Wireless Communication Device LBT Failure Handling
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Solution Overview
Problem
In unlicensed bands, wireless communication devices face instability due to Listen Before Talk (LBT) failures, which can prevent necessary information from being transmitted, leading to communication link instability.
Innovation Solution
A novel terminal device and wireless communication method that dynamically designates resources for transmission and employs countermeasures for LBT failures, such as extending the random access response window or providing multiple RACH procedure settings, to ensure successful RACH procedures even in cases of LBT failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Listen Before Talk (LBT) is performed before transmission in unlicensed bands, then channel access fairness is maintained, but transmission may be blocked when LBT fails, leading to communication link instability
Solution Approach 1:
The base station performs LBT in advance before the terminal device needs to transmit. If LBT succeeds, the base station designates resources for the terminal's transmission. This preliminary action ensures that when the terminal attempts transmission, the channel is already prepared, avoiding LBT failure blocks and maintaining communication stability.
Solution Approach 2:
The base station provides feedback information to the terminal device about the LBT result and designated transmission resources. This feedback mechanism allows the terminal to adapt its transmission timing and resources based on the base station's LBT outcome, ensuring successful communication even when the terminal would have failed LBT on its own.
2Reliability
If the random access response window is extended to accommodate LBT failures, then transmission reliability improves, but time consumption increases
Solution Approach 1:
The base station dynamically adjusts the random access response window timing based on the LBT result and designated resource timing. Instead of using a fixed extended window, the base station calculates the appropriate response timing relative to the designated transmission resources, optimizing the window duration to balance reliability and time efficiency.
3Adaptability or versatility
If multiple RACH procedure settings are provided to handle different LBT scenarios, then adaptability improves, but device complexity increases
Solution Approach 1:
The base station provides multiple RACH procedure settings as separate configuration options, each tailored for specific LBT scenarios (e.g., LBT success case, LBT failure case). This segmentation allows the terminal to select the appropriate pre-configured procedure based on the actual LBT outcome, simplifying the terminal's decision logic compared to implementing complex adaptive algorithms.
Data Source
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AI summary
There is provided a wireless communication device capable of making the wireless communication link more stable in a communication system using an unlicensed band. There is provided a wireless communication device including a determination unit (243) configured to determine whether a channel is clear or busy, a communication unit (220) configured to transmit an uplink signal of a RACH procedure, and a setting unit (243) configured to set at least a first resource and a second resource to transmit the uplink signal, in which the first resource is selected from a set of resources set by information in an RRC layer, and the second resource is designated by downlink information in a physical layer.