USB Self-Idle Suspend Mechanism for Mobile Power Conservation

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Solution Overview

Problem

Traditional USB suspend/resume protocols are inefficient, causing significant overhead in time and power consumption, making them unsuitable for mobile devices that require frequent suspend/resume operations to conserve resources.

Innovation Solution

A USB device is configured to self-idle by immediately suspending operations without waiting for confirmation from the host, entering a suspend mode in less than one millisecond and maintaining an idle mode to conserve power, allowing it to periodically wake up and check for network traffic without waking the host.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional USB suspend/resume protocol is used, then USB communication reliability is ensured, but power consumption and time overhead increase significantly

Engineering Contradiction:

ImproveUSB communication reliabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The USB device enters suspend mode proactively without waiting for host confirmation, performing the suspend action in advance. This eliminates the need to wait for the 3ms quiet period and host confirmation that traditionally precede suspend mode entry, thereby reducing power consumption and time overhead while maintaining communication reliability through the preserved idle mode signaling.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If traditional USB suspend/resume protocol is used, then proper suspend confirmation is ensured, but time overhead increases to at least 30ms

Engineering Contradiction:

Improvesuspend confirmationVSAvoidtime overhead

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The USB device autonomously enters suspend mode without requiring host confirmation or participation in the suspend decision process. The device serves itself by monitoring its own idle state and transitioning to suspend mode independently, eliminating the time-consuming host confirmation sequence while maintaining proper suspend behavior through continued idle mode presentation to the host.

Inventive Principle:

Principle #25Self-service

3Reliability

If USB device waits for host confirmation before suspending, then protocol compliance is maintained, but suspend speed decreases to more than one millisecond

Engineering Contradiction:

Improveprotocol complianceVSAvoidsuspend speed

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The USB device performs the suspend action in advance by entering suspend mode immediately when idle conditions are met, without waiting for host confirmation. This preliminary action eliminates the confirmation delay while maintaining protocol compliance through continued presentation of the idle mode to the host, thereby achieving suspend speeds of less than one millisecond.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS8839016B2USB self-idling techniques

Publication Date: 2014.09.16 MARVELL ASIA PTE LTD

AI summary

USB self-idling techniques are described. In one or more embodiments, a Universal Serial Bus (USB) device comprises one or more modules to communicate via USB and self-idle by presenting an idle mode to a USB host and entering a suspend mode after the idle mode, the suspend mode being entered while the USB host is presented with the idle mode.