RRC Inactive UE Scheduling for Low-Latency Subsequent Transmission
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Solution Overview
Problem
In 5G NR networks, UEs in the RRC_INACTIVE state experience unnecessary power consumption and signaling overhead due to frequent transitions between states for small and infrequent data transmissions, as they need to return to the RRC_CONNECTED state for feedback and subsequent data, which undermines the efficiency of the INACTIVE state.
Innovation Solution
The UE monitors a physical downlink control channel (PDCCH) for UE dedicated scheduling during an active period after initial data transmission without transitioning to RRC_CONNECTED state, allowing for subsequent data transmission or reception while remaining in RRC_INACTIVE.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE transitions to RRC_CONNECTED state for feedback reception and subsequent data transmission, then reliable communication is ensured, but power consumption increases and latency is introduced due to state transitions
Solution Approach 1:
The network configures the UE with uplink grant resources and downlink monitoring configurations before the UE transitions to RRC_IDLE or RRC_INACTIVE state. This preliminary configuration enables the UE to perform feedback transmission and monitor subsequent downlink data without immediate state transition, thereby reducing latency while maintaining communication reliability.
Solution Approach 2:
The patent implements dynamic state management where the UE can flexibly transition between RRC_CONNECTED, RRC_IDLE, and RRC_INACTIVE states based on data transmission requirements. The network can dynamically allocate resources and adjust monitoring configurations to optimize the balance between power consumption, latency, and reliability for different traffic scenarios.
2Productivity
If the UE frequently transitions between RRC states for small data transmissions, then data transmission capability is maintained, but power consumption increases unnecessarily
Solution Approach 1:
The network provides preliminary uplink grant configurations and downlink monitoring parameters to the UE before it enters RRC_IDLE or RRC_INACTIVE state. This allows the UE to handle small data transmissions, feedback, and subsequent downlink data reception without transitioning to RRC_CONNECTED state, thereby maintaining data transmission capability while significantly reducing power consumption.
Solution Approach 2:
The patent implements partial state activation where the UE maintains only the necessary minimum functionality (feedback transmission and downlink monitoring) in RRC_IDLE/RRC_INACTIVE state rather than fully transitioning to RRC_CONNECTED state. This partial action approach enables small data handling with reduced power consumption while avoiding the overhead of complete connection establishment.
3Reliability
If the UE returns to RRC_CONNECTED state for feedback transmission, then communication protocol requirements are met, but signaling overhead increases
Solution Approach 1:
The patent extracts the essential feedback transmission and downlink monitoring functions from the RRC_CONNECTED state and implements them directly in RRC_IDLE or RRC_INACTIVE state using pre-configured resources. This extraction eliminates the need for full state transitions and associated signaling overhead while maintaining protocol compliance for feedback transmission.
Solution Approach 2:
The network provides preliminary configurations for uplink feedback resources and downlink monitoring parameters before the UE enters idle or inactive state. This preliminary action enables the UE to comply with communication protocols for feedback transmission without requiring state transition, thereby reducing signaling overhead while maintaining protocol requirements.
Data Source
AI summary
A user equipment (UE) device including an antenna, a memory, a RF circuitry commutatively coupled to the antenna, and a processor configured to perform operations is described. In an exemplary embodiment, the operations include receiving a Radio Resource Control (RRC) release message from a base station, wherein the RRC release message comprises a suspend configuration to transition the UE to an RRC_INACTIVE state. In addition, the operations include entering the RRC_INACTIVE state. The operations include performing, while the UE is in the RRC_INACTIVE state, an initial data transmission without transitioning from the RRC_INACTIVE state to a RRC_CONNECTED state. Additionally, the operations include monitoring a physical downlink control channel (PDCCH) for a UE dedicated scheduling for a transmission or reception of a subsequent data during an active period, while the UE is in the RRC INACTIVE state. Further, the operations include performing the transmission or reception of the subsequent data based on the monitoring of the PDCCH.