Rank Indicator Bit Width Determination in MIMO Terminals
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Solution Overview
Problem
In LTE radio systems, there is a mismatch between the actual and assumed operations of base station and terminal devices, leading to communication inefficiencies due to differences in bit width for Rank Indicators (RI) and other parameters.
Innovation Solution
The implementation of a terminal device and base station device communication method that transmits and receives Rank Indicators (RI) associated with CSI-RS resources, along with capability information, to accurately determine and adjust bit widths based on the maximum number of layers supported, ensuring efficient communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the terminal device uses a fixed bit width for Rank Indicator (RI) based on default assumptions, then the device complexity is reduced, but communication reliability deteriorates due to mismatch between actual and assumed operations at the base station
Solution Approach 1:
The terminal device performs preliminary determination of the RI bit width by calculating it based on the maximum number of layers supported by the terminal device and the number of antenna ports, rather than using fixed default values. This preliminary calculation ensures that the RI bit width is correctly aligned with the actual MIMO capabilities before communication occurs, resolving the mismatch issue while maintaining device complexity at an acceptable level.
Solution Approach 2:
The invention changes the parameter determination approach from using fixed default assumptions to dynamically calculating the RI bit width based on actual device capabilities (maximum number of layers and number of antenna ports). This parameter change ensures that the RI bit width adapts to the actual operational parameters, improving communication reliability without significantly increasing device complexity.
2Productivity
If the terminal device transmits detailed capability information including maximum number of layers and bandwidth class, then communication efficiency is improved through accurate parameter alignment, but the quantity of information transmitted increases
Solution Approach 1:
The capability information structure is designed to be universal and multi-functional. The terminal device transmits a compact set of parameters (maximum number of layers, bandwidth class, and number of antenna ports) that can be used to determine RI bit width for multiple different RI types (first RI, second RI, third RI) and various MIMO configurations. This universal approach improves communication efficiency across different scenarios while keeping the transmitted information quantity minimal.
Solution Approach 2:
The capability information is structured with local quality by providing specific parameters (maximum number of layers per bandwidth class) that are precisely targeted to the needs of RI bit width determination. Rather than transmitting all possible capability parameters, the invention transmits only the essential local information needed for accurate RI calculation, optimizing the balance between communication efficiency and information quantity.
Data Source
AI summary
A terminal device and a base station device efficiently communicate with each other. For the terminal device, in a case that third information is configured, a third maximum number of the layers assumed for determining a bit width for a first RI and a fourth maximum number of the layers assumed for determining a bit width for a second RI are provided, based on the third information. In case that the third information is not configured, the third maximum number and the fourth maximum number are provided, based on a smallest one of a first number and a second number. The first number is a second maximum number of the layers indicated by second information, and the second number is a largest one of the number of antenna ports of a first CSI-RS resource and the number of antenna ports of a second CSI-RS resource.