TO SHORT-RANGE WIRELESS NETWORKS

• US 20120057486A1
• Filed: 02/09/2010
• Published: 03/08/2012
• Est. Priority Date: 03/04/2009
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Abedi, Saied, Chebbo, Hind
• Granted Patent: US 9,736,884 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/0219 where the power saving management affects multiple terminals
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A wireless sensor network of devices including a sensor and a coordinator:

• • the sensor comprising sensing means operable to detect values of a parameter; transmission and reception means for wireless communication with other devices in the network; and sensor control means operable to control a sleep pattern of the sensor; and
  • the coordinator comprising transmission and reception means for wireless communication with other devices in the network; wherein
  • the sensor transmission means is operable to transmit value information as to the parameter values and the coordinator transmission means is operable to transmit an indication of a suitable sensor sleep pattern taking into account the value information.

Claims

1. A wireless sensor network of devices including a sensor and a coordinator:

the sensor comprising sensing means operable to detect values of a parameter;

transmission and reception means for wireless communication with other devices in the network; and

sensor control means operable to control a sleep pattern of the sensor; and

the coordinator comprising transmission and reception means for wireless communication with other devices in the network;

wherein

the sensor transmission means is operable to transmit value information as to the parameter values and the coordinator transmission means is operable to transmit an indication of a suitable sensor sleep pattern taking into account the value information.

2. A network according to claim 1, wherein the sensor is one of a plurality of duty-cycling devices in the network, the coordinator being operable to transmit suitable sleep patterns for each of the duty-cycling devices, and preferably wherein the suitable sleep pattern transmitted to at least one of the duty-cycling devices additionally takes into account at least one external factor not related to that device.

3. A network according to claim 2, wherein one such external factor is based on the value information.

4. A network according to claim 2, wherein the suitable sleep pattern transmitted to the at least one of the duty-cycling devices takes into account as an external factor the number of the other devices in the network in a predefined emergency state.

5. A network according to claim 2, wherein each duty-cycling device has a priority, which determines to what extent, if at all, the coordinator takes any external factors into account to determine its suitable sleep pattern.

6. A network according to claim 2, wherein the coordinator further comprises determining means operable to determine the suitable sleep pattern or wherein the coordinator reception means is operable to receive the suitable sleep pattern from a central monitoring unit, which is in wired or wireless communication with the coordinator.

7. A network according to claim 2, wherein the coordinator transmission means is operable to transmit the indication in at least one control field of a transmission frame, preferably using a value set in the MAC header, such as in the frame control field to a predetermined value.

8. A network according to claim 2, in which a plurality of predefined sleep patterns is provided, the choice of a suitable sleep pattern being determined according to a number of parameter value thresholds, each threshold defining a boundary between a lower wake-up and a higher wake-up sleep pattern.

9. A network according to claim 2, wherein the sensor further comprises a battery and wherein the sensor control means is operable to control the sleep pattern taking into account both the indication and a current battery charge.

10. A sensor according to claim 9, wherein the sensor control means allows or rejects suitable sleep patterns according to at least one predefined limit of acceptable battery charge, and preferably overrides any rejected suitable sleep pattern with a lower wake-up sleep pattern.

11. A network according to claim 9, wherein the sensor transmission means is operable to transmit battery charge information relating to the battery charge, preferably in a control field of a transmission frame in the form of a value set in the MAC header, such as the frame control field to a predetermined value.

12. A network according to claim 11, wherein the coordinator reception means is operable to receive the battery charge information and wherein the coordinator comprises response means operable to respond to a predefined value of charge information by taking action with respect to the battery.

13. A coordinator in a wireless sensor network of devices including a sensor and the coordinator, wherein the coordinator comprises

reception means operable to receive value information from the sensor as to the detected values of a parameter;

determining means operable to determine a suitable sleep pattern for the sensor taking into account the value information; and

transmission means operable to transmit an indication of the suitable sleep pattern.

14. A sensor in a wireless sensor network of devices including the sensor and a coordinator, the sensor comprising:

sensing means operable to detect values of a parameter;

sensor control means operable to control a sleep pattern of the sensor;

transmission means operable to transmit value information as to the parameter values; and

reception means operable to receive an indication of a suitable sensor sleep pattern determined taking into account the value information;

wherein

the sensor control means control the sleep pattern of the sensor taking the suitable sensor sleep pattern into account.

15. A central monitoring unit, which is in wired or wireless communication with a wireless sensor network of devices including a sensor and a coordinator:

the sensor comprising sensing means operable to detect values of a parameter;

transmission and reception means for wireless communication with other devices in the network; and

sensor control means operable to control a sleep pattern of the sensor; and

the coordinator comprising transmission and reception means for wireless communication with other devices in the network;

wherein in use

the sensor transmission means is operable to transmit value information as to the parameter values and the coordinator transmission means is operable to transmit an indication of a suitable sensor sleep pattern taking into account the value information;

the central monitoring unit comprising;

determining means operable to determine a suitable sleep pattern for the sensor taking the value information into account, and communication means operable to send an indication of the suitable sleep pattern to a device of the network.