NB-IoT Carrier Alignment with 5G NR Resource Blocks
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Solution Overview
Problem
The challenge lies in achieving efficient coexistence and migration of narrowband Internet-of-Things (NB-IoT) networks within fifth-generation (5G) new radio (NR) in time division duplex (TDD) bands without service interruptions, particularly in ensuring orthogonality and resource block alignment to prevent interference.
Innovation Solution
The solution involves determining optimal locations for NB-IoT carriers within NR carriers to achieve subcarrier and resource block alignment, reducing overhead and improving resource efficiency, by aligning NB-IoT carriers with NR subcarriers and resource blocks, especially in TDD bands with subcarrier spacing-based channel rasters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If NB-IoT carrier is placed arbitrarily to satisfy channel raster requirement, then placement flexibility is improved, but guard band size increases to prevent interference
Solution Approach 1:
The patent changes the frequency offset parameter of NB-IoT carrier from arbitrary placement to specific offset values (0, 180kHz, 360kHz, 540kHz) relative to NR carrier frequency. This parameter constraint enables subcarrier alignment between NB-IoT and NR, eliminating the need for large guard bands while maintaining placement flexibility within the defined offset framework.
2Productivity
If NB-IoT carrier is embedded inside NR carrier, then resource utilization efficiency is improved, but interference between systems increases
Solution Approach 1:
The patent applies local quality by ensuring subcarrier alignment at specific frequency offsets (0, 180kHz, 360kHz, 540kHz) where NB-IoT carriers are embedded within NR carrier. This localized alignment ensures orthogonality and prevents interference only at the critical subcarrier boundaries, while allowing flexible resource block allocation within the aligned framework, thus achieving both high resource utilization and interference prevention.
3Object-affected harmful factors
If subcarrier and resource block alignment is achieved, then interference is reduced, but carrier placement options decrease
Solution Approach 1:
The patent achieves universality by defining a set of frequency offsets (0, 180kHz, 360kHz, 540kHz) that work across different NR carrier configurations and bandwidths. These universal offset values ensure subcarrier alignment and interference prevention regardless of the specific NR carrier frequency or bandwidth, providing both interference reduction and adequate placement flexibility through a standardized approach.
Data Source
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AI summary
According to some embodiments, a method performed by a network node for communicating using time division duplexing (TDD) on a first radio access technology (RAT) carrier located within a frequency band of a second RAT comprises transmitting a first communication on the first RAT carrier to a first wireless device. A carrier center frequency of the first RAT carrier aligns with a middle of a resource block (RB) of the second RAT. In particular embodiments, the location of the center carrier frequency of the first RAT satisfies raster requirements of the first RAT.