Efficient piconet formation and maintenance in a bluetooth wireless network

• US 20030099212A1
• Filed: 11/19/2002
• Published: 05/29/2003
• Est. Priority Date: 11/29/2001
• Status: Active Grant

• Current Assignee: Nytell Software LLC (Intellectual Ventures LLC)
• Original Assignee: Telcordia Licensing Co LLC (Telefonaktiebolaget LM Ericsson)
• Inventors: Jain, Ravi, Anjum, Farooq, Adamou, Maria
• Granted Patent: US 7,496,065 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: H04W 84/20 Master-slave selection or change arrangements
• CPC Class Codes: H04W 92/02 Inter-networking arrangements

Abstract

The invention is addressing the problem of efficient formation and maintenance of piconets with assistance from the master of an already existing piconet. The master of an existing piconet initiates the formation of a new helper piconet by at least two of its slaves. One of the slaves of the existing piconet becomes the master of the newly formed helper piconet and the other slave becomes a slave of the helper piconet. This process can be used to expand the number of Bluetooth devices that can use an Internet access point. It can also be used to permit two slave devices to communicate directly with one another so as not to unnecessarily use bandwidth available through the master. Finally, the method and system could be used to provide a method of efficient hand-off from one piconet to another.

Claims

1. A method of communication within a network of wireless devices, wherein the network comprises one or more piconets each having a master device and one or more slave devices, the method comprising the step of:

transmitting a command from the master device of a first piconet to a first slave device in the first piconet indicative of a desire to establish a helper piconet;

establishing said first slave device of the first piconet as the master device of the helper piconet;

transmitting a command from the master device of the first piconet to a second slave device of the first piconet to join the helper piconet;

establishing said second slave device of the first piconet as a slave device of the helper piconet;

communicating from the master device of the first piconet to the slave device of the helper piconet through the master device of the helper piconet wherein the master device of the helper piconet remains a slave device of the first piconet.

2. The method of claim 1 wherein the master and slave devices are Bluetooth capable devices.

3. The method of claim 1 further comprising the transmission of commands from the master device of the first piconet to the first and second slave devices of the first piconet negotiating the amount of time said first and second slave devices remain inactive in the first piconet during which time the slaves establish the helper piconet.

4. The method of claim 1 further comprising the step of indicating to the master device of the first piconet that communication between said first and second slaves in the helper piconet has been established.

5. The method of claim 1 further comprising the step of determining, prior to establishing a helper piconet, if the number of addresses available in the first piconet for additional slaves is insufficient or near zero.

6. The method of claim 1 further comprising the step of receiving, prior to establishing a helper piconet, a request from a slave in the first piconet to communicate directly with another slave in the first piconet.

7. The method of claim 1 further comprising the step of receiving, prior to establishing a helper piconet, an indication from a slave in the first piconet to transfer to another piconet having a different master device.

8. A method of expanding the number of slave devices in a first piconet that are capable of communicating with a network through an access point that acts as a master device for the first piconet comprising the steps of:

requesting a first slave device and a second slave device in communication with the master device to become inactive in the first piconet at a predetermined time for a specified duration;

receiving an acknowledgement at the master from said first and second slave devices to become inactive at the predetermined time for the specified duration;

at the predetermined time, transmitting a command from the master device to said first slave with connection information for enabling connection of said second slave;

wherein once connected said first slave acts a master to said second slave and provides a means for the master device to communicate with said second slave for the specified duration.

9. The method of claim 8 wherein the connection information is the frequency hop synchronization (FHS) packet of said second slave.

10. The method of claim 8 further comprising the step of indicating to the master device that communication between said first and second slaves has been established.

11. The method of claim 10 further comprising the step of terminating communication between the master and said second slave.

12. A method for communicating directly between two slave devices in a first piconet that are capable of communicating with a network through an access point that acts as a master device for the first piconet comprising the steps of:

requesting a first slave device and a second slave device in communication with the master device to become inactive in the first piconet at a predetermined time for a specified duration;

receiving an acknowledgement from at the master from said first and second slave devices to become inactive at the predetermined time for a specified duration;

at the predetermined time, transmitting a command from the master device to said first slave with connection information for enabling connection of said second slave;

wherein once connected said first slave acts a master to said second slave and provides a means for the direct communication between the first and second slaves for the specified duration.

13. The method of claim 12 wherein the connection information is the frequency hop synchronization (FHS) packet of said second slave.

14. The method of claim 12 further comprising the step of indicating to the master device that direct communication between said first and second slaves has been established.

15. The method of claim 14 further comprising the steps of having said first and second slave devices return as active slave devices in the first network upon expiration of the specified duration.

16. A method for handing off communication from a first slave in a first piconet, capable of communicating with a network through a first access point that acts as a first master device, to a second piconet, comprising the steps of:

receiving at the first master device a request from the first slave to transfer to the second piconet;

selecting a second slave device to be the master device in a sleeper piconet;

requesting a first slave device and a second slave device in communication with the first master device to become inactive in the first piconet at a predetermined time for a specified duration;

receiving an acknowledgement at the first master device from the first and second slave devices to become inactive at the predetermined time for a specified duration;

at the predetermined time, transmitting a command from the first master device to the second slave with connection information for enabling connection to the first slave;

wherein once connected as sleeper piconet the second slave acts a master to the first slave and provides a means for the first slave and second slave to synchronize;

determining at the first master device that the first slave device is beyond the range of the first master device;

communicating from the first master device to the first slave device through the sleeper piconet by way of the second slave device until such time as the first slave device becomes active in the second piconet.

17. The method of claim 16 wherein the connection information is the frequency hop synchronization (FHS) packet of said second slave.

18. The method of claim 16 wherein the step of selecting the second slave device to act as the master device in the sleeper piconet is based on the speed and/or direction of travel of the first slave device.

19. The method of claim 16 wherein the step of selecting the second slave device to act as the master device in the sleeper piconet is based on the signal strength of the first slave device.