Bus Bit Inversion Using Hamming Distance to Cut Transmission Power

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Solution Overview

Problem

High-speed and high-bandwidth data transmission in mobile or wireless devices faces challenges due to increased power consumption and area overhead from additional communication channels, particularly in minimizing wire connections while maintaining reliability.

Innovation Solution

A method that calculates a parity check code and Hamming distance for data codes, inverting them if the distance is greater than half the number of bits, and transmitting without additional wires for inversion signaling, reducing power consumption and circuit complexity by dividing the bus into groups for parallel calculations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If additional communication channels are added to increase bandwidth, then data transmission capacity is improved, but power consumption and area overhead increase

Engineering Contradiction:
Improvedata transmission bandwidthVSAvoidpower consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent applies bus inversion by periodically inverting the polarity of the entire bus signal when the number of transitions exceeds a threshold. This reduces the number of transitions on individual wires, thereby reducing power consumption while maintaining high bandwidth utilization. The inversion technique allows the system to achieve high data transmission capacity without proportionally increasing power consumption.

Inventive Principle:
Principle #13The other way round (Inversion)

2Productivity

If additional communication channels are added to increase bandwidth, then data transmission capacity is improved, but wire connection count increases

Engineering Contradiction:
Improvedata transmission bandwidthVSAvoidwire connection count
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent merges multiple data bits into a single differential bus signal, transmitting multiple bits simultaneously over a reduced number of physical wires. By using differential signaling and bus inversion techniques, the system achieves high bandwidth over fewer wire connections, reducing area overhead while maintaining high data transmission capacity.

Inventive Principle:
Principle #5Merging (Combining)

3Use of energy by moving object

If bus inversion is implemented with additional inversion signal lines, then power consumption is reduced, but device complexity increases

Engineering Contradiction:
Improvepower consumptionVSAvoidcircuit complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent implements self-service bus inversion where the transmitter autonomously determines when inversion is needed based on the data pattern being transmitted. The system calculates the number of transitions required and automatically applies inversion when beneficial, without requiring external control signals or additional complexity. This self-managing approach reduces power consumption while avoiding the complexity of external inversion control circuitry.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4097883B1Bit inversion for data transmission
Publication Date: 2024.12.11 QUALCOMM INC
  • EP4097883B1 patent drawingFigure 1
  • EP4097883B1 patent drawingFigure 2
  • EP4097883B1 patent drawingFigure 3

AI summary

In certain aspects, a method for sending data over a bus comprises: calculating a parity check code for a new data code, wherein the new data code comprises a number of bits in the new data code; calculating a Hamming distance between the new data code and a prior data code; and if the Hamming distance is greater than half of the number of bits in the new data code: inverting the new data code and the parity check code to obtain an inverted new data code and an inverted parity check code; and sending the inverted new data code and the inverted parity check code to the bus.