Wireless device and wireless system

• US 20110053493A1
• Filed: 05/17/2010
• Published: 03/03/2011
• Est. Priority Date: 08/25/2009
• Status: Active Grant

• Current Assignee: OKI Electric Industry Company Limited
• Original Assignee: OKI Electric Industry Company Limited
• Inventors: Yanagihara, Kentarou
• Granted Patent: US 9,288,837 B2
• Time in Patent Office: Days
• US Class Current: 455/7
• CPC Class Codes: H04W 52/0225 using monitoring of external events, e.g. the presence of a signal
• CPC Class Codes: H04W 84/20 Master-slave selection or change arrangements
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A wireless device operates in a first mode, in which it relays communications between neighboring wireless devices, and a second mode, in which it does not relay communications. The wireless device periodically transmits information indicating its operating mode to the neighboring wireless devices. In the first mode, when not transmitting mode information or communication data, the wireless device stands by with its receiver powered, ready to receive mode information or communication data from neighboring wireless devices. In the second mode, the wireless device is normally in a sleep state and wakes up only at scheduled intervals to transmit and receive mode information and communication data. The wireless device stores the received mode information and selects its operating mode according to the stored mode information, selecting the second mode when this does not prevent the prevent communication with or among the neighboring wireless devices.

Claims

1. A wireless device for use in a wireless communication network including at least one or more neighboring wireless devices with which the wireless device can communicate directly, the wireless device being operable in a first mode and a second mode, the wireless device relaying communications between the neighboring wireless devices in the first mode but not in the second mode, the wireless device comprising:

a power controller for performing power control in the wireless device in different ways, depending on whether or not the wireless device operates in the first mode or the second mode;

a transmitter controlled by the power controller to transmit mode information and data to the neighboring wireless devices, the transmitted mode information indicating whether the wireless device is operating in the first mode or the second mode;

a receiver controlled by the power controller to receive mode information and data from the neighboring wireless devices, the received mode information indicating whether the neighboring wireless devices are operating in the first mode or the second mode;

a storage facility for storing the received mode information; and

a mode controller for deciding whether to have the wireless device operate in the first mode or the second mode, depending at least on the presence of a neighboring wireless device operating in the first mode, as indicated by the stored mode information.

2. The wireless device of claim 1, wherein based on the mode information, the mode controller has the wireless device operate in the first mode when no neighboring device is operating in the first mode.

3. The wireless device of claim 2, wherein the received mode information also indicates the ability of the neighboring wireless devices to communicate with each other, and the mode controller has the wireless device operate in the second mode when the stored mode information indicates that operating in the second mode does not prevent the neighboring wireless devices from communicating with each other and that at least one of the neighboring wireless devices is operating in the first mode.

4. The wireless device of claim 3, wherein the received mode information includes two-hop information listing wireless devices with which the neighboring wireless devices can communicate directly and indicating whether the listed wireless devices are operating in the first mode or the second mode.

5. The wireless device of claim 4, wherein the mode controller has the wireless device operate in the first mode when the stored mode information indicates that some neighboring wireless device operating in the second mode cannot communicate directly with any other wireless device operating in the first mode.

6. The wireless device of claim 4, wherein the mode controller has the wireless device operate in the second mode when the stored mode information indicates that only one neighboring wireless device is operating in the first mode and all neighboring wireless devices operating in the second mode can communicate directly with at least one wireless device, other than the wireless device itself, operating in the first mode.

7. The wireless device of claim 4, wherein the mode controller has the wireless device operate in the first mode when the stored mode information indicates that at least two neighboring wireless devices are operating in the first mode and the stored mode information does not indicate that all the neighboring wireless devices operating in the first mode can communicate with each other without having communications relayed by the wireless device itself.

8. The wireless device of claim 4, wherein the mode controller has the wireless device operate in the second mode when the stored mode information indicates that at least two neighboring wireless devices are operating in the first mode, that all the neighboring wireless devices operating in the first mode can communicate with each other without having communications relayed by the wireless device itself, and that all neighboring wireless devices operating in the second mode can communicate directly with at least one wireless device, other than the wireless device itself, operating in the first mode.

9. The wireless device of claim 1, further comprising a transition request signal transmitter for, when the wireless device is operating in the first mode and the stored mode information indicates that all the neighboring wireless devices operating in the second mode are able to communicate directly with at least one wireless device, other than the wireless device itself, operating in the first mode, transmitting a transition request signal to one of the neighboring wireless devices operating in the second mode to direct the one of the neighboring wireless devices to operate in the first mode.

10. The wireless device of claim 9, wherein the transition request signal transmitter selects a neighboring wireless device able to communicate directly with a largest number of wireless devices operating in the first mode and transmits the transition request signal to the selected neighboring wireless device.

11. The wireless device of claim 9, wherein the receiver also receives transition request signals from the neighboring wireless devices and the mode controller has the wireless device operate in the first mode when a transition request signal is received.

12. The wireless device of claim 1, wherein when the wireless device is operating in the first mode, the power controller powers the transmitter to transmit the mode information at regular intervals, powers the transmitter as necessary to transmit the data, and powers the receiver to stand by to receive whenever the transmitter is not transmitting.

13. The wireless device of claim 12 wherein, when the wireless device is operating in the first mode, the power controller periodically places the wireless device in a sleep state if no communication with any of the neighboring wireless devices takes place for a predetermined time.

14. The wireless device of claim 12 wherein, when the wireless device is operating in the first mode, the power controller periodically places the wireless device in a sleep state if the mode information and data received by the receiver remain unchanged for a predetermined time.

15. The wireless device of claim 1, wherein when the wireless device is operating in the second mode, the power controller powers the transmitter to transmit the mode information and data during scheduled transmission periods, powers the receiver to stand by to receive during scheduled reception periods, and places the wireless device in a sleep state during times other than the scheduled transmission periods and the scheduled reception periods.

16. The wireless device of claim 15, wherein the scheduled reception periods immediately follow the scheduled transmission periods.

17. A wireless system comprising wireless devices as described in claim 1.