Data communication device, data communication method and program thereof

1. A communication device, comprising:

a communication unit including plural function operation units performing communication with an external device at plural prescribed communication speeds, the plural prescribed communication speeds corresponding to data transfer rates of a wireless local area network; and

a control unit configured to,

allow the communication unit to receive a content data from the external device,

estimate an optimum prescribed communication speed in which a power consumption amount becomes smallest from the plural prescribed communication speeds based on a bit rate of the content data, one of the plural prescribed communication speeds, and an actual communication speed calculated during the receiving of the content data, the bit rate corresponding to a compression rate of the content data, and the content data including at least one of audio and video multimedia content,

select a given function operation unit from the plural function operation units based on the estimated optimum communication speed,

allow the selected function operation unit to receive the content data at the estimated prescribed communication speed, and

control power consumption to the function operation units other than the function operation unit selected from the plural function operation units to be less than a fixed value.

2. The communication device according to claim 1 ,

wherein the control unit allows the function operation unit to transmit an affirmative response indicating a normal reception of the content data to the external device at the optimum prescribed communication speed.

3. The communication device according to claim 1 ,

wherein the control unit allows the selected function operation unit to transmit an affirmative response indicating a normal reception of content data to the external device when the selected function operation unit receives the content data from the external device at the optimum prescribed communication speed.

4. The communication device according to claim 1 ,

wherein the control unit detects occurrence of collisions in communication by the communication unit, and when it is determined that the occurrence frequency of collisions increased, allows the communication unit to receive content data at prescribed communication speed higher than the estimated optimum prescribed communication speed.

5. The communication device according to claim 1 , further comprising:

a battery; and

wherein the control unit supplies electric power from the battery to function operation units in the communication unit.

6. The communication unit according to claim 1 ,

wherein the communication unit is a wireless communication unit.

7. The communication method according to claim 1 ,

wherein the step of transmitting the affirmative response allows the selected function operation unit to transmit the affirmative response indicating a normal reception of content data to the external device when the selected function operation unit receives the content data from the external device at the optimum prescribed communication speed.

8. The communication device according to claim 1 , wherein

the control unit is further configured to switch off electric power to the function operation units other than the function operation unit selected, and

the function operation units include modulation/demodulation circuits.

9. The communication device according to claim 1 , wherein the control unit is further configured to allow the communication unit to receive list information of a plurality of available content data from the external device before receiving the content data, the list information including information of a bit rate of each of the plurality of available content data.

10. The communication device according to claim 1 , wherein the communication unit including the plural function operation units perform communication with the external device through the wireless local area network.

11. The communication device according to claim 1 , further comprising:

a storage unit configured to store, in an associated relationship in a table, the plural prescribed communication speeds, values of power consumption in transmission, values of power consumption in reception, values of standard communication time, and values of retry occurrence probability.

12. A communication method, comprising the steps of:

allowing a communication unit having plural function operation units performing communication at plural prescribed communication speeds to receive a content data from an external device, the plural prescribed communication speeds corresponding to data transfer rates of a wireless local area network;

estimating an optimum prescribed communication speed in which a power consumption amount becomes smallest from the plural prescribed communication speeds based on a bit rate of the content data, one of the plural prescribed communication speeds, and an actual communication speed calculated during the receiving of the content data, the bit rate corresponding to a compression rate of the content data, and the content data including at least one of audio and video multimedia content;

selecting a given function operation unit in the plural function operation units based on the estimated optimum prescribed communication speed;

allowing the selected function operation unit to receive the content data at the estimated prescribed communication speed; and

controlling power consumption to the function operation units other than the selected function operation unit from the plural function operation units to be less than a fixed value.

13. The communication method according to claim 12 , further comprising the step of:

allowing the function operation unit to transmit an affirmative response indicating a normal reception of the content data to the external device at the optimum prescribed communication speed.

14. The communication method according to claim 12 , further comprising the steps of:

detecting occurrence of collisions in communication by the communication unit; and

allowing the communication unit to receive content data at prescribed communication speed which is higher than the estimated optimum prescribed communication speed when it is determined that the occurrence frequency of collisions increased.

15. The communication method according to claim 12 , further comprising the step of:

supplying electric power from a battery to the function operation units in the communication unit.

16. The communication method according to claim 12 ,

wherein the communication unit is a wireless communication unit.

17. A non-transitory recording medium having computer executable instructions recorded thereon, wherein the instructions, when executed by a computer, cause the computer to perform a method comprising:

allowing a communication unit having plural function operation units performing communication at plural prescribed communication speeds to receive a content data from an external device, the plural prescribed communication speeds corresponding to data transfer rates of a wireless local area network;

estimating an optimum prescribed communication speed in which a power consumption amount becomes smallest from the plural prescribed communication speeds based on a bit rate of the content data, one of the plural prescribed communication speeds, and an actual communication speed calculated during the receiving of the content data, the bit rate corresponding to a compression rate of the content data, and the content data including at least one of audio and video multimedia content;

selecting a given function operation unit from the plural function operation units based on the estimated optimum prescribed communication speed;

allowing the selected function operation unit to receive the content data at the estimated prescribed communication speed; and

controlling power consumption to the function operation units other than the selected function operation unit from the plural function operation units to be less than a fixed value.

18. The recording medium according to claim 17 ,

further comprising:

allowing the function operation unit to transmit an affirmative response indicating a normal reception of the content data to the external device at the optimum prescribed communication speed.

19. The recording medium according to claim 17 ,

wherein the step of transmitting the affirmative response allows the selected function operation unit to transmit the affirmative response indicating a normal reception of content data to the external device when the selected function operation unit receives the content data from the external device at the optimum prescribed communication speed.

20. The recording medium according to claim 17 ,

further comprising:

detecting occurrence of collisions in communication by the communication unit; and

allowing the communication unit to receive content data at prescribed communication speed which is higher than the estimated optimum prescribed communication speed when it is determined that the occurrence frequency of collisions increased.

21. The recording medium according to claim 17 ,

further comprising:

supplying electric power from a battery to the function operation units in the communication unit.

22. The recording medium according to claim 17 ,

wherein the communication unit is a wireless communication unit.