WIRELESS COMMUNICATION APPARATUS

• US 20090086802A1
• Filed: 03/20/2008
• Published: 04/02/2009
• Est. Priority Date: 09/28/2007
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Nabetani, Toshihisa
• Granted Patent: US 7,957,346 B2
• Time in Patent Office: Days
• US Class Current: 375/225
• CPC Class Codes: H04W 28/20 Negotiating bandwidth
• 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 52/0287 changing the clock frequency of a controller in the equipment
• CPC Class Codes: H04W 74/08 Non-scheduled access, e.g. ALOHA hybrid access H04W74/02
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

According to an aspect of the invention, there is provided a wireless communication apparatus for performing a first wireless communication with a first channel having a first bandwidth, and a second wireless communication with a second channel having a second bandwidth wider than the first bandwidth and having a frequency band covering the first channel, in accordance with CSMA/CA system by carrier sense, including: a predicting unit predicting a first time required until a transmission right for the first wireless communication is captured, and a second time required until a transmission right for the second wireless communication is captured; a judging unit judging that either one communication is recommended based upon the first and second times; and a producing unit producing, when judged that a wireless communication different from a present wireless communication is recommended, a notification frame including information indicative of the recommended wireless communication.

Claims

1. A wireless communication apparatus for performing a first wireless communication with a first channel having a first bandwidth, and a second wireless communication with a second channel having a second bandwidth wider than the first bandwidth and having a frequency band covering the first channel, in accordance with CSMA/CA system by a carrier sense, comprising:

a predicting unit configured to predict a first time required until a transmission right for the first wireless communication is captured, and a second time required until a transmission right for the second wireless communication is captured, respectively;

a judging unit configured to judge that either one of the first wireless communication and the second wireless communication is recommended based upon the first time and the second time which are predicted by the predicting unit; and

a producing unit producing, when the judging unit judges that a wireless communication different from a present wireless communication is recommended, a notification frame including information indicative of the recommended wireless communication, wherein the produced notification frame is transmitted.

2. A wireless communication apparatus according to claim 1, wherein the recommended wireless communication is selected from the first wireless communication and the second wireless communication, and

wherein a data frame to be transmitted is received by the selected wireless communication.

3. A wireless communication apparatus according to claim 1, wherein the predicting unit predicts the first time by a channel utilization ratio in the first channel, and

wherein the predicting unit predicts the second time by a channel utilization ratio in the second channel.

4. A wireless communication apparatus according to claim 3, wherein:

the channel utilization ratio predicted by the predicting unit is calculated based upon a ratio of a time period indicative of “

busy”

within a predetermined time period when a channel is carrier-sensed within the predetermined time period.

5. A wireless communication apparatus according to claim 1, wherein the predicting unit counts time required until a transmission right is captured each time with respect to a transmission performed by the first channel for the first wireless communication within a certain time period, and averages the counted time so as to predict the first time;

and

wherein the predicting unit counts time required until a transmission right are captured each time with respect to a transmission performed by the second channel for the second wireless communication within a certain time period, and averages the counted time so as to predict the second time.

6. A wireless communication apparatus according to claim 1, comprising:

a battery; and

a detecting unit configured to detect a remaining energy amount of the battery

wherein the judging unit judges that either one of the first wireless communication and the second wireless communication is recommended based upon the first time and the second time which are predicted by the predicting unit, and the detected remaining battery energy amount.

7. A wireless communication apparatus according to claim 3, comprising:

a battery; and

a detecting unit configured to detect a remaining energy amount of the battery

wherein the judging unit judges that either one of the first wireless communication and the second wireless communication is recommended based upon the first time and the second time which are predicted by the predicting unit, and the detected remaining battery energy amount.

8. A wireless communication apparatus according to claim 1, wherein the judging unit judges to recommend the first bandwidth is employed in either one among first to third cases,

wherein the first case is that the predicted first time is smaller than a first threshold value, and the predicted second time is larger than a second threshold value,

wherein the second case that a ratio of the predicted second time with respect to the predicted first time is larger than a third threshold value, and

wherein the third case that time obtained by subtracting the predicted first time from the predicted second time is larger than a fourth threshold value.

9. A wireless communication apparatus according to claim 3, wherein the judging unit judges to recommend the first bandwidth is employed in either one among first to third cases,

wherein the first case is that the predicted first time is smaller than a first threshold value, and the predicted second time is larger than a second threshold value,

wherein the second case that a ratio of the predicted second time with respect to the predicted first time is larger than a third threshold value, and

wherein the third case that time obtained by subtracting the predicted first time from the predicted second time is larger than a fourth threshold value.

10. A wireless communication apparatus as claimed in claim 8, wherein, after a notification frame for recommending that the first bandwidth is employed is transmitted with respect to an external communication terminal, the judging unit judges to recommend that the second bandwidth is employed in either one case among first to third cases,

wherein the first case is that the predicted first time is larger than a fifth threshold value, and the predicted second time is smaller than a sixth threshold value,

wherein the second case is that a ratio of the predicted second time with respect to the predicted first time is smaller than a seventh threshold value,

wherein the third case is that time obtained by subtracting the predicted first time from the predicted second time is smaller than an eighth threshold value, and

wherein the notification frame is produced by including information indicative of a wireless communication for recommending that the second bandwidth is employed.

11. A wireless communication apparatus as claimed in claim 9, wherein, after a notification frame for recommending that the first bandwidth is employed is transmitted with respect to an external communication terminal, the judging unit judges to recommend that the second bandwidth is employed in either one case among first to third cases,

wherein the first case is that the predicted first time is larger than a fifth threshold value, and the predicted second time is smaller than a sixth threshold value,

wherein the second case is that a ratio of the predicted second time with respect to the predicted first time is smaller than a seventh threshold value,

wherein the third case is that time obtained by subtracting the predicted first time from the predicted second time is smaller than an eighth threshold value, and

wherein the notification frame is produced by including information indicative of a wireless communication for recommending that the second bandwidth is employed.

12. A wireless communication apparatus as claimed in claim 1, wherein the judging unit judges to recommend that the second bandwidth is employed in either one case among first to third cases,

wherein the first case is that the predicted first time is larger than a fifth threshold value, and the predicted second time is smaller than a sixth threshold value,

wherein the second case is that a ratio of the predicted second time with respect to the predicted first time is smaller than a seventh threshold value,

wherein the third case is that time obtained by subtracting the predicted first time from the predicted second time is smaller than an eighth threshold value, and

wherein the notification frame is produced by including information indicative of a wireless communication for recommending that the second bandwidth is employed.

13. A wireless communication apparatus as claimed in claim 3, wherein the judging unit judges to recommend that the second bandwidth is employed in either one case among first to third cases,

wherein the first case is that the predicted first time is larger than a fifth threshold value, and the predicted second time is smaller than a sixth threshold value,

wherein the second case is that a ratio of the predicted second time with respect to the predicted first time is smaller than a seventh threshold value,

wherein the third case is that time obtained by subtracting the predicted first time from the predicted second time is smaller than an eighth threshold value, and

wherein the notification frame is produced by including information indicative of a wireless communication for recommending that the second bandwidth is employed.

14. A wireless communication apparatus according to claim 10, comprising:

a battery; and

a detecting unit configured to detect a remaining energy amount of the battery; and

wherein, if the remaining battery energy amount detected by the detecting unit is smaller than a first predetermined value, the judging unit sets that the first threshold value is large and the second threshold value is small, or the third threshold value is small, otherwise the fourth threshold value is small, and

wherein, if the remaining battery energy amount detected by the detecting unit is larger than a second predetermined value, the judging unit sets that the fifth threshold value is small and the sixth threshold value is large, or the seventh threshold value is large, otherwise the eighth threshold value is large.

15. A wireless communication apparatus according to claim 11, comprising:

a battery; and

a detecting unit configured to detect a remaining energy amount of the battery; and

wherein, if the remaining battery energy amount detected by the detecting unit is smaller than a first predetermined value, the judging unit sets that the first threshold value is large and the second threshold value is small, or the third threshold value is small, otherwise the fourth threshold value is small, and

wherein, if the remaining battery energy amount detected by the detecting unit is larger than a second predetermined value, the judging unit sets that the fifth threshold value is small and the sixth threshold value is large, or the seventh threshold value is large, otherwise the eighth threshold value is large.