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

• US 8,897,777 B2
• Filed: 01/10/2006
• Issued: 11/25/2014
• Est. Priority Date: 07/27/2005
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Choi, Hyong-uk
• Primary Examiner(s): Cai, Wayne
• Assistant Examiner(s): HEIBER, SHANTELL LAKETA
• Application Number:
  US11/328,215
• Publication Number:
  US 20070025293A1
• Time in Patent Office: 3,241 Days
• Field of Search: 455/436, 455/456.1, 455/446, 455/437, 455/440, 455/452.2, 455/457, 370/331
• US Class Current: 455/436
• CPC Class Codes: H04W 36/0085 Hand-off measurements
• CPC Class Codes: H04W 36/322 by location data
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

A fast hand-over method of a mobile device roaming in a wireless LAN environment includes: receiving GPS information; based on the received location information of the mobile device, searching one or more APs; by scanning the searched APs, detecting an AP to reassociate with; and reassociating with the detected AP. According to the method, when roaming in a wireless LAN environment, a mobile device calculates a moving path by using GPS information and then, by scanning only APs belonging to channels allocated to areas related to the moving direction, the mobile device can reduce a hand-over period, and as a result, a QoS guaranteed service can be provided continuously. Also, by using GPS information, the mobile device can selectively switch to an optimum network service in an area to which different network services are applied.

Claims

1. 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;

based on the received GPS information of the mobile device, identifying by the mobile device at least one access point (AP) other than the existing AP, to which the mobile device is currently connected, to be scanned for;

by scanning for the identified AP, detecting by the mobile device an AP to reassociate with; and

reassociating the mobile device with the detected AP,

wherein the identifying by the mobile device of the at least one AP comprises;

estimating a moving direction or moving path of the mobile device by using a plurality of GPS information items; and

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 a channel table stored in the mobile device including location information of APs on a plurality of channels,

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.

2. The method of claim 1, wherein the detecting of the AP comprises:

generating a list including obtained AP information;

updating an existing scanning channel list with the generated list; and

detecting an AP to be reassociated with, by scanning for the APs of the updated channel list.

3. The method of claim 1, wherein the scanning includes hierarchically scanning last a predetermined searching range classified into a first level including APs on all channels, after a second level including APs on channels within a first angle relative to an axis represented by the estimated moving direction or path, after a third level including APs on channels within a second angle relative to the axis represented by the estimated moving direction or path and which is less than the first angle, after a fourth level including an AP within a narrowest angle relative to the axis represented by the estimated moving direction or moving path of the mobile device.

4. The method of claim 3, wherein the identifying of at least one AP to be scanned for includes identifying the AP belonging to the searching range of the fourth level first.

5. The method of claim 3, wherein the identifying of at least one AP to be scanned for includes identifying the APs belonging to the searching range of the third level.

6. The method of claim 3, wherein the identifying of at least one AP to be scanned for includes identifying the APs belonging to the searching range of the second level.

7. The method of claim 3, wherein the identifying of at least one AP to be scanned for and detecting the AP comprise:

identifying the AP to be scanned for of the fourth level, as a predetermined minimized searching range, based on the moving direction or moving path of the mobile device;

if as the result of the scanning for the AP of the fourth level, a matching AP is not detected, identifying the APs to be scanned for belonging to the third level other than APs of the fourth level;

if as the result of the scanning for the APs of the third level, a matching AP is not detected, identifying the APs to be scanned for belonging to the second level other than APs of the fourth and third levels; and

if as the result of the scanning for the APs of the second level, a matching AP is not detected, identifying the APs to be scanned for belonging to the first level other than APs of the fourth, third, and second levels.

8. The method of claim 1, wherein:

the identifying of at least one AP to be scanned for includes identifying the AP belonging to a searching range of a fourth level selected from first through fourth levels of fields of view,

a searching range of the first level is greater than a searching range of the second level;

the searching range of the second level is greater than a searching range of the third level; and

the searching range of the third level is greater than the searching range of the fourth level.

9. The method of claim 1, wherein:

the identifying of at least one AP to be scanned for includes identifying the APs belonging to a searching range of a third level selected from first through fourth levels of fields of view,

a searching range of the first level is greater than a searching range of the second level;

the searching range of the second level is greater than the searching range of the third level; and

the searching range of the third level is greater than a searching range of the fourth level.

10. The method of claim 1, wherein:

the identifying of at least one AP to be scanned for includes identifying the APs belonging to a searching range of a second level selected from first through fourth levels of fields of view,

a searching range of the first level is greater than the searching range of the second level;

the searching range of the second level is greater than a searching range of the third level; and

the searching range of the third level is greater than a searching range of the fourth level.

11. The method of claim 1, wherein the identifying of at least one AP to be scanned for and scanning for the identified AP comprise:

identifying the AP of a fourth level, as a predetermined minimized searching range, to be scanned for on the basis of the estimated moving direction or moving path of the mobile device;

if as the result of the scanning for the AP of the fourth level, a matching AP is not detected, identifying the APs belonging to a third level other than APs of the fourth level to be scanned for;

if as the result of the scanning for the APs of the third level other than the fourth level, a matching AP is not detected, identifying the APs belonging to a second level other than APs of the fourth and third levels to be scanned for; and

if as the result of the scanning for the APs of the second level, a matching AP is not detected, identifying the APs belonging to a first level other than APs of the fourth, third, and second level to be scanned for.

12. The method of claim 1, wherein each of AP related information items stored in the channel table comprises a basic service set (BSS) ID, an AP address, channel information, GPS information of the AP or combinations thereof.

13. The method as claimed in claim 1, further comprising:

based on the received GPS information, received in the mobile device, obtaining current location information of the mobile device;

based on the obtained current location information of the mobile device, recognizing at least one Local Access Network (LAN) network service receivable by the mobile device at the current location;

if the number of the recognized LAN network services is two or more, selecting one of the recognized LAN network services according to a predetermined condition; and

switching to the selected LAN network service.

14. The method of claim 13, wherein the recognizing of the network services includes identifying network services being provided at the current location of the mobile device from a database in the mobile device, which stores types of a variety of networks and applied areas in advance.

15. The method of claim 13, wherein the predetermined condition is set in terms of a most efficient price of unit-service of services.

16. The method of claim 1, wherein the detecting of the AP comprises:

generating a list including the obtained AP information;

updating an existing scanning channel list with the generated list; and

detecting an AP to be reassociated with, by scanning for the APs of the update channel list.

17. The method of claim 1, wherein:

the identifying of the at least one AP comprises the mobile device estimating the moving direction or moving path of the mobile device by using the plurality of GPS information items, and

the obtaining the information comprises the mobile device retrieving from a memory of the mobile device the channel table and obtaining the information on the at least one AP to be scanned for, based on which of the searching ranges is set to be next be scanned, from the retrieved channel table.

18. The method of claim 1, wherein the detecting of the AP comprises:

generating within the mobile device a list including obtained AP information;

retrieving from a memory of the mobile device an existing scanning channel list based which of the searching ranges is set to be next scanned;

updating within the mobile device the retrieved existing scanning channel list with the generated list to define which APs to scan for; and

detecting an AP to be reassociated with, by scanning for the APs of the updated channel list.

19. 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.

20. The mobile device of claim 19, wherein the AP detecting unit generates a list including the obtained AP information, updates an existing scanning channel list with the generated list, and detects an AP to be reassociated with, by scanning for the APs of the update channel list.

21. The mobile device of claim 19, wherein the scanning includes hierarchically scanning last a predetermined searching range classified into a first level including APs on all channels, after a second level including APs on channels within a first angle relative to an axis represented by the moving direction or path, after a third level including APs on channels within a second angle relative to the axis represented by the moving direction or path less than the first angle, and after a fourth level including an AP within a narrowest angle relative to the axis represented by the moving direction or moving path of the mobile device.

22. The mobile device of claim 21, wherein the AP identifying unit identifies the AP to be scanned for belonging to the searching range of the fourth level first.

23. The mobile device of claim 21, wherein the AP identifying unit identifies the APs to be scanned for belonging to the searching range of the third level.

24. The mobile device of claim 21, wherein the AP identifying unit identifies the APs to be scanned for belonging to the searching range of the second level.

25. The mobile device of claim 21, wherein the AP identifying unit and the AP detection unit identify the AP of the fourth level, as a predetermined minimized searching range, to be scanned for based on the moving direction or moving path of the mobile device;

if as the result of the scanning for the AP of the fourth level, a matching AP is not detected, identify the APs to be scanned for belonging to the third level other than APs of the fourth level;

if as the result of the scanning for the APs of the third level, a matching AP is not detected, identify the APs to be scanned for belonging to the second level other than APs of the fourth and third levels; and

if as the result of the scanning for the APs of the second level, a matching AP is not detected, identify the APs to be scanned for belonging to the first level other than APs of the fourth, third, and second levels.

26. The mobile device of claim 19, wherein:

the AP identifying unit identifies the AP to be scanned for belonging to a searching range of a fourth level selected from first through fourth levels,

a searching range of the first level is greater than a searching range of the second level;

the searching range of the second level is greater than a searching range of the third level; and

the searching range of the third level is greater than the searching range of the fourth level.

27. The mobile device of claim 19, wherein:

the AP identifying unit identifies the APs to be scanned for belonging to a searching range of a third level selected from first through fourth levels,

a searching range of the first level is greater than a searching range of the second level;

the searching range of the second level is greater than the searching range of the third level; and

the searching range of the third level is greater than a searching range of the fourth level.

28. The mobile device of claim 19, wherein:

the AP identifying unit identifies the APs to be scanned for belonging to a searching range of a second level selected from first through fourth levels,

a searching range of the first level is greater than the searching range of the second level;

the searching range of the second level is greater than a searching range of the third level; and

the searching range of the third level is greater than a searching range of the fourth level.

29. The mobile device of claim 19, wherein the AP identifying unit and the AP detection unit:

identifies the at least one AP of a fourth level, as a predetermined minimized searching range, to be scanned for based on the moving direction or moving path of the mobile device;

if as the result of the scanning for the AP of the fourth level, a matching AP is not detected, identifies the APs to be scanned for belonging to a third level other than APs of the fourth level;

if as the result of the scanning for the APs of the third level, a matching AP is not detected, identifies the APs to be scanned for belonging to a second level other than APs of the fourth and third levels; and

if as the result of the scanning for the APs of the second level, a matching AP is not detected, identifies the APs to be scanned for belonging to a first level, including all APs, other than APs of the fourth, third, and second levels.

30. The mobile device of claim 19, wherein the channel table includes a basic service set (BSS) ID, an AP address, channel information, GPS information of the AP or combinations thereof.

31. The mobile device of claim 19, wherein the unit detecting an AP to reassociate with, by scanning for the at least one identified AP, generates a list including the obtained AP information, updates an existing scanning channel list with the generated list, and detects an AP to be reassociated with, by scanning for the APs of the update channel list.

32. 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.

33. 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.

34. 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.

35. The method of claim 34, wherein the reassociating includes requesting an association with the found AP and delaying association with the found AP until after the found AP confirms a maintenance of a Quality of Service (QoS) connection for the mobile device and another device, the QoS maintenance confirmation being confirmed by the found AP after requesting by the found AP of the corresponding QoS connection from the existing AP.

36. The method of claim 34, wherein the scanning for the at least one AP comprises:

estimating a moving direction or moving path of the mobile device by using a plurality of GPS information items; and

sequentially obtaining information of respective APs included in each select searching range from a channel table including location information of APs on a plurality of channels, with all searching ranges being based on the moving direction or moving path.

37. The method of claim 34, wherein the increasing and overlapping searching ranges are defined according to angles of degree from an axis represented by an estimated moving direction or moving path of the mobile device, such that APs within a smallest of the searching ranges would be represent those APs that fall within a predetermined smallest angle from the axis in the moving direction or moving path, and APs within a greater searching range would represent APs that fall with a greater predetermined angle from the axis in the moving direction or moving path, such that the APs that fall within the smallest angle from the axis also fall within the greater angle from the axis.

38. The method of claim 34, wherein the detecting of the AP comprises:

generating a list including obtained AP information for a currently selected searching range;

updating an existing scanning channel list, which is based on a previous scanned searching range, based on the generated list, with the generating of the list being performed before scanning the currently selected searching range; and

scanning for the APs of the updated channel list for the scanning of the currently selected searching range.

39. The method of claim 38, wherein the generated list for the greatest searching range includes a complete listing of all available channels to be scanned,

the generated list for a middle searching range, smaller than the greatest searching range and greater than the smaller searching range, includes a middle listing of the available channels, less than all of the available channels, to be scanned, and

the generated list for the smaller searching range includes a smaller listing of the available channels, less than the middle listing of the available channels, to be scanned.

40. The method of claim 39, wherein the generated list for the smaller searching range includes only a single channel.

41. 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.

42. The mobile device of claim 41, wherein the reassociating of the reassociating unit includes requesting an association with the found AP and delaying association with the found AP until after the found AP confirms a maintenance of a Quality of Service (QoS) connection for the mobile device and another device, the QoS maintenance confirmation being confirmed by the found AP after requesting by the found AP of the corresponding QoS connection from the existing AP.

43. The mobile device of claim 41, wherein the AP identification unit further comprises:

an estimating unit estimating a moving direction or moving path of the mobile device by using a plurality of GPS information items; and

an information obtaining unit sequentially obtaining information of respective APs included in each select searching range from a channel table including location information of APs on a plurality of channels, with all searching ranges being based on the moving direction or moving path.

44. The mobile device of claim 41, wherein the increasing and overlapping searching ranges are defined according to angles of degree from an axis represented by an estimated moving direction or moving path of the mobile device, such that APs within a smallest of the searching ranges would be represent those APs that fall within a predetermined smallest angle from the axis in the moving direction or moving path, and APs within a greater searching range would represent those APs that fall with a greater predetermined angle from the axis in the moving direction or moving path, such that the APs that fall within the smallest angle from the axis also fall within the greater angle from the axis.

45. The mobile device of claim 41, wherein the AP detecting unit generates a list including obtained AP information for a currently selected searching range, updates an existing scanning channel list, which is based on a previous scanned searching range, based on the generated list, with the generating of the list being performed before scanning the currently selected searching range, and scanning for the APs of the updated channel list for the scanning of the currently selected searching range.

46. The mobile device of claim 45, wherein the generated list for the greatest searching range includes a complete listing of all available channels to be scanned,

the generated list for a middle searching range, smaller than the greatest searching range and greater than the smaller searching range, includes a middle listing of the available channels, less than all of the available channels, to be scanned, and

the generated list for the smaller searching range includes a smaller listing of the available channels, less than the middle listing of the available channels, to be scanned.

47. The method of claim 46, wherein the generated list for the smaller searching range includes only a single channel.