Antenna Grouping for MIMO Capacity
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Solution Overview
Problem
Current mobile communication systems face limitations in communication capacity due to the imbalance between the number of transmission and reception antennas, particularly in the spatial multiplexing scheme, which restricts data transmission rates and error rates, especially in forward links.
Innovation Solution
A method for grouping transmission antennas based on channel covariance matrices to maximize communication capacity, where the base station receives feedback from the mobile terminal to form transmission antenna groups that optimize signal-to-noise rates and eigenvalues, allowing for simultaneous transmission of different symbols through each group.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spatial multiplexing scheme is used with multiple transmission antennas, then communication capacity increases, but the number of transmission antennas must be smaller than reception antennas which limits the scheme when base station has more antennas than mobile terminal
Solution Approach 1:
The invention divides the multiple transmission antennas into multiple groups, where each group transmits a separate data stream. This segmentation allows the system to handle cases where the number of transmission antennas exceeds the number of reception antennas, as each group can be independently processed by the receiver's limited antennas.
Solution Approach 2:
The invention introduces a grouping dimension to the antenna configuration, transforming the problem from a single-dimensional constraint (total number of antennas) to a multi-dimensional solution (multiple groups of antennas). This allows the system to achieve spatial multiplexing gain without requiring the receiver to have more antennas than the total number of transmission antennas.
2Reliability
If beamforming scheme is used to improve receiving performance, then receiving performance improves, but frequency efficiency deteriorates because the same symbols are transmitted through multiple antennas
Solution Approach 1:
The invention applies different transmission strategies to different antenna groups. Each group transmits different symbols with optimized beamforming weights tailored to the specific channel conditions for that group, achieving both high receiving performance and efficient use of frequency resources.
Solution Approach 2:
The invention merges the advantages of spatial multiplexing (different symbols from different antennas) and beamforming (optimized weights for receiving performance) by applying beamforming weights within each antenna group while maintaining different symbol transmission across groups.
3Productivity
If more transmission antennas are used to increase communication capacity, then data transmission rate increases, but the imbalance between transmission and reception antennas limits the system performance
Solution Approach 1:
The invention segments the excess transmission antennas into multiple groups, allowing the system to utilize all transmission antennas effectively. Each group can be independently managed and transmitted to the receiver, which processes them through successive interference cancellation or other detection schemes.
Solution Approach 2:
The invention performs preliminary grouping of transmission antennas based on channel covariance matrix analysis before data transmission. This preliminary action optimizes the antenna configuration to match channel conditions, maximizing data transmission rate while managing the complexity of having more transmission than reception antennas.
Data Source
AI summary
Disclosed is a method for configuring transmission antenna groups in a mobile communication system with multiple transmission antennas and multiple reception antennas. The method includes the steps of: receiving a first matrix having a size of ‘Nt×Nt’, which corresponds to Nt number of transmission antennas, fedback from the mobile terminal, generating combinations of sub-matrixes of the first matrix corresponding to Nr number of reception antennas, and calculating sums of maximum eigenvalues; determining combinations of the sub-matrixes having a maximum value from among the calculated sums of eigenvalues to be transmission antenna groups for the Nt number of transmission antennas; and transmitting different relevant symbols from each other through the transmission antenna groups.