Radio communication system

• US 7,356,360 B2
• Filed: 02/03/2003
• Issued: 04/08/2008
• Est. Priority Date: 02/05/2002
• Status: Expired due to Fees

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Access Corp. (Honda Motor Company), Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Oishi, Yasuo, Katayama, Mutsumi, Kushida, Kazumitsu
• Primary Examiner(s): Nguyen; Duc M.
• Assistant Examiner(s): Lee; Justin
• Application Number:
  US10/356,712
• Publication Number:
  US 20030220076A1
• Time in Patent Office: 1,891 Days
• Field of Search: 455/91, 455/95, 455/99, 455/102, 455/103, 455/115.2, 455/123, 455/130, 455/127.1, 455/127.5, 455/132, 455/151.2, 455/171.1, 455/181.1, 455/343.5, 455/343.1
• US Class Current: 455/574
• 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 52/0277 according to available power supply, e.g. switching off when a low battery condition is detected
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: H04W 84/20 Master-slave selection or change arrangements
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

The present invention provides a radio communication system in which not only a communication unit operating in a slave mode but also a communication unit operating in a master mode can be changed into a power saving mode.

Among a plurality of communication units, one of them is operating in the master mode while the others are operating in the slave mode. Only the communication units operating in the slave mode are allowed to be changed into a suspend state. The communication unit operating in the master mode stops transmission/reception in synchronization with transition into the stop state of the communication units operating in the slave mode.

Claims

1. A radio communication system comprising:

a plurality of communication units in a radio network, wherein one of the plurality of communication units is a master and operates in a master mode and other communication units are slaves and operate in a slave mode,

wherein a transition into a Sniff mode is allowed during operation in the slave mode,

wherein each of the plurality of communication units includes a battery as driving power,

wherein each slave in the Sniff mode communicates with the master during a Sniff duration in every Sniff period, and each Sniff duration includes two or more Sniff slots,

wherein the communication unit operating in the master mode stops transmission/reception operations in synchronization with all slaves in the Sniff mode which are out of the Sniff duration, and

wherein the Sniff periods of the communication units operating in the slave mode are substantially in synchronization and in phase with each other or out of chase with each other.

2. The radio communication system according to claim 1, wherein the radio network is in an intercommunication system.

3. The radio communication system according to claim 1, wherein the radio network is a Personal Area Network which utilizes Bluetooth.

4. The radio communication system according to claim 1, wherein the communication units operating in the slave mode are all transitioned into the Sniff duration substantially in synchronization with each other.

5. The radio communication system according to claim 1, wherein the Sniff duration of the communication units operating in the slave mode are sequential.

6. The radio communication system according to claim 1, wherein the master mode and the slave mode are switched so as to equalize remaining battery life of the communication units.

7. The radio communication system according to claim 6, wherein

each of the communication units comprises:

means for calculating an operation maintaining time in the master mode,

wherein when the operation maintaining time becomes longer than a predetermined reference time, the master mode and the slave mode are switched between the communication unit operating in the master mode and one of the communication units operating in the slave mode.

8. The radio communication system according to claim 6, wherein

each of the communication units comprises:

means for detecting a remaining battery life; and

means for exchanging information about a detected remaining battery life with other communication units,

wherein the master mode is assigned to a communication unit of which a remaining battery life is relatively high.

9. The radio communication system according to claim 6, wherein

each of the communication units comprises:

means for calculating an operation maintaining estimated time in an actual operation mode; and

means for exchanging information about the operation maintaining estimated time with other communication units,

wherein the master mode is assigned to a communication unit of which an operation maintaining estimated time is relatively long.

10. The radio communication system according to claim 6, wherein

each of the communication units comprises:

means for calculating a cumulative time of operating in a master mode; and

means for exchanging information about the cumulative time with other communication units,

wherein the master mode is assigned to a communication unit of which a cumulative time is relatively short.

11. The radio communication system according to claim 6, wherein

each of the communication units comprises:

means for calculating a cumulative time of operating in a power saving mode; and

means for exchanging information about the cumulative time with other communication units,

wherein the master mode is assigned to a communication unit of which a cumulative time is relatively long.

12. The radio communication system according to claim 6, wherein the battery is a lithium ion battery.

13. A radio communication system comprising:

a plurality of communication units in a radio network, wherein one of the plurality of communication units is a master and operates in a master mode and other communication units are slaves and operate in a slave mode,

wherein a transition into a power saving mode is allowed during operation in the slave mode and a transition into the power saving mode is forbidden during operation in the master mode,

wherein each of the plurality of communication units includes a battery as driving power, wherein each slave in the power saving mode communicates with the master periodically during a communication duration, and

wherein each of the communication units comprises;

means for calculating a cumulative time of operating in the master mode; and

means for exchanging information about the cumulative time with other communication units,

wherein the master mode is assigned to one of the plurality of communication units of which the cumulative time is relatively short,

wherein the communication unit operating in the master mode switches roles with the communication unit having the shortest cumulative time when the cumulative time of the communication unit operating in the master mode is longer than the shortest cumulative time among the exchanged cumulative times by at least a predetermined switching reference time.

14. The radio communication system according to claim 13, wherein the battery is a lithium ion battery.

15. The radio communication system according to claim 13, wherein each of the communication units is in conformity with Bluetooth standards.

16. A radio communication system comprising:

a plurality of communication units in a radio network, wherein one of the plurality of communication units is a master and operates in a master mode and other communication units are slaves and operate in a slave mode,

wherein a transition into a power saving mode is allowed during operation in the slave mode and a transition into the power saving mode is forbidden during operation in the master mode,

wherein each of the plurality of communication units includes a battery as driving power, wherein each slave in the power saving mode communicates with the master periodically during a communication duration, and

wherein each of the communication units comprises;

means for calculating a cumulative time of operating in power saving mode; and

means for exchanging information about the cumulative time with other communication units,

wherein the master mode is assigned to one of the plurality of communication units of which the cumulative time is relatively long

wherein the communication unit operating in the master mode switches roles with the communication unit having the longest cumulative time when the longest cumulative time among the exchanged cumulative times is longer than the cumulative time of the communication unit operating in the master mode by at least a predetermined switching reference time.

17. The radio communication system according to claim 16, wherein the battery is a lithium ion battery.

18. The radio communication system according to claim 16, wherein each of the communication units is in conformity with Bluetooth standards.

19. A radio communication system comprising:

a plurality of communication units in a radio network, wherein one of the plurality of communication units is a master and operates in a master mode and other communication units are slaves and operate in a slave mode,

wherein a transition into a power saving mode is allowed during operation in the slave mode,

wherein each slave in the power saving mode communicates with the master periodically during a communication duration,

wherein the communication unit operating in the master mode stops transmission/reception operations in synchronization with all slaves in the power saving mode which are out of the communication duration, and

wherein each of the communication units comprises;

means for calculating a cumulative time of operating in the power saving mode; and

means for exchanging information about the cumulative time with other communication units, and

wherein the communication unit operating in the master mode switches roles with the communication unit having the longest cumulative time when the longest cumulative time among the exchanged cumulative times is longer than the cumulative time of the communication unit operating in the master mode by at least a predetermined switching reference time.

20. The radio communication system according to claim 19, wherein the battery is a lithium ion battery.

21. The radio communication system according to claim 19, wherein each of the communication units is in conformity with Bluetooth standards.