Control of low power wireless networks for power conservation

• US 20070165545A1
• Filed: 01/11/2007
• Published: 07/19/2007
• Est. Priority Date: 01/11/2006
• Status: Active Grant

• Current Assignee: Fisher-Rosemount Systems Incorporated (Emerson Electric Company)
• Original Assignee: Fisher-Rosemount Systems Incorporated (Emerson Electric Company)
• Inventors: Orth, Kelly, Dobrowski, Patrick, Lovegren, Eric, Stotz, Kyle
• Granted Patent: US 7,903,596 B2
• Time in Patent Office: Days
• US Class Current: 370/254
• CPC Class Codes: G05B 2219/31162 Wireless lan
• CPC Class Codes: H04L 41/00 Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
• CPC Class Codes: H04L 41/12 Discovery or management of network topologies
• CPC Class Codes: H04L 41/22 comprising specially adapted graphical user interfaces [GUI]
• CPC Class Codes: H04L 43/045 for graphical visualisation of monitoring data
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/24 Multipath
• CPC Class Codes: H04L 45/28 using route fault recovery
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/28 in relation to timing considerations
• CPC Class Codes: H04L 47/34 ensuring sequence integrity, e.g. using sequence numbers
• CPC Class Codes: H04W 16/18 Network planning tools
• CPC Class Codes: H04W 16/22 Traffic simulation tools or models
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 28/02 Traffic management, e.g. flow control or congestion control
• CPC Class Codes: H04W 4/18 Information format or content conversion, e.g. adaptation by the network of the transmitted or received information for the purpose of wireless delivery to users or terminals
• CPC Class Codes: H04W 40/00 Communication routing or communication path finding
• CPC Class Codes: H04W 40/08 based on transmission power
• CPC Class Codes: H04W 40/10 based on available power or energy
• CPC Class Codes: H04W 40/22 using selective relaying for reaching a BTS [Base Transceiver Station] or an access point
• CPC Class Codes: H04W 40/24 : Connectivity information management, e.g. connectivity discovery or connectivity update
• CPC Class Codes: H04W 52/02 : Power saving arrangements in wired systems H04L12/12; signaling of mobile application services, e.g. low battery notifications H04W4/20
• CPC Class Codes: H04W 52/0225 : using monitoring of external events, e.g. the presence of a signal
• CPC Class Codes: H04W 52/0229 : where the received signal is a wanted signal
• CPC Class Codes: H04W 56/00 : Synchronisation arrangements
• CPC Class Codes: H04W 76/20 : Manipulation of established connections
• CPC Class Codes: H04W 8/04 : Registration at HLR or HSS [Home Subscriber Server]
• CPC Class Codes: H04W 8/26 : Network addressing or numbering for mobility support
• CPC Class Codes: H04W 80/00 : Wireless network protocols or protocol adaptations to wireless operation
• CPC Class Codes: H04W 84/18 : Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: H04W 88/16 : Gateway arrangements
• CPC Class Codes: H04W 92/00 : Interfaces specially adapted for wireless communication networks
• CPC Class Codes: Y02D 30/70 : in wireless communication networks

Abstract

A wireless mesh network routes messages between a host computer and a plurality of field devices. The mesh network is synchronized to a global regular active schedule that defines active periods when messages can be transmitted or received by nodes of the network, and inactive periods when messages cannot be transmitted or received. Based upon messages to be sent by the host computer to selected field devices, the network is controlled to selectively maintain active those nodes required to route messages to the selected field devices. Those required nodes are maintained in an active state as long as communication with the selected field devices continues, while other nodes are allowed to return to a low power inactive state. When communication between the host computer and the selected field devices is no longer required, the entire network is allowed to enter the low power inactive state.

Claims

1. A method of operating a wireless mesh network to route messages between a host computer and a plurality of field devices, the wireless network having a plurality of nodes capable of transmitting and receiving messages with each node being associated with at least one of the field devices, the method comprising:

synchronizing the nodes of the network to a global regular active schedule that defines when messages can be transmitted and received by the nodes;

receiving a message from the host computer addressed to a selected field device;

activating nodes of the network according to the global regular active schedule; and

maintaining those nodes required to route messages to the selected field device in an active state as long as the host computer is communicating with the selected field device.

2. The method of claim 1 and further comprising:

automatically returning to the nodes required to route messages to an inactive state when communication between the host computer and the selected field device has ceased.

3. The method of claim 1 wherein the nodes required to route messages are determined based upon the address of the selected field devices and communication topology of the wireless mesh network.

4. The method of claim 1 and further comprising:

extending a period of time that the nodes required to route messages will stay active during a next active state of the global regular active schedule.

7. The control system of claim 1, wherein the field devices have a sleep state and an active state.

8. The control system of claim 7, wherein the wireless nodes control whether the field devices associated with them are in the sleep state or the active state.

5. A control system comprising:

a plurality of field devices;

a host computer for sending control messages to and receiving response messages from the field devices;

a plurality of wireless nodes that cycle between a sleep state and an active state according to a wireless network power cycle, at least one of the field devices being associated with each node; and

a gateway between the host computer and the wireless nodes, the gateway providing selected wireless nodes, in response to a message addressed to a selected field device, a command to remain in an extended active state as long as messages are being transmitted between the host computer and the selected field device.

6. The control system of claim 5, wherein the gateway controls cycling of the wireless nodes between the sleep state and the active state.

9. A method of communicating between a host computer and field devices, the method comprising:

delivering a control message addressed to a selected field device from the host computer to a wireless network;

periodically turning on the wireless network to transmit and receive messages;

transmitting a control message to a selected field device over the wireless network to a wireless node associated with the selected field device;

turning on the field device in response to a control message received that is addressed to the selected field device;

generating a response message from the selected field device;

transmitting the response message over the wireless network;

delivering the response message to the host; and

maintaining in an on state those modes of the wireless network required to route messages to and from the selected field device until communication between the host and the selected device field device is completed.

10. A control system comprising:

a plurality of field devices, each field device having a unique field device address;

a host computer for sending messages to and receiving messages from the field devices, each message to one of the field devices including the unique field device address of that field device; and

a wireless network including;

a plurality of wireless nodes, each node having a unique wireless address and including a radio for transmitting and receiving wireless messages, and a wireless device router for routing a received wireless message to a field device based upon the field device address contained in the received wireless message; and

a gateway that interfaces the wireless network with the host computer, the gateway controlling active and inactive states of the wireless network and providing a command that causes selected wireless nodes to remain in an extended active state as long as messages are being transmitted between the host computer and one of the field devices.

11. A method of sending messages between a host and a field device over a wireless network, the method comprising:

generating at the host a message to the field device;

sending the message to the wireless network;

sending a command to the wireless network to cause selected nodes to remain in an extended active state until communication between the host and the field device is complete;

transmitting the message over the wireless network to a node at which the field device is located;

receiving the message at the node; and

delivering the message to the field device.

12. The method of claim 11 and further comprising:

generating a response message by the field device; and

sending the response message through the wireless network to the host.