Adjusting PRS Bandwidth for NB-IoT Power Savings
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Solution Overview
Problem
Conventional positioning reference signals (PRS) in LTE systems require high processing bandwidth, which is undesirable for low-power devices like NarrowBand Internet of Things (IoT) and LTE Cat-M devices due to increased power consumption and cost, especially in low Signal-to-Noise Ratio (SNR) conditions.
Innovation Solution
A method to adjust the processing bandwidth of PRS based on the Carrier-to-Interference-and-Noise Ratio (CINR), reducing the bandwidth when the CINR is above a threshold to conserve power while maintaining positioning accuracy, by implementing frequency domain buffer decimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the processing bandwidth of PRS is increased to maintain positioning accuracy, then the measurement precision is improved, but the use of energy increases
Solution Approach 1:
The patent applies dynamics by making the PRS processing bandwidth adjustable rather than fixed. The UE can dynamically select between different bandwidth configurations (first bandwidth for high accuracy, second bandwidth for low power) based on current positioning requirements and signal conditions, resolving the contradiction between maintaining accuracy and reducing power consumption
Solution Approach 2:
The patent changes the bandwidth parameter of PRS processing based on operating conditions. By configuring the UE to use different bandwidths (narrower second bandwidth vs wider first bandwidth) depending on whether power saving or positioning accuracy is the priority, the system adapts the processing parameters to resolve the energy-accuracy tradeoff
2Use of energy by moving object
If the processing bandwidth of PRS is reduced to save power, then the use of energy is reduced, but the measurement precision deteriorates
Solution Approach 1:
The system dynamically adjusts bandwidth based on needs. When power saving is prioritized, the UE uses the narrower second bandwidth; when positioning accuracy is critical, it switches to the wider first bandwidth. This dynamic adaptation resolves the contradiction by making bandwidth a flexible parameter rather than a fixed compromise
Solution Approach 2:
The patent implements parameter changes by configuring the UE with multiple bandwidth options and allowing selection based on operational context. The bandwidth parameter is changed from a static value to a conditional variable, enabling the system to optimize between power consumption and measurement precision based on current requirements
3Adaptability or versatility
If multiple PRS bandwidths are transmitted simultaneously to support UEs with different bandwidth requirements, then the adaptability is improved, but the device complexity increases
Solution Approach 1:
The patent segments the PRS transmission into multiple bandwidth configurations (first bandwidth and second bandwidth). Each eNodeB can transmit PRS in different bandwidths, and UEs can selectively receive and process only the bandwidth configuration they need, reducing overall system complexity while maintaining adaptability to different UE capabilities
Solution Approach 2:
The system achieves universality by designing PRS transmission to support multiple bandwidth configurations within the same infrastructure. The eNodeBs and UEs are configured to handle multiple bandwidth options, allowing the system to serve diverse UE types (with different bandwidth capabilities) using a unified multi-functional approach rather than requiring separate systems for each bandwidth requirement
Data Source
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AI summary
Aspects of the disclosure are related to a method, apparatus and system for adjusting a processing bandwidth or frequency domain buffer decimation associated with reference signals, for example, positioning reference signals (PRS). By reducing the number of, for example, resource blocks and/or resource elements to be processed, the power involved in processing the reference signal can be reduced. Hence, in some implementations, aspects of the disclosure can enable low-power low-bandwidth devices, such as NarrowBand Internet of Things (IoT) (NBIoT), to decode reference signals such as PRS.