Inter-RAT SIB Configuration for Low-Power NB-IoT Reselection
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Solution Overview
Problem
Current NB-IoT technology lacks support for inter-Radio Access Technology (RAT) mobility, leading to devices being stuck in poor radio conditions and high power consumption during cell selection or reselection, with no efficient mechanism for switching to better networks like LTE or GSM for improved coverage and data rates.
Innovation Solution
Implementing a system information block (SIB) that includes inter-RAT information, allowing devices to perform cell selection or reselection without measurements, using historical data and event triggers, and configuring measurement parameters based on power and coverage conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inter-RAT cell selection or reselection process is implemented in NB-IoT devices, then mobility between different RATs is enabled and coverage is improved, but power consumption increases
Solution Approach 1:
The network node pre-configures measurement parameters, frequency lists, and cell selection criteria in system information blocks before the device needs to perform inter-RAT selection. This allows the device to have measurement instructions ready in advance, reducing the need for continuous active measurements and lowering power consumption while maintaining mobility capability
Solution Approach 2:
The patent implements differentiated measurement parameters based on device power sensitivity. Network nodes can configure different measurement frequencies, threshold values, and reporting intervals for devices with high versus low power sensitivity. This allows power-constrained devices to perform fewer measurements while still achieving reliable inter-RAT mobility when conditions warrant
2Measurement precision
If continuous measurements on multiple RATs are performed, then cell selection accuracy is improved, but power consumption and processing overhead increase
Solution Approach 1:
Instead of continuously measuring all configured frequencies and RATs, the device performs measurements selectively based on triggered events or network-configured conditions. The patent allows partial measurement of frequency lists where only certain frequencies need to be measured at full depth, reducing overall measurement burden while maintaining adequate cell selection accuracy
Solution Approach 2:
The network node provides self-service by pre-configuring measurement parameters, frequency lists, and evaluation criteria in system information. Devices with high power sensitivity can rely on these pre-configured parameters to make cell selection decisions without requiring continuous network guidance or extensive measurements, reducing their power consumption while maintaining selection accuracy
3Ease of operation
If comprehensive inter-RAT information is broadcast in SIBs, then device autonomy in cell selection is improved, but signaling overhead increases
Solution Approach 1:
The patent segments inter-RAT information into multiple system information blocks rather than broadcasting all information in a single SIB. Different SIBs can contain different types of information (frequency lists, cell selection criteria, measurement parameters for specific RATs), allowing devices to selectively process only the information relevant to their current needs and power constraints, reducing overall signaling overhead while maintaining device autonomy
Data Source
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AI summary
Techniques are described for facilitating an inter-Radio Access Technology (RAT) selection or measurement process for a dual-mode or a multi-mode device. For example, a wireless communication method includes a network node transmitting to a communication node a system information block (SIB) that includes information about Radio Access Technologies (RATs). The information includes any one or more of a first carrier priority value and a first threshold value of a serving frequency associated with a RAT, a second carrier priority value and a second threshold value of a serving cell associated with the RAT, an indicator to indicate existence of one or more additional RATs, carrier information for the one or more additional RATs, and access information to access the one or more additional RATs.