Controlling a power state of a cellular packet data subsystem in a portable electronic device

A non-transitory computer-readable storage medium containing instructions that, when executed by a portable electronic device, cause the portable electronic device to perform a method for using the portable electronic device, wherein the portable electronic device includes:

• a wireless local area network (WLAN) subsystem;
• a cellular packet data subsystem for communicating packet data;
• a cellular voice subsystem for communicating cellular voice information;
• and
• a processing subsystem;
• wherein the method comprises:
• the WLAN subsystem establishing a connection to a WLAN;
• the WLAN subsystem determining a signal strength of the connection to the WLAN;
• the processing subsystem, on condition that the signal strength exceeds a threshold:
• selecting the WLAN subsystem for the communication of packet data to and from the portable electronic device;
• putting the cellular packet data subsystem into a reduced power state that reduces power consumption of the cellular packet data subsystem;
• and
• the WLAN subsystem communicating packet data to and from the portable electronic device while the cellular data subsystem is in the reduced power state.

An apparatus that controls a power state of a cellular packet data subsystem in a portable electronic device, comprising:

• the cellular packet data subsystem;
• a cellular voice subsystem;
• a wireless local area network (WLAN) subsystem;
• and
• a processing subsystem, coupled to the WLAN subsystem, the cellular packet data subsystem, and the cellular voice subsystem, wherein the processing subsystem is configured to:
• receive, from the WLAN subsystem, a signal strength of a connection to a WLAN;
• on condition that the signal strength exceeds a threshold, select the WLAN subsystem for the communication of packet data to and from the portable electronic device;
• put the cellular packet data subsystem into a reduced power state that reduces a power consumption of the cellular packet data subsystem;
• and
• communicate packet data to and from the portable electronic device using the WLAN subsystem while the cellular data subsystem is in the reduced power state.