Listen-Before-Talk Procedure Reset on Bandwidth Part Switch
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Solution Overview
Problem
Conventional wireless communication systems are inefficient when changing an active Bandwidth Part (BWP) during an ongoing Listen-Before-Talk (LBT) procedure, as the LBT procedure is based on the channel status of the original BWP, leading to potential delays due to large contention windows in overloaded BWPs.
Innovation Solution
The user equipment (UE) resets the LBT procedure when switching from a first BWP to a second BWP, initiating a new LBT procedure based on the channel status of the new active BWP, allowing for more efficient and quicker channel access by adjusting parameters such as contention windows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE continues the LBT procedure on the original BWP after a BWP change is commanded, then the LBT procedure is based on the original BWP's channel status, but this results in delays due to large contention windows in overloaded BWPs
Solution Approach 1:
The UE switches to the new BWP in advance before completing the LBT procedure, so that when LBT is resumed or restarted, it operates on the new BWP with potentially better channel conditions and smaller contention windows, reducing overall delay
Solution Approach 2:
The UE dynamically adapts the LBT procedure to the current active BWP status. When a BWP change is commanded during LBT, the UE modifies its behavior to continue or restart LBT on the new BWP rather than sticking to the original BWP, making the system flexible and responsive to changing conditions
2Productivity
If the UE switches to a new BWP during an ongoing LBT procedure, then the UE can utilize the new BWP's channel conditions, but this requires resetting and restarting the LBT procedure
Solution Approach 1:
The UE monitors for BWP change commands from the network during the LBT procedure and provides feedback by adapting its LBT behavior accordingly. When a BWP change is detected, the UE restarts LBT on the new BWP, creating a feedback loop that ensures LBT always operates on the current active BWP with optimal parameters
Data Source
AI summary
This document describes techniques and apparatuses for performing listen-before-talk procedures on bandwidth parts. These techniques include a user equipment (UE) initiating a first listen-before-talk (LBT) procedure on an active bandwidth part used in a radio resource control (RRC) connection between a UE and a base station. During the first LBT procedure, the UE receives a configuration message from the base station instructing the UE to change the active bandwidth part from the first bandwidth part to a second bandwidth part. Responsively, the UE changes the active bandwidth part and initiates a second LBT procedure on the second bandwidth part.