UE Channel Access Using LBT-Free Preamble Transmission
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently determining channel access in unlicensed spectra, particularly in shared networks, leading to inefficiencies and potential interference.
Innovation Solution
The proposed method involves a UE performing a first transmission without Listen Before Talk (LBT) for a preamble and sensing the channel for subsequent transmissions, allowing for more flexible and efficient channel access strategies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Listen Before Talk (LBT) is performed for all transmissions, then channel access reliability is improved, but transmission delay and complexity increase
Solution Approach 1:
The patent segments the transmission process into two distinct parts: preamble transmission (which does not require LBT) and data transmission (which requires LBT). This segmentation allows the system to reduce delay for initial access while maintaining reliability for actual data transfer, resolving the contradiction between speed and reliability.
Solution Approach 2:
The patent applies partial LBT action by performing LBT only for data transmissions rather than all transmissions. This partial application of the LBT mechanism reduces overall transmission delay and complexity while still ensuring reliable channel access when actually needed for data transfer.
2Object-affected harmful factors
If LBT is performed for every transmission, then interference reduction is improved, but channel access efficiency deteriorates
Solution Approach 1:
By separating preamble transmission from data transmission and applying different LBT requirements to each, the patent reduces unnecessary LBT operations. This segmentation maintains interference reduction for actual data transmissions while improving overall channel access efficiency by eliminating redundant LBT for preambles.
Solution Approach 2:
The patent applies LBT selectively only to data transmissions rather than all transmissions, representing a partial application of the interference avoidance mechanism. This approach maintains the beneficial interference reduction effect while avoiding the productivity loss from performing LBT on every transmission.
3Reliability
If channel sensing is performed for all signals, then channel access reliability is improved, but device complexity and energy consumption increase
Solution Approach 1:
The patent segments the transmission signals into preamble and data portions, applying different channel access procedures to each. Preamble transmission is simplified without sensing, while data transmission includes full sensing. This segmentation reduces device complexity for initial access while maintaining reliability for actual data communication.
Solution Approach 2:
The patent applies channel sensing only partially - specifically for data transmissions rather than all transmissions. This partial application reduces the overall complexity and energy consumption of the device while still ensuring reliable channel access when it matters most for data transfer.
Data Source
AI summary
A method and apparatus are disclosed. In an example from the perspective of a User Equipment (UE), the UE performs a first transmission without Listen Before Talk (LBT), wherein the first transmission is a preamble transmission. The UE performs LBT for a second transmission for a signal other than preamble.