NR Cell BWP Switching for Zero-Latency Handovers
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Solution Overview
Problem
Current 5G NR systems face limitations in bandwidth adaptation and handover processes, particularly in super-wide band frequencies, where UE maximum channel bandwidths are restricted, and beamforming for UL signals is complex due to UE orientation and lack of TRP knowledge.
Innovation Solution
A scalable NR cell structure with multiple TRPs operating on multiple layers of component carriers, configuring BWPs for adaptive switching and aggregation, allowing UEs to operate with indexed BWPs across carriers, and enabling periodic RRM/CSI measurements to optimize bandwidth usage and handover latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If UE operates on super-wide band frequencies with restricted maximum channel bandwidth, then frequency band coverage is improved, but bandwidth adaptation capability deteriorates
Solution Approach 1:
The patent segments the wideband carrier into multiple Bandwidth Parts (BWPs), each with different bandwidth configurations. The UE can be configured with multiple BWPs (e.g., BWP1, BWP2, BWP3) of varying sizes, allowing the system to provide wideband coverage while enabling adaptive bandwidth selection. Each BWP represents a segment of the total carrier bandwidth that can be independently activated based on service requirements.
Solution Approach 2:
The patent implements dynamic BWP switching where the UE can transition between different bandwidth parts during operation. The network can configure the UE with multiple BWPs and switch between them based on traffic conditions, service type, and power considerations. This dynamic adaptation allows the system to optimize bandwidth usage in real-time while maintaining coverage on super-wide bands.
2Reliability
If beamforming is implemented for UL signals in multi-TRP system, then signal coverage and quality are improved, but system complexity increases due to UE orientation and TRP knowledge requirements
Solution Approach 1:
The patent implements self-service beamforming where the UE autonomously determines the appropriate TRP and beam configuration without explicit network control. The UE uses reference signals (RS) transmitted by multiple TRPs to automatically identify the best serving TRP and perform beamforming adjustments. This eliminates the need for complex network-side beam management and reduces signaling overhead.
Solution Approach 2:
The patent changes the beamforming parameters dynamically based on UE position and channel conditions. The network configures multiple TRPs with different beam directions and the UE selects the optimal TRP-beam pair by measuring reference signals. The system adjusts beamforming parameters (such as beam width, direction, and power) based on measured channel quality, enabling adaptive beamforming without complex manual configuration.
3Productivity
If multiple TRPs operate on multiple layers of component carriers, then cell capacity and flexibility are improved, but system configuration and management complexity increases
Solution Approach 1:
The patent creates a universal multi-TRP architecture where each TRP can operate on multiple component carriers and provide multiple functions (data transmission, reference signaling, channel state information). The same BWP configuration mechanism serves multiple TRPs and multiple UEs simultaneously. This universal design allows the system to scale capacity by adding TRPs without proportionally increasing configuration complexity.
Solution Approach 2:
The patent adds the TRP dimension to the existing carrier and BWP structure. Instead of managing complexity through a single-dimensional approach, the system organizes resources across multiple dimensions: carriers, BWPs, and TRPs. This multi-dimensional organization allows independent optimization at each level while maintaining overall system coherence through standardized configuration procedures.
4Loss of time
If handover process is optimized for zero latency, then mobility performance is improved, but measurement and switching accuracy requirements increase
Solution Approach 1:
The patent performs preliminary measurements and BWP configurations before handover is needed. The network pre-configures multiple BWPs on different carriers and TRPs, and the UE continuously measures reference signals from potential target TRPs in advance. This preliminary preparation eliminates the need for measurement and configuration during the actual handover event, achieving zero-latency switching.
Solution Approach 2:
The patent implements continuous feedback mechanisms where the UE reports channel quality and measurement results to the network in real-time. The network uses this feedback to pre-determine the optimal target TRP and BWP configuration before handover. The feedback loop enables the system to maintain high measurement accuracy through continuous monitoring while executing handovers without latency.
Data Source
AI summary
A method for use in a scalable New Radio (NR) cell system comprises, at a gNB: configuring a physical transmission and reception point (TRP) in a New Radio (NR) cell as a high power gNB's distribution unit (DU) operating on a first component carrier (CC) layer; configuring the remaining physical TRPs in the NR cell as low power gNB's DUs operating on one or multiple second CC layers; further configuring the carrier bandwidths on the first CC layer and second CC layers to comprise multiple bandwidth parts (BWPs); via high layer signaling, configuring one or more advanced UEs in services or requesting services with a set of indexed BWPs and a configurable “initial BWP” for active BWP switching operation; and via high layer signaling, configuring one or more advanced UEs in services or requesting services with two or more sets of indexed BWPs for active BWPs aggregation operation.