Dynamic-Precision Signal Coding for Low-Energy Digital MAC Operations

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Solution Overview

Problem

Existing computing architectures for artificial neural networks face high energy consumption due to the restrictive number of multiply-accumulate (MAC) operations required for real-time operation, particularly when dealing with signals of varying dynamic ranges, leading to sub-optimal sizing of computing operators and increased energy usage.

Innovation Solution

A method and device for coding digital signals with dynamic precision, where signals are decomposed into maximum values and residual values, allowing for reduced bit size and optimized MAC operations, thereby minimizing energy consumption by adapting to the statistical distribution of signal values across different layers of the neural network.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If fixed-bit quantization is used for all signal samples, then the computing operators can be sized consistently, but the energy consumption increases due to sub-optimal sizing when dynamic range varies

Engineering Contradiction:
Improveenergy consumptionVSAvoidcomputing operator sizing complexity
Core Design Contradiction:
Use of energy by stationary objectVSDevice complexity

Solution Approach 1:

The patent applies dynamic quantization where the bit depth for coding signal samples is adjusted based on the actual dynamic range of the signal. Instead of using a fixed number of bits for all samples, the system determines the appropriate bit depth dynamically according to the signal's statistical properties, thereby optimizing the sizing of computing operators (particularly MAC operators) to match the actual signal requirements and reduce energy consumption.

Inventive Principle:
Principle #15Dynamics

2Use of energy by stationary object

If the number of MAC operations is reduced for real-time operation, then energy consumption decreases, but the precision of computations may be degraded

Engineering Contradiction:
Improveenergy consumptionVSAvoidcomputation precision
Core Design Contradiction:
Use of energy by stationary objectVSMeasurement precision

Solution Approach 1:

The patent changes the parameter of signal representation by decomposing samples into a sum of maximum values (equal to 2^Np-1) and residual values. This parameter transformation allows the system to perform MAC operations with reduced bit width (Np bits) while maintaining computational precision, as the decomposition preserves the essential information needed for accurate computation despite using fewer bits.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If quantization on a fixed number of bits is applied to all samples, then the coding process is simplified, but the dynamic range representation becomes sub-optimal

Engineering Contradiction:
Improvecoding implementation simplicityVSAvoiddynamic range precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent segments each signal sample into multiple components: a sum of maximum values (each equal to 2^Np-1) and a residual value. This segmentation allows the system to represent the full dynamic range of the signal using a combination of standardized maximum value units and a smaller residual component, achieving both simplified coding (using repeated maximum values) and precise dynamic range representation (through the residual).

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS20230004351A1Method and device for additive coding of signals in order to implement digital mac operations with dynamic precision
Publication Date: 2023.01.05 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • US20230004351A1 patent drawing
  • US20230004351A1 patent drawing
  • US20230004351A1 patent drawing

AI summary

A computer-implemented method is provided for coding a digital signal quantized on a given number Nd of bits and intended to be processed by a digital computing system, the signal being coded on a predetermined number Np of bits which is strictly less than Nd, the method including the steps of: receiving a digital signal composed of a plurality of samples, decomposing each sample into a sum of k maximum values which are equal to 2NP−1 and a residual value, with k being a positive or zero integer, successively transmitting the values obtained after decomposition to an integration unit for carrying out a MAC operation between the sample and a weighting coefficient.