TRANSMISSION APPARATUS, TRANSMISSION METHOD, COMMUNICATION SYSTEM, AND COMMUNICATION METHOD

• US 20110305286A1
• Filed: 01/07/2010
• Published: 12/15/2011
• Est. Priority Date: 01/08/2009
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Shimezawa, Kazuyuki, Nogami, Toshizo, Yoshimoto, Takashi, Yamada, Ryota, Kato, Katsuya
• Granted Patent: US 8,693,560 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04L 27/2607 Cyclic extensions
• CPC Class Codes: H04L 27/2646 using feedback from receiver for adjusting OFDM transmission parameters, e.g. transmission timing or guard interval length
• CPC Class Codes: H04L 27/2688 Resistance to perturbation, e.g. noise, interference or fading

Abstract

In a transmission apparatus which multicarrier-modulates and transmits symbols, which are basic units of digital signals, a subcarrier in which a symbol is arranged in a first multicarrier symbol having a first guard interval and a subcarrier in which a symbol is arranged in a second multicarrier symbol having a second guard interval longer than the first guard interval are scattered among a plurality of subcarriers constituting a multicarrier at the same time. Therefore, it is possible to improve the resistance to inter-symbol interference without substantially degrading transmission efficiency.

Claims

1. A transmission apparatus which multicarrier-modulates and transmits symbols, which are basic units of digital signals,

wherein a subcarrier in which a symbol is arranged in a first multicarrier symbol having a first guard interval and a subcarrier in which a symbol is arranged in a second multicarrier symbol having a second guard interval longer than the first guard interval are mapped to part of subcarriers constituting a multicarrier at the same symbol.

2. The transmission apparatus according to claim 1, comprising:

a phase control section which phase-rotates some symbols to which the second guard interval longer than the first guard interval is added, and generates a symbol that is arranged one before in a time direction of the same subcarriers as those of the some symbols and constitutes part of the second guard interval added to the some symbols;

a multiplexing section which multiplexes a symbol to which the first guard interval is added, the symbols to which the second guard interval is added, and the symbol generated by the phase control section in a frequency domain;

an inverse Fourier transform section which performs transformation into a time domain signal by inverse-Fourier-transforming the symbols multiplexed by the multiplexing section; and

a guard interval inserting section which adds a guard interval longer than the first guard interval to the time domain signal into which the transformation is performed by the inverse Fourier transform section,

wherein the first multicarrier symbol and the second multicarrier symbol are generated.

3. The transmission apparatus according to claim 2, wherein the phase control section controls a phase rotation amount when a phase rotation is performed based on a length of the first guard interval.

4. The transmission apparatus according to claim 1, wherein an effective symbol interval of the second multicarrier symbol is consistent with any effective symbol interval of the first multicarrier symbol in a time direction.

5. The transmission apparatus according to claim 1, further comprising:

a symbol storage section which stores the second multicarrier symbol.

6. The transmission apparatus according to claim 1, wherein the second multicarrier symbol is a pilot symbol comprising a pilot signal known between the transmission apparatus and a reception apparatus that communicates therewith.

7. The transmission apparatus according to claim 1, wherein the second multicarrier symbol is a control data symbol comprising a control signal for a reception apparatus that communicates with the transmission apparatus.

8. The transmission apparatus according to claim 1, wherein the first multicarrier symbol is an information data symbol comprising information data for a reception apparatus that communicates with the transmission apparatus.

9. The transmission apparatus according to claim 1, wherein the first multicarrier symbol is an information data symbol comprising information data for a reception apparatus that communicates with the transmission apparatus and a control data symbol comprising a control signal for the reception apparatus that communicates with the transmission apparatus.

10. The transmission apparatus according to claim 9, wherein the first multicarrier symbol, which is the control data symbol, is arranged in a subcarrier adjacent to a subcarrier in which the second multicarrier symbol is arranged.

11. The transmission apparatus according to claim 1, comprising:

a plurality of transmission processing sections each comprising the phase control section, the multiplexing section, the inverse Fourier transform section, and the guard interval inserting section,

wherein the second multicarrier symbol within one transmission processing section is mutually spatially independent of another transmission processing section.

12. The transmission apparatus according to claim 1, comprising:

a first multicarrier symbol generating section which generates the first multicarrier symbol by adding the first guard interval to some symbols;

a second multicarrier symbol generating section which generates the second multicarrier symbol by adding the second guard interval to other symbols; and

a multiplexing section which multiplexes the first multicarrier symbol and the second multicarrier symbol in a time domain.

13. The transmission apparatus according to claim 12, wherein:

the first multicarrier symbol generating section arranges each of the some symbols in any one of regions comprising a time and a frequency having predetermined widths and generates a time domain signal of the first multicarrier symbol to which the first guard interval is added, and

the second multicarrier symbol generating section arranges each of the other symbols in any one of regions, excluding regions where the some symbols are arranged, that comprises a time and a frequency having predetermined widths, and generates a time domain signal of the second multicarrier symbol to which the second guard interval is added.

14. A communication system comprising a transmission apparatus which multicarrier-modulates and transmits symbols, which are basic units of digital signals, and a reception apparatus,

wherein the transmission apparatus transmits a multicarrier signal in which a subcarrier in which a symbol is arranged in a first multicarrier symbol having a first guard interval and a subcarrier in which a symbol is arranged in a second multicarrier symbol having a second guard interval longer than the first guard interval are mapped to part of subcarriers constituting a multicarrier at the same symbol, and

the reception apparatus separates the part of subcarriers by multicarrier-demodulating the multicarrier signal transmitted from the transmission apparatus, and extracts the first multicarrier symbol and the second multicarrier symbol.

15. The communication system according to claim 14, wherein the reception apparatus receives the multicarrier signal transmitted from the transmission apparatus, and

the reception apparatus comprises:

a first guard interval removing section which removes the first guard interval comprised in the received multicarrier signal; and

a second guard interval removing section which removes the second guard interval comprised in the received multicarrier signal.

16. The communication system according to claim 14, wherein the reception apparatus receives the multicarrier signal transmitted from the transmission apparatus, and

the reception apparatus comprises:

a first guard interval removing section which removes the first guard interval comprised in the received multicarrier signal; and

a symbol extracting section which extracts the second multicarrier symbol comprised in the multicarrier signal from the multicarrier signal from which the first guard interval removing section removes the first guard interval.

17. The communication system according to claim 16, wherein an effective symbol interval extracted by the symbol extracting section is an effective symbol interval of the second multicarrier symbol.

18. A transmission method of a transmission apparatus which multicarrier-modulates and transmits symbols, which are basic units of digital signals,

wherein a subcarrier in which a symbol is arranged in a first multicarrier symbol having a first guard interval and a subcarrier in which a symbol is arranged in a second multicarrier symbol having a second guard interval longer than the first guard interval are mapped to part of subcarriers constituting a multicarrier at the same symbol.

19. The transmission method according to claim 18, comprising:

phase-rotating some symbols to which the second guard interval longer than the first guard interval is added, and generating a symbol that is arranged one before in a time direction of the same subcarriers as those of the some symbols and constitutes part of the second guard interval added to the some symbols;

multiplexing the symbol to which the first guard interval is added, the symbols to which the second guard interval is added, and the generated symbol;

performing transformation into a time domain signal by inverse-Fourier-transforming the multiplexed symbols; and

adding a guard interval longer than the first guard interval to the time domain signal into which the transformation is performed,

wherein the first multicarrier symbol and the second multicarrier symbol are generated.

20. The transmission method according to claim 18, which is a transmission method in a transmission apparatus which multicarrier-modulates and transmits symbols, which are basic units of digital signals, the transmission method comprising:

generating, by the transmission apparatus, the first multicarrier symbol by adding the first guard interval to some symbols;

generating, by the transmission apparatus, the second multicarrier symbol by adding the second guard interval to other symbols; and

multiplexing, by the transmission apparatus, the first multicarrier symbol and the second multicarrier symbol in a time domain.

21. A communication method comprising a transmission method of multicarrier-modulating and transmitting symbols, which are basic units of digital signals, and a reception method,

wherein the transmission method comprises transmitting a multicarrier signal in which a subcarrier in which a symbol is arranged in a first multicarrier symbol having a first guard interval and a subcarrier in which a symbol is arranged in a second multicarrier symbol having a second guard interval longer than the first guard interval are mapped to part of subcarriers constituting a multicarrier at the same symbol, and

the reception method comprises separating the part of subcarriers by multicarrier-demodulating the transmitted multicarrier signal, and extracting the first multicarrier symbol and the second multicarrier symbol.

22. The communication method according to claim 21, wherein the reception method comprises receiving the transmitted multicarrier signal, and

the reception method further comprises:

removing the first guard interval comprised in the received multicarrier signal; and

removing the second guard interval comprised in the received multicarrier signal.

23. The communication method according to claim 21, wherein the reception method comprises receiving the transmitted multicarrier signal, and

the reception method further comprises:

removing the first guard interval comprised in the received multicarrier signal; and

extracting the second multicarrier symbol comprised in the multicarrier signal from the multicarrier signal from which the first guard interval was removed.