Paging Optimization for NB-IoT UEs in eDRX Mode
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Solution Overview
Problem
Existing paging solutions for NB-IoT UEs in eDRX mode are inefficient as they require high repetition of paging messages to ensure all UEs receive the message, leading to resource wastage due to the relaxed reachability requirements of eDRX UEs.
Innovation Solution
A method where a network node determines a reference terminal device with the worst radio link quality and selects target terminal devices based on their radio link qualities and previous paging occasions to optimize paging by reducing the repetition number of the paging message.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high repetition of paging messages is used to ensure all UEs receive the message, then reliability of paging delivery is improved, but resource usage for paging increases
Solution Approach 1:
The patent applies local quality by differentiating paging repetition strategies based on UE categories and radio link qualities. Instead of uniformly applying high repetition to all UEs, the network node identifies UEs with different characteristics (eDRX vs. DRX, different CE levels) and applies appropriate repetition numbers tailored to each UE's actual needs, thereby improving reliability where necessary while conserving resources where not needed.
Solution Approach 2:
The patent implements dynamics by making the paging repetition number adaptive rather than static. The network node dynamically determines repetition numbers based on current radio link quality measurements, UE mobility states, and UE category information. This allows the system to adjust repetition levels in real-time, using high repetition only when radio conditions deteriorate or for UEs that require it, thereby resolving the contradiction between reliability and resource usage.
2Reliability
If paging message repetition is increased for worst radio link quality UEs, then coverage for poor link UEs is improved, but overall paging efficiency deteriorates
Solution Approach 1:
The patent applies segmentation by dividing the UE population into distinct groups based on radio link quality, eDRX configuration, and mobility characteristics. The network node segments UEs into categories (e.g., Category A for eDRX UEs with poor link quality, Category B for DRX UEs, etc.) and assigns different paging repetition strategies to each segment. This ensures that UEs with poor link quality receive adequate coverage through higher repetition, while UEs with good link quality are paged with minimal repetition, thereby maintaining high paging efficiency overall.
Solution Approach 2:
The patent utilizes parameter changes by adjusting the paging repetition number based on UE-specific parameters such as radio link quality (RSRP/RSRQ measurements), eDRX cycle length, and UE mobility state. The network node changes the repetition parameter dynamically for different UE groups, increasing it for UEs with poor link quality to ensure coverage, while keeping it low for UEs with good link quality to maintain efficiency, thus resolving the contradiction between coverage and efficiency.
3Reliability
If paging is performed for all terminal devices at every PO, then no paging messages are lost, but resource consumption for paging increases
Solution Approach 1:
The patent applies preliminary action by having the network node pre-identify and categorize UEs that require paging before actual paging transmission. The network node performs preliminary assessment of UE radio link quality, eDRX status, and mobility characteristics, and prepares differentiated paging strategies in advance. This allows the system to apply high repetition only to UEs that genuinely need it, rather than uniformly applying high repetition to all UEs, thereby reducing overall resource consumption while maintaining reliability.
Solution Approach 2:
The patent implements local quality by applying different paging repetition levels to different UEs based on their individual characteristics. Instead of using a uniform high repetition strategy for all UEs at every PO, the network node locally adapts the repetition number for each UE based on its radio link quality, eDRX configuration, and mobility state. This ensures that each UE receives the minimum necessary repetition to guarantee reception, thereby reducing total resource consumption while maintaining reliability for all UEs.
Data Source
AI summary
A method and a network node for paging are disclosed. According to an embodiment, the network node determines, for current paging occasion (PO), a reference terminal device that has the worst radio link quality among one or more terminal devices needed to be paged at the current PO or a subsequent PO in current paging time window (PTW). The network node determines, from multiple terminal devices needed to be paged in the current PTW, one or more target terminal devices to be paged at the current PO together with the reference terminal device, based at least on radio link qualities of the multiple terminal devices. The network node pages the one or more target terminal devices and the reference terminal device at the current PO, using link adaptation based on the reference terminal device.