RRC_INACTIVE Small Data Transmission Using Configured Grants
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Solution Overview
Problem
Current wireless communication networks do not specify mobile-terminated small data transmission in RRC_INACTIVE mode, requiring user equipment to transition to the fully connected RRC_CONNECTED state, which increases signaling overhead and latency.
Innovation Solution
User equipment determines the appropriate user equipment identification for small data transmission based on whether it has moved to a new radio cell, using cell-specific or non-cell-specific identification, and utilizes configured grant or random access resources for uplink data transmission in RRC_INACTIVE mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If user equipment transitions to RRC_CONNECTED state to receive downlink data, then data transmission reliability is improved, but signaling overhead and latency increase
Solution Approach 1:
The patent segments the data transmission process into two parts: control signaling (which requires RRC_CONNECTED state) and small data transmission (which can occur in RRC_INACTIVE state). This allows the user equipment to maintain a lightweight connection for data transmission without establishing a full connected state, thereby reducing signaling overhead and latency while maintaining transmission reliability.
Solution Approach 2:
The patent introduces dynamic state management where the user equipment can flexibly transition between RRC_INACTIVE and RRC_CONNECTED states based on data transmission needs. The network can dynamically configure parameters such as activation timer, inactivity timer, and maximum inactivity timer to control state transitions, enabling adaptive connection management that balances reliability and signaling overhead.
2Device complexity
If user equipment remains in RRC_INACTIVE mode for small data transmission, then signaling overhead is reduced, but data transmission capability is limited
Solution Approach 1:
The patent enables partial data transmission capability in RRC_INACTIVE state by allowing small data transmission without requiring full connection establishment. The network provides limited uplink resources and configured grants specifically for small data transmission, enabling the user equipment to transmit data partially in inactive state and only transition to connected state when necessary, thus balancing signaling overhead reduction with adequate data transmission capability.
3Reliability
If network provides multiple random-access channel resources for user equipment selection, then data transmission reliability is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by having the network pre-configure multiple random-access channel resources and their corresponding parameters before the user equipment needs to transmit data. The network also pre-establishes the mapping between these resources and user equipment identifiers. When data transmission is needed, the user equipment can directly select from the pre-configured resources without complex real-time calculations, thereby improving reliability while limiting complexity increase.
Data Source
AI summary
Wireless communication is performed by: receiving downlink control information including by a user equipment in an inactive state, a cyclic redundancy check scrambled by a radio network with at least one base-station with paging-Radio Network Temporary Identifier at least one user equipment, user equipment monitors paging message in inactive state and uses paging-Radio Network Temporary Identifier to decode reception of paging message, wherein the user equipment receives more than one random-access channel resources from the network and the indication of Small Data transmission and user equipment selects the random-access channel resources.