Bandwidth Part Switching for Non-Terrestrial Networks
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Solution Overview
Problem
Current NR systems face challenges in beam management and bandwidth part (BWP) operation for Non-Terrestrial Networks (NTNs), particularly with frequency reuse, where dynamic BWP switching is slowed by data scheduling, and in low Earth orbit scenarios where satellite velocity and propagation delay hinder efficient BWP switching, leading to potential radio link failures and increased complexity due to polarization differences among UEs.
Innovation Solution
A method for user equipment (UE) and access network nodes to autonomously switch between bandwidth parts based on received ephemeris and polarization information, allowing for efficient BWP switching without data scheduling, and explicit polarization notification to UEs to prevent interference, using periodic updates for ephemeris and polarization information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dynamic BWP switching is implemented in current NR systems, then BWP switching capability is improved, but switching speed is reduced due to data scheduling requirements
Solution Approach 1:
The patent applies preliminary action by pre-configuring multiple BWPs with different bandwidths and numerologies before the UE needs to switch. The network node provides configuration information including BWP identifiers, bandwidth values, and numerology parameters in advance, allowing the UE to quickly select and switch to an appropriate BWP without waiting for data scheduling decisions. This resolves the contradiction by enabling fast switching capability while maintaining system flexibility.
2Adaptability or versatility
If frequent BWP switching is performed in low Earth orbit scenarios, then adaptability to satellite movement is improved, but radio link reliability deteriorates due to propagation delay
Solution Approach 1:
The patent applies preliminary action by having the network node provide advance notification information about upcoming BWP switches before the actual switch occurs. The UE receives indication information that tells it which BWP will be activated next, allowing the UE to prepare internally and maintain continuous communication. This resolves the contradiction by enabling frequent switches to track satellite movement while preventing radio link failures through proper timing and preparation.
Solution Approach 2:
The patent implements feedback mechanisms where the UE reports its position, speed, and acceleration information to the network node, which then adjusts BWP configuration accordingly. The network also monitors UE communication status and provides feedback on polarization information. This closed-loop feedback system resolves the contradiction by continuously adapting BWP settings to match actual UE movement conditions, maintaining reliability during frequent switches.
3Productivity
If multiple polarization modes are supported for frequency reuse, then network capacity is improved, but UE complexity increases due to polarization detection and handling
Solution Approach 1:
The patent applies self-service by having the UE automatically detect and report its polarization capability to the network node without manual configuration. The UE autonomously determines whether it supports linear or circular polarization and communicates this information to the network, which then selects appropriate polarization modes for frequency reuse. This resolves the contradiction by enabling multiple polarization modes for increased capacity while keeping UE operations automated and simple.
Data Source
AI summary
A communication system is disclosed in which a user equipment (UE) receives, from a node of an access network, information for identifying an initial bandwidth part for communication between the UE and the access network in a first part of a communication coverage area provided by the access network, and information for identifying a set of one or more bandwidth parts, each bandwidth part of the set of bandwidth parts respectively being for potential future communication between the UE and the access network in a corresponding further part of the communication coverage area. A next bandwidth part of the set of bandwidth parts is identified, for switching to from the initial bandwidth part as a position of the UE relative to the communication coverage area enters, or approaches, the further part of the communication coverage area corresponding to the identified next bandwidth part.