Service discovery methods

1. A method for service discovery, comprising:

receiving a first service advertisement by a first device, the first service advertisement including at least a service of a second device;

updating a service directory of the first device to include the service of the second device;

broadcasting a beacon including an information element, the information element including at least a Media Access Control (MAC) address of the second device and a service discovery protocol data unit (SPDU) including at least a service attribute of the service of the second device, for a second service advertisement by the first device, the second service advertisement including at least the service of the second device, wherein the second service advertisement is used by a third device to effect use of the service of the second and

identifying physical location of the second device from common attributes of a root service class, the at least the service attribute of the service of the second device being defined as an attribute of a sub-class of the root service class.

2. The method of claim 1 , wherein the second service advertisement includes at least a service of the first device.

3. The method of claim 1 wherein the first service advertisement is not received by the third device.

4. The method of claim 1 , wherein broadcasting for the second service advertisement by the first device, further comprises:

transmitting the second service advertisement at least while positions of the first and third devices stay the same as when the first device receives the first service advertisement.

5. The method of claim 1 , further comprising:

including another information element for at least a service of the first device in a message; and

transmitting the message.

6. The method of claim 1 , further comprising:

transmitting the second service advertisement by the first device at least while the second device is operating in a power save state or while the second device is not within wireless communication range of the third device.

7. A wireless device, comprising:

a transceiver module configured to receive service advertisements from other devices and transmit service advertisements to other devices;

a memory module configured to store a service directory; and

a processor configured to obtain from the transceiver module a first service advertisement that includes at least a service of a first device, update the service directory to include the service of the first device, and instruct the transceiver module to broadcast a beacon including an information element, the information element including at least a Media Access Control (MAC) address of a second device and a service discovery protocol data unit (SPDU) including at least a service attribute of a service of the second device, for a second service advertisement that includes the service of the first device, wherein the second service advertisement is used by a second device to effect use of the service of the first device, a physical location of the second device is identified from common attributes of a root service class, the at least the service attribute of the service of the second device being defined as an attribute of a sub-class of the root service class.

8. The wireless device of claim 7 , wherein the second service advertisement further includes at least a service of the wireless device.

9. The wireless device of claim 7 , wherein the processor is further configured to include another information element for at least the service of the first device in a message and the transceiver module is further configured to transmit the message.

10. The wireless device of claim 9 , wherein the other information element includes at least a Media Access Control (MAC) address of the first device and a service discovery protocol data unit (SPDU) including at least a service attribute of the service of the first device.

11. The wireless device of claim 7 , wherein the first service advertisement is not received by the second device.

12. The wireless device of claim 7 , wherein the processor is further configured to instruct the transceiver module to transmit the second service advertisement at least while the first device is configured to operate in a power save state or while the first device is not within wireless communication range of the second device.

13. A network for service discovery, comprising:

a first device configured to transmit a first service advertisement that includes at least a service of the first device;

a second device configured to receive the first service advertisement, update a service directory to include the service of the first device, and broadcast a beacon including an information element, the information element including at least a Media Access Control (MAC) address of the second device and a service discovery protocol data unit (SPDU) including at least a service attribute of a service of the second device, for a second service advertisement that includes at least the service of the second device and the service of the first device, wherein a physical location of the second device is identified from common attributes of a root service class, the at least the service attribute of the service of the second device being defined as an attribute of a sub-class of the root service class; and

a third device configured to receive the second service advertisement, and communicate with the first device to use the service of the first device.

14. The network of claim 13 , wherein the second device is further configured to include another information element for the service of the first device in a message, and transmit the message.

15. The network of claim 13 , wherein the first service advertisement is not received by the third device.

16. The network of claim 13 , wherein the second device is further configured to transmit the second service advertisement at least while the first device is configured to be in a power save state or while the first device is not within wireless communication range of the third device.