System for dynamically shifting beacons in distributed wireless network and method thereof

• US 7,548,521 B2
• Filed: 07/21/2005
• Issued: 06/16/2009
• Est. Priority Date: 07/21/2004
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Arunan, Thenmozhi, Kim, Yong-suk, Jogi, Sunil Dilipkumar, Holur, Balaji Srinivas, Wason, Prashant, Choudhary, Manoj
• Primary Examiner(s): Appiah; Charles N
• Assistant Examiner(s): Karikari; Kwasi
• Application Number:
  US11/185,795
• Publication Number:
  US 20060018298A1
• Time in Patent Office: 1,426 Days
• Field of Search: 370/320, 370/338, 370/350, 370/235, 370/312, 370/348, 455/11.1, 455/454, 455/452.1, 455/450, 455/509
• US Class Current: 370/328
• CPC Class Codes: H04W 74/08 Non-scheduled access, e.g. ALOHA hybrid access H04W74/02

Abstract

A system for dynamically shifting beacons in a distributed wireless network and a method thereof are disclosed. In a medium access control for a wireless personal area network based on a mobile ad-hoc network, beacons are shifted to other free lower slots in order to reduce the size of a beacon period. Also, collisions that may occur during the shifting of the beacons are detected and avoided. According to the system and method, the size of the beacon period for transmitting data can sufficiently be secured by dynamically reducing the size of the beacon period without collisions.

Claims

1. A method for dynamically shifting beacons in a distributed wireless network, said method comprising:

selecting a slot among free lower slots which are anterior beacon slots, that are not used during a beacon period of a superframe;

requesting protection of the selected free lower slot in a beacon group so as to shift a beacon of an external device to the selected free lower slot; and

at a device, receiving a response to the protection request and shifting the beacons to the selected free lower slot to broadcast the beacons,

wherein the response is made by neighboring devices in the beacon group that receive the protection request,

wherein the response is for the protection request for a device having a higher slot index, and

wherein at least one of the neighboring devices receives the protection request for the selected free lower slot from the device, and receives another protection request from another device, and the protection request and the another protection request are for the same selected free lower slot.

2. The method as claimed in claim 1, wherein the network is a distributed wireless personal area network based on a UWB (Ultra Wide Band) ad-hoc.

3. The method as claimed in claim 1, wherein the selecting the free lower slot comprises:

receiving beacons of neighboring devices and receiving beacon period occupancy information elements included in the beacons; and

confirming an occupancy state of the beacon period slots by the neighboring devices by confirming the beacon period occupancy information elements and selecting the free lower slot.

4. The method as claimed in claim 3, wherein at least one of the beacon period occupancy information elements is an occupancy information element of the beacon period provided by at least one of the neighboring devices that broadcasts a beacon, and includes a slot index in which said at least one neighboring device is presently beaconing in the beacon group.

5. The method as claimed in claim 3, wherein the free lower slot selected among the free lower slots is the most anterior free slot in the beacon period.

6. The method as claimed in claim 1, wherein a protection request is made by broadcasting the beacon period occupancy information element, which includes information of the device and an index of the selected free lower slot, to neighboring devices through a beacon.

7. The method as claimed in claim 1, wherein the response includes the beacon period occupancy information element that includes information of the device, a first index of a present beacon slot, and a second index of the selected free lower slot.

8. The method as claimed in claim 1, wherein the response is made through a beacon period occupancy information element that includes information about the device that has made the protection request, a first index of the selected free lower slot, and a second index of the present beacon slot corresponding to the device that has made the protection request.

9. The method as claimed in claim 1, wherein if at least one of the neighboring devices receives a protection request for a same slot as the selected free lower slot from another device, a response is made denying the protection request of one of a device having a highest DEVID and a device having a lowest DEVID among one of a series of DEVIDs of a plurality of devices that have made protection requests and a device having the highest original beacon slot index.

10. The method as claimed in claim 1, wherein the device shifts the beacons to the selected free lower slots only if the response is received from all neighboring devices.

11. A system for dynamically shifting beacons in a distributed wireless network based on a mobile ad-hoc network having at least one device, the system comprising:

a requesting device which selects a slot among free lower slots which we anterior beacon slots that are not used during a beacon period of a superframe, requests protection of the selected free lower slot in a beacon group so as to shift a beacon of an external device to the selected free lower slot, receives a response from all neighboring devices, and shifts the beacons to the selected free lower slot to broadcast the beacons,

wherein the response is for the protection request for a device having a higher slot index

wherein the responding device receives the protection request and another protection request for the same slot as the selected free lower slot from another device, wherein the protection request and the another protection request are for the same selected free lower slot.

12. The system as claimed in claim 11, wherein the network is a UWB (Ultra Wide Band) wireless personal area network.

13. The system as claimed in claim 11, wherein the requesting device selects the free lower slot by receiving the beacons of the responding devices, receiving beacon period occupancy information elements included in the beacons, and providing an occupancy state of the beacon period slots by neighboring devices.

14. The system as claimed in claim 13, wherein at least one of the beacon period occupancy information elements is an occupancy information element of the beacon period provided by at least one of the neighboring devices that broadcasts the beacon, and includes a slot index that the at least one of neighboring devices is presently beaconing in the beacon group.

15. The system as claimed in claim 13, wherein the requesting device, in selecting the free lower slot, selects the most anterior slot among the free lower slots in the beacon period.

16. The system as claimed in claim 11, wherein the protection request is made by the requesting device'"'"'s broadcasting of the beacon period occupancy information element that includes information related to the requesting device and an index of the selected free lower slot.

17. The system as claimed in claim 11, wherein the response is made through the beacon period occupancy information element that includes information of the requesting device, an index of the selected free lower slot, and an index of the present beacon slot.

18. The system as claimed in claim 11, wherein the response is made through the beacon period occupancy information element that includes information about the device that has sent the protection request to which the response is to be sent, an index of the selected free lower slot, and an index of the present beacon slot corresponding to the device that has made the protection request to which the response is to be sent.

19. The system as claimed in claim 11, wherein if the responding device receives a protection request for the same slot as the selected free lower slot from another device, the response is made denying the protection request of one of the device having a highest DEVID and the device having a lowest DEVID among a series of DEVIDs of the devices that have sent the protection requests.

20. The system as claimed in claim 11, wherein the requesting device shifts the beacons to selected free lower slots only if the responses are received from all the neighboring devices.