Multiple Stream Co-phasing for MIMO Antenna Partitioning
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Solution Overview
Problem
Conventional closed-loop MIMO schemes face limitations in utilizing all transmit antennas efficiently, particularly in low SNR conditions, systems with correlated antennas, and channels with fewer receive antennas than transmit antennas, leading to reduced channel capacity.
Innovation Solution
The Multiple Stream Co-phasing (MSC) method partitions transmit antennas into mutually exclusive subsets and applies relative phase rotations based on instantaneous channel-state information to maximize received signal power and channel capacity, allowing for an adaptive number of data streams to be transmitted using all antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If PARC transmits as many data streams as the number of transmit antennas, then the channel capacity is maximized in ideal conditions, but the system performs poorly in low SNR conditions, systems with correlated antennas, and channels with Ricean fading
Solution Approach 1:
The patent segments the set of transmit antennas into multiple mutually exclusive subsets, with each subset dedicated to transmitting a separate data stream. This segmentation allows the system to adaptively select which subsets to use based on channel conditions, thereby maintaining reliability in challenging environments while preserving channel capacity through efficient antenna utilization.
2Reliability
If S-PARC uses the same number of transmit antennas as there are data streams, then the system performs better in low SNR and correlated antenna conditions, but the capacity is significantly lower than optimum closed-loop MIMO because not all transmit antennas are utilized
Solution Approach 1:
The patent creates a universal MIMO transmission framework where each antenna subset can independently transmit data streams with adaptive coding rates. The system can dynamically adjust the number of active subsets and their corresponding data streams based on channel conditions, achieving both reliability in challenging environments and high capacity when conditions permit, thus providing multi-functional adaptability.
Solution Approach 2:
The system dynamically adjusts the number of active antenna subsets and data streams based on instantaneous channel-state information. The receiver feeds back channel quality indicators, and the transmitter adapts by activating or deactivating specific antenna subsets, thereby optimizing the balance between reliability and capacity in real-time according to varying channel conditions.
3Productivity
If optimum closed-loop MIMO schemes use all transmit antennas to transmit data streams, then the channel capacity is maximized, but a large amount of instantaneous channel information must be fed back from the receiver to the transmitter
Solution Approach 1:
The patent extracts only the essential channel information needed for adaptation by having the receiver feed back indicators of channel quality for each antenna subset rather than complete channel state information. This extraction approach maintains the ability to optimize capacity through adaptive transmission while significantly reducing the feedback information burden compared to full channel state feedback requirements.
Data Source
AI summary
A system and method for transmitting multiple independent data streams from subsets of a plurality of radio antennas. The method includes determining by the receiver, an antenna partitioning, including relative phase rotations to be applied to each antenna, that results in the highest channel capacity among the possible partitionings. The receiver then provides partitioning information to the transmitter, including the number of antenna subsets, which antennas are included in each subset, the capacity of the data stream to be transmitted from each antenna subset, and the relative phase rotations to be applied to the antennas in each subset. The transmitter partitions the plurality of radio antennas into mutually exclusive subsets in accordance with the partitioning information, applies the relative phase rotation to each antenna, and transmits an independent data stream from each subset of antennas with a rate not greater than the stream capacity.