RLC Context Caching for Small Data Transmission in RRC_INACTIVE
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Solution Overview
Problem
Current 5G NR systems face inefficiencies in small data transmission (SDT) from the RRC_INACTIVE state due to unnecessary power consumption, signaling overhead, and increased packet latency, particularly in scenarios where UEs frequently transition between RRC_INACTIVE and RRC_CONNECTED states for small data transfers.
Innovation Solution
Implementing UE-specific RLC context storage at previous target nodes to facilitate RLC processing without anchor relocation, allowing efficient SDT procedures by leveraging stored context information for returning UEs, thereby reducing backhaul signaling and maintaining context synchronization across network nodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If anchor relocation is performed for SDT, then context retrieval is enabled, but backhaul signaling overhead and power consumption increase
Solution Approach 1:
The patent extracts the RLC context storage function from the anchor node and places it at the target node. This allows the target node to retain UE context locally, eliminating the need for anchor relocation and associated backhaul signaling while maintaining reliable context availability for SDT operations
Solution Approach 2:
The target node performs preliminary action by storing UE context in advance before the UE returns for SDT. This pre-positioning of context eliminates the need for real-time context retrieval during SDT, reducing signaling overhead and power consumption while ensuring context availability
2Reliability
If anchor relocation is performed for SDT, then context retrieval is enabled, but backhaul signaling overhead increases
Solution Approach 1:
The patent extracts the RLC context storage function from the anchor node and places it at the target node. This allows the target node to retain UE context locally, eliminating the need for anchor relocation and associated backhaul signaling while maintaining reliable context availability for SDT operations
Solution Approach 2:
The target node acts as an intermediary by caching UE context locally. This intermediary storage mechanism eliminates the need for complex anchor relocation procedures and extensive backhaul signaling, simplifying the overall system architecture while ensuring context retrieval reliability
3Productivity
If UE transitions to RRC_CONNECTED state for small data transmission, then data transmission capability is enabled, but power consumption increases
Solution Approach 1:
The target node performs preliminary action by storing UE context in advance before the UE returns for SDT. This pre-positioning of context eliminates the need for real-time context retrieval during SDT, reducing signaling overhead and power consumption while ensuring context availability
Solution Approach 2:
The patent introduces dynamic context storage at target nodes that can adapt to returning UEs. This dynamic mechanism allows the network to maintain connection efficiency for frequent small data transmissions without forcing full RRC_CONNECTED state transitions, thereby reducing power consumption while preserving data transmission capability
Data Source
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AI summary
Systems, methods, apparatuses, and computer program products for improved signaling of small data transmission (SDT) are provided. One method may include storing, at a first target network node, a user equipment (UE)-specific uplink (UL) small data transmission (SDT) context for a user equipment (UE) in a non-connected radio resource control (RRC) state that previously had initiated a small data transmission (SDT) procedure without anchor relocation via the first target network node or a second target network node. The method may also include performing radio link control (RLC) processing of the radio link control (RLC) protocol data units (PDUs) received from the user equipment (UE) using the stored user equipment (UE)-specific uplink (UL) small data transmission (SDT) context.