Variable Quantization Step Size for Channel Decoding

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Solution Overview

Problem

In next-generation communication systems using OFDM or OFDMA, the efficiency of channel decoding is compromised due to fixed quantization step sizes, leading to decreased performance and increased power consumption, as they fail to adapt to changing channel characteristics and signal conditions.

Innovation Solution

A method and apparatus for determining a variable quantization step size based on channel characteristic parameters such as average channel estimation, signal-to-noise ratio, modulation, and MIMO parameters, which are used to calculate an optimal quantization step size for improved channel decoding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a fixed quantization step size is used in channel decoding, then the device complexity is reduced and ease of operation is improved, but the channel decoding performance deteriorates and power consumption increases

Engineering Contradiction:
Improveease of operationVSAvoidchannel decoding performance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent implements dynamic quantization step size adjustment by calculating the step size based on channel characteristic parameters (SNR, modulation scheme, MIMO configuration) rather than using a fixed value. The quantization step size is adapted in real-time according to channel conditions, allowing the system to optimize decoding performance dynamically while maintaining manageable complexity through algorithmic adjustment.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the quantization parameter (step size) based on channel conditions. By modifying the quantization step size parameter according to SNR, modulation type, and MIMO settings, the system achieves better decoding performance without requiring complete redesign of the decoding architecture, thus balancing performance improvement with complexity control.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a high number of bits is used in quantization operation, then the channel decoding performance is improved, but the power consumption and device complexity increase

Engineering Contradiction:
Improvechannel decoding performanceVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent adjusts the quantization step size parameter to optimize the number of bits used in quantization. By changing this parameter based on channel conditions, the system uses more bits when channel conditions are poor (requiring higher precision) and fewer bits when conditions are good, thereby improving power efficiency while maintaining decoding performance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies partial quantization precision selectively - using higher precision (more bits) only when necessary based on channel conditions, rather than uniformly applying high precision across all situations. This avoids the excessive power consumption associated with always using high-bit quantization while maintaining performance when needed.

Inventive Principle:
Principle #16Partial or excessive action

3Use of energy by stationary object

If a low number of bits is used in quantization operation, then the power consumption and device complexity are reduced, but the channel decoding performance deteriorates

Engineering Contradiction:
Improvepower consumptionVSAvoidchannel decoding performance
Core Design Contradiction:
Use of energy by stationary objectVSReliability

Solution Approach 1:

The patent dynamically changes the quantization step size parameter based on channel conditions to avoid the performance degradation that would result from consistently using low-bit quantization. When channel conditions are poor, the system increases precision; when conditions are good, it reduces precision, thus avoiding unnecessary power consumption while preventing performance deterioration.

Inventive Principle:
Principle #35Parameter changes

4Device complexity

If a fixed quantization step size is used, then the device complexity is reduced, but the adaptability to changing channel characteristics deteriorates

Engineering Contradiction:
Improvedevice complexityVSAvoidadaptability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic adaptation by calculating the quantization step size based on channel characteristic parameters including SNR, modulation scheme, and MIMO configuration. This allows the system to adapt to changing channel conditions automatically through algorithmic adjustment rather than hardware reconfiguration, maintaining low complexity while achieving high adaptability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the quantization parameter based on channel conditions (SNR, modulation, MIMO) to achieve adaptability without increasing device complexity. By using parameter adjustment rather than structural changes, the system maintains simplicity while becoming adaptable to various channel characteristics.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS8223868B2Method of determining a variable quantization step size for improving channel decoding, method and apparatus of performing channel decoding operation based on a variable quantization step size
Publication Date: 2012.07.17 I&C TECH
  • US8223868B2 patent drawing
  • US8223868B2 patent drawing
  • US8223868B2 patent drawing

AI summary

A method of determining a variable quantization step size is disclosed. In the method of determining a variable quantization step size, a channel characteristic parameter is obtained in order to calculate a quantization step size (Δ) used in channel decoding. The quantization step size (Δ) is variably determined based on the channel characteristic parameter. Therefore, the method of determining a variable quantization step size may improve channel decoding.