Electronic apparatus and method

1. An electronic apparatus comprising:

a transmitter to transmit a signal to a first electronic apparatus with one of patterns including at least a first pattern which is a first order and which uses first to n-th frequency bands in first to n-th periods and a second pattern which is a second order different from the first order and which uses the first to n-th frequency bands in the first to n-th periods, where n is an integer greater than or equal to two;

a processor configured to switch a pattern to be used among the patterns in accordance with a communication situation; and

a receiver to receive a signal from the first electronic apparatus at the same frequency band as one of the first to n-th frequency bands used at the time the signal was last transmitted to the first electronic apparatus,

wherein the transmitter:

transmits a first signal to the first electronic apparatus at a first frequency band,

transmits the first signal to the first electronic apparatus at a second frequency band when a second signal is not received from the first electronic apparatus at the first frequency band after the first signal is transmitted at the first frequency band, and

transmits the first signal to the first electronic apparatus at a third frequency band when a third signal is not received from the first electronic apparatus at the second frequency band after the first signal is transmitted at the second frequency band.

2. The electronic apparatus of claim 1 , wherein the processor is configured to determine the patterns using a first method for periodically changing a frequency band.

3. The electronic apparatus of claim 2 , wherein the processor is configured to determine each of the patterns using the first method with a parameter which is randomly determined.

4. The electronic apparatus of claim 2 , wherein the first method is frequency hopping.

5. The electronic apparatus of claim 1 , wherein the processor is configured to switch the pattern to be used among the patterns by canceling connection with the first electronic apparatus and establishing connection with the first electronic apparatus in accordance with the communication situation.

6. The electronic apparatus of claim 1 , wherein the processor is configured to switch the pattern to be used among the patterns by restarting at least one of the transmitter and the receiver in accordance with the communication situation.

7. The electronic apparatus of claim 1 , wherein the transmitter transmits, when the first signal transmitted with the first pattern did not reach the first electronic apparatus for more than a first time, the first signal with the second pattern.

8. The electronic apparatus of claim 7 , wherein the transmitter:

transmits the first signal to the first electronic apparatus at the first frequency band,

transmits the first signal to the first electronic apparatus at the second frequency band when the second signal is not received from the first electronic apparatus at the first frequency band after elapse of a second time from the transmission of the first signal at the first frequency band, and

transmits the first signal to the first electronic apparatus at the third frequency band when the third signal is not received from the first electronic apparatus at the second frequency band after elapse of the second time from the transmission of the first signal at the second frequency band.

9. The electronic apparatus of claim 8 , wherein the first time is an integral multiple of the second time.

10. The electronic apparatus of claim 2 , further comprising a first synchronization unit configured to synchronize the electronic apparatus and a second electronic apparatus which transmits a signal with a pattern determined using the first method.

11. The electronic apparatus of claim 10 , wherein the first synchronization unit is configured to use a crystal oscillator connected to the electronic apparatus and the second electronic apparatus with cables for synchronizing the electronic apparatus and the second electronic apparatus, or transmit a synchronous signal to the second electronic apparatus for synchronizing the electronic apparatus and the second electronic apparatus.

12. The electronic apparatus of claim 10 , wherein the transmitter transmits a signal to the first electronic apparatus at a time point determined by the first synchronization unit.

13. The electronic apparatus of claim 10 , further comprising a second synchronization unit configured to synchronize the first electronic apparatus and the electronic apparatus.

14. The electronic apparatus of claim 13 , wherein the second synchronization unit is configured to transmit a synchronous signal to the first electronic apparatus for synchronizing the first electronic apparatus and the electronic apparatus.

15. The electronic apparatus of claim 13 , wherein the receiver receives a signal transmitted from the first electronic apparatus at a time point determined by the second synchronization unit.

16. A method comprising:

transmitting a signal to a first electronic apparatus with one of patterns including at least a first pattern which is a first order and which uses first to n-th frequency bands in first to n-th periods and a second pattern which is a second order different from the first order and which uses the first to n-th frequency bands in the first to n-th periods, where n is an integer greater than or equal to two;

switching a pattern to be used among the patterns in accordance with a communication situation; and

receiving a signal from the first electronic apparatus at the same frequency band as one of the first to n-th frequency bands used at the time the signal was last transmitted to the first electronic apparatus,

wherein the transmitting comprises:

transmitting a first signal to the first electronic apparatus at a first frequency band,

transmitting the first signal to the first electronic apparatus at a second frequency band when a second signal is not received from the first electronic apparatus at the first frequency band after the first signal is transmitted at the first frequency band, and

transmitting the first signal to the first electronic apparatus at a third frequency band when a third signal is not received from the first electronic apparatus at the second frequency band after the first signal is transmitted at the second frequency band.

17. An electronic apparatus comprising:

a transmitter to transmit a signal to a first electronic apparatus with one of patterns including at least a first pattern which is a first order and which uses first to n-th frequency bands in first to n-th periods and a second pattern which is a second order different from the first order and which uses the first to n-th frequency bands in the first to n-th periods, where n is an integer greater than or equal to two;

a processor configured to switch a pattern to be used among the patterns in accordance with a communication situation; and

a receiver to receive a signal from the first electronic apparatus at the same frequency band as one of the first to n-th frequency bands used at the time the signal was last transmitted to the first electronic apparatus,

wherein the transmitter transmits a first signal to the first electronic apparatus with a third pattern which is a third order different from the first order and the second order and which uses the first to n-th frequency bands in the first to n-th periods when the first signal transmitted with the second pattern did not reach the first electronic apparatus for more than a first time.

18. A method comprising:

transmitting a signal to a first electronic apparatus with one of patterns including at least a first pattern which is a first order and which uses first to n-th frequency bands in first to n-th periods and a second pattern which is a second order different from the first order and which uses the first to n-th frequency bands in the first to n-th periods, where n is an integer greater than or equal to two;

switching a pattern to be used among the patterns in accordance with a communication situation; and

receiving a signal from the first electronic apparatus at the same frequency band as one of the first to n-th frequency bands used at the time the signal was last transmitted to the first electronic apparatus,

wherein the transmitting comprises transmitting a first signal to the first electronic apparatus with a third pattern which is a third order different from the first order and the second order and which uses the first to n-th frequency bands in the first to n-th periods when the first signal transmitted with the second pattern did not reach the first electronic apparatus for more than a first time.