COMMUNICATION APPARATUS, COMMUNICATION METHOD, TERMINAL APPARATUS, AND COMMUNICATION SYSTEM

• US 20120307702A1
• Filed: 12/13/2011
• Published: 12/06/2012
• Est. Priority Date: 12/20/2010
• Status: Active Grant

• Current Assignee: Sovereign Peak Ventures, LLC (Dominion Harbor Enterprises, LLC)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Nakae, Hironori, Ukita, Yosuke, Hayashino, Hiroshi
• Granted Patent: US 8,804,590 B2
• Time in Patent Office: Days
• US Class Current: 370/311
• CPC Class Codes: H04W 28/22 Negotiating communication rate
• CPC Class Codes: H04W 48/12 using downlink control channel
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

Provided is a communication apparatus which allows multi-rate control causing less waste of communication band as compared to conventional, the communication apparatus according to the present invention includes: the wireless communication unit for performing wireless communication with the terminal apparatus; a transfer rate setting unit for setting a transfer rate; a beacon generation unit for generating a beacon which is a first control signal; and a control unit for causing the wireless communication unit to wirelessly transmit, for every predetermined period, the beacon, and, to cause the wireless communication unit to wirelessly transmit the beacon, the control unit causes the transfer rate setting unit to set a transfer rate different from the transfer rate previously used for the wireless transmission of the beacon, and causes the wireless communication unit to transmit the beacon to the terminal apparatus.

Claims

1. A communication apparatus comprising:

a wireless communication unit configured to perform wireless communication with one or more terminal apparatuses;

a transfer rate setting unit configured to set a transfer rate of the wireless communication performed by the wireless communication unit;

a beacon generation unit configured to generate a beacon which is a first control signal to be transmitted by the wireless communication unit; and

a control unit configured to cause the wireless communication unit to wirelessly transmit, for every predetermined period, the beacon generated by the beacon generation unit,

wherein when causing the wireless communication unit to wirelessly transmit the beacon, the control unit is configured to cause the transfer rate setting unit to set the transfer rate different from a transfer rate previously used for wirelessly transmitting the beacon and cause the wireless communication unit to transmit the beacon to the one or more terminal apparatuses.

2. The communication apparatus according to claim 1,

wherein the beacon includes a first period, a second period, a first transfer rate which is the transfer rate in association with the first period, and a second transfer rate which is the transfer rate in association with the second period and different from the first transfer rate, and

the control unit is configured to

cause the transfer rate setting unit to set the transfer rate to the first transfer rate when causing the wireless communication unit to wirelessly transmit the beacon in the first period, and

cause the transfer rate setting unit to set the transfer rate to the second transfer rate when causing the wireless communication unit to wirelessly transmit the beacon in the second period.

3. The communication apparatus according to claim 2,

wherein the beacon further includes a first time which is a time within the first period, and

if an error rate which is a value corresponding to the number of times for which the wireless communication unit has failed to wirelessly receive a data signal is greater than or equal to a predetermined first threshold value at the first time, the control unit is configured to (A) cause the transfer rate setting unit to set the transfer rate to the second transfer rate and (B) cause the wireless communication unit to wirelessly transmit, to all the one or more terminal apparatuses, a second control signal for setting a transfer rate of the one or more terminal apparatuses to the second transfer rate.

4. The communication apparatus according to claim 3,

wherein the beacon further includes a second time which is a time within the first period and later than the first time, and

when the error rate is less than the predetermined first threshold value at the first time and if the error rate is greater than or equal to a predetermined second threshold value at the second time, the control unit is configured to cause the transfer rate setting unit to set the transfer rate to the second transfer rate and cause the wireless communication unit to wirelessly transmit, to all the one or more terminal apparatuses, the second control signal for setting the transfer rate of the one or more terminal apparatuses to the second transfer rate.

5. The communication apparatus according to claim 3,

wherein the control unit is configured to transmit a data signal the earlier in time to one of the one or more terminal apparatuses the data signal transmitted from which has the larger received power when received by the wireless communication unit.

6. The communication apparatus according to claim 2,

wherein the beacon further includes a first time which is a time within the first period,

if an error rate which is a value corresponding to the number of times for which the wireless communication unit has failed to wirelessly receive a data signal is greater than or equal to a predetermined first threshold value at the first time, the control unit is configured to cause the wireless communication unit to wirelessly transmit, to all the one or more terminal apparatuses, a second control signal which includes a second time and is a control signal for keeping a transfer rate of the one or more terminal apparatuses at the first transfer rate until the second time which is a time within the second period, and

the first transfer rate has a smaller value of the transfer rate than the second transfer rate.

7. The communication apparatus according to claim 2,

wherein the control unit is configured to cause the beacon generation unit to generate the beacon such that, among a total number of terminal apparatuses, the smaller the number of terminal apparatuses that receive the beacon wirelessly transmitted at the first transfer rate is relative to the number of terminal apparatuses that receive the beacon wirelessly transmitted at the second transfer rate, the shorter the first period is relative to the second period.

8. The communication apparatus according to claim 2,

wherein the control unit is configured to cause the beacon generation unit to generate the beacon such that (A) among a total number of terminal apparatuses, the smaller the number of terminal apparatuses that receive the beacon wirelessly transmitted at the first transfer rate is relative to the number of terminal apparatuses that receive the beacon wirelessly transmitted at the second transfer rate and (B) the higher the first transfer rate is relative to the second transfer rate, the shorter the first period is relative to the second period.

9. The communication apparatus according to claim 1,

wherein the beacon includes a first period in association with a first transfer rate and a second period in association with a second transfer rate lower than the first transfer rate, and

when the wireless communication unit fails to wirelessly transmit a data signal at the first transfer rate in the first period, the control unit is configured to cause the wireless communication unit to retransmit the data signal at the second transfer rate in the second period.

10. The communication apparatus according to claim 1,

wherein the beacon includes a first period, a second period, a third period, a first transfer rate which is the transfer rate in association with the first period, a second transfer rate which is the transfer rate in association with the second period and different from the first transfer rate, and a third transfer rate which is the transfer rate in association with the third period and different from the first transfer rate and the second transfer rate, and

the control unit is configured to

cause the transfer rate setting unit to set the transfer rate to the first transfer rate to cause the wireless communication unit to wirelessly transmit the beacon in the first period,

cause the transfer rate setting unit to set the transfer rate to the second transfer rate to cause the wireless communication unit to wirelessly transmit the beacon in the second period, and

cause the transfer rate setting unit to set the transfer rate to the third transfer rate to cause the wireless communication unit to wirelessly transmit the beacon in the third period.

19. A communication system comprising

the communication apparatus according to claim 1 and a terminal apparatus having a wireless communication unit,

wherein the wireless communication unit included in the terminal apparatus is configured to receive, among beacons, a beacon that is transmitted from the communication apparatus at a transfer rate receivable by the wireless communication unit of the terminal apparatus.

11. A terminal apparatus comprising:

a wireless communication unit which can perform wireless communication at a transfer rate selected from among a plurality of transfer rates;

a transfer rate setting unit configured to set a transfer rate which is used by the wireless communication unit for the wireless communication; and

a control unit configured to cause the transfer rate setting unit to set the transfer rate, based on a beacon which is a first control signal received by the wireless communication unit,

wherein the beacon includes a first period, a second period, a first transfer rate which is the transfer rate in association with the first period, and a second transfer rate which is the transfer rate in association with the second period, and

the control unit is configured to cause the transfer rate setting unit to set the transfer rate to the first transfer rate in the first period, and cause the transfer rate setting unit to set the transfer rate to the second transfer rate in the second period.

12. The terminal apparatus according to claim 11,

wherein the beacon further includes a first time which is a time within the first period, and

the control unit is configured

to cause the transfer rate setting unit to set, at the first time, the transfer rate to the second transfer rate, and determines whether the wireless communication unit has received a second control signal at the second transfer rate,

to cause the transfer rate setting unit to set the transfer rate to the first transfer rate when the second control signal has not been received, and

not to cause the transfer rate setting unit to change the transfer rate when the second control signal has been received.

13. The terminal apparatus according to claim 11,

wherein when the wireless communication unit fails to wirelessly transmit a data signal at the first transfer rate greater than or equal to a predetermined number of times in the first period, the control unit is configured to cause the wireless communication unit to retransmit, in the second period, the data signal at the second transfer rate.

14. The terminal apparatus according to claim 11,

wherein prior to causing the wireless communication unit to perform wireless transmission, the control unit is configured to perform carrier sensing which is a process of determining whether other terminal apparatus is performing wireless transmission, and if it is determined that no other terminal apparatus is performing the wireless transmission, the control unit is configured to determine a backoff time, which is a wait time until when the control unit causes the wireless communication unit to perform the wireless transmission after the carrier sensing is performed, such that the smaller received power of the beacon is, the longer the backoff time is, and after the backoff time is passed, the control unit is configured to cause the wireless communication unit to perform the wireless transmission.

15. A communication method comprising:

generating a beacon which is a control signal;

instructing a wireless communication unit to wirelessly transmit the generated beacon for every predetermined period; and

setting a transfer rate, which is used by the wireless communication unit for wirelessly transmitting the beacon, to a transfer rate different from a transfer rate previously used for wirelessly transmitting the beacon,

wherein the wireless communication unit is configured to wirelessly transmit the beacon.

17. A non-transitory computer-readable recording medium having recorded therein a computer to execute the communication method according to claim 15.

16. (canceled)

18. An integrated circuit comprising:

a wireless communication unit configured to perform wireless communication with one or more terminal apparatuses;

a transfer rate setting unit configured to set a transfer rate of the wireless communication performed by the wireless communication unit;

a beacon generation unit configured to generate a beacon which is a first control signal to be transmitted from the wireless communication unit; and

a control unit configured to cause the wireless communication unit to wirelessly transmit, for every predetermined period, the beacon generated by the beacon generation unit,

wherein when causing the wireless communication unit to wirelessly transmit the beacon, the control unit is configured to cause the transfer rate setting unit to set a transfer rate different from a transfer rate previously used for wirelessly transmitting the beacon, and cause the wireless communication unit to transmit the beacon to the one or more terminal apparatuses.