PDCP Duplication via MAC-CE Control for 5G Reliability
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Solution Overview
Problem
Current 5G NR communication systems face challenges in optimizing power headroom and latency, particularly in scenarios requiring low latency and high reliability, such as ultra-reliable low latency communications (URLLC), due to limitations in error correction and retransmission processes at the RLC layer.
Innovation Solution
Implementing PDCP duplication above the RLC layer, utilizing dual connectivity and carrier aggregation to process and transmit duplicated traffic packets through different physical resources, with RLC entity activation/deactivation controlled by RRC configuration and MAC layer elements to improve latency and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PDCP duplication is implemented to improve reliability and reduce latency, then transmission reliability and latency are improved, but device complexity and power consumption increase
Solution Approach 1:
The patent segments the duplication control into multiple layers: RRC configuration establishes the foundation, MAC-CE provides dynamic activation/deactivation control, and DCI offers fine-grained per-packet control. This segmentation allows the system to achieve high reliability through duplication while managing complexity by distributing control functions across different protocol layers.
Solution Approach 2:
The patent implements dynamic control mechanisms where MAC-CE messages can activate or deactivate duplication bearers based on current channel conditions and traffic requirements, and DCI can dynamically select which duplication bearer to use for each packet. This dynamic approach allows the system to adapt to changing conditions, improving reliability when needed while reducing complexity and power consumption when duplication is not required.
2Loss of time
If PDCP duplication is implemented to reduce latency, then transmission latency is reduced, but power consumption increases
Solution Approach 1:
The patent employs periodic or event-driven activation of duplication based on MAC-CE commands received from the network. Instead of continuously maintaining duplication active, the system activates duplication bearers periodically or when specific events occur (such as channel degradation or high-priority traffic), processes packets through the appropriate bearer, and then deactivates when no longer needed. This periodic action pattern reduces power consumption while still achieving low latency when required.
Solution Approach 2:
The dynamic activation and deactivation of duplication bearers through MAC-CE and DCI control allows the system to consume power only when duplication is actually needed for latency-critical transmissions. The system can switch between single-bearer and dual-bearer modes dynamically, optimizing the trade-off between latency reduction and power consumption based on real-time network conditions and traffic requirements.
3Reliability
If multiple RLC entities are configured for PDCP duplication, then transmission reliability improves, but control signaling overhead increases
Solution Approach 1:
The patent segments control signaling into three distinct types with different functions and granularities: RRC configuration messages establish the duplication bearers and their parameters, MAC-CE messages provide medium-term activation/deactivation control, and DCI messages provide short-term per-packet bearer selection. This segmentation allows the system to maintain multiple RLC entities for reliability while managing signaling overhead by using the appropriate control mechanism for each situation.
Solution Approach 2:
The patent implements partial control where MAC-CE activates or deactivates entire duplication bearers based on traffic flow requirements, and DCI provides selective control on a per-packet basis only when needed. This partial control approach reduces signaling overhead compared to controlling every aspect at the finest granularity, while still maintaining the ability to achieve high reliability through duplication when required.
Data Source
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AI summary
A user equipment (UE) may utilize multiple radio link control (RLC) entities to duplicate packet data convergence protocol (PDCP) packets for improved reception. The UE may receive a configuration for dual connectivity with a master cell group and with a secondary cell group, wherein the configuration identifies a plurality of configured RLC entities, each RLC entity being associated with one of the master cell group or the secondary cell group. The UE may receive, at the UE, an indication of an activation status for each of at least a first subset of the configured RLC entities from one cell group of the master cell group or the secondary cell group. The UE may set the activation status of each of the first subset of the configured RLC entities that are associated with the one cell group from which the indication is received based on the indication.