PDCCH-Triggered Cell Switching for Fast Uplink Synchronization
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Solution Overview
Problem
Existing uplink synchronization in wireless communication systems, particularly in scenarios requiring handover between cells, suffers from long delays and high signaling overhead due to L3-based implementations, which hinders efficient mobility and synchronization.
Innovation Solution
A method and apparatus for L1/L2-based mobility enhancement using a first information block and PDCCH to dynamically switch between source and target cells, ensuring uplink synchronization through random access preamble sequences, with configurations determined by candidate values and fields, reducing complexity and cost across various scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If L3-based serving cell change is implemented, then uplink synchronization can be achieved, but the delay is long and signaling overhead is high
Solution Approach 1:
The patent introduces an L1/L2-based mobility mechanism that acts as an intermediary between the source and target cells. The network device sends indication information through PDCCH to trigger the UE to perform random access to the target cell, bypassing the lengthy L3 reconfiguration process. This intermediary mechanism enables faster cell switching while maintaining synchronization reliability.
Solution Approach 2:
The patent prepares target cell configuration information in advance and configures multiple candidate target cells before handover is needed. The UE is pre-configured with target cell IDs, uplink frequency, and random access parameters, so that when handover is triggered, the UE can immediately execute the switch without waiting for lengthy L3 reconfiguration messages.
2Reliability
If L3-based serving cell change is implemented, then uplink synchronization can be maintained, but signaling overhead increases
Solution Approach 1:
The patent extracts the essential handover functionality from the L3 RRC reconfiguration process and implements it at the L1/L2 layer. By taking out the core synchronization and cell switching functions and placing them in the physical and MAC layers, the patent eliminates the need for extensive L3 signaling messages, thereby reducing signaling overhead while maintaining synchronization reliability.
Solution Approach 2:
The patent uses indication information copied from L3 configuration but transmitted through L1/L2 channels. The target cell configuration parameters are prepared in advance and copied into compact indication messages that can be transmitted efficiently through PDCCH, reducing the signaling overhead compared to full L3 reconfiguration messages.
3Productivity
If L1/L2-based mobility enhancement is implemented, then switching speed increases, but system complexity increases
Solution Approach 1:
The patent segments the mobility enhancement functionality into distinct components: candidate target cell configuration, indication information transmission, random access triggering, and synchronization maintenance. Each component is implemented in a separate module or layer, making the complex system manageable and easier to implement while achieving fast switching speeds.
4Adaptability or versatility
If multiple candidate target cells are configured, then handover flexibility increases, but configuration complexity increases
Solution Approach 1:
The patent applies local quality by configuring different parameters for different candidate target cells based on their specific characteristics. Each candidate cell has its own configuration parameters (cell ID, uplink frequency, random access preamble) that are optimized for that specific cell, enabling flexible handover while managing configuration complexity through localized parameter settings.
Data Source
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AI summary
Disclosed in the present application are a method and apparatus used in a node for wireless communication. The method comprises: a node receiving a first information block, which is used for determining X1 candidate configurations, the node receiving a first PDCCH, which carries a first domain, and the node sending a first signal, which carries a random access preamble sequence, wherein any one of the X1 candidate configurations is used for determining at least one cell; when the value of the first domain carried by the first PDCCH is equal to a value other than X1 candidate values, the first signal is associated with a cell to which the first PDCCH belongs; and when the value of the first domain carried by the first PDCCH is equal to one of the X1 candidate values, the value of the first domain carried by the first PDCCH is used for determining a target configuration from among the X1 candidate configurations, and the first signal is associated with at least one cell determined by means of the target configuration. The present application ensures the synchronization performance.