Secondary Cell BWP Activation Signaling for Dormant UE Switching
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently switching user equipment (UE) from dormant to active bandwidth parts (BWPs) in secondary cells, particularly for low-power UEs with limited receiver bandwidth capability, leading to inefficiencies and increased signaling overhead.
Innovation Solution
The described techniques enable UE to switch to an active BWP in a secondary cell group (SCG) by receiving downlink control information (DCI) from a master node, using bitmaps, radio resource control (RRC) configurations, and radio network temporary identifiers (RNTIs) to facilitate seamless transitions, even when the UE is in an inactive state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional signaling methods are used to activate BWP in secondary cells, then the UE can be switched from dormant to active state, but the signaling overhead increases and the switching efficiency decreases
Solution Approach 1:
The patent segments the BWP activation signaling into two parts: (1) RRC configuration that pre-configures multiple BWPs and their parameters in advance, and (2) MAC CE or DCI signaling that only activates a specific pre-configured BWP. This segmentation reduces the signaling overhead for activation while maintaining reliability, as the bulk of configuration information is transmitted once during RRC setup rather than repeatedly during activation events.
Solution Approach 2:
The patent implements preliminary action by pre-configuring multiple BWPs and their parameters through RRC signaling before the activation event occurs. The RRC configuration includes BWP-ID, frequency location, bandwidth, and other parameters. When activation is needed, the system only needs to transmit a compact activation command (MAC CE or DCI) referencing the pre-configured BWP, rather than transmitting complete configuration information at activation time.
2Use of energy by moving object
If the UE remains in dormant BWP state to save power, then energy consumption decreases, but the switching response time to active state increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring multiple BWPs with all necessary parameters (frequency location, bandwidth, subcarrier spacing, cyclic prefix length) during RRC setup phase. This allows the UE to remain in a low-power dormant state while having all configuration information readily available in memory. When activation is commanded via MAC CE or DCI, the UE can immediately switch to the specified BWP without waiting for configuration transmission, thus reducing switching time while maintaining power savings.
Solution Approach 2:
The patent implements dynamics by enabling the UE to dynamically switch between dormant and active BWP states based on network commands. The system maintains flexibility by allowing rapid state transitions through compact MAC CE or DCI signaling, while the UE can remain in dormant state for extended periods to conserve power. The dynamic switching capability is achieved through pre-configured BWP parameters that can be quickly activated without full reconfiguration.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. The described techniques provide signaling formats to cause a UE to switch to an active BWP in a secondary cell (SCell) secondary cell group (SCG). The techniques may be used when the UE is connected to a secondary node on a dormant BWP such that the UE connects to the secondary node on the active BWP. The UE may receive, from a master node, downlink control information (DCI) indicating a transition to an active BWP for the communication link with the secondary node. The UE may then perform a communication with the secondary node on the active bandwidth part in accordance with the DCI. The DCI may include SCell or SCG bitmaps, extra bits that signal to the UE that an activation corresponds to a SCG, and/or RNTIs that signal to the UE that the activation corresponds to a SCG.