Link path searching and maintaining method for a bluetooth scatternet

• US 7,298,761 B2
• Filed: 05/09/2003
• Issued: 11/20/2007
• Est. Priority Date: 05/09/2003
• Status: Active Grant

• Current Assignee: Institute For Information Industry
• Original Assignee: Institute For Information Industry
• Inventors: Hong, Alexander T. P.
• Primary Examiner(s): Rao; Seema S.
• Assistant Examiner(s): Wu; Jianye
• Application Number:
  US10/434,201
• Publication Number:
  US 20040223512A1
• Time in Patent Office: 1,656 Days
• Field of Search: 370/466, 370/310, 455 411- 413, 455/444, 455/449
• US Class Current: 370/466
• CPC Class Codes: H04W 8/005 Discovery of network devices, e.g. terminals
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: H04W 92/02 Inter-networking arrangements

Abstract

A link path search and maintain method for establishing link search table between two bluetooth devices such that the devices can transfer data to/from others device located in a bluetooth scatternet. When initialization of a slave bluetooth device, the new member in a bluetooth piconet receives a link search table that transmitted from a master bluetooth device to establish a local link search table; as the link is broken or the link search table needs be updated, the slave bluetooth device executes a link search establishment transmission procedure or a link search establishment receiving procedure to update the local link search table or establish a new link search table. Then, the slave bluetooth device encapsulates the bluetooth data packet according the information of the local link search table in order to transfer data packet in a scatternet.

Claims

1. A link searching and maintaining method for establishing a link search table between a first bluetooth device in one piconet to a second bluetooth device in another piconet with both piconets located in a bluetooth scatternet, each bluetooth device including a link update variable, a link update timer, an initialization procedure executing timer, an initialization procedure trigger timer, a missing timer and a link search table, wherein the first Bluetooth device sends a link searching packet to the second bluetooth device to establish the link search table, wherein the link searching packet comprises a link number field, a source IP address field, a source bluetooth address (BD_Addr) field, a sender bluetooth address (BD_Addr) field, a link search number field, and multiple search link identification fields, the method comprising:

(A) filling the corresponding fields of the link search packet;

(B) enabling the link update variable and link update timer;

(C) filling the link number field with 0; and

(D) encapsulating with the bluetooth packet header and transmitting through the bluetooth channel.

2. The link searching and maintaining method for establishing a link search table between two bluetooth devices as claimed in claim 1, wherein the corresponding fields of the link search packet includes the source IP, source BD_Addr, sender BD_Addr, link search number and multiple search link fields.

3. The link searching and maintaining method for establishing a link search table between two bluetooth devices as claimed in claim 1, wherein when the bluetooth device in a scatternet receives a link search packet, the following steps are executed:

(E) un-packing the link search packet;

(F) determining whether the link number field of the link search packet is equal 0 or not;

(G) recording the corresponding fields of the link search packet to a comparison table if step (F) determines that value of the link number field is equal 0;

(H) comparing each field in the comparison table and the link search table and generating a flag;

(I) determining whether to re-transmit the received link search packed or not according to the flag;

(J) determining whether the link update variable is enabled or not if step (I) decides not to re-transmit the received link search packet;

(K) updating the link update timer if step (J) decides that the link update variable is enabled;

(L) determining whether others link search packet is received or not;

(M) determining whether the link update timer is expired or not if step (L) decides no other link search packet is received;

(N) disabling the link update variable of the bluetooth device if step (M) decides that the link update timer is expired; and

(O) clearing the records in the comparison table.

4. The link searching and maintaining method for establishing 1a ink search table between two bluetooth devices as claimed in claim 3, wherein when step

(M) determines that the link update timer is not expired, step (L) is executed.

5. The link searching and maintaining method for establishing a link search table between two bluetooth devices as claimed in claim 3, wherein when step (L) determines that there is other link search packet received, step (E) is executed.

6. The link searching and maintaining method for establishing a link search table between two bluetooth devices as claimed in claim 3, wherein when step (J) determines that the link update variable is not enabled, step (A) is executed.

7. The link searching and maintaining method for establishing a link search table between two bluetooth devices as claimed in claim 3, wherein step (H) further comprises:

(H1) retrieving data from the comparison table;

(H2) determining whether the source IP address is equal to the IP address of the bluetooth device or not;

(H3) determining whether the source BD_addr is equal to the BD_addr of the bluetooth device or not if step (H2) determines that the source PP address is not equal to the IP address of the bluetooth device;

(H4) determining whether the sender BD_addr is equal to the BD_addr of the bluetooth device or not if step (H3) determines that the source BD_addr is not equal to the BD_addr of the bluetooth device;

(H5) determining whether the link search number is equal to a pre-determined value or not if step (H4) determines that the sender BD_addr is not equal to the BD_addr of the bluetooth device;

(H6) recording corresponding data to the link search table of the bluetooth device;

(H7) generating a flag for continuously transmitting the link search packet.

8. The link searching and maintaining method for establishing a link search table between two bluetooth devices as claimed in claim 7, wherein, in step (H5), the pre-determined value is equal 15.

9. The link searching and maintaining method for establishing a link search table between two bluetooth devices as claimed in claim 7, wherein when step (H2) determines that the source IP address is equal to the IP address of the bluetooth device, step (H3) determines that the source BD_addr is equal to the BD_addr of the bluetooth device, step (H4) determines that the sender BD_addr is equal to the BD_addr of the bluetooth device, or step (H5) determines that the link search number is equal to 15, step

(H8) is executed f or stopping the searching procedure and generating a stop searching flag.

10. The link searching and maintaining method for establishing a link search table between two bluetooth devices as claimed in claim 3, wherein when step (I) determines to re-transmit the received link search packet, it further comprises:

(I1) filling the ID of the link that receives the search link packet into the search link IDm field of the search link packet;

(I2) retrieving corresponding search link IDs in the comparison table and filling the same into the search link field of the search link packet;

(I3) adding 1 to the link search number field and filling the sender BD_addr with the bluetooth address of the bluetooth device;

(I4) filling the source IP address, source BD_addr with data retrieving from the comparison table; and

(I5) encapsulating the link search packet with the standard bluetooth header and transmitting the packet by the bluetooth channel.

11. The link searching and maintaining method for establishing a link search table between two bluetooth devices as claimed in claim 3, wherein when step (F) determines that value of the link number field is not equal to 0, a data packet transmission/receiving procedure is further executed.