MIMO Channel Information Compression via Discrete Cosine Transform

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Solution Overview

Problem

Conventional methods for channel information compression in MIMO systems either increase radio resource usage due to large channel response matrices or degrade precoding effectiveness due to imprecise matching of precoders with channel response matrices.

Innovation Solution

A channel information compression device using discrete cosine transform (DCT) to compress high-frequency components of channel information, with adjustable compression factors and transform units based on mobility, throughput, and hardware constraints, and an inverse DCT for decompression to maintain accurate channel information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If channel response matrix is transmitted from receiver to transmitter, then precoding accuracy is improved, but radio resource consumption increases

Engineering Contradiction:

Improveprecoding accuracyVSAvoidradio resource consumption

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent extracts and transmits only the essential components of channel information - specifically DCT coefficients representing channel characteristics - rather than transmitting the complete channel response matrix. This extraction approach maintains precoding accuracy while significantly reducing the quantity of data transmitted over radio resources.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent transforms channel information from spatial domain (channel response matrix) to frequency domain (DCT coefficients) through discrete cosine transform. This parameter transformation compresses the information representation, reducing the number of parameters that need to be transmitted while preserving the essential channel characteristics needed for accurate precoding.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If channel information is compressed, then radio resource usage is reduced, but channel information accuracy deteriorates

Engineering Contradiction:

Improveradio resource usageVSAvoidchannel information accuracy

Core Design Contradiction:

Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent applies discrete cosine transform as a preliminary processing step to channel information before compression and transmission. This preliminary transformation organizes the channel data in a way that enables efficient compression while preserving the most significant channel characteristics, ensuring that accuracy is maintained even after compression.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The DCT coefficients serve as an intermediary representation between the complete channel response matrix and the compressed transmitted data. This intermediary form captures the essential channel information in a compact format, allowing radio resource usage to be reduced while maintaining sufficient accuracy for effective precoding.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9118440B2Channel information compressing apparatus adapted to a MIMO system and method

Publication Date: 2015.08.25 KDDI CORP

AI summary

A channel information compressing apparatus of the present invention includes a DCT part that performs discrete cosine transform on channel information (CSI) representing the state of a communication channel, and an information compressor that compresses high frequency components of information included in discrete cosine transform data which is produced by way of discrete cosine transform, thus compressing information while maintaining a good accuracy of channel information.