Adaptive System Information Acquisition for Quasi-Stationary Cells
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Solution Overview
Problem
Current implementations in MTC and NB-IoT technologies face significant challenges with prolonged system information acquisition delays, particularly during cell handover or reselection, where the time required to acquire necessary information can be as long as 2.56 seconds, which is critical and inefficient.
Innovation Solution
A Wireless Device (WD) and network node system that determines whether a target cell will transmit quasi-stationary system information (QSI), allowing it to adapt its acquisition procedure by combining fields from multiple SI transmissions for faster acquisition if QSI is expected, or using a legacy procedure if non-QSI is expected, thereby reducing the time to obtain the Cell Global Identity (CGI) of the target cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the WD uses the legacy SI acquisition procedure to ensure reliable acquisition of system information, then the acquisition reliability is improved, but the acquisition time is significantly prolonged (up to 2.56 seconds)
Solution Approach 1:
The patent applies dynamics by making the SI acquisition procedure adaptive rather than static. The WD dynamically selects between first and second acquisition procedures based on whether QSI is detected in the target cell. This dynamic adaptation allows the system to switch between fast acquisition (when QSI is present) and reliable acquisition (when QSI is absent), resolving the contradiction between speed and reliability
Solution Approach 2:
The patent changes the acquisition parameter by introducing a detection mechanism for QSI. When QSI is detected, the WD changes its acquisition strategy to use the first procedure with shorter time periods and combines fields from multiple SI transmissions. This parameter change enables faster acquisition while maintaining reliability through the combination approach
2Speed
If the WD combines fields from multiple SI transmissions to accelerate acquisition, then the acquisition speed is improved, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the SI acquisition process into two distinct procedures. The first procedure is used when QSI is detected and involves combining fields from multiple transmissions; the second procedure is the legacy approach. This segmentation allows the complex field-combining operation to be isolated to specific conditions, reducing overall procedural complexity while maintaining speed benefits when applicable
Solution Approach 2:
The patent introduces an intermediary detection mechanism that determines which acquisition procedure to use. This intermediary QSI detection step acts as a mediator between the simple legacy procedure and the complex field-combining procedure, enabling the WD to only engage the complex procedure when necessary, thus balancing speed improvement with acceptable complexity
3Measurement precision
If the WD continuously monitors SI transmissions to detect QSI, then the acquisition accuracy is improved, but the power consumption increases
Solution Approach 1:
The patent applies periodic action by having the WD monitor SI transmissions at regular intervals to detect QSI. Rather than continuous monitoring, the WD checks for QSI in periodic SI transmissions, which reduces power consumption while maintaining sufficient detection accuracy. This periodic approach balances the need for accurate QSI detection with energy conservation in MTC devices
Data Source
AI summary
A Wireless Device (WD), a network node and corresponding methods are disclosed. The WD comprises processing circuitry and a memory, the WD being adapted to obtain a Cell Global Identity (CGI) of a target cell within a first time period if the target cell transmits System Information (SI) where the fields other than frame numbers do not change in different transmission periods over a certain period of time, and otherwise, to obtain the CGI of the target cell within a second time period longer than the first time period. The WD is adapted to use information as to whether or not the target cell is going to transmit Quasi-Stationary SI (QSI) to select a first or a second SI acquisition procedure to obtain the CGI of the target cell within the first time period if QSI is transmitted, or within a second time period is non QSI is transmitted. The network node determines whether or not the target cell is going to transmit QSI and informs a base station or the WD about whether or not the target cell is going to transmit QSI enabling the WD to optimize its SI acquisition procedure accordingly.