Selective Suspend



Today's computer users expect to be connected everywhere. As a result operators, cell phone retailers, and PC stores are more frequently bundling mobile broadband capabilities into their laptops. Win-win? Well...

The Problem

Wireless browsing is an extremely “bursty” activity, with short periods of high data rate transfer and longer periods of inactivity while the user reads. Even when the data card seems to be idle, some “chatter” between the application and the data card can contribute to battery discharge. Unless the USB port is intelligently monitored, notebook battery consumption can be enough to reduce battery life by as much as 30%. Since Windows XP, a feature called Selective Suspend has been available, which attempts to monitor the USB port for activity and shut down the USB device when idle. However, Windows XP, and Vista lack the sophistication necessary to optimize power consumption for mobile broadband data cards.

The Solution

MCCI® Selective Suspend is a user transparent feature that suspends the portion of the USB bus that is connected to the data card when it detects that the card is idle — it does so even while the system itself remains in a fully operational power state, thereby saving battery life. With MCCI Selective Suspend, the USB connection is suspended after five seconds (configurable between five to sixty seconds) of idle time, saving battery life. The USB bus is resumed either when the user initiates a data transfer or when the data card receives traffic that needs to go to the PC. The average power savings is around 5 watts.

discharge

There's no doubt mobile broadband is a huge market success. To ensure user satisfaction, in-the-know OEMs and ODMs are integrating MCCI's basic mobile broadband product—which includes the Selective Suspend functionality—into their USB class driver offerings.