Base Station Pre-Coding Flag Indicator for MIMO Overhead Reduction
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Solution Overview
Problem
In MIMO mobile communication systems, existing methods for channel compensation in shared data channels with pre-coding require significant resources and overhead, and may lead to inefficient use of downlink resources due to the need for continuous transmission of pre-coding matrix indicators (PMI), which can cause interference and degrade signal quality if not correctly recognized.
Innovation Solution
A base station apparatus that receives a PMI from user equipment, determines whether to use the specified pre-coding matrix for downlink communications, and transmits a flag indicator to reduce overhead by using a default pre-coding matrix when the specified matrix is not suitable, thereby optimizing resource use and preventing signal degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pre-coding matrix indicators (PMI) are continuously transmitted to enable accurate channel compensation, then channel estimation accuracy is improved, but downlink overhead increases and radio resources are consumed
Solution Approach 1:
The patent extracts only the essential information needed for channel compensation by using a flag indicator to signal whether the transmitted PMI should be used, rather than continuously transmitting full pre-coding matrix information. This reduces downlink overhead while maintaining necessary channel estimation accuracy.
Solution Approach 2:
Instead of continuously transmitting complete PMI information, the system transmits only partial information (the flag indicator) that is sufficient to enable the receiver to determine whether to use the previously transmitted PMI, thereby reducing resource consumption while maintaining functionality.
2Measurement precision
If the specified pre-coding matrix is always used for downlink communications, then channel compensation accuracy is maintained, but signal quality deteriorates when the matrix is not suitable
Solution Approach 1:
The patent introduces dynamic adaptability by allowing the system to flexibly switch between using the transmitted PMI and not using it, based on the flag indicator. This enables the system to adapt to varying channel conditions and prevent signal quality deterioration when the specified pre-coding matrix is not suitable.
Solution Approach 2:
The system changes the operational parameter of pre-coding matrix usage dynamically by introducing a flag indicator that controls whether the transmitted PMI is applied, allowing optimization of signal quality based on actual channel conditions rather than rigidly following the transmitted PMI.
3Productivity
If pre-coding matrices are transmitted frequently to optimize downlink resource use, then resource allocation efficiency is improved, but interference increases and signal quality degrades
Solution Approach 1:
Instead of continuous PMI transmission, the system uses periodic or event-driven transmission where PMI is transmitted only when necessary, controlled by the flag indicator mechanism. This reduces interference caused by frequent transmissions while maintaining resource allocation efficiency.
Solution Approach 2:
The patent extracts only the essential control information (flag indicator) needed to manage pre-coding matrix usage, removing the need for frequent complete PMI transmissions. This reduces interference while preserving the ability to optimize downlink resource allocation when needed.
Data Source
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AI summary
A disclosed base station apparatus is capable of communicating with a user equipment terminal in a multi-input multi-output (MIMO) mobile communication system using Pre-coding. The base station apparatus includes a receiving unit receiving a Pre-coding Matrix Indicator (PMI) indicating a specific Pre-coding matrix, a determination unit determining a value of a flag indicator indicating whether the Pre-coding matrix specified in the PMI is to be used for downlink communications, a control signal generation unit generating a downlink control signal including at least the flag indicator, and a transmission unit transmitting a signal including the downlink control signal in downlink.