Method and mobile device for performing fast hand-over in WLAN and method of switching services using GPS information

A mobile device performing hand-over when roaming in a wireless local area network (LAN) environment comprising:

• a receiving unit receiving global positioning system (GPS) information of the mobile device;
• an access point (AP) identifying unit identifying at least one AP, other than an existing AP to which the mobile device is connected, to be scanned for based on the received GPS information of the mobile device;
• a detecting unit detecting an AP to reassociate with, by scanning for the at least one identified AP;
• and
• a reassociating unit reassociating the mobile device with the detected AP,
• wherein the AP identifying unit comprises:
• an estimating unit estimating a moving direction or moving path of the mobile device by using a plurality of GPS information of the mobile device;
• a memory storing a channel table including GPS information of APs on a plurality of channels;
• and
• a unit obtaining information on at least one AP included in a predetermined searching range on the basis of the estimated moving direction or moving path, from the channel table,
• wherein the scanning for the at least one identified AP includes hierarchically scanning for one or more identified APs through plural increasing and overlapping searching ranges, including the predetermined searching range, in different scanning operations until the identified AP to reassociate with is detected.

A hand-over method of a mobile device roaming in a wireless network environment, the method comprising:

• detecting, by the mobile device, positional information indicating at least a movement of the mobile device relative to one access point to which the mobile device is connected;
• anticipating, by the mobile device, another access point to which the mobile device is connectable according to the indicated movement and a table storing a location of the another access point, the table being stored in the mobile device;
• and
• reassociating, by the mobile device, the mobile device with the anticipated another access point,
• wherein the anticipating includes obtaining, from the table, information on at least the another access point included in a first searching range selected on the basis of a direction of the indicated movement, and obtaining, from the table, information on at least an additional access point other than the other access point included in a second larger searching range, in the direction and greater than the first searching range, when the other access point is not found in a scanning of the first searching range.

A mobile device performing hand-over when roaming in a wireless network environment, comprising:

• a wireless communication unit transmitting data with respect to one access point (AP) and which is capable of communicating with another AP;
• and
• a controller which determines a motion of the mobile device relative to the one AP, retrieves location information on the another AP based on the determined motion, and uses the wireless communication unit to reassociate the mobile device with the another AP and disconnect the mobile device from the one AP while maintaining a quality of service (QoS) connection,
• wherein the retrieving of location information for the other AP includes obtaining information on at least the other AP included in a hierarchically selected searching range, by the controller, selected from increasing and overlapping searching ranges for a same direction of the determined motion, and, if the other AP is not found in a scanning of the selected searching range, retrieving location information for an additional AP included in a larger searching range of the searching ranges and scanning for the additional AP in the larger searching range.

A hand-over method of a mobile device roaming in a wireless local area network (LAN) environment, the method comprising:

• receiving global positioning system (GPS) information of the mobile device;
• identifying at least one access point (AP), other than the existing AP to which the mobile device is currently connected, that exists within a select searching range from increasing and overlapping searching ranges all relative to the received GPS information, wherein the identifying sequentially selects a current select searching range for respective scanning for a respectively identified AP in sequence beginning with a smaller searching range of the searching ranges, smaller than a greatest searching range of the searching ranges, and sequencing from the smaller searching range toward the greatest searching range until the respectively identified AP is found;
• scanning for the current select searching range based on the respectively identified AP, before the identifying identifies an AP to be scanned for in a next current select searching range of the sequentially selected searching ranges;
• and
• reassociating the mobile device with an AP found in the scanning.

A mobile device performing hand-over when roaming in a wireless local area network (LAN) environment comprising:

• a receiving unit receiving global positioning system (GPS) information of the mobile device;
• an access point (AP) identification unit identifying at least one AP, other than the existing AP to which the mobile device is currently connected, that exists within a select searching range from increasing and overlapping searching ranges all relative to the received GPS information, wherein the identifying sequentially selects a current select searching range for respective scanning for a respectively identified AP in sequence beginning with a smaller searching range of the searching ranges, smaller than a greatest searching range of the searching ranges, and sequencing from the smaller searching range toward the greatest searching range until the respectively identified AP is found;
• an AP detecting unit scanning the current select searching range for the respectively identified AP, before the identifying identifies an AP to be scanned for in a next current select searching range of the sequentially selected searching ranges;
• and
• a reassociating unit reassociating the mobile device with an AP found in the scanning.