DISTRIBUTED MEDIUM ACCESS PROTOCOL FOR WIRELESS MESH NETWORKS

• US 20120106522A1
• Filed: 01/09/2012
• Published: 05/03/2012
• Est. Priority Date: 05/14/2009
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Reumerman, Hans-Juergen, Hiertz, Guido Roland, Max, Gustaf Sebastian, Zang, Yunpeng
• Granted Patent: US 8,625,546 B2
• Time in Patent Office: Days
• US Class Current: 370/337
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365
• CPC Class Codes: H04W 28/26 Resource reservation
• CPC Class Codes: H04W 40/246 Connectivity information discovery
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 84/10 Small scale networks; Flat hierarchical networks
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

This invention defines a medium access protocol for the support of mesh networking in wireless communications. It defines a phase for intra-cell and a phase for inter-cell traffic. During the inter-cell traffic a beacon phase is used for the reservation of transmissions. In this phase also information about the mesh topology is included and parallel transmission are supported.

Even though this medium access protocol is intended to be proposed in standardization of IEEE 802.11 mesh networks (802.11) it could be used in any wireless mesh network.

Claims

1-19. -19. (canceled)

20. A method of medium access control in a network (10), the method comprising:

dividing a time interval (76) into a first phase (70) for intra-cell communication and a second phase (72) for inter-cell communication, the second phase including a beacon period (82);

dividing the beacon period into slots (84);

dynamically defining respective lengths for respective beacons of respective devices in the network (10), whereby a beacon length corresponds to an integer number of slots (84) in the beacon period (82), so as to allow the devices to dynamically enlarge their corresponding beacons; and

defining a beacon period duration.

21. The method of claim 20, wherein the first phase is used for AP-traffic (70).

22. The method of claim 20, wherein the beacon period (82), when sent from a transmitting device (24), includes beacons associated with neighboring devices (22) in the network (10).

23. The method of claim 20, further comprising announcing a Contention Free Period (CFP) (74) in the beacon period, the CFP announcement instructs predetermined stations in the network to be silent during the CFP period (74).

24. The method of claim 20, wherein the beacon period (82) duration is a multiple of a TxOP duration (120).

25. The method of claim 24, wherein the beacon period duration is calculated to be the maximum of a last received beacon duration period, the amount of time as reported from other beacons received in the present beacon period, and the amount of time as reported from beacons in the last received beacon period plus a number of free slots such that the beacon period duration is said multiple of a TxOP (120).

26. The method of claim 25, wherein said beacon duration is not greater than a mMaxBPLength (92).

27. The method of claim 20, further including ordering the respective beacons in the beacon period by length (122, 128).

28. The method of claim 20, further comprising allowing a Mesh Point (36) to send a first and a second beacon in one beacon period provided that information in said first beacon is different that information in said second beacon.

29. The method according to claim 20, further comprising filling unused slots in said beacon period by sliding or by jumping (162).

30. The method according to claim 20, comprising defining a beacon frame structure as being compliant with an IEEE 802.11 standard.

31. The method according to claim 30, further comprising including a Beacon Period Occupancy (BPO) Information Element (IE) (150).

32. The method according to claim 31, wherein said BPOIE comprises a beacon period length field (154), a beacon period bitmap (156) and an owner vector.

33. A wireless network (10) comprising:

a plurality of master modules (34, 36); and

a plurality of slave modules (22, 24),

said master modules and said slave modules communicating using a medium access point protocol (MAC) for a wireless distribution system;

characterized in that said MAC comprising a first phase for intra-cell traffic (70) and a second phase for inter-cell traffic (72), said second phase comprising a beacon period (82);

the beacon period being divided into a plurality of slots (84) that dynamically define respective lengths for respective beacons in the beacon period, a duration of said plurality of slots being at least a portion of a beacon period duration.

34. The network of claim 33, wherein a master module (34) is an Access Point in said wireless network (10).

35. The network of claim 33, wherein said MAC protocol supports parallel transmission by the means of TxOP reservation.

36. The network of claim 33, wherein said intra-DS traffic is Mesh Traffic (74).

37. The network of claim 36, wherein said beacon period (82) has a beacon period duration that is a multiple of a TxOP duration (120).

38. The network of claim 36, wherein said plurality of slots are organized in said beacon period by size.