MIMO Feedback Rate Gain Indicators Bandwidth Reduction
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Solution Overview
Problem
In multiple-input multiple-output (MIMO) wireless communication systems, feedback of channel estimates or statistics requires significant bandwidth, which is undesirable, and existing methods do not efficiently improve throughput without dedicating excessive bandwidth to feedback.
Innovation Solution
Providing indicators of rate and/or gain for each data substream as feedback, computed based on channel estimates at the receiver, allows for improved throughput with significantly less bandwidth, using one-dimensional data coding and separate antennas for each substream, and calculating rates and powers to maximize channel capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If channel estimate or channel statistics are fed back to the transmitter, then throughput is improved, but bandwidth consumption increases significantly
Solution Approach 1:
The patent extracts only the essential information needed for throughput improvement (rate and gain indicators) from the complete channel estimate, eliminating redundant data while preserving the beneficial feedback effect
Solution Approach 2:
Instead of providing uniform detailed channel information for all substreams, the patent applies differentiated feedback by providing only rate and gain indicators for each data substream, optimizing the feedback quality to match the specific needs of each substream
2Reliability
If complete channel estimate is fed back, then system performance is maximized, but feedback bandwidth requirements become excessive
Solution Approach 1:
The patent extracts only the critical performance parameters (rate and gain indicators) from the complete channel estimate, achieving the essential feedback function with minimal bandwidth consumption
Solution Approach 2:
The patent transforms the feedback from detailed channel state information to simplified rate and gain indicators, changing the parameter representation to reduce bandwidth while maintaining performance benefits
Data Source
AI summary
In a wireless communication system using multiple antennas at the transmitter and multiple antennas at the receiver, a so called multiple-input multiple-output (MIMO) system, a substantial improvement in capacity over the case of no feedback can be achieved using considerably less bandwidth than is required to feedback the channel estimate or channel statistics, by supplying as feedback for each data substream of an overall data stream an indicator of a rate and/or an indicator of a gain for transmission of that data substream. The indicator of the rate and/or the indicator of the gain may be the rate and/or gain directly or an encoded representation of the rate and/or gain. Typically, the best performance is achieved if indicators of both the rate and the gain are fed back. If the invention is implemented for wireless systems, then typically for each data substream there is a separate, independent antenna. The rate and the gain are computed as a function of a channel estimate which is developed at the receiver. Advantageously, the transmitter may employ only one-dimensional data coding for each of the data substreams.