NB-IoT Response Time Management Using RRT Feedback
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Solution Overview
Problem
Current systems fail to include Requested Retransmission Time (RRT) in Mobile Terminal Data Answer (TDA) messages, leading to unaddressed buffered data and inefficient power-saving mechanisms for NB-IoT devices, particularly in cases of paging failure.
Innovation Solution
Incorporating RRT in TDA messages sent to the Service Capability Exposure Function (SCEF) to manage response time, enabling automatic retry of buffered data requests and optimizing power-saving modes like PSM and eDRX for NB-IoT devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If RRT is not included in TDA messages, then the system maintains simplicity in message structure, but buffered data requests cannot be automatically retried and power-saving mechanisms are inefficient
Solution Approach 1:
The MME calculates and includes the Requested Retransmission Time (RRT) parameter in the TDA message before sending it to the SCEF. This preliminary calculation of the optimal retransmission time enables the SCEF to automatically retry buffered data requests at the appropriate moment without requiring complex retry logic or continuous polling, thus automating the retry process while maintaining relatively simple message structure.
2Reliability
If NB-IoT devices remain in active mode to ensure immediate data reception, then data delivery reliability is improved, but power consumption increases and battery life decreases
Solution Approach 1:
The system implements a feedback mechanism where the MME provides the RRT parameter to the SCEF based on the NB-IoT device's power-saving mode status. When the device is in PSM or eDRX mode, the MME calculates an appropriate RRT that aligns with the device's wake-up schedule. This feedback enables the SCEF to retry data transmission at the optimal time when the device is awake, ensuring reliable data delivery while allowing the device to remain in low-power mode for extended periods.
3Duration of action of moving object
If the system uses Power Saving Mode (PSM) and extended Discontinuous Reception (eDRX) for NB-IoT devices, then battery life is extended, but response time to deliver data increases
Solution Approach 1:
The system dynamically adjusts the RRT parameter based on the NB-IoT device's current power-saving mode state. When the device is in PSM or eDRX mode, the MME calculates an RRT that predicts when the device will next be in active mode. This dynamic adjustment ensures that data transmission is scheduled to coincide with the device's active periods, maintaining acceptable response times while allowing the device to spend most of its time in low-power states, thus extending battery life.
Data Source
AI summary
A system and method for management of response time to the at least one NB-IoT device. The method comprises receiving, at an MME from a SCEF, at least one mobile terminal data request (TDR). The method thereafter comprises buffering, at the MME, each of the received at least one TDR. Further, the method comprises calculating, by the MME, a requested retransmission time (RRT) for each of the buffered at least one (TDR). The method thereafter comprises transmitting, from the MME to the SCEF, at least one mobile terminal data answer (TDA) corresponding to each of the buffered at least one TDR for management of response time to the at least one NB-IoT device, wherein the at least one TDA comprises of at least the calculated RRT for each of the corresponding buffered at least one TDR.