Method and apparatus for waking device from power save mode

Abstract

A method for waking a device from a power save mode to an active mode includes: transmitting, by a first device, a magic packet through a predetermined channel to a second device, which operates in the power save mode by repeating a doze state and an awake state according to a predetermined period of time, for notifying the second device to switch to the active mode; and retransmitting the magic packet to the second device through the predetermined channel if a response to the magic packet has not been received from the second device and a predetermined time has not elapsed after transmitting the magic packet through the predetermined channel.

What is claimed is: 
     
         1 . A method for switching a second device from a power save mode to an active mode by a first device, the method comprising:
 transmitting, by the first device, a magic packet through a predetermined channel to the second device, which operates in the power save mode by repeating a doze state and an awake state periodically according to a predetermined period of time, for notifying the second device to switch to the active mode, wherein the magic packet includes contents of a command for switching a value of a power management field which is a subfield of a frame control field of the second device receiving the magic packet; and   retransmitting the magic packet to the second device through the predetermined channel if a response to the magic packet has not been received from the second device and a predetermined time has not elapsed after transmitting the magic packet through the predetermined channel.   
     
     
         2 . The method of  claim 1 , further comprising transmitting the magic packet through a different channel from the predetermined channel if the response to the magic packet has not been received from the second device and the predetermined time has elapsed after first transmitting the magic packet through the predetermined channel. 
     
     
         3 . The method of  claim 1 , wherein the predetermined time is longer than a time for the second device to be in the doze state. 
     
     
         4 . The method of  claim 1 , wherein the predetermined time is the same as the predetermined period of time. 
     
     
         5 . The method of  claim 1 , wherein the predetermined period of time is a beacon interval. 
     
     
         6 . The method of  claim 1 , wherein the predetermined channel comprises a channel, which was last used by the first device to communicate with the second device. 
     
     
         7 . The method of  claim 1 , wherein the predetermined channel comprises a social channel. 
     
     
         8 . The method of  claim 1 , further comprising the first device forming a Peer to Peer (P2P) group with the second device if the response to the magic packet has been received from the second device. 
     
     
         9 . The method of  claim 8 , wherein the forming of the P2P group comprises the first device forming the P2P group with the second device by using Credentials stored in the first device. 
     
     
         10 . The method of  claim 1 , wherein the first device is a P2P client, and the second device is a P2P group owner. 
     
     
         11 . The method of  claim 1 , wherein the magic packet is a probe request frame, wherein a value of a bit  6  or  7  of a device capability bitmap field of a P2P capability subelement of the probe request frame is 1. 
     
     
         12 . The method of  claim 1 , wherein the magic packet is a P2P public action frame, a type value of which is one of 9 to 255. 
     
     
         13 . The method of  claim 1 , wherein the magic packet is a P2P action frame, a type value of which is one of 4 to 255. 
     
     
         14 . The method of  claim 1 , wherein the first device and the second device are wireless fidelity (Wi-Fi) P2P devices. 
     
     
         15 . A method for switching from a power save mode to an active mode by a second device communicating with a first device, the method comprising:
 receiving, from the first device, a magic packet for notifying the second device to switch to the active mode when the second device operating in the power save mode by repeating a doze state and an awake state is in the awake state, wherein the magic packet includes contents of a command for switching a value of a power management field which is a subfield of a frame control field of the second device receiving the magic packet; and   switching to the active mode upon receiving the magic packet.   
     
     
         16 . The method of  claim 15 , wherein the receiving the magic packet comprises the second device receiving the magic packet in a state of not being synchronized with the first device. 
     
     
         17 . The method of  claim 15 , further comprising the second device forming a Peer to Peer (P2P) group with the first device after switching to the active mode. 
     
     
         18 . The method of  claim 17 , wherein the forming of the P2P group comprises the second device forming the P2P group with the first device by using Credentials stored in the second device. 
     
     
         19 . The method of  claim 15 , further comprising performing synchronization by the second device forming a P2P group with the first device,
 wherein the receiving of the magic packet comprises receiving the magic packet from the first device when the second device is in the awake state, based on the synchronization.   
     
     
         20 . An apparatus for switching a peer device from a power save mode to an active mode, the apparatus comprising:
 a transmitter for transmitting through a predetermined channel a magic packet for notifying the peer device, which operates in the power save mode by repeating a doze state and an awake state periodically according to a predetermined period of time to switch to the active mode, wherein the magic packet includes contents of a command for switching a value of a power management field which is a subfield of a frame control field of the peer device receiving the magic packet; and   a receiver for receiving a response to the magic packet from the peer device,   wherein the transmitter retransmits the magic packet to the peer device through the predetermined channel if a response to the magic packet has not been received from the peer device and a predetermined time has not elapsed after transmitting the magic packet through the predetermined channel.