Beam-Based LBT for 5G Massive MIMO Channel Access
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Solution Overview
Problem
In the context of 5G NR systems, the adoption of Massive MIMO leads to varying interference situations across different beam directions, necessitating an enhanced method to reflect interference in specific beam directions and improve channel access and system capacity.
Innovation Solution
The implementation of a beam-based Listen Before Talk (LBT) method, where a UE receives a precoding matrix indicating K transmission parameter groups, allowing it to perform channel listening within limited beam coverage and transmit radio signals only when the channel is idle, thereby increasing channel access opportunities and improving system capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional LBT-based radio signal transmission is used in Massive MIMO systems, then interference in specific beam directions cannot be accurately reflected, but beamforming is applied to improve communication quality
Solution Approach 1:
The patent segments the channel access process into multiple beam-specific LBT operations. Instead of a single omnidirectional LBT, the system performs separate LBT checks for each beam direction indicated by the precoding matrix, allowing accurate interference measurement in specific spatial directions while maintaining beamforming benefits
Solution Approach 2:
The patent introduces a spatial dimension to the LBT process by evaluating channel availability in multiple beam directions rather than a single omnidirectional view. This dimensional expansion allows the system to identify and exploit spatial opportunities for transmission that would be invisible to traditional LBT
2Productivity
If a single channel access occasion is used in traditional techniques, then channel access chance is limited, but system capacity needs to be improved
Solution Approach 1:
The patent segments the single channel access occasion into multiple beam-specific access opportunities. Each beam direction represented in the precoding matrix becomes an independent LBT opportunity, effectively multiplying the number of chances to access the channel within the same time resource
Solution Approach 2:
The patent changes the parameter of channel access from a single omnidirectional attempt to multiple directional attempts. By varying the spatial parameter (beam direction) across multiple LBT operations, the system increases the probability of finding an available channel while maintaining efficient use of time resources
Data Source
AI summary
The present disclosure provides a method and device in UE and base station used for wireless communications. The UE receives first information, the first information being used for indicating a first precoding matrix; and transmits a first radio signal through a first antenna port group within a first time-domain resource in a first sub-band, or, drops wireless transmission through a first antenna port group within a first time-domain resource in a first sub-band. The first precoding matrix is used for determining K transmission parameter groups, K being a positive integer greater than 1; a first transmission parameter group is one of the K transmission parameter groups, and the first transmission parameter group is used for generating the first antenna port group, the first antenna port group comprising a positive integer number of antenna port(s). The method helps enhance the chance of uplink channel access, thereby improving the system capacity.