Apparatus and method for asynchronous peer-to-peer discovery
Apparatus and method are provided for performing asynchronous discovery among multiple peers in a wireless peer-to-peer (P2P) network. In an aspect of the disclosure, a peer selects a duty cycle C corresponding to a probability that the peer is in either a scanning state or an advertising state, rather than a sleeping state, wherein the duty cycle C is selected in accordance with a power consumption of the peer. The peer also selects a first probability P t for being in the advertising state, and performs an asynchronous discovery protocol in accordance with the duty cycle C and the first probability P t .
1. A method operable at a peer in a wireless peer-to-peer (P2P) network, the peer being configured to discover other peers by utilizing an asynchronous discovery protocol comprising a scanning state, an advertising state, and a sleeping state in accordance with a duty cycle C, the method comprising:
determining the duty cycle C in accordance with a power consumption of the peer, wherein the duty cycle C corresponds to a first probability P t that the peer is in the advertising state and a second probability P r that the peer is in the scanning state;
determining the first probability P t in accordance with the duty cycle C and a number of peers N in communication range of the peer; and
performing the asynchronous discovery protocol in accordance with the duty cycle C and the first probability P t .
2. The method of claim 1 , further comprising:
increasing the first probability P t in response to an availability of updated content at the peer for sharing with the other peers.
3. The method of claim 2 , further comprising:
gradually decreasing the first probability P t as the updated content ages over time.
4. The method of claim 2 , further comprising:
decreasing the second probability P r by an amount equal to an increased amount of the first probability P t .
5. The method of claim 4 , wherein the increased amount of the first probability P t is greater than zero, and less than or equal to C−P t .
6. The method of claim 4 , wherein the second probability P r is substantially equal to zero.
7. The method of claim 1 , wherein the determining the first probability P t further comprises calculating:
P
t
*
=
(
2
+
CN
-
C
-
C
2
(
N
-
1
)
2
+
4
(
1
-
C
)
)
2
N
wherein P t * is a value of the first probability P t for maximizing an expected number of discoveries among peers, C is the duty cycle, and N is the number of peers.
8. The method of claim 1 , wherein the asynchronous discovery protocol is configured to support three or more of the other peers concurrently.
9. The method of claim 1 , wherein determining the first probability P t comprises determining the first probability P t such that an expected number of successful discoveries of the peers N in communication range of the peer is maximized.
10. The method of claim 1 , further comprising estimating a value of N.
11. A peer in a wireless peer-to-peer (P2P) network, comprising:
means for discovering other peers by utilizing an asynchronous discovery protocol comprising a scanning state, an advertising state, and a sleeping state in accordance with a duty cycle C;
means for determining the duty cycle C in accordance with a power consumption of the peer, wherein the duty cycle C corresponds to a first probability P t that the peer is in the advertising state and a second probability P r that the peer is in the scanning state;
means for determining the first probability P t in accordance with the duty cycle C and a number of peers N in communication range of the peer,
wherein the means for discovering comprises means for performing the asynchronous discovery protocol in accordance with the duty cycle C and the first probability P t .
12. The peer of claim 11 , further comprising:
means for increasing the first probability P t in response to an availability of updated content at the peer for sharing with the other peers.
13. The peer of claim 12 , further comprising:
means for gradually decreasing the first probability P t as the updated content ages over time.
14. The peer of claim 12 , further comprising:
means for decreasing the second probability P r by an amount equal to an increased amount of the first probability P t .
15. The peer of claim 14 , wherein the increased amount of the first probability P t is greater than zero, and less than or equal to C−P t .
16. The peer of claim 14 , wherein the second probability P r is substantially equal to zero.
17. The peer of claim 11 , wherein the means for determining the first probability P t is configured to calculate:
P
t
*
=
(
2
+
CN
-
C
-
C
2
(
N
-
1
)
2
+
4
(
1
-
C
)
)
2
N
wherein P t * is a value of the first probability P t for maximizing an expected number of discoveries among peers, C is the duty cycle, and N is the number of peers.
18. The peer of claim 11 , wherein the asynchronous discovery protocol is configured to support three or more of the other peers concurrently.
19. A
non-transitory computer-readable storage medium comprising code for causing a peer in a wireless peer-to-peer (P2P) network to:
discover other peers by utilizing an asynchronous discovery protocol comprising a scanning state, an advertising state, and a sleeping state in accordance with a duty cycle C;
determine the duty cycle C in accordance with a power consumption of the peer, wherein the duty cycle C corresponds to a first probability P t that the peer is in the advertising state and a second probability P r that the peer is in the scanning state;
determine the first probability P t in accordance with the duty cycle C and a number of peers N in communication range of the peer; and
perform the asynchronous discovery protocol in accordance with the duty cycle C and the first probability P t .
20. The computer-readable storage medium of claim 19 , further comprising code for causing the peer to:
increase the first probability P, in response to an availability of updated content at the peer for sharing with the other peers.
21. The computer-readable storage medium of claim 20 , further comprising code for causing the peer to:
gradually decrease the first probability P t as the updated content ages over time.
22. The computer-readable storage medium of claim 20 , further comprising code for causing the peer to:
decrease the second probability P r by an amount equal to an increased amount of the first probability P t .
23. The computer-readable storage medium of claim 22 , wherein the increased amount of the first probability P t is greater than zero, and less than or equal to C−P t .
24. The computer-readable storage medium of claim 22 , wherein the second probability P r is substantially equal to zero.
25. The computer-readable storage medium of claim 19 , further comprising code for causing the peer to calculate:
P
t
*
=
(
2
+
CN
-
C
-
C
2
(
N
-
1
)
2
+
4
(
1
-
C
)
)
2
N
wherein P t * is a value of the first probability P t for maximizing an expected number of discoveries among peers, C is the duty cycle, and N is the number of peers.
26. The computer-readable storage medium of claim 19 , wherein the asynchronous discovery protocol is configured to support three or more of the other peers concurrently.
27. A peer operable in a wireless peer-to-peer (P2P) network and configured to discover other peers by utilizing an asynchronous discovery protocol comprising a scanning state, an advertising state, and a sleeping state in accordance with a duty cycle C, the peer comprising:
at least one processor;
a communication interface coupled to the at least one processor; and
a memory coupled to the at least one processor,
wherein the at least one processor is configured to:
determine the duty cycle C in accordance with a power consumption of the peer, wherein the duty cycle C corresponds to a first probability P t that the peer is in the advertising state and a second probability P r that the peer is in the scanning state;
determine the first probability P t in accordance with the duty cycle C and a number of peers N in communication range of the peer; and
perform, by utilizing the communication interface, the asynchronous discovery protocol in accordance with the duty cycle C and the first probability P t .
28. The peer of claim 27 , wherein the at least one processor is further configured to:
increase the first probability P t in response to an availability of updated content at the peer for sharing with the other peers.
29. The peer of claim 28 , wherein the at least one processor is further configured to:
gradually decrease the first probability P t as the updated content ages over time.
30. The peer of claim 28 , wherein the at least one processor is further configured to:
decrease the second probability P r by an amount equal to an increased amount of the first probability P t .
31. The peer of claim 30 , wherein the increased amount of the first probability P t is greater than zero, and less than or equal to C−P t .
32. The peer of claim 30 , wherein the second probability P r is substantially equal to zero.
33. The peer of claim 27 , wherein the at least one processor is further configured to calculate:
P
t
*
=
(
2
+
CN
-
C
-
C
2
(
N
-
1
)
2
+
4
(
1
-
C
)
)
2
N
wherein P t * is a value of the first probability P t for maximizing an expected number of discoveries among peers, C is the duty cycle, and N is the number of peers.
34. The peer of claim 27 , wherein the asynchronous discovery protocol is configured to support three or more of the other peers concurrently.