Antenna Selection Control in Dual Connectivity User Terminals
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Solution Overview
Problem
In LTE systems, antenna selection diversity methods face challenges when dual connectivity is employed, as multiple radio base stations operate asynchronously, making it difficult for user terminals to select the same transmitting antenna across different cell groups, which can lead to reduced communication quality.
Innovation Solution
A user terminal is designed to control antenna selection on a per cell group or per cell basis, allowing it to operate effectively even when connected to multiple radio base stations with asynchronous scheduling, by using closed-loop or open-loop antenna selection methods and reporting antenna selection information from radio base stations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If antenna selection is employed in dual connectivity with multiple radio base stations, then communication diversity gain can be achieved, but it becomes difficult to select the same transmitting antenna across different cell groups due to asynchronous operation
Solution Approach 1:
The patent segments the antenna selection control by cell group rather than treating all cells uniformly. The user terminal is configured to select antennas independently for each cell group (MCG and SCG), allowing appropriate antenna selection in each asynchronous cell group while maintaining overall system reliability through coordinated control.
2Device complexity
If a common transmitting antenna is used across all cells in carrier aggregation, then circuit complexity in the user terminal can be reduced, but this approach does not work effectively in dual connectivity where multiple radio base stations operate asynchronously
Solution Approach 1:
The patent applies different antenna selection strategies to different cell groups based on their operational characteristics. While carrier aggregation uses a common antenna approach to reduce complexity, dual connectivity employs cell-group-specific antenna selection to maintain reliability despite asynchronous operation, allowing each cell group to be optimized independently.
3Adaptability or versatility
If multiple radio base stations carry out scheduling independently in dual connectivity, then system flexibility and adaptability are improved, but antenna selection coordination becomes difficult and communication quality may deteriorate
Solution Approach 1:
The patent introduces dynamic antenna selection control where the user terminal can be configured to use different transmitting antennas for different cell groups. This dynamic approach allows the system to adapt to independent scheduling decisions made by multiple radio base stations while maintaining communication quality through coordinated antenna selection based on actual channel conditions in each cell group.
Data Source
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AI summary
The present invention is designed to control the antenna selection in a user terminal adequately even when the user terminal connects with a plurality of radio base stations by employing dual connectivity (DC). A user terminal supports communication which uses dual connectivity with a plurality of radio base stations that each configure a cell group formed with one or more cells, and this user terminal has a transmission section that transmits UL signals to one or a plurality of cell groups, and a control section that controls the antenna selection for transmitting the UL signals, and, when antenna selection for a serving cell (UE transmit antenna selection) is configured, the control section controls the antenna selection expecting that the plurality of cell groups are not configured.