NB-IoT PRS Scheduling to Avoid LTE Signal Collisions
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Solution Overview
Problem
The scheduling of positioning reference signals (PRS) in narrowband-Internet of Things (NB-IoT) is challenging due to the co-existence of NB-IoT signals and other LTE signals, leading to potential collisions and suboptimal performance, especially at low signal-to-noise ratios.
Innovation Solution
The implementation of narrowband positioning reference signal (NPRS) scheduling and transmission mechanisms that avoid collisions with other LTE signals by configuring positioning subframes, puncturing or skipping pre-configured time-frequency resources, and employing staggered frequency patterns and repetitions to enhance performance at low SNR conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If positioning reference signals (PRS) are scheduled in NB-IoT networks, then positioning capability is enabled, but collisions with other LTE signals occur leading to suboptimal performance
Solution Approach 1:
The patent segments the PRS transmission into narrowband positioning reference signals (NPRS) that are specifically designed for NB-IoT devices, separating them from wideband PRS used by other LTE devices. This segmentation prevents frequency resource collisions between NB-IoT positioning signals and other LTE signals while enabling dedicated positioning capability for IoT devices.
Solution Approach 2:
The patent applies local quality by configuring NPRS with specific narrowband frequency resources tailored for NB-IoT devices, rather than using generic wideband PRS resources. This localized resource allocation ensures that positioning signals for IoT devices do not collide with other LTE signals in different frequency bands, improving positioning reliability without interference.
2Measurement precision
If narrowband positioning reference signals are transmitted, then positioning accuracy at low SNR is improved, but frequency resource configuration complexity increases
Solution Approach 1:
The patent changes the frequency band parameter by transmitting NPRS in narrowband frequency resources specifically allocated for NB-IoT, rather than using wideband resources. This parameter change improves measurement precision at low SNR conditions by reducing bandwidth and concentrating power, while the network configures these resources through standardized signaling to manage complexity.
Solution Approach 2:
The patent makes the NPRS configuration universal by using the same narrowband frequency resource allocation mechanism for all NB-IoT devices in the network. This multi-functional approach allows the system to serve multiple IoT devices with positioning capability using a standardized configuration framework, reducing individual device complexity while maintaining high positioning accuracy.
Data Source
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AI summary
Wireless communications systems and methods related to communicating positioning reference signals (PRSs) for narrowband communication are provided. A first wireless communication device determines a time-frequency PRS pattern based at least in part on a narrowband communication frequency band configuration and a PRS subframe configuration mode associated with a set of subframes. The first wireless communication device communicates, with a second wireless communication device, a plurality of PRSs using the determined PRS time-frequency pattern in the set of subframes. The PRS subframe configuration mode can indicate a first configuration including a bitmap indicating a set of PRS subframes positioned within a group of contiguous subframes, a second configuration indicating a subset of the group of contiguous subframes that may carry the PRSs, or a combination thereof. The first configuration and/or the second configuration can be used to indicate the set of subframes.