DISTRIBUTED MEDIUM ACCESS PROTOCOL FOR WIRELESS MESH NETWORKS

• US 20090279487A1
• Filed: 05/12/2006
• Published: 11/12/2009
• Est. Priority Date: 05/12/2005
• 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: Max, Gustaf Sebastian, Reumerman, Hans-Jurgen, Yupeng, Zahg, Hiertz, Guido Roland
• Granted Patent: US 8,116,295 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04W 40/24 Connectivity information management, e.g. connectivity discovery or connectivity update
• CPC Class Codes: H04W 40/246 Connectivity information discovery
• CPC Class Codes: H04W 40/248 Connectivity information update
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor 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. A method of medium access control in a network, the method comprising:

dividing a time interval into a first phase and a second phase, the second phase including a beacon period;

dividing the beacon period into one or more slots, where a plurality of devices in the network may use the slots to dynamically enlarge their corresponding beacons;

dynamically defining a slot length for each of the slots in the beacon period; and

defining a beacon period duration.

2. The method of claim 1, wherein the first phase is used for AP-traffic.

3. The method of claim 1, wherein the beacon period, when sent from a transmitting device, includes beacons associated with neighboring devices in the network.

4. The method of claim 1, further comprising announcing a Contention Free Period (CFP) in the beacon period, the CFP announcement instructs predetermined stations in the network to be silent during the CFP period.

5. The method of claim 1, wherein the beacon period duration is a multiple of a TxOP duration.

6. The method of claim 5, 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.

7. The method of claim 6, wherein said beacon duration is not greater than a mMaxBPLength.

8. The method of claim 1, further including ordering slot lengths for each of the slots in the beacon period by duration size.

9. The method of claim 1, further comprising allowing a Mesh Point 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.

10. The method according to claim 1, further comprising filling unused slots in said beacon period by sliding or by jumping.

11. The method according to claim 1, comprising defining a beacon frame structure as being compliant with an IEEE 802.11 standard.

12. The method according to claim 11, further comprising including a Beacon Period Occupancy (BPO) Information Element (IE).

13. The method according to claim 12, wherein said BPOIE comprises a beacon period length field, a beacon period bitmap and an owner vector.

14. A wireless network comprising:

a plurality of master modules; and

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

said MAC comprising;

a first phase for intra-BSS traffic and a second phase for intra DS traffic, said second phase comprising a beacon period;

the beacon period being divided into one or more slots that dynamically define a slot length for each of a plurality of slots in the beacon period, a duration of said plurality of slots being at least a portion of a beacon period duration.

15. The network of claim 14, wherein a master module is an Access Point in said wireless network.

16. The network of claim 14, wherein said MAC protocol supports parallel transmission by the means of TxOP reservation.

17. The network of claim 14, wherein said intra-DS traffic is Mesh Traffic.

18. The network of claim 17, wherein said beacon period as a beacon period duration that is a multiple of a TxOP duration.

19. The network of claim 17, wherein said plurality of slots are organized in said beacon period by size.