Beam Management and BWP Operation for Non-Terrestrial Networks
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Solution Overview
Problem
Current NR specifications face challenges in beam management and bandwidth part operations for non-terrestrial networks (NTNs), particularly in handling frequent satellite spot beam switching and co-channel interference, which leads to data interruption and increased latency due to outdated CSI reporting and limited simultaneous active BWP support.
Innovation Solution
The proposed solution includes methods for beam management that broadcast transmission configuration indication (TCI) states and implement beam failure detection, along with BWP operations that enable simultaneous TCI updates and increased BWP configurations using group common PDCCH, supporting multiple active BWPs and efficient BWP switching in NR NTN environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional beam management methods are used in NR NTN, then system complexity is reduced, but beam switching latency increases and data interruption occurs due to frequent satellite spot beam switching
Solution Approach 1:
The network pre-configures multiple Transmission Configuration Indication (TCI) states at the UE before beam switching is needed. These TCI states contain beam information that will be needed for future switching operations. When beam switching is required, the network simply indicates which pre-configured TCI state to use, eliminating the need for real-time beam parameter negotiation and reducing switching latency.
2Productivity
If traditional BWP operation with single active BWP is used, then device complexity is reduced, but productivity decreases due to data interruption during BWP switching in satellite spot beam scenarios
Solution Approach 1:
The system transitions from a static single-active-BWP model to a dynamic multi-active-BWP model. Multiple BWPs can be simultaneously active at the UE, and the network can dynamically indicate which BWP(s) should be used for specific transmissions. This allows seamless BWP switching without data interruption, as the UE maintains multiple active BWPs and can switch between them instantaneously based on network indication.
3Measurement precision
If traditional CSI reporting mechanisms are used, then signaling overhead is reduced, but measurement precision decreases due to outdated CSI information in rapidly changing satellite beam environments
Solution Approach 1:
The system enhances the existing TCI state mechanism to serve dual purposes: (1) indicating beam information for transmission configuration, and (2) triggering implicit CSI reporting. When the network updates TCI states at the UE, this same update serves as a trigger for the UE to report CSI measurements. This multi-functional approach ensures accurate CSI reporting without requiring separate signaling mechanisms, thus maintaining low signaling overhead while improving measurement precision.
4Adaptability or versatility
If multiple active BWPs are supported simultaneously, then adaptability increases for satellite spot beam switching, but device complexity increases due to increased BWP configuration and management requirements
Solution Approach 1:
The system merges BWP management with the existing TCI state mechanism. Instead of creating a separate, complex BWP management system, the patent combines BWP configuration and switching control with the already-established TCI state framework. The network configures multiple BWPs and associates them with TCI states, allowing unified management of both beam and bandwidth resources through the same signaling mechanisms, thereby reducing overall device complexity while maintaining high adaptability.
Data Source
AI summary
Methods, apparatus, and systems for beam management and BWP operations for NR NTN. Beam management methods for both one beam per cell and for multiple beams per cell may be implemented. A transmission configuration indication (TCI) state sequence also may be implemented, in which a network node may broadcast the transmission of TCI states.