Layer 2 Signaling for Low-Latency Serving Cell Mobility
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Solution Overview
Problem
Conventional handover procedures in wireless communications systems suffer from high latency and delay due to the use of Layer 3 (L3) signaling, which is not compatible with the requirements of modern wireless applications and services.
Innovation Solution
Implementing Layer 2 (L2) signaling using medium access control-control element (MAC-CE) message structures to activate and deactivate primary and secondary cells, enabling handover procedures through faster L2 signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Layer 3 (L3) signaling is used for handover procedures, then reliability of control signaling is maintained, but latency and delay increase
Solution Approach 1:
The patent segments the handover control signaling into two parts: L3 signaling for configuration and parameter setup, and L2 signaling for actual handover execution. This segmentation allows the time-consuming L3 configuration to be performed in advance while the critical handover switching action is executed rapidly through L2 signaling, thus reducing overall handover latency while maintaining reliability.
Solution Approach 2:
The patent implements preliminary action by performing L3 signaling operations (configuration, parameter setup, resource allocation) before the actual handover is needed. The network entity pre-configures the UE with handover parameters and maintains readiness states, so when handover is required, the UE can quickly switch cells using L2 signaling without waiting for lengthy L3 reconfiguration, thereby reducing handover latency.
2Adaptability or versatility
If Layer 3 (L3) signaling is used for handover procedures, then compatibility with existing systems is maintained, but efficiency and speed decrease
Solution Approach 1:
The patent merges L3 and L2 signaling mechanisms into a coordinated handover procedure. L3 signaling provides the configuration framework and parameter sets, while L2 signaling executes the actual handover command. This combination allows the system to maintain compatibility with existing L3-based handover protocols while introducing faster L2 signaling for the critical switching operation, thereby improving handover efficiency without sacrificing system compatibility.
Solution Approach 2:
The patent creates a universal handover mechanism that can operate in multiple modes: traditional L3-based handover for backward compatibility, and the new hybrid L3-L2 handover for improved efficiency. The network can select the appropriate mode based on UE capabilities, network configuration, and service requirements, making the system versatile and adaptable to different scenarios while improving overall productivity.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may be configured to receive, from a first serving cell, Layer 3 (L3) control signaling indicative of multiple sets of parameters for primary serving cell and secondary serving cell operation. The UE may receive, from the first serving cell, via Layer 2 (L2) control signaling indicating an activation of a second serving cell at the UE and an indication that specifies that the second serving cell is to be activated as a primary serving cell. The UE may then communicate with the second serving cell as the primary serving cell based on receiving the second signaling and in accordance with a set of parameters from the multiple sets of parameters indicated by the L3 control signaling.