METHOD OF COMMUNICATING WITHIN A MESH NETWORK

• US 20090052463A1
• Filed: 08/24/2007
• Published: 02/26/2009
• Est. Priority Date: 08/24/2007
• Status: Active Grant

• Current Assignee: Strong Force IoT Portfolio 2016, LLC (Strong Force Intellectual Capital, LLC)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Chen, Ye, Emeott, Stephen P., Gossain, Hrishikesh
• Granted Patent: US 8,270,429 B2
• Time in Patent Office: Days
• US Class Current: 370/406
• CPC Class Codes: H04W 72/543 based on requested quality, e.g. QoS
• CPC Class Codes: H04W 74/0808 using carrier sensing, e.g. carrier sense multiple access [CSMA]
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

A method of communicating within a mesh network comprises scheduling a mesh access reservation time period for transmission of one or more frames by the mesh device on a channel. During the scheduled mesh access reservation time period: contention for the channel is performed with one or more other mesh devices in the network; and at least one frame is transmitted when the mesh device wins the contention. After the scheduled mesh access reservation time period: when one or more frames scheduled for transmission during the scheduled mesh access reservation time period remain to be transmitted; contention for the channel continues; and the one or more frames are transmitted when the mesh device wins the contention for the channel and when another mesh device has not reserved the channel for the time period.

Claims

1. A method of operation of a mesh device for communicating within a mesh network comprising:

scheduling a mesh access reservation time period for transmission of one or more frames by the mesh device on a channel;

during the scheduled mesh access reservation time period;

performing contention for the channel with one or more other mesh devices in the network; and

transmitting at least one frame when the mesh device wins the contention for the channel; and

after the scheduled mesh access reservation time period;

determining whether one or more frames scheduled for transmission during the scheduled mesh access reservation time period remain to be transmitted;

continuing to perform contention for the channel with one or more other mesh devices in the network;

determining whether another mesh device has reserved the channel for a time period after the scheduled mesh access reservation time period; and

transmitting the one or more frames when the mesh device wins the contention for the channel and when another mesh device has not reserved the channel for the time period.

2. A method as claimed in claim 1, wherein the performing contention for the channel with one or more other mesh devices in the network during the scheduled mesh access reservation time period comprises performing contention for the channel using a quality of service channel access function during the scheduled mesh access reservation time period;

and

further wherein the continuing to perform contention for the channel with one or more other mesh devices in the network after the scheduled mesh access reservation time period comprises continuing to perform contention for the channel using the same quality of service channel access function after the scheduled mesh access reservation time period.

3. A method as claimed in claim 1, further comprising prior to the scheduled mesh access reservation time period:

obtaining one or more frames to transmit starting at the scheduled mesh access reservation time period.

4. A method as claimed in claim 3, wherein the obtaining step is performed by a scheduled access buffer, and further wherein the obtaining step comprises:

obtaining the one or more frames by the scheduled access buffer from one of a group comprising one or more upper layers and one or more neighboring mesh device.

5. A method as claimed in claim 1, further comprising after the scheduled mesh access reservation time period:

determining whether one or more frames transmitted during the scheduled mesh access reservation time period require retransmission;

continuing to perform contention for the channel with one or more other mesh devices in the network;

determining whether another mesh device has reserved the channel for a time period after the scheduled mesh access reservation time period; and

transmitting the one or more frames requiring retransmission when the mesh device wins the contention for the channel and when another mesh device has not reserved the channel for the time period.

6. A method as claimed in claim 5, wherein the performing contention for the channel with one or more other mesh devices in the network during the scheduled mesh access reservation time period comprises performing contention for the channel using a quality of service channel access function during the scheduled mesh access reservation time period;

and

further wherein the continuing to perform contention for the channel with one or more other mesh devices in the network after the scheduled mesh access reservation time period comprises continuing to perform contention for the channel using the same quality of service channel access function after the scheduled mesh access reservation time period.

7. A method as claimed in claim 1, wherein the scheduling step comprises:

negotiating by the mesh device with one or more other mesh devices to schedule a reservation for the mesh access reservation time period;

establishing a mutually agreed upon mesh access reservation time period; and

advertising the scheduled mesh access reservation time period to one or more neighbor mesh devices.

8. A method as claimed in claim 7, wherein the advertising step comprises:

broadcasting a reservation information associated with the scheduled mesh access reservation time period by the mesh device on a management frame.

9. A method as claimed in claim 7, wherein the reservation information comprises a scheduled time and a duration for transmitting the frame.

10. A method as claimed in claim 7, where the advertising step further comprises:

periodically broadcasting by the plurality of mesh devices the reservation information associated with the plurality of mesh access time periods to a one or more neighbor mesh devices.

11. A method as claimed in claim 10, wherein the reservation information comprises a scheduled time and a duration for transmitting the frame.

12. A method as claimed in claim 7, further comprising:

periodically checking for frames to be transmitted at a scheduled start of each of a plurality of scheduled mesh access time periods associated with one or more neighbor mesh devices; and

transmitting the frames during the scheduled mesh access time periods.

13. A method as claimed in claim 7, further comprising:

avoiding transmission by the one or more neighbor mesh devices during the scheduled mesh access reservation time period.

14. A method as claimed in claim 13, further comprising:

resuming transmission by the one or more neighbor mesh devices after the scheduled mesh access reservation time period.

15. A method as claimed in claim 1, further comprising:

suspending channel access during the time period after the scheduled mesh access reservation time period when another mesh device has reserved the channel for the time period.

16. A method as claimed in claim 1, further comprising:

continuing to transmit the frame on the channel until the frame is either successfully transmitted or a retransmission limit is reached.

17. A method of operation of a mesh device for communicating within a mesh network comprising:

receiving a schedule including a reservation of a scheduled mesh access reservation time period for each of the one or more received frames;

receiving one or more frames to forward to another destination node from at least one neighbor mesh device;

buffering the received one or more frames;

releasing a buffered frame to a transmit queue of a channel access function at a start of an associated scheduled mesh access reservation time for the buffered frame; and

disabling one or more queues with non scheduled mesh access traffic during each of the reserved scheduled mesh access reservation time periods.