Wireless Base Station CSI Sharing for Coherent Joint Transmission
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Solution Overview
Problem
The overhead in notifying channel state information (CSI) between access points (APs) and terminals for coherent joint transmission (CJT) is high, leading to reduced effective rates in wireless LAN systems.
Innovation Solution
A wireless base station that generates and transmits channel state information, capability information, and weight synchronization information to another wireless base station for efficient joint transmission, using eigenvalue decomposition and Gram-Schmidt orthonormalization methods to synchronize weights across multiple APs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If channel state information is notified between each AP and terminal for coherent joint transmission, then accurate weight calculation is achieved, but overhead increases and effective rate decreases
Solution Approach 1:
The patent combines channel state information from multiple APs into a unified data structure. Instead of each AP independently notifying the terminal of separate CSI, the system merges CSI from multiple APs into a single comprehensive notification, reducing redundant information transmission while maintaining the accuracy needed for coherent joint transmission weight calculation.
2Device complexity
If centralized control AP calculates CJT weight based on fed back information, then weight calculation is simplified, but communication overhead increases
Solution Approach 1:
The patent extracts only the essential channel state information parameters needed for weight calculation from the complete CSI feedback, removing redundant data. By selecting and transmitting only the critical components required for CJT weight computation, the system reduces communication overhead while enabling the centralized AP to perform accurate weight calculation.
Data Source
AI summary
A weight (weighting factor, and Matrix of Steering Vectors) for performing joint transmission together with another wireless base station is efficiently generated. The wireless base station performs the joint transmission with the another wireless base station. The wireless base station includes a wireless control unit and a communication unit. The wireless control unit generates information regarding channel state information between a terminal which is a destination at the time of performing the joint transmission and a plurality of wireless base stations which is a transmission source of the joint transmission. The communication unit transmits the information regarding the generated channel state information to the another wireless base station that performs the joint transmission.