HARQ-Mapped Packet Combining for 5G NR Duplication
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Solution Overview
Problem
Current 5G NR DC/MC specifications do not support soft combining of independently transmitted data packets, which are essential for improving transmission reliability and reducing latency, particularly for ultra-reliable low-latency-communication (URLLC) services.
Innovation Solution
Implement a soft-combining method by providing a pointer to the first PHY transmission of a PDU from a master node to a secondary node, enabling the receiver to combine transmissions from both nodes using HARQ process IDs, redundancy versions, and New Data Indicator values, and configuring HARQ process ID mapping to facilitate soft combining at the physical layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If independent packet transmission from multiple nodes is implemented, then transmission reliability is improved, but the ability to combine packets for better decoding is lost
Solution Approach 1:
The patent introduces HARQ process IDs and redundancy version indicators as intermediary elements that enable the receiver to identify and combine packets from different transmission nodes. These intermediaries carry metadata that links independent transmissions to the same logical data unit, restoring packet combining capability without sacrificing transmission independence.
Solution Approach 2:
The patent segments the packet transmission process into distinct phases: initial transmission with full data, and subsequent transmissions with redundancy information. By dividing the transmission into multiple segments with different redundancy versions, the system enables progressive decoding while maintaining the ability to combine segments from different nodes.
2Reliability
If multiple copies of packets are retransmitted over split bearers, then decoding probability is improved, but transmission latency increases
Solution Approach 1:
The patent performs preliminary actions by pre-configuring HARQ process IDs and redundancy versions at the transmitter before actual data transmission. This preparation enables the receiver to immediately process and combine incoming packets without waiting for complete transmission cycles, thereby reducing latency while maintaining high decoding probability.
Solution Approach 2:
The patent maintains continuity of useful action by enabling parallel processing of multiple packet copies through different nodes. Instead of sequential retransmission, the system continuously receives and combines packets from multiple sources simultaneously, eliminating idle time and reducing overall transmission latency.
3Reliability
If packet duplication is implemented across multiple nodes, then transmission robustness is improved, but system complexity increases
Solution Approach 1:
The patent implements universality by designing a single, unified HARQ process management mechanism that handles packet duplication, identification, and combining across multiple nodes. This universal approach uses the same HARQ process IDs and redundancy version indicators regardless of the number or configuration of transmitting nodes, thereby improving robustness without proportionally increasing system complexity.
Data Source
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AI summary
Systems, methods, apparatuses, and computer program products for packet combining for PDCP duplication, e.g., in ultra-reliable low-latency-communication (URLLC) scenarios are provided. One method may include providing, from a network node to at least one second node, a pointer to an earlier or first transmission of a protocol data unit (PDU). The pointer may be used by subsequent transmissions of the protocol data unit (PDU) through the at least one second node to indicate to a user equipment (UE) what transmissions are to be combined.