NR Carrier Aggregation Using Dormant BWPs and Multi-Cell Grants
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Solution Overview
Problem
Existing carrier aggregation techniques in New Radio (NR) for frequencies between 52.6 GHz and 71 GHz face challenges due to high propagation losses, beam misalignment, time-frequency synchronization errors, and latency issues, particularly when utilizing dormant bandwidth parts (BWPs) for efficient bandwidth utilization.
Innovation Solution
The implementation of multi-cell grants allowing resource allocation across active and dormant BWPs using a single Downlink Control Information (DCI) format, enabling UE to receive grants on dormant BWPs without monitoring the physical downlink control channel, and utilizing PRACH signaling or autonomous timing advance adjustments to manage uplink timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carrier aggregation is used to utilize wide bandwidths in the 52.6 GHz-71 GHz frequency range, then spectrum utilization is improved, but propagation losses and beam misalignment increase
Solution Approach 1:
The wide bandwidth is divided into multiple component carriers (CCs) that can be aggregated. Each CC operates independently with its own beam management, allowing the system to utilize wide spectrum while managing beam alignment challenges on a per-carrier basis rather than requiring perfect alignment across the entire bandwidth.
Solution Approach 2:
The patent implements timing advance mechanisms where the gNB measures uplink signals from the UE and sends timing advance commands to adjust uplink timing. This closed-loop feedback system continuously corrects for beam misalignment and propagation variations, maintaining reliable communication despite the challenging high-frequency environment.
2Use of energy by moving object
If dormant bandwidth parts are used for efficient bandwidth utilization, then energy consumption is reduced, but latency increases due to additional activation signaling
Solution Approach 1:
The system pre-configures multiple bandwidth parts including dormant BWPs during initial connection setup. The UE is pre-provisioned with the necessary configuration information for dormant BWPs, so when activation is needed, the UE can quickly switch to the pre-configured BWP without requiring extensive setup signaling, thereby reducing activation latency while maintaining power efficiency.
3Adaptability or versatility
If multiple timing advance groups are used to support multiple serving cells, then carrier aggregation capability is improved, but device complexity increases
Solution Approach 1:
The timing advance mechanism is designed to be universal across multiple timing advance groups. The gNB can manage multiple TAGs using the same basic procedures and signaling structures, allowing the system to support multiple serving cells and diverse carrier aggregation scenarios without requiring separate complex mechanisms for each case, thereby managing device complexity while maintaining versatility.
Data Source
AI summary
Methods and apparatus for supporting use of multiple bandwidth parts, some of which are in a dormant state from the perspective of a User Equipment device (UE) are described. In various embodiments a multi-cell grant is supported in which a UE can be, and sometimes is, granted resources corresponding of an active bandwidth part (BWP) corresponding to a cell which is active from the UE's perspective and a BWP of a dormant cell with the multi-cell grant being transmitted to the UE on the active BWP of the active cell. Various features relate to timing determination operations used to determine downlink and/or uplink timing to be used for bandwidth portions corresponding to a dormant cell. In some embodiments a UE PRACH signal transmission on a bandwidth part of a dormant cell can be triggered by a control signal sent on a bandwidth part of an active cell.