Complex Vector Quantization Using Real-Valued Decoding

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Solution Overview

Problem

In multi-user MIMO communication systems, quantizing complex channel vectors is computationally intensive due to the need for extensive receiver overhead in hardware, software, and processing time, especially when dealing with complex components.

Innovation Solution

A method is introduced where a codeword approximating a complex vector is identified by maximizing the real part of its product with a scaled version, using a set of constants and decoding algorithms that handle real input values, allowing for efficient reconstruction of channel vectors and increased information transmission rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If complex vectors are quantized using traditional methods in MIMO systems, then measurement precision is improved, but device complexity increases due to extensive receiver overhead in hardware, software, and processing time

Engineering Contradiction:
Improvechannel vector quantization accuracyVSAvoidreceiver overhead
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transforms the complex vector quantization problem by changing the parameter domain - converting complex-valued operations into real-valued operations through parameter transformation. The complex channel vector is processed using real arithmetic operations, fundamentally changing the computational parameters from complex numbers to real numbers, which reduces the computational burden and receiver complexity while maintaining quantization accuracy.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent substitutes the traditional complex arithmetic processing mechanism with a real-valued computational mechanism. Instead of performing complex multiplications and comparisons, the system uses real-valued decoding algorithms processed through a transformation framework, replacing the mechanically intensive complex number operations with simpler real number operations that reduce hardware and software overhead.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If complex channel vectors are processed with high precision, then information transmission rate is improved, but loss of time increases due to extensive processing time

Engineering Contradiction:
Improveinformation transmission rateVSAvoidprocessing time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent applies parameter changes by transforming the computational domain from complex to real values, which accelerates processing. The real-valued decoding algorithms require fewer computational steps and less processing time compared to traditional complex arithmetic, thereby reducing the time loss while maintaining the information transmission rate through accurate channel vector quantization.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent performs preliminary transformation of the complex channel vector into a form suitable for real-valued processing before quantization. By pre-processing the complex vector through a transformation framework and preparing real-valued input for decoding algorithms, the system eliminates the need for time-consuming complex arithmetic operations during the actual quantization process, thus reducing processing time while preserving transmission accuracy.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If traditional complex vector quantization is used, then channel state information accuracy is improved, but ease of operation deteriorates due to extensive hardware and software requirements

Engineering Contradiction:
Improvechannel state information accuracyVSAvoidimplementation complexity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent substitutes complex mechanical and computational systems with a simplified real-valued processing system. The traditional complex arithmetic operations requiring extensive hardware and software are replaced with real-valued decoding algorithms that are computationally simpler and easier to implement, reducing implementation complexity while maintaining channel state information accuracy through the transformation framework.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operational parameters from complex numbers to real numbers, fundamentally simplifying the ease of operation. The real-valued parameter domain requires simpler data structures, fewer computational resources, and less complex algorithms, making the system easier to operate and implement while preserving the accuracy of channel state information through the mathematical transformation approach.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS7995668B2Method and apparatus for quantizing complex vectors in communication system
Publication Date: 2011.08.09 ALCATEL LUCENT SA
  • US7995668B2 patent drawing
  • US7995668B2 patent drawing
  • US7995668B2 patent drawing

AI summary

Improved techniques are disclosed for quantizing complex vectors in communication systems. For example, a method includes the following steps. At least one complex vector representative of at least one element of a communication system is obtained. A codeword that approximates the complex vector is identified. The identified codeword is a codeword, from a set of codewords, wherein a real part of a product of the codeword and a scaled version of the complex vector is about maximal over the set of codewords. The scaled version of the complex vector is the product of the complex vector and a constant from a set of constants. In one embodiment, the element of the communication system that the complex vector represents is a channel between a base station and a user terminal in the communication system.