Dedicated RACH Relay Handover for Indirect V2X Connection Setup
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Solution Overview
Problem
In wireless communication systems, efficiently establishing connections between user equipment (UEs) for vehicle-to-everything (V2X) communication, especially during mobility to a target cell, is challenging, particularly when indirect connections through relay UEs are required.
Innovation Solution
A method and apparatus for a first wireless device to receive a dedicated random access channel (RACH) configuration from a serving base station, establish a connection with a second wireless device, and transmit this configuration to facilitate contention-free random access to a target base station, enabling indirect mobility through a relay UE.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If indirect connection through relay UE is established for mobility to target cell, then connection establishment is enabled when direct connection is unavailable, but connection establishment time increases and reliability decreases
Solution Approach 1:
The source base station pre-configures dedicated RACH resources and provides them to the remote UE before handover. This preliminary preparation enables the relay UE to immediately perform contention-free random access to the target base station upon receiving the handover command, significantly reducing access time and improving connection reliability compared to contention-based access.
Solution Approach 2:
The relay UE acts as an intermediary between the remote UE and the target base station. It receives the dedicated RACH configuration from the source base station, forwards it to the remote UE, and subsequently uses this configuration to establish connection with the target base station on behalf of the remote UE, enabling indirect mobility.
2Ease of manufacture
If contention-based random access is used for indirect mobility through relay UE, then connection can be established without dedicated resources, but access time increases and collision probability increases
Solution Approach 1:
Dedicated RACH resources are pre-configured and allocated by the source base station before handover occurs. This preliminary allocation eliminates the need for contention-based random access, allowing the relay UE to directly access the target base station using the pre-assigned resources, thereby reducing access time and avoiding collisions.
3Use of energy by moving object
If relay UE is in inactive state during handover, then resource consumption is reduced, but connection establishment becomes more difficult
Solution Approach 1:
The source base station acts as an intermediary by directly providing the dedicated RACH configuration to the remote UE through the relay UE, even when the relay UE is inactive. This approach eliminates the need for the inactive relay UE to actively participate in configuration exchange, maintaining energy efficiency while enabling connection establishment.
Data Source
AI summary
The present disclosure relates to connection establishment in a wireless communication system. According to one embodiment of the present disclosure, a method performed by a first wireless device in a wireless communication system comprises the steps of: receiving, from a serving base station, a mobility command including a dedicated random access channel (RACH) configuration for a contention-free random access of a target base station; establishing a connection with a second wireless device in response to the reception of the mobility command; transmitting the dedicated RACH configuration through the connection to the second wireless device; and receiving, from the second wireless device, information for notifying that the dedicated RACH configuration-based mobility has been completed.