Narrowband Positioning Reference Signal Design for NB-IoT
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Solution Overview
Problem
Current narrowband IoT (NB-IoT) systems face challenges in providing effective positioning due to constraints such as interference, lack of synergy with legacy LTE PRS, and non-unified designs for inband, guardband, and standalone deployments, which affect positioning accuracy and resource utilization.
Innovation Solution
A new narrowband positioning reference signal (NPRS) design that leverages a subsequence of a wideband reference signal sequence, optimized for NB-IoT, with features like pseudo-random QPSK sequences, explicit multi-antenna transmission, and adaptable resource mapping patterns to enhance hearability and reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a narrowband positioning reference signal is designed for NB-IoT systems, then positioning accuracy and hearability are improved, but device complexity and design difficulty increase
Solution Approach 1:
The patent segments the wideband reference signal sequence into multiple narrowband reference signal sequences, each suitable for NB-IoT bandwidth constraints. This allows the system to maintain positioning functionality while adapting to the limited bandwidth of narrowband devices, thereby improving positioning accuracy without requiring full wideband capabilities in low-complexity devices.
Solution Approach 2:
The patent changes key parameters of the reference signal design including bandwidth, sequence length, and resource element mapping patterns to optimize for narrowband operation. By adjusting these parameters, the system achieves improved hearability and positioning accuracy for NB-IoT devices while maintaining compatibility with existing LTE infrastructure.
2Adaptability or versatility
If a unified narrowband positioning reference signal design is implemented across inband, guardband, and standalone deployments, then adaptability is improved, but design complexity increases
Solution Approach 1:
The patent creates a universal narrowband positioning reference signal design that functions across all three deployment modes (inband, guardband, and standalone). The same basic signal structure and generation methodology are applied universally, with only minor configuration parameter adjustments needed for each deployment type, thereby achieving adaptability without proportionally increasing design complexity.
Solution Approach 2:
The patent introduces dynamic configuration parameters that allow the positioning reference signal to adapt its characteristics based on the deployment mode. Through configurable parameters such as bandwidth allocation, resource element mapping, and sequence initialization, the system dynamically adjusts to different deployment scenarios while maintaining a unified underlying design framework.
3Measurement precision
If narrowband positioning reference signals are transmitted in NB-IoT systems, then positioning functionality is improved, but interference and resource utilization challenges worsen
Solution Approach 1:
The patent utilizes the time domain dimension by spreading positioning reference signals across multiple subframes and symbols, and the frequency dimension through careful resource element allocation. This multi-dimensional resource distribution reduces temporal and spectral interference while improving positioning functionality through enhanced signal detection capability.
Solution Approach 2:
The patent implements periodic transmission of narrowband positioning reference signals with configurable periods and patterns. This periodic structure allows for predictable resource allocation, reduces random interference, and enables efficient resource utilization by concentrating positioning measurements in specific time windows rather than continuous transmission.
Data Source
AI summary
A user equipment is configured for operation in a narrowband wireless communication system. The user equipment is configured to detect receipt of a narrowband positioning reference signal that comprises a narrowband reference signal sequence. The narrowband reference signal sequence is a subsequence of a wideband reference signal sequence. The wideband reference signal sequence is configured for a wideband frequency bandwidth that is wider than a maximum frequency bandwidth defined for the narrowband wireless communication system. The user equipment is also configured to perform a positioning measurement using the narrowband positioning reference signal.