CQI Feedback Mechanism for Dual MIMO Operation
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Solution Overview
Problem
The existing wireless packet data communication systems face increased Channel Quality Indicator (CQI) feedback overhead when supporting both Single-User MIMO and Multi-User MIMO operations, which can lead to reduced system performance due to excessive resource management restrictions or increased feedback burden.
Innovation Solution
The proposed solution sets a default MIMO operation mode for either Single-User or Multi-User MIMO, with the access terminal calculating CQI based on this mode and reporting an absolute value, along with a DELTA CQI to facilitate switching to the alternative mode, thereby reducing feedback overhead through quantization and upper signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the system supports both Single-User MIMO and Multi-User MIMO operations, then the adaptability and versatility of the system is improved, but the CQI feedback overhead increases
Solution Approach 1:
The CQI feedback is segmented into two parts: a first CQI value for the first MIMO operation mode and a second CQI value for the second MIMO operation mode. This segmentation allows the system to support multiple operation modes while managing feedback overhead by only transmitting necessary CQI information for each mode.
Solution Approach 2:
The system implements partial action by conditionally transmitting CQI information based on the scheduled operation mode. When the first operation mode is scheduled, only the first CQI value is transmitted; when the second operation mode is scheduled, only the second CQI value is transmitted. This avoids the excessive action of transmitting both CQI values in all scenarios, thereby reducing feedback overhead.
2Measurement precision
If separate CQI feedback is implemented for each MIMO operation mode, then the measurement precision for each mode is improved, but the device complexity increases
Solution Approach 1:
The system dynamically adjusts the CQI feedback mechanism based on the scheduled operation mode. The base station determines which operation mode to use and accordingly processes only the relevant CQI information. This dynamic approach maintains measurement precision for each mode while avoiding the static complexity of processing both CQI values simultaneously in all cases.
3Reliability
If the access terminal reports CQI for both operation modes, then the reliability of resource management is improved, but the loss of time for feedback transmission increases
Solution Approach 1:
The system implements partial action by having the access terminal report only the CQI information necessary for the currently scheduled operation mode. This reduces the feedback transmission time while maintaining resource management reliability, as the base station only requires CQI information for the mode it has selected to operate in.
Data Source
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AI summary
A Channel Quality Indicator (CQI) expression and feedback method prevents an excessive increase in the CQI feedback overhead while supporting both Single-User MIMO and Multi-User MIMO operations. When a default MIMO operation is set to Single-User MIMO or Multi-User MIMO, an access network can receive MIMO CQI feedback optimized for the corresponding MIMO operation. However, when a scheduler has selected an alterative MIMO operation other than the default MIMO operation, the access network calculates a CQI necessary for the alternative MIMO operation based on the default MIMO CQI feedback for the default MIMO operation and the DELTA CQI feedback for the alterative MIMO operation. In this manner, the invention enables the best operation in the default MIMO operation by providing a correct CQI, and enables the second best operation in the alternative MIMO operation.