SDT Timer and Field Mechanism for Wireless Communication Node
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Solution Overview
Problem
In wireless communication systems, particularly in the New Radio (NR) and other scenarios like LTE, NB IoT, and V2X, there is a challenge in transmitting small packets in the RRC_INACTIVE state due to the inability to transmit data endlessly, leading to potential transmission failures and inefficiencies in signaling interaction between User Equipment (UE) and the base station.
Innovation Solution
A method is introduced where a timer is defined for the Small Data Transmission (SDT) procedure, and a field is used to assist in determining the transmission of messages, helping the base station to manage the SDT process by updating the RRC state and adjusting the timer expiration value, thereby enhancing the success probability of SDT and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a timer is defined for the SDT procedure to control data transmission in RRC_INACTIVE state, then the transmission reliability is improved, but the device complexity increases due to enhanced signaling interaction requirements
Solution Approach 1:
The base station pre-configures the SDT timer and transmission parameters before the UE enters RRC_INACTIVE state. This preliminary configuration allows the UE to autonomously manage small data transmissions without real-time base station intervention, improving reliability while avoiding continuous signaling overhead that would increase complexity
Solution Approach 2:
The UE autonomously monitors the SDT timer and manages its own data transmission within RRC_INACTIVE state using pre-configured parameters. This self-service approach eliminates the need for continuous base station control signaling, maintaining reliability through timer-based control while reducing overall system complexity
2Reliability
If the SDT timer expiration value is extended to allow more transmission attempts, then the transmission reliability is improved, but the power consumption increases
Solution Approach 1:
The SDT timer expiration value is dynamically adjusted based on UE mobility conditions. For low-mobility UEs, a longer timer allows more transmission attempts improving reliability. For high-mobility UEs, the timer is shortened to reduce power consumption since the UE may have moved out of coverage. This dynamic adaptation resolves the contradiction between reliability and power consumption
Solution Approach 2:
The system changes the timer parameter based on observed transmission success and UE behavior patterns. Initially, a conservative timer value is used; if transmissions succeed, the timer may be extended for future transmissions. If failures occur or power constraints are detected, the timer is reduced. This parameter adaptation allows the system to optimize both reliability and power consumption
3Device complexity
If the existing BSR triggering mechanism is used for small packet services, then the device complexity is kept low, but the productivity decreases due to delayed data volume reporting
Solution Approach 1:
The buffer status reporting is segmented into two mechanisms: the existing periodic BSR for general buffer status (maintaining low complexity) and a new event-triggered BSR specifically for small packet services in RRC_INACTIVE state (improving productivity). The event-triggered mechanism activates only when small data packets arrive, providing timely reporting without continuously increasing device complexity
Solution Approach 2:
An intermediary event-triggered BSR mechanism is introduced between the existing periodic BSR and the small data transmission process. This intermediary provides timely buffer status updates when needed for small packets while relying on the existing periodic mechanism for overall buffer management, thus improving productivity without fully replacing the low-complexity existing system
Data Source
AI summary
Present application provides a method and a device in a communication node for wireless communications. A communication node, accompanying a first message, starts a first timer; transmits the first message, the first message comprises an RRC signaling; transmits a first field; monitors a second message, the second message comprises an RRC signaling, the second message is used to respond to the first message; as a response to any condition in a first condition set being satisfied, updates from RRC_INACTIVE state to a first RRC state; if the second message is received, stops the first timer; the first field is used to assist in determining a transmission of the second message; two conditions in the first condition set are respectively the first timer being expired and the second message being received; the present application increases the success probability of SDT transmission and reduces the power consumption of the first node.