Parallel Handover Using Multi-Chain UE Links Across Source and Target Cells
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Solution Overview
Problem
Wireless communications systems face challenges in maintaining reliable communication during handovers due to interruptions in the user plane, especially for time-critical services, and existing dual active protocol stack (DAPS) techniques are complex and limit simultaneous communication with multiple cells.
Innovation Solution
Implementing a parallel handover (PHO) procedure that allows a user equipment (UE) to communicate with both a source and target cell using multiple transmit and receive chains, exchanging capability and preference messages to configure the PHO, and receiving configuration messages for efficient handover.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional handover procedures are used, then the handover process is simple, but communication reliability deteriorates due to user plane interruptions
Solution Approach 1:
The handover procedure is segmented into parallel paths: one path maintains connection with the source cell while another path establishes connection with the target cell. This segmentation allows the UE to communicate with both cells simultaneously using different transmit and receive chains, thereby maintaining communication reliability without requiring a single complex sequential handover procedure.
Solution Approach 2:
The UE performs preliminary actions by establishing connection with the target cell before fully disconnecting from the source cell. The capability message and preference information are exchanged in advance to configure the parallel handover, allowing the UE to prepare both communication paths before switching, thus preventing user plane interruptions.
2Reliability
If DAPS techniques are used, then communication reliability improves, but device complexity increases due to simultaneous communication with multiple cells
Solution Approach 1:
The communication resources are segmented into separate transmit and receive chains, where each chain can independently communicate with different cells. This segmentation allows the UE to maintain simple protocol stacks for each chain while achieving reliable simultaneous communication with multiple cells, avoiding the complexity of a unified DAPS protocol stack.
Solution Approach 2:
The UE employs multiple transmit and receive chains (excessive action) to communicate with multiple cells simultaneously, rather than using a single protocol stack. This partial implementation of communication paths for each chain simplifies the overall protocol complexity while maintaining reliability through redundancy.
3Productivity
If multiple transmit and receive chains are used, then communication efficiency improves, but device complexity increases
Solution Approach 1:
The multiple transmit and receive chains are designed with universal functionality to handle different cell communications. Each chain can be configured to work with either the source cell or target cell, allowing the hardware to perform multiple functions without requiring specialized components for each cell, thus improving communication efficiency while controlling hardware complexity.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may exchange a set of messages with a network entity to enable the UE to perform a parallel handover (PHO) procedure. The UE may transmit a capability message indicating that the UE supports the PHO procedure, during which the UE may be configured to communicate with both a source cell and a target cell associated with the PHO procedure simultaneously using a set of transmit and receive chains of the UE. The UE may transmit a second message indicating a respective quantity of transmit and receive chains corresponding to one or more transmission and reception points (TRPs) associated with the PHO procedure, one or more respective TRPs corresponding to the source cell and the target cell, or both. Then, the UE may receive a configuration message based on the capability message.