PRS Scheduling in NB-IoT via Dynamic Pattern Selection
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Solution Overview
Problem
The scheduling of positioning reference signals (PRS) in narrowband-Internet of Things (NB-IoT) systems often results in collisions with other LTE signals, leading to performance degradation due to overlapping time-frequency resources.
Innovation Solution
The proposed solution involves configuring positioning subframes to avoid collisions by marking certain subframes as invalid for data transmission, determining a PRS time-frequency pattern that excludes pre-configured resources, and transmitting PRS with repetitions or puncturing the pattern to skip over fixed-scheduled channel signals, allowing for effective communication of PRS without interfering with other network signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PRS is transmitted using fixed time-frequency resources, then positioning reference signal communication is enabled, but collisions with other LTE signals occur leading to performance degradation
Solution Approach 1:
The patent applies dynamics by making the PRS time-frequency pattern configurable and adaptable rather than fixed. The network can dynamically select from multiple PRS patterns (first pattern with contiguous RBs, second pattern with non-contiguous RBs) based on network conditions and signal collision scenarios, allowing the system to optimize PRS transmission reliability under different operating conditions
Solution Approach 2:
The patent changes physical parameters of the PRS transmission by introducing different resource allocation patterns. The first pattern uses contiguous resource blocks while the second pattern uses non-contiguous resource blocks, effectively changing the frequency domain distribution parameter to avoid collisions with other LTE signals while maintaining positioning functionality
2Productivity
If PRS uses contiguous resource blocks, then resource utilization efficiency is improved, but collision with fixed-scheduled channels increases
Solution Approach 1:
The system dynamically switches between contiguous and non-contiguous resource block patterns based on network configuration and collision scenarios. When contiguous RBs cause collisions with fixed-scheduled channels, the network can reconfigure to use non-contiguous RBs, maintaining resource utilization efficiency while avoiding harmful interference
Solution Approach 2:
The patent changes the frequency domain allocation parameter from contiguous to non-contiguous resource blocks. This parameter change allows PRS to skip over fixed-scheduled channel locations, reducing collision probability while still achieving efficient resource utilization through optimized pattern selection
3Object-affected harmful factors
If PRS uses non-contiguous resource blocks, then collision with other signals is reduced, but resource utilization efficiency decreases
Solution Approach 1:
The system dynamically adapts between non-contiguous and contiguous patterns based on actual network conditions. When signal collision is detected or anticipated, non-contiguous patterns are used to reduce interference; when collision-free conditions exist, contiguous patterns are switched to improve resource utilization efficiency, optimizing both objectives under different scenarios
4Reliability
If subframes are marked as invalid for data transmission, then PRS collision avoidance is achieved, but available transmission resources are reduced
Solution Approach 1:
The patent segments the available resource blocks into different patterns (contiguous and non-contiguous allocations). By segmenting resources in this way, the system can identify and isolate specific RB groups that are safe for PRS transmission without invalidating entire subframes, thereby maintaining more available transmission resources while achieving collision avoidance
Data Source
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.