WIRELESS COMMUNICATION APPARATUS AND METHOD

• US 20080279292A1
• Filed: 03/20/2008
• Published: 11/13/2008
• Est. Priority Date: 05/08/2007
• Status: Abandoned Application

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Egashira, Yoshimasa, Sato, Kazumi, TANABE, Yasuhiko
• Application Number:
  US12/052,012
• Publication Number:
  US 20080279292A1
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04L 25/022 of frequency response
• CPC Class Codes: H04L 25/0226 sounding signals per se
• CPC Class Codes: H04L 27/261 Details of reference signals
• CPC Class Codes: H04L 5/0051 of dedicated pilots, i.e. pilots destined for a single user or terminal

Abstract

The wireless transmission apparatus generates one or a plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols for channel estimation, each OFDM symbol including plural subcarriers and having a known signal sequence of known signals which are linearly independent between adjacent subcarriers, and transmits the OFDM symbols.

Claims

1. A wireless transmission apparatus comprising:

a generating unit configured to generate one or a plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols for channel estimation, each OFDM symbol including plural subcarriers and having a known signal sequence of known signals which are linearly independent between adjacent subcarriers; and

a transmission unit configured to transmit the OFDM symbols.

2. The apparatus according to claim 1, wherein different subcarriers of the plural subcarriers are used to transmit the known signal sequence for the respective OFDM symbols, and subcarriers, of the plural subcarriers, which transmit the known signal sequence of each OFDM symbol are not adjacent to each other.

3. The apparatus according to claim 2, wherein the subcarriers which transmit the known signal sequence of each OFDM symbol are at asymmetrical positions with respect to a center frequency of the plural subcarriers.

4. The apparatus according to claim 2, wherein the known signals included in the known signal sequence are orthogonal to each other between subcarriers at symmetrical positions with respect to a center frequency of the plural subcarriers.

5. The apparatus according to claim 3, wherein a complex conjugate signal of a known signal which is included in the known signal sequence of one of the OFDM symbols and is transmitted with one of two subcarriers at symmetrical positions with respect to the center frequency of the plural subcarriers is identical to a known signal which is included in the known signal sequence of another of the OFDM symbols and is transmitted with the other of the two subcarriers.

6. The apparatus according to claim 2, wherein the subcarriers which transmit the known signal sequence are determined for every M subcarriers, M being a positive integer not less than one.

7. The apparatus according to claim 5, wherein the generating unit includes

a memory to store a time-domain signals of a first OFDM symbol of the OFDM symbols, and

a second symbol generating unit configured to generate a second OFDM symbol of the OFDM symbols by inverting at least one of an in-phase channel signal and a quadrature-phase channel signal of the time-domain signals stored in the memory.

8. A wireless transmission apparatus comprising:

a generating unit configured to generate one or a plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols for channel estimation, each OFDM symbol including plural subcarriers and having a known signal sequence of known signals which are linearly independent among a predetermined specific subcarrier of the plural subcarriers and subcarriers adjacent thereto; and

a transmission unit configured to transmit the OFDM symbols.

9. The apparatus according to claim 8, wherein subcarriers, of the plural subcarriers, which transmit the known signal sequence are not adjacent to the specific subcarrier.

10. The apparatus according to claim 8, wherein a known signal included in the known signal sequence and transmitted with the specific subcarrier, and another known signal included in the known signal sequence and transmitted with a subcarrier adjacent to the specific subcarrier are orthogonal to each other.

11. The apparatus according to claim 9, wherein the subcarriers which transmit the known signal sequence are located in asymmetrical positions with the specific subcarrier with respect to a center frequency of the plural subcarriers.

12. The apparatus according to claim 10, wherein a known signal, which is included in the known signal sequence and is transmitted by a subcarrier at a symmetrical position with the specific subcarrier with respect to a center frequency of the plural subcarriers, is orthogonal to the known signal which is transmitted with the specific subcarrier.

13. A wireless transmission method comprising:

generating one or a plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols for channel estimation, each OFDM symbol including plural subcarriers and having a known signal sequence of known signals which are linearly independent between adjacent subcarriers; and

transmitting the OFDM symbols.

14. The method according to claim 13, wherein different subcarriers of the plural subcarriers are used to transmit the known signal sequence for the respective OFDM symbols, and subcarriers, of the plural subcarriers, which transmit the known signal sequence of each OFDM symbol are not adjacent to each other.

15. The method according to claim 14, wherein the subcarriers which transmit the known signal sequence of each OFDM symbol are located in asymmetrical positions with respect to a center frequency of the plural subcarriers.

16. The method according to claim 14, wherein the known signals included in the known signal sequence are orthogonal to each other between subcarriers at symmetrical positions with respect to a center frequency of the plural subcarriers.

17. The apparatus according to claim 15, wherein a complex conjugate signal of a known signal which is included in the known signal sequence of one of the OFDM symbols and is transmitted with one of two subcarriers at symmetrical positions with respect to the center frequency of the plural subcarriers is identical to a known signal which is included in the known signal sequence of another of the OFDM symbols and is transmitted with the other of the two subcarriers.

18. The method according to claim 14, wherein the subcarriers which transmit the known signal sequence are determined for every M subcarriers, M being a positive integer not less than one.

19. A wireless transmission method comprising:

generating one or a plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols for channel estimation, each OFDM symbol including plural subcarriers and having a known signal sequence of known signals which are linearly independent among a predetermined specific subcarrier of the plural subcarriers and subcarriers adjacent thereto; and

transmitting the OFDM symbols.

20. The method according to claim 19, wherein subcarriers, of the plural subcarriers, which transmit the known signal sequence are not adjacent to the specific subcarrier.

21. The method according to claim 19, wherein a known signal included in the known signal sequence and transmitted with the specific subcarrier and another known signal included in the known signal sequence and transmitted with a subcarrier adjacent to the specific subcarrier are orthogonal to each other.

22. The method according to claim 20, wherein the subcarriers which transmit the known signal sequence are located in asymmetrical positions with the specific subcarrier with respect to a center frequency of the plural subcarriers.

23. The method according to claim 21, wherein a known signal, which is included in the known signal sequence and is transmitted with a subcarrier at a symmetrical position with the specific subcarrier with respect to a center frequency of the plural subcarriers, is orthogonal to the known signal which is transmitted with the specific subcarrier.