) using a single downlink grant via a physical downlink shared channel (PDSCH), with improved encoding techniques and superposition coding to increase reliability and capacity, allowing for higher aggregation levels and frequency diversity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple UEs are scheduled using separate PDCCH downlink grants, then each UE can be reliably addressed and data can be transmitted, but the control channel overhead increases and retransmission reliability decreases under high load
Solution Approach 1:
The patent merges multiple separate PDCCH downlink grants into a single shared PDCCH grant that schedules a multi-UE transport block containing data for multiple UEs. This consolidation reduces control channel overhead and the number of PDCCH transmissions required, while maintaining reliable data delivery through unified scheduling and individual MAC PDU segmentation at the receiver side.
Solution Approach 2:
The shared PDCCH grant is designed with universal applicability to serve multiple UEs simultaneously. The single downlink grant contains scheduling information that can be interpreted by multiple UEs, each extracting their specific data portions from the shared transport block based on their assigned MAC PDU segments, thereby reducing control signaling while maintaining individual UE service quality.
2Reliability
If retransmissions are increased to meet high reliability requirements, then data transmission reliability improves, but latency increases which violates URLLC requirements
Solution Approach 1:
The patent employs preliminary error detection and correction mechanisms within the multi-UE transport block structure, including MAC PDU segmentation with individual headers containing sequence numbers and destination UE identifiers. This preliminary organization enables efficient retransmission of only specific failed segments rather than entire transport blocks, reducing retransmission latency while maintaining URLLC reliability requirements.
Solution Approach 2:
The transport block is segmented into multiple MAC PDUs, each destined for a specific UE, with individual headers containing segmentation information. This segmentation allows for selective retransmission of only the failed MAC PDU segments rather than retransmitting the entire transport block, thereby reducing retransmission latency while maintaining high reliability for URLLC services.
3Reliability
If aggregation level is increased to improve PDCCH reliability, then control channel reliability improves, but resource consumption increases and frequency diversity is limited
Solution Approach 1:
The patent merges multiple PDCCH grants into a single shared PDCCH transmission that schedules data for multiple UEs. This consolidation achieves comparable or superior reliability to individual high-aggregation grants while consuming fewer control channel resources, as the single shared grant is transmitted once rather than multiple separate grants at high aggregation levels.
Solution Approach 2:
The patent introduces a new dimension of multi-UE scheduling in the PDCCH structure, where a single grant can serve multiple UEs simultaneously through shared transport blocks. This dimensional change in scheduling approach allows for frequency diversity and resource efficiency improvements compared to traditional single-UE per grant approaches, achieving reliability without proportional resource consumption increases.
Data Source
AI summary
Certain aspects of the present disclosure provide techniques for a multi-user data packet, such as a physical downlink shared channel (PDSCH) packet. A method by a base station (BS) includes sending a control channel, such as physical downlink control channel (PDCCH), scheduling a plurality of user equipment (UEs) for a data packet transmission and sending data for the plurality of UEs in a single transport block on the scheduled data packet. The UE receives the control channel and data packet, and determines the data in the multi-user data packet that is intended for the UE.