COMMUNICATION APPARATUS, COMMUNICATION METHOD AND COMMUNICATION SYSTEM

• US 20160211953A1
• Filed: 01/13/2016
• Published: 07/21/2016
• Est. Priority Date: 01/15/2015
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Iizuka, Shunsuke, Ezaki, Takato, Jitsukawa, Daisuke
• Granted Patent: US 10,148,471 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04L 27/0014 Carrier regulation of chaotic carriers H04L27/001; for multicarrier receivers H04L27/2657
• CPC Class Codes: H04L 27/06 Demodulator circuits; Receiver circuits
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver

Abstract

A communication apparatus includes a memory, and a processor coupled to the memory and configured to receive a first reception signal and a second reception signal in a first period, calculate a first phase rotation quantity between the first reception signal and the second reception signal, receive a third reception signal and a fourth reception signal in a second period, calculate a second phase rotation quantity between the third reception signal and the fourth reception signal, determine whether to compensate for a frequency offset of a fifth reception signal based on a difference between the first phase rotation quantity and the second phase rotation quantity, and when it is determined to compensate for the frequency offset of the fifth reception signal, compensate for the frequency offset of the fifth reception signal.

Claims

1. A communication apparatus comprising:

a memory; and

a processor coupled to the memory and configured to;

receive a first reception signal and a second reception signal in a first period,

calculate a first phase rotation quantity between the first reception signal and the second reception signal,

receive a third reception signal and a fourth reception signal in a second period,

calculate a second phase rotation quantity between the third reception signal and the fourth reception signal,

determine whether to compensate for a frequency offset in a fifth reception signal based on a difference between the first phase rotation quantity and the second phase rotation quantity, and

when it is determined to compensate for the frequency offset in the fifth reception signal, compensate for the frequency offset in the fifth reception signal.

2. The communication apparatus according to claim 1, wherein the processor is further configured not to compensate for the frequency offset of the fifth reception signal when the difference is equal to or more than a certain value, and to compensate for the frequency offset in the fifth reception signal using the first phase rotation quantity and the second phase rotation quantity when the difference is less than the certain value.

3. The communication apparatus according to claim 2, wherein the processor is further configured to:

calculate an average phase rotation quantity by averaging the first phase rotation quantity and the second phase rotation quantity, and

add a correction phase rotation quantity, the correction phase rotation quantity being a substantially same quantity as the average phase rotation quantity and having a direction opposite to a direction of the average phase rotation quantity to the fifth reception signal.

4. The communication apparatus according to claim 1, further comprising:

a first reception antenna; and

a second reception antenna,

wherein the processor is configured to;

calculate the first phase rotation quantity by averaging a third phase rotation quantity between the first reception signal and the second reception signal received in the first period using the first reception antenna and a fourth phase rotation quantity between the first reception signal and the second reception signal received in the first period using the second reception antenna, and

calculate the second phase rotation quantity by averaging a fifth phase rotation quantity between the third reception signal and the fourth reception signal received in the second period using the first reception antenna and a sixth phase rotation quantity between the third reception signal and the fourth reception signal received in the second period using the second reception antenna.

5. The communication apparatus according to claim 1, wherein the processor is further configured to:

calculate the first phase rotation quantity by correlation based on the first reception signal and the second reception signal, and

calculate the second phase rotation quantity by correlation based on the third reception signal and the fourth reception signal.

6. The communication apparatus according to claim 1, wherein the processor is further configured to determine whether to compensate for the frequency offset in the fifth reception signal based on a ratio of the difference between the first phase rotation quantity and the second phase rotation quantity to amplitudes of the first phase rotation quantity and the second phase rotation quantity.

7. The communication apparatus according to claim 1, wherein the first reception signal, the second reception signal, the third reception signal, and the fourth reception signal respectively include a known first signal sequence, a known second signal sequence, a known third signal sequence, and a known fourth signal sequence received from the other communication apparatus.

8. The communication apparatus according to claim 7, wherein the processor is further configured to:

remove the known first signal sequence from the first reception signal,

remove the known second signal sequence from the second reception signal,

remove the known third signal sequence from the third reception signal, and

remove the known fourth signal sequence from the fourth reception signal.

9. The communication apparatus according to claim 1, wherein the first reception signal, the second reception signal, the third reception signal, and the fourth reception signal individually include a reference signal, respectively, and the fifth reception signal comprises a data signal.

10. The communication apparatus according to claim 1, wherein the communication apparatus comprises a base station apparatus or a terminal apparatus.

18. The communication apparatus according to claim 1, wherein the second period is configured to immediately follows the first period, the first and second periods comprising a subframe in accordance with a telecommunication standard.

19. The communication apparatus according to claim 18,

wherein the telecommunication standard comprises a long term evolution (LTE) or LTE-Advanced (LTE-A), and

wherein the first period and the second period are each configured to include seven orthogonal frequency division multiplexing (OFDM) symbols.

11. A communication method comprising:

receiving a first reception signal and a second reception signal in a first period;

calculating a first phase rotation quantity between the first reception signal and the second reception signal;

receiving a third reception signal and a fourth reception signal in a second period;

calculating a second phase rotation quantity between the third reception signal and the fourth reception signal;

determining whether to compensate for a frequency offset in a fifth reception signal based on a difference between the first phase rotation quantity and the second phase rotation quantity; and

when it is determined to compensate for the frequency offset in the fifth reception signal, compensating for the frequency offset in the fifth reception signal.

12. The communication method according to claim 11, the communication method further comprising:

when the difference is equal to or greater than a certain value, not compensating for the frequency offset in the fifth reception signal using the first phase rotation quantity and the second phase rotation quantity, and

when the difference is less than the certain value, compensating for the frequency offset in the fifth reception signal using the first phase rotation quantity and the second phase rotation quantity.

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

calculating an average phase rotation quantity by averaging the first phase rotation quantity and the second phase rotation quantity; and

adding a correction phase rotation quantity, the correction phase rotation quantity being substantially same quantity as the average phase rotation quantity and having a direction opposite to a direction of the average phase rotation quantity to the fifth reception signal.

14. The communication method according to claim 11, wherein the communication method is executed by a communication apparatus including a first reception antenna and a second reception antenna, and

the communication method further comprising:

calculating the first phase rotation quantity by averaging a third phase rotation quantity between the first reception signal and the second reception signal received in the first period using the first reception antenna and a fourth phase rotation quantity between the first reception signal and the second reception signal received in the first period using the second reception antenna; and

calculating the second phase rotation quantity by averaging a fifth phase rotation quantity between the third reception signal and the fourth reception signal received in the second period using the first reception antenna and a sixth phase rotation quantity between the third reception signal and the fourth reception signal received in the second period using the second reception antenna.

15. The communication method according to claim 11, the communication method further comprising:

calculating the first phase rotation quantity by correlation based on the first reception signal and the second reception signal; and

calculating the second phase rotation quantity by correlation based on the third reception signal and the fourth reception signal.

16. The communication method according to claim 11, the communication method further comprising:

determining whether to compensate for the frequency offset in the fifth reception signal based on a ratio of the difference between the first phase rotation quantity and the second phase rotation quantity to amplitudes of the first phase rotation quantity and the second phase rotation quantity.

17. The communication method according to claim 11, wherein the communication first reception signal, the second reception signal, the third reception signal, and the fourth reception signal respectively include a known first signal sequence, a known second signal sequence, a known third signal sequence, and a known fourth signal sequence received from the other communication method.

20. A communication system comprising:

a terminal device; and

a base station device including a memory and a processor coupled to the memory, wherein the processor is configured to;

receive a first reception signal and a second reception signal from the terminal device in a first period of time,

calculate a first phase rotation quantity between the first reception signal and the second reception signal,

receive a third reception signal and a fourth reception signal from the terminal device in a second period of time,

calculate a second phase rotation quantity between the third reception signal and the fourth reception signal,

determine whether to compensate for a frequency offset in a fifth reception signal based on a difference between the first phase rotation quantity and the second phase rotation quantity, and

when it is determined to compensate for the frequency offset in the fifth reception signal, compensate for the frequency offset in the fifth reception signal.

21. The communication system according to claim 20, wherein the communication system comprises a long term evolution (LTE) system or a LTE-Advanced (LTE-A) system.