Multi-radio unification protocol

• US 20060142033A1
• Filed: 02/24/2006
• Published: 06/29/2006
• Est. Priority Date: 03/20/2003
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Bahl, Paramvir, Adya, Atul, Padhye, Jitendra D., Wolman, Alastair, Zhou, Lidong
• Granted Patent: US 7,283,834 B2
• Time in Patent Office: Days
• US Class Current: 455/509
• CPC Class Codes: H04L 69/14 Multichannel or multilink protocols
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04W 72/54 based on quality criteria
• CPC Class Codes: H04W 74/02 Hybrid access
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: H04W 88/04 adapted for relaying to or from another terminal or user
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals
• CPC Class Codes: H04W 92/18 between terminal devices

Abstract

An invention is disclosed whereby a wireless network node, equipped with two or more radio transceivers statically tuned to non-interfering frequency channels, can make decisions regarding which channel to use when communicating with a neighboring wireless node. A multi-radio unification protocol implemented in a wireless node coordinates the use of multiple wireless network interface cards and provides a virtual layer that hides the multiple physical network interfaces from higher layers of a node'"'"'s network protocol stack. The invention is applicable to wireless networks generally, including those in which some nodes do not have multiple radios or do not recognize the multi-radio unification protocol. The invention makes possible simultaneous transmissions using available channels, thereby reducing interference and delay while increasing the overall capacity of the network.

Claims

1. In a wireless network comprising a plurality of nodes, a method for selecting, by a first node, a channel for communicating with a second node, the first node having at least two network interfaces with radios tuned to orthogonal channels, the method comprising:

discovering network interfaces of the second node available for communicating with the first node;

with respect to each available network interface of the second node, periodically making a channel quality estimate; and

making a channel selection.

3. The method of claim 1 wherein discovering available network interfaces is in accordance with a protocol, and wherein discovering available network interfaces further comprises discovering whether the second node is capable of operating in accordance with the protocol.

6. The method of claim 1 wherein making a channel quality estimate comprises:

sending a probe message along the network interface;

receiving a response to the probe message from the second node; and

calculating a round-trip latency time associated with sending the probe message and receiving the response.

8. The method of claim 6 wherein the probe message is assigned a highest scheduling priority level so that the probe message may be transmitted ahead of other packets.

9. The method of claim 8 wherein the network interface is conformant to IEEE standard 802.11e.

10. The method of claim 1 wherein making a channel selection is performed at a time determined by a randomized interval.

11. The method of claim 1 wherein making a channel selection comprises

selecting a channel associated with a network interface of the second node having a best channel quality estimate.

12. The method of claim 1 wherein making a channel selection comprises:

if a first network interface of the second node has a channel quality estimate that is preferable to channel quality estimates of other network interfaces of the second node, and if the channel quality estimate of the first network interface provides an improvement, above a threshold, over the channel quality estimate of a currently-selected network interface of the second node, selecting the first network interface; and

otherwise retaining the currently-selected network interface.

13. The method of claim 1, further comprising:

making at least one additional channel selection, wherein communicating with the second node comprises striping data among selected channels.

14. The method of claim 1 wherein communicating with the second node comprises forwarding a packet received from a third node.

15. The method of claim 1 wherein the wireless network is a multi-hop network, an ad hoc network, an infrastructure network or a wireless community network.

16. The method of claim 1 wherein the wireless network is linked to a second network.

17. The method of claim 16 wherein the second network is a wired network.

18. The method of claim 16 wherein the second network is a wide-area network.

19. The method of claim 1 wherein one or more network interfaces in the wireless network conform to IEEE standard 802.11, IEEE standard 802.11a, IEEE standard 802.11b, or IEEE standard 802.11g.

2. (canceled)

4-5. -5. (canceled)

7. (canceled)

20. Computer-readable media storing one or more modules comprising a driver that implements a method for selecting a channel for wireless communication from a first device to a second device, the first device having at least two network interfaces comprising radios tuned to orthogonal channels, the method comprising:

discovering available network interfaces of the second device;

with respect to each available network interface of the second device, periodically making a channel quality estimate; and

making a channel selection.

21. The computer-readable media of claim 20 wherein the driver is an operating system kernel-mode driver.

22-24. -24. (canceled)

25. A device for deploying as a node in a wireless network, comprising:

a plurality of wireless network interface cards;

a network protocol stack comprising a plurality of layers; and

a virtual layer within the network protocol stack and above the plurality of wireless network interface cards, the virtual layer presenting a single network interface to higher layers in the network protocol stack.

26. The device of claim 25 wherein the wireless network interface cards comprise radio transceivers tunable to orthogonal frequency channels.

27. The device of claim 25 wherein the device can be used to forward data from a first wireless network node to a second wireless network node.

28. The device of claim 25 wherein the virtual layer is implemented as a data link layer protocol.

29. The device of claim 25 wherein the virtual layer is situated below a network layer of the network protocol stack.

30. The device of claim 25 wherein one or more wireless network interface cards conform to IEEE standard 802.11.

31. The device of claim 25 wherein one or more wireless network interface cards conform to IEEE standard 802.11b.

32. The device of claim 25 wherein one or more wireless network interface cards conform to IEEE standard 802.11a.

33. The device of claim 25 wherein one or more wireless interface cards conform to IEEE standard 802.11g.

34. The device of claim 25 wherein the device is deployable as a node in any one of a multi-hop network, an ad hoc network, an infrastructure network, a wireless mesh network or a wireless community network.

35. The device of claim 34 wherein the device is deployable as a mesh router.

36. The device of claim 25 wherein the device is deployable as a node in a wireless network that is linked to a second network.