Massive MIMO Antenna Phase Adjustment for RF Chain Reduction
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Solution Overview
Problem
Massive MIMO communication systems face challenges such as performance gaps between simple precoding techniques and zero-forcing or MMSE methods, high complexity, and prohibitive feedback overhead in FDD systems, along with hardware costs and energy usage issues due to the large number of RF chains.
Innovation Solution
The system employs a method to adjust antenna phases based on equivalent channel information, using a reduced number of RF chains and compressed sensing for feedback, to modify equivalent channel gains and increase the determinant of the equivalent channel matrix, allowing for efficient data transmission with reduced hardware complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large number of RF chains are used in massive MIMO systems, then the system can achieve better performance with zero-forcing or MMSE methods, but the hardware cost and device complexity increase significantly
Solution Approach 1:
The patent segments the RF chains into two types: first RF chains connected to first antenna groups for receiving equivalent channel information, and second RF chains connected to second antenna groups for transmitting data. This segmentation allows the system to achieve good communication performance without requiring a large number of RF chains, thereby reducing hardware cost and device complexity while maintaining reliability.
2Device complexity
If simple precoding techniques are used in massive MIMO systems, then the device complexity is reduced, but the communication performance falls short of zero-forcing or MMSE methods
Solution Approach 1:
The patent introduces equivalent channel information as an intermediary that captures the essential channel characteristics. By using this intermediary, the system can achieve communication performance comparable to complex zero-forcing or MMSE methods while employing simpler precoding techniques. The equivalent channel information serves as a mediator that bridges the gap between simplicity and performance.
3Reliability
If FDD systems use traditional feedback methods, then the system can maintain channel information, but the feedback overhead becomes prohibitive
Solution Approach 1:
The patent extracts only the essential equivalent channel information from the full channel state, which captures the key characteristics needed for communication. By taking out only this critical information rather than transmitting the complete channel state, the system maintains channel information accuracy while dramatically reducing feedback overhead in FDD systems.
4Device complexity
If the number of antenna groups is reduced, then the hardware cost is lowered, but the system capacity and multiplexing capabilities may be compromised
Solution Approach 1:
The patent merges multiple antennas into antenna groups that are connected to RF chains, creating a hybrid architecture. This merging allows the system to reduce the number of individual RF chains and antennas while maintaining equivalent channel information and data transmission capabilities. The combined antenna-RF chain structure preserves system capacity and multiplexing capabilities with reduced hardware cost.
Data Source
AI summary
A system and method of adjusting an equivalent channel for a downlink in a multiple-antenna communication system is disclosed herein. The system includes at least one user device and a base station having a plurality of analog RF chains, each analog RF chain having a plurality of antennas. The method comprises the base station obtaining equivalent channel information and adjusting the phases of the antennas in order to modify equivalent channel gains from the analog RF chains to the at least one user device, based on the equivalent channel information.