OPEN-LOOP TRANSMIT DIVERSITY SCHEMES WITH FOUR TRANSMIT ANTENNAS

• US 20090202016A1
• Filed: 02/04/2009
• Published: 08/13/2009
• Est. Priority Date: 02/08/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Seong, Kibeom, Luo, Tao
• Granted Patent: US 8,509,291 B2
• Time in Patent Office: Days
• US Class Current: 375/267
• CPC Class Codes: H04B 7/0426 Power distribution
• CPC Class Codes: H04B 7/068 using space frequency diversity space-frequency coding H04L1/0606
• CPC Class Codes: H04B 7/0686 Hybrid systems, i.e. switching and simultaneous transmission
• CPC Class Codes: H04L 1/0606 Space-frequency coding
• CPC Class Codes: H04L 1/0631 Receiver arrangements

Abstract

In a wireless communication system, SFBC-based (Space-Frequency Block-Code) transmission diversity schemes provide enhancement for multiple antennas, such as the illustrative four, in order to achieve better performance than SFBC-FSTD (SFBC-Frequency Switching Transmit Diversity) alone. SFBC-PFSTD (Precoded Frequency Switching Transmit), which is multiplying a precoding matrix to the SFBC-FSTD signals, opens up the possibility of utilizing the pilot tones in synchronization channels (SSC and/or PSC) to enhance the channel estimation performance for antenna 2 and 3 that have only the half as many pilot tones as antenna 0 and 1. Further improvements are disclosed for use of Frequency Time Switching Transmit Diversity (FTSTD) and Precoding Vector Switch.

Claims

1. A method for receiving a physical broadcast channel (PBCH), comprising:

receiving a physical broadcast channel (PBCH) transmitted by Space Frequency Block Code (SFBC) from a plurality of transmit antennas assigned a different density of pilot tones; and

decoding the SFBC-based PBCH by detecting the different density of pilot tones from each respective transmit antenna that are transmitted at a transmit power for each transmit antenna corresponding to the density.

2. The method of claim 1, further comprising receiving a diversified portion of the SFB-based PBCH transmitted at a transmit gain inversely adjusted per the density of pilot tones to match a total transmit power for another transmit antenna having a different density of pilot tones.

3. The method of claim 2, further comprising performing SFBC-Frequency Switching Transmit Diversity (FSTD) on a pair of two receive antennas from four transmit antennas by,

receiving a first pair of diversified signals from a first and third transmit antenna, wherein the third transmit antenna transmits half of a number of pilot tones as the first antenna transmitted at twice the power;

subsequently receiving a second pair of diversified signals from a second and fourth transmit antenna, wherein the fourth transmit antenna transmits half of a number of pilot tones as the second antenna transmitted at twice the power; and

decoding the received pairs of diversified signals by use of a mapping matrix for FSTD.

4. The method of claim 3, further comprising decoding the received pairs of diversified signals by use of a mapping matrix for Frequency Time Switching Transmit Diversity (FTSTD).

5. The method of claim 1, further comprising decoding the SFBC-based PBCH by detecting the different density of pilot tones from each respective transmit antenna that are transmitted at an increased transmit power for each transmit antenna by detecting pilot tones of a synchronization channel and the SFBC-based PBCH.

6. The method of claim 5, further comprising:

accessing a precoding matrix for the synchronization channel; and

decoding the pilot tones for both the synchronization channel and the SFBC-based PBCH using the precoding matrix.

7. The method of claim 5, further comprising decoding pilot tones from a primary synchronization channel, a secondary synchronization channel, and the SFBC-based PBCH.

8. The method of claim 5, further comprising performing SFBC-PVS (Precoded Vector Switch) on a pair of two receive antennas from four transmit antennas by,

decoding pilot tones of a PBCH precoded by a precoding matrix used by a synchronization channel;

and

decoding pilot tones of the synchronization channel by use of the precoding matrix.

9. The method of claim 5, further comprising performing SFBC-Precoding Frequency Switching Transmit Diversity (PFSTD) on a pair of two receive antennas from four transmit antennas by,

decoding pilot tones of an FSTD encoded PBCH precoded by a precoding matrix used by a synchronization channel;

decoding pilot tones of the synchronization channel by use of the precoding matrix; and

decoding by use of a mapping matrix for Frequency Switching Transmit Diversity (FSTD).

10. The method of claim 9, further comprising decoding by use of a mapping matrix for Frequency Time Switching Transmit Diversity (FTSTD).

11. The method of claim 1, further comprising decoding SFBC by use of Alamouti code in frequency domain.

12. At least one processor for receiving a physical broadcast channel (PBCH), comprising:

a first module for receiving a physical broadcast channel (PBCH) transmitted by Space Frequency Block Code (SFBC) from a plurality of transmit antennas assigned a different density of pilot tones; and

a second module for decoding the SFBC-based PBCH by detecting the different density of pilot tones from each respective transmit antenna that are transmitted at a transmit power for each transmit antenna corresponding to the density.

13. A computer program product for receiving a physical broadcast channel (PBCH), comprising:

a computer-readable storage medium comprising,

a first set of codes for causing a computer to receive a physical broadcast channel (PBCH) transmitted by Space Frequency Block Code (SFBC) from a plurality of transmit antennas assigned a different density of pilot tones; and

a second set of codes for causing the computer to decode the SFBC-based PBCH by detecting the different density of pilot tones from each respective transmit antenna that are transmitted at a transmit power for each transmit antenna corresponding to the density.

14. An apparatus for receiving a physical broadcast channel (PBCH), comprising:

means for receiving a physical broadcast channel (PBCH) transmitted by Space Frequency Block Code (SFBC) from a plurality of transmit antennas assigned a different density of pilot tones; and

means for decoding the SFBC-based PBCH by detecting the different density of pilot tones from each respective transmit antenna that are transmitted at a transmit power for each transmit antenna corresponding to the density.

15. An apparatus for receiving a physical broadcast channel (PBCH), comprising:

a receiver for receiving a physical broadcast channel (PBCH) transmitted by Space Frequency Block Code (SFBC) from a plurality of transmit antennas assigned a different density of pilot tones; and

a computing platform for decoding the SFBC-based PBCH by detecting the different density of pilot tones from each respective transmit antenna that are transmitted at a transmit power for each transmit antenna corresponding to the density.

16. The apparatus of claim 15, wherein the receiver is further for receiving a diversified portion of the SFB-based PBCH transmitted at a transmit gain inversely adjusted per the density of pilot tones to match a total transmit power for another transmit antenna having a different density of pilot tones.

17. The apparatus of claim 16, wherein the receiver comprises a pair of receive antennas for performing SFBC-Frequency Switching Transmit Diversity (FSTD) from four transmit antennas by,

receiving a first pair of diversified signals from a first and third transmit antenna, wherein the third transmit antenna transmits half of a number of pilot tones as the first antenna transmitted at twice the power;

and

subsequently receiving a second pair of diversified signals from a second and fourth transmit antenna, wherein the fourth transmit antenna transmits half of a number of pilot tones as the second antenna transmitted at twice the power, and wherein the computing; and

wherein the computing platform is further for decoding the received pairs of diversified signals by use of a mapping matrix for FSTD.

18. The apparatus of claim 17, wherein the computing platform is further for decoding the received pairs of diversified signals by use of a mapping matrix for Frequency Time Switching Transmit Diversity (FTSTD).

19. The apparatus of claim 15, further comprising the computing platform is further for decoding the SFBC-based PBCH by detecting the different density of pilot tones from each respective transmit antenna that are transmitted at an increased transmit power for each transmit antenna by detecting pilot tones of a synchronization channel and the SFBC-based PBCH.

20. The apparatus of claim 19, further comprising:

accessing a precoding matrix for the synchronization channel; and

decoding the pilot tones for both the synchronization channel and the SFBC-based PBCH using the precoding matrix.

21. The apparatus of claim 19, further comprising the computing platform for decoding pilot tones from a primary synchronization channel, a secondary synchronization channel, and the SFBC-based PBCH.

22. The apparatus of claim 19, wherein the receiver comprises a pair of receive antennas, and wherein the computing platform is for performing SFBC-PVS (Precoded Vector Switch) on the pair of two receive antennas from four transmit antennas by,

decoding pilot tones of a PBCH precoded by a precoding matrix used by a synchronization channel;

and

decoding pilot tones of the synchronization channel by use of the precoding matrix.

23. The apparatus of claim 19, wherein the receiver comprises a pair of receive antennas, and wherein computing platform is further for performing SFBC-Precoding Frequency Switching Transmit Diversity (PFSTD) on the pair of two receive antennas from four transmit antennas by,

decoding pilot tones of an FSTD encoded PBCH precoded by a precoding matrix used by a synchronization channel;

decoding pilot tones of the synchronization channel by use of the precoding matrix; and

decoding by use of a mapping matrix for Frequency Switching Transmit Diversity (FSTD).

24. The apparatus of claim 23, wherein the computing platform is further for decoding by use of a mapping matrix for Frequency Time Switching Transmit Diversity (FTSTD).

25. The apparatus of claim 15, wherein the computing platform is further for decoding SFBC by use of Alamouti code in frequency domain.

26. A method for transmitting a physical broadcast channel (PBCH), comprising:

transmitting a physical broadcast channel (PBCH) transmitted by Space Frequency Block Code (SFBC) from a plurality of transmit antennas assigned a different density of pilot tones; and

encoding the SFBC-based PBCH by transmitting the different density of pilot tones from each respective transmit antenna at a transmit power for each transmit antenna corresponding to the density.

27. The method of claim 26, further comprising transmitting a diversified portion of the SFB-based PBCH transmitted at a transmit gain inversely adjusted per the density of pilot tones to match a total transmit power for another transmit antenna having a different density of pilot tones.

28. The method of claim 27, further comprising performing SFBC-Frequency Switching Transmit Diversity (FSTD) from four transmit antennas to a pair of receive antennas by,

transmitting a first pair of diversified signals from a first and third transmit antenna, wherein the third transmit antenna transmits half of a number of pilot tones as the first antenna transmitted at twice the power;

subsequently transmitting a second pair of diversified signals from a second and fourth transmit antenna, wherein the fourth transmit antenna transmits half of a number of pilot tones as the second antenna transmitted at twice the power; and

encoding the transmitted pairs of diversified signals by use of a mapping matrix for FSTD.

29. The method of claim 28, further comprising encoding the transmitted pairs of diversified signals by use of a mapping matrix for Frequency Time Switching Transmit Diversity (FTSTD).

30. The method of claim 26, further comprising encoding the SFBC-based PBCH for decoding by transmitting pilot tones of a synchronization channel for detection with the SFBC-based PBCH.

31. The method of claim 30, further comprising:

accessing a precoding matrix; and

encoding the pilot tones for both the synchronization channel and the SFBC-based PBCH using the precoding matrix.

32. The method of claim 30, further comprising encoding pilot tones from a primary synchronization channel, a secondary synchronization channel, and the SFBC-based PBCH.

33. The method of claim 30, further comprising performing SFBC-PVS (Precoded Vector Switch) from four transmit antennas by,

encoding pilot tones of a PBCH precoded by a precoding matrix used by a synchronization channel;

and

encoding pilot tones of the synchronization channel by use of the precoding matrix.

34. The method of claim 30, further comprising performing SFBC-Precoding Frequency Switching Transmit Diversity (PFSTD) from four transmit antennas to a pair of receive antennas by,

encoding pilot tones of an FSTD encoded PBCH precoded by a precoding matrix used by a synchronization channel;

encoding pilot tones of the synchronization channel by use of the precoding matrix; and

encoding by use of a mapping matrix for Frequency Switching Transmit Diversity (FSTD).

35. The method of claim 34, further comprising encoding by use of a mapping matrix for Frequency Time Switching Transmit Diversity (FTSTD).

36. The method of claim 26, further comprising encoding SFBC by use of Alamouti code in frequency domain.

37. At least one processor for transmitting a physical broadcast channel (PBCH), comprising:

a first module for transmitting a physical broadcast channel (PBCH) transmitted by Space Frequency Block Code (SFBC) from a plurality of transmit antennas assigned a different density of pilot tones; and

a second module for encoding the SFBC-based PBCH by transmitting the different density of pilot tones from each respective transmit antenna at a transmit power for each transmit antenna corresponding to the density.

38. A computer program product for transmitting a physical broadcast channel (PBCH), comprising:

a computer-readable storage medium comprising,

a first set of codes for causing a computer to transmit a physical broadcast channel (PBCH) transmitted by Space Frequency Block Code (SFBC) from a plurality of transmit antennas assigned a different density of pilot tones; and

a second set of codes for causing the computer to encode the SFBC-based PBCH by transmitting the different density of pilot tones from each respective transmit antenna at a transmit power for each transmit antenna corresponding to the density.

39. An apparatus for transmitting a physical broadcast channel (PBCH), comprising:

means for transmitting a physical broadcast channel (PBCH) transmitted by Space Frequency Block Code (SFBC) from a plurality of transmit antennas assigned a different density of pilot tones; and

means for encoding the SFBC-based PBCH by transmitting the different density of pilot tones from each respective transmit antenna at a transmit power for each transmit antenna corresponding to the density.

40. An apparatus for transmitting a physical broadcast channel (PBCH), comprising:

a transmitter for transmitting a physical broadcast channel (PBCH) transmitted by Space Frequency Block Code (SFBC) from a plurality of transmit antennas assigned a different density of pilot tones; and

a computing platform for encoding the SFBC-based PBCH by transmitting the different density of pilot tones from each respective transmit antenna at a transmit power for each transmit antenna corresponding to the density.

41. The apparatus of claim 40, wherein the transmitter is further for transmitting a diversified portion of the SFB-based PBCH transmitted at a transmit gain inversely adjusted per the density of pilot tones to match a total transmit power for another transmit antenna having a different density of pilot tones.

42. The apparatus of claim 41, further comprising:

four transmit antennas for performing SFBC-Frequency Switching Transmit Diversity (FSTD) to a pair of receive antennas,

wherein the transmitter is further for transmitting a first pair of diversified signals from a first and third transmit antenna, wherein the third transmit antenna transmits half of a number of pilot tones as the first antenna transmitted at twice the power,

wherein the transmitter is further for subsequently transmitting a second pair of diversified signals from a second and fourth transmit antenna, wherein the fourth transmit antenna transmits half of a number of pilot tones as the second antenna transmitted at twice the power; and

wherein the computing platform is further for encoding the transmitted pairs of diversified signals by use of a mapping matrix for FSTD.

43. The apparatus of claim 42, wherein the computing platform is further for encoding the transmitted pairs of diversified signals by use of a mapping matrix for Frequency Time Switching Transmit Diversity (FTSTD).

44. The apparatus of claim 40, wherein the computing platform is further for encoding the SFBC-based PBCH for decoding by transmitting pilot tones of a synchronization channel for detection with the SFBC-based PBCH.

45. The apparatus of claim 44, wherein the computing platform is further for accessing a precoding matrix, and for encoding the pilot tones for both the synchronization channel and the SFBC-based PBCH using the precoding matrix.

46. The apparatus of claim 44, wherein the computing platform is further for encoding pilot tones from a primary synchronization channel, a secondary synchronization channel, and the SFBC-based PBCH.

47. The apparatus of claim 44, further comprising:

four transmit antennas for performing SFBC-PVS (Precoded Vector Switch),

wherein the computing platform is further for encoding pilot tones of a PBCH precoded by a precoding matrix used by a synchronization channel, and for encoding pilot tones of the synchronization channel by use of the precoding matrix.

48. The apparatus of claim 44, further comprising four transmit antennas for performing SFBC-Precoding Frequency Switching Transmit Diversity (PFSTD) to a pair of two receive antennas,

wherein the computing platform is further for encoding pilot tones of an FSTD encoded PBCH precoded by a precoding matrix used by a synchronization channel, for encoding pilot tones of the synchronization channel by use of the precoding matrix, and for encoding by use of a mapping matrix for Frequency Switching Transmit Diversity (FSTD).

49. The apparatus of claim 48, wherein the computing platform is further for encoding by use of a mapping matrix for Frequency Time Switching Transmit Diversity (FTSTD).

50. The apparatus of claim 40, wherein the computing platform is further for encoding SFBC by use of Alamouti code in frequency domain.

51. A method for receiving a physical broadcast channel (PBCH), comprising:

receiving a physical broadcast channel (PBCH) and a synchronization channel transmitted from a base station; and

decoding the PBCH by detecting pilot tones of the PBCH and pilot tones of the synchronization channel.

52. At least one processor for receiving a physical broadcast channel (PBCH), comprising:

a first module for receiving a physical broadcast channel (PBCH) and a synchronization channel transmitted from a base station; and

a second module for decoding the PBCH by detecting pilot tones of the PBCH and pilot tones of the synchronization channel.

53. A computer program product for receiving a physical broadcast channel (PBCH), comprising:

a computer-readable storage medium comprising,

a first set of codes for causing a computer to receive a physical broadcast channel (PBCH) and a synchronization channel transmitted from a base station; and

a second set of codes for causing the computer to decode the PBCH by detecting pilot tones of the PBCH and pilot tones of the synchronization channel.

54. An apparatus for receiving a physical broadcast channel (PBCH), comprising:

means for receiving a physical broadcast channel (PBCH) and a synchronization channel transmitted from a base station; and

means for decoding the PBCH by detecting pilot tones of the PBCH and pilot tones of the synchronization channel.

55. An apparatus for receiving a physical broadcast channel (PBCH), comprising:

a receiver for receiving a physical broadcast channel (PBCH) and a synchronization channel transmitted from a base station; and

a computing platform for decoding the PBCH by detecting pilot tones of the PBCH and pilot tones of the synchronization channel.