Apparatus and method for full-diversity, full-rate space-time block coding for even number of transmit antennas

• US 20050281351A1
• Filed: 06/21/2005
• Published: 12/22/2005
• Est. Priority Date: 06/21/2004
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Park, Dong-Seek, Kim, Jae-Yoel, Jeong, Hong-Sil, Chae, Chan-Byoung
• Application Number:
  US11/157,444
• Publication Number:
  US 20050281351A1
• Time in Patent Office: Days
• US Class Current: 375/267
• CPC Class Codes: H04L 1/0069 Puncturing patterns
• CPC Class Codes: H04L 1/0618 Space-time coding

Abstract

A mobile communication system using an STBC scheme having an even number of Tx antennas is provided. In a transmitter having an even number of Tx antennas, a pre-coder pre-codes an input symbol sequence using a pre-coding matrix. The pre-coding matrix is a matrix produced by puncturing a unitary matrix. A space-time coder space-time-encodes the pre-coded symbol sequence received from the pre-coder using a coding matrix.

Claims

1. A transmitter having an even number of (N_t) transmit antennas, comprising:

a pre-coder for pre-coding an input symbol sequence using a pre-coding matrix, the pre-coding matrix produced by puncturing a unitary matrix; and

a space-time coder for space-time-encoding the pre-coded symbol sequence received from the pre-coder using a coding matrix.

2. The transmitter of claim 1, wherein the space-time coder comprises:

a mapper for generating a plurality of vectors by grouping the symbols of the pre-coded symbol sequence by twos; and

a plurality of coders for encoding each of the vectors in an Alamouti coding scheme and transmitting each of the coded vectors through two antennas.

3. The transmitter of claim 2, wherein an i^th coder from among the plurality of coders encodes an i^th vector in the Alamouti coding scheme and transmits the coded vector through two antennas for (2i-1)^th and 2i^th time intervals, where i=1, 2, 3, . . . , N_t/2.

4. The transmitter of claim 1, wherein the coding matrix is

$S=[\begin{array}{ccccc}{r}_1& r_2& 0& 0& \cdots \end{array}$

0 - r 2 * r 1 * 0 0 ⋯

0 0 0 r 3 r 4 0 0 0 0 - r 4 * r 3 * 0 0 ⋮

⋮

⋰

⋰

⋮

⋮

0 0 ⋯

⋯

r N t - 1 r N t 0 0 ⋯

⋯

- r N t * r N t - 1 * ]

where r₁, r₂, . . . , r_Nt is a symbol sequence output from the pre-coder, an i^th row in the matrix S denotes transmission in an i^th time interval, and a j^th column denotes transmission through a j^th Tx antenna.

5. The transmitter of claim 1, wherein the pre-coding matrix is produced by puncturing N_t/2 columns in an N_t×

N_t Vandermonde matrix, sequentially grouping the rows of the punctured matrix by twos, and shifting one row of each group.

6. The transmitter of claim 1, wherein if the number of transmit antennas is 4 (N_t=4), the pre-coding matrix is

$\Theta$

= 1 2 ⁡

[ 1 ⅇ

- j ⁢

 

⁢

θ

0 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

θ

0 1 ⅇ

- j ⁢

 

⁢

θ

1 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

θ

1 ]

where 0≦

θ

₀, θ

₁≦

2π

, and |θ

₁-θ

₂|=180°

.

7. The transmitter of claim 1, wherein if the number of transmit antennas is 6 (N_t=6), the pre-coding matrix is

$\Theta$

= 1 3 ⁡

[ 1 ⅇ

- j ⁢

 

⁢

5 9 ⁢

π

ⅇ

- j ⁢

 

⁢

10 9 ⁢

π

0 0 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

5 9 ⁢

π

ⅇ

- j ⁢

 

⁢

10 9 ⁢

π

1 ⅇ

- j ⁢

 

⁢

11 9 ⁢

π

ⅇ

- j ⁢

 

⁢

4 9 ⁢

π

0 0 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

11 9 ⁢

π

ⅇ

- j ⁢

 

⁢

4 9 ⁢

π

1 ⅇ

- j ⁢

 

⁢

17 9 ⁢

π

ⅇ

- j ⁢

 

⁢

16 9 ⁢

π

0 0 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

17 9 ⁢

π

ⅇ

- j ⁢

 

⁢

16 9 ⁢

π

]

8. The transmitter of claim 1, wherein for the even number of transmit antennas (N_t=even number), the pre-coding matrix is

$\Theta$

= 1 N t / 2 ⁡

[ 1 α

0 1 ⋯

α

0 N t / 2 - 1 0 0 ⋯

0 0 0 ⋯

0 1 α

0 1 ⋯

α

0 N t / 2 - 1 ⋮

⋮

⋰

⋯

⋯

⋰

⋮

⋮

1 α

N t - 2 1 ⋯

α

N t - 2 N t / 2 - 1 0 0 ⋯

0 0 0 ⋯

0 1 α

N t - 2 1 ⋯

α

N t - 2 N t / 2 - 1 ]

where α

_i=exp(j2π

(i+1/4)/N_t), i=0, 1, 2, . . . , N_t/2-1.

9. The transmitter of claim 1, further comprising:

a coder for encoding transmission data;

a modulator for modulating the coded symbols received from the coder and providing the modulated symbols to the pre-coder; and

a radio frequency (RF) modulator for modulating the plurality of antenna signals received form the space-time coder to RF signals and outputting the RF signals to antennas.

10. A pre-coding matrix generator in a system where transmission data is pre-coded and then space-time-encoded, comprising:

a matrix generator for generating a unitary matrix;

a puncturer for puncturing half the columns of the unitary matrix; and

a shifter for generating a pre-coding matrix by sequentially grouping the rows of the punctured matrix by twos and shifting one row of each group.

11. The pre-coding matrix generator of claim 10, wherein the unitary matrix is a Vandermonde matrix.

12. The pre-coding matrix generator of claim 10, wherein for four transmit antennas, the pre-coding matrix is

$\Theta$

= 1 2 ⁡

[ 1 ⅇ

- j ⁢

 

⁢

θ

0 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

θ

0 1 ⅇ

- j ⁢

 

⁢

θ

1 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

θ

1 ]

where 0≦

θ

₀, θ

₁≦

2π

, and |θ

₁-θ

₂|=180°

.

13. The apparatus of claim 10, wherein for six transmit antennas, the pre-coding matrix is

$\Theta$

= 1 3 ⁡

[ 1 ⅇ

- j ⁢

 

⁢

5 9 ⁢

π

ⅇ

- j ⁢

 

⁢

10 9 ⁢

π

0 0 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

5 9 ⁢

π

ⅇ

- j ⁢

 

⁢

10 9 ⁢

π

1 ⅇ

- j ⁢

 

⁢

11 9 ⁢

π

ⅇ

- j ⁢

 

⁢

4 9 ⁢

π

0 0 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

11 9 ⁢

π

ⅇ

- j ⁢

 

⁢

4 9 ⁢

π

1 ⅇ

- j ⁢

 

⁢

17 9 ⁢

π

ⅇ

- j ⁢

 

⁢

16 9 ⁢

π

0 0 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

17 9 ⁢

π

ⅇ

- j ⁢

 

⁢

16 9 ⁢

π

]

14. The apparatus of claim 10, wherein for N_t transmit antennas, the pre-coding matrix is

$\Theta$

= 1 N t / 2 ⁡

[ 1 α

0 1 ⋯

α

0 N t / 2 - 1 0 0 ⋯

0 0 0 ⋯

0 1 α

0 1 ⋯

α

0 N t / 2 - 1 ⋮

⋮

⋰

⋯

⋯

⋰

⋮

⋮

1 α

N t - 2 1 ⋯

α

N t - 2 N t / 2 - 1 0 0 ⋯

0 0 0 ⋯

0 1 α

N t - 2 1 ⋯

α

N t - 2 N t / 2 - 1 ]

where α

_i=exp(j2π

(i+1/4)/N_t), i=0, 1, 2, . . . , N_t/2-1.

15. A receiver in a mobile communication system using a space-time coding scheme with an even number of (N_t) transmit antennas, comprising:

a matrix generator for multiplying a channel response matrix H by a pre-coding matrix Θ and

calculating a Hermitian matrix (HΘ

)^H of the product matrix; and

a signal combiner for calculating a vector of size N_t by multiplying a signal received through at least one receive antenna and the Hermitian matrix (HΘ

)^H, and dividing the vector into two vectors.

16. The receiver of claim 15, further comprising a signal decider for estimating symbols transmitted from a transmitter by decoding each of the two vectors received from the signal combiner according to a decoding method.

17. The receiver of claim 15, wherein the decoding method is maximum likelihood (ML) decoding.

18. The receiver of claim 15, wherein the pre-coding matrix is produced by puncturing N_t/2 columns in an N_t×

N_t Vandermonde matrix, sequentially grouping the rows of the punctured matrix by twos, and shifting one row of each group.

19. The receiver of claim 15, wherein if the number of transmit antennas is 4 (N_t=4), the pre-coding matrix is

$\Theta$

= 1 2 ⁡

[ 1 ⅇ

- j ⁢

 

⁢

θ

0 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

θ

0 1 ⅇ

- j ⁢

 

⁢

θ

1 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

θ

1 ]

where 0≦

θ

₀, θ

₁≦

2π

, and |θ

₁-θ

₂|=180°

.

20. The receiver of claim 15, wherein if the number of transmit antennas is 6 (N_t=6), the pre-coding matrix is

$\Theta$

= 1 3 ⁡

[ 1 ⅇ

- j ⁢

 

⁢

5 9 ⁢

π

ⅇ

- j ⁢

 

⁢

10 9 ⁢

π

0 0 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

5 9 ⁢

π

ⅇ

- j ⁢

 

⁢

10 9 ⁢

π

1 ⅇ

- j ⁢

 

⁢

11 9 ⁢

π

ⅇ

- j ⁢

 

⁢

4 9 ⁢

π

0 0 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

11 9 ⁢

π

ⅇ

- j ⁢

 

⁢

4 9 ⁢

π

1 ⅇ

- j ⁢

 

⁢

17 9 ⁢

π

ⅇ

- j ⁢

 

⁢

16 9 ⁢

π

0 0 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

17 9 ⁢

π

ⅇ

- j ⁢

 

⁢

16 9 ⁢

π

]

21. The receiver of claim 15, wherein for an even number of transmit antennas (N_t=even number), the pre-coding matrix is

$\Theta$

= 1 N t / 2 ⁡

[ 1 α

0 1 ⋯

α

0 N t / 2 - 1 0 0 ⋯

0 0 0 ⋯

0 1 α

0 1 ⋯

α

0 N t / 2 - 1 ⋮

⋮

⋰

⋯

⋯

⋰

⋮

⋮

1 α

N t - 2 1 ⋯

α

N t - 2 N t / 2 - 1 0 0 ⋯

0 0 0 ⋯

0 1 α

N t - 2 1 ⋯

α

N t - 2 N t / 2 - 1 ]

where α

_i=exp(j2π

(i+1/4)/N_t), i=0, 1, 2, . . . , N_t/2-1.

22. The receiver of claim 16, further comprising:

a radio frequency (RF) processor for downconverting the signal received through the at least one receive antenna to a baseband signal and providing the baseband signal to a channel estimator and the signal combiner;

the channel estimator for calculating the channel response matrix H using the baseband signal;

a demodulator for demodulating the estimated symbols received from the signal decider; and

a decoder for decoding the demodulated symbols received form the demodulator.

23. A transmission method in a transmitter using an even number of (N_t) transmit antennas, comprising the steps of:

pre-coding an input symbol sequence using a pre-coding matrix, the pre-coding matrix being produced by puncturing a unitary matrix; and

space-time-encoding the pre-coded symbol sequence using a coding matrix.

24. The transmission method of claim 23, wherein the space-time-encoding step comprises the steps of:

generating a plurality of vectors by grouping the symbols of the pre-coded symbol sequence by twos; and

encoding each of the vectors in an Alamouti coding scheme and transmitting each of the coded vectors through two antennas.

25. The transmission method of claim 24, wherein the encoding and transmitting step comprises the step of encoding ani^th vector from among the plurality of vectors in the Alamouti coding scheme and transmitting the coded vector through two antennas for (2i-1)^th and 2i^th time intervals, where i=1, 2, 3, . . . , N_t/2.

26. The transmission method of claim 23, wherein the coding matrix is given by is

$S=[\begin{array}{ccccc}{r}_1& r_2& 0& 0& \cdots \end{array}$

0 - r 2 * r 1 * 0 0 ⋯

0 0 0 r 3 r 4 0 0 0 0 - r 4 * r 3 * 0 0 ⋮

⋮

⋰

⋰

⋮

⋮

0 0 ⋯

⋯

r N t - 1 r N t 0 0 ⋯

⋯

- r N t * r N t - 1 * ]

where r₁, r₂, . . . , r_Nt is a pre-coded symbol sequence, an i^th row in the matrix S denotes transmission in an i^th time interval, and a j^th column denotes transmission through a j^th Tx antenna.

27. The transmission method of claim 23, wherein the pre-coding matrix is produced by puncturing N_t/2 columns in an N_t×

N_t Vandermonde matrix, sequentially grouping the rows of the punctured matrix by twos, and shifting one row of each group.

28. The transmission method of claim 23, wherein if the number of transmit antennas is 4 (N_t=4), the pre-coding matrix is

$\Theta$

= 1 2 ⁡

[ 1 ⅇ

- j ⁢

 

⁢

θ

0 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

θ

0 1 ⅇ

- j ⁢

 

⁢

θ

1 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

θ

1 ]

where 0≦

θ

₀, θ

₁≦

2π

, and |θ

₁-θ

₂|=180°

.

29. The transmission method of claim 23, wherein if the number of transmit antennas is 6 (N_t=6), the pre-coding matrix is

$\Theta$

= 1 3 ⁡

[ 1 ⅇ

- j ⁢

 

⁢

5 9 ⁢

π

ⅇ

- j ⁢

 

⁢

10 9 ⁢

π

0 0 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

5 9 ⁢

π

ⅇ

- j ⁢

 

⁢

10 9 ⁢

π

1 ⅇ

- j ⁢

 

⁢

11 9 ⁢

π

ⅇ

- j ⁢

 

⁢

4 9 ⁢

π

0 0 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

11 9 ⁢

π

ⅇ

- j ⁢

 

⁢

4 9 ⁢

π

1 ⅇ

- j ⁢

 

⁢

17 9 ⁢

π

ⅇ

- j ⁢

 

⁢

16 9 ⁢

π

0 0 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

17 9 ⁢

π

ⅇ

- j ⁢

 

⁢

16 9 ⁢

π

]

30. The transmission method of claim 23, wherein for an even number of transmit antennas (N_t=even number), the pre-coding matrix is

$\Theta$

= 1 N t / 2 ⁡

[ 1 α

0 1 ⋯

α

0 N t / 2 - 1 0 0 ⋯

0 0 0 ⋯

0 1 α

0 1 ⋯

α

0 N t / 2 - 1 ⋮

⋮

⋰

⋯

⋯

⋰

⋮

⋮

1 α

N t - 2 1 ⋯

α

N t - 2 N t / 2 - 1 0 0 ⋯

0 0 0 ⋯

0 1 α

N t - 2 1 ⋯

α

N t - 2 N t / 2 - 1 ]

where α

_i=exp(j2π

(i+1/4)/N_t), i=0, 1, 2, . . . , N_t/2-1.

31. The transmission method of claim 23, further comprising the steps of:

generating coded symbols by encoding transmission data;

modulating the coded symbols and providing the modulated symbols for pre-coding; and

modulating a plurality of antenna signals generated by space-time encoding to radio frequency (RF) signals and transmitting the RF signals.

32. A method of generating a pre-coding matrix in a system where transmission data is pre-coded and then space-time-encoded, comprising the steps of:

generating a unitary matrix;

puncturing half the columns of the unitary matrix; and

generating the pre-coding matrix by sequentially grouping the rows of the punctured matrix by twos and shifting one row of each group.

33. The method of claim 32, wherein the unitary matrix is a Vandermonde matrix.

34. The method of claim 32, wherein for four transmit antennas, the pre-coding matrix is

$\Theta$

= 1 2 ⁡

[ 1 ⅇ

- j ⁢

 

⁢

θ

0 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

θ

0 1 ⅇ

- j ⁢

 

⁢

θ

1 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

θ

1 ]

where 0≦

θ

₀, θ

₁≦

2π

, and |θ

₁-θ

₂|=180°

.

35. The method of claim 32, wherein for six transmit antennas, the pre-coding matrix is

$\Theta$

= 1 3 ⁡

[ 1 ⅇ

- j ⁢

 

⁢

5 9 ⁢

π

ⅇ

- j ⁢

 

⁢

10 9 ⁢

π

0 0 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

5 9 ⁢

π

ⅇ

- j ⁢

 

⁢

10 9 ⁢

π

1 ⅇ

- j ⁢

 

⁢

11 9 ⁢

π

ⅇ

- j ⁢

 

⁢

4 9 ⁢

π

0 0 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

11 9 ⁢

π

ⅇ

- j ⁢

 

⁢

4 9 ⁢

π

1 ⅇ

- j ⁢

 

⁢

17 9 ⁢

π

ⅇ

- j ⁢

 

⁢

16 9 ⁢

π

0 0 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

17 9 ⁢

π

ⅇ

- j ⁢

 

⁢

16 9 ⁢

π

]

36. The method of claim 32, wherein for N_t transmit antennas, the pre-coding matrix is

$\Theta$

= 1 N t / 2 ⁡

[ 1 α

0 1 ⋯

α

0 N t / 2 - 1 0 0 ⋯

0 0 0 ⋯

0 1 α

0 1 ⋯

α

0 N t / 2 - 1 ⋮

⋮

⋰

⋯

⋯

⋰

⋮

⋮

1 α

N t - 2 1 ⋯

α

N t - 2 N t / 2 - 1 0 0 ⋯

0 0 0 ⋯

0 1 α

N t - 2 1 ⋯

α

N t - 2 N t / 2 - 1 ]

where α

_i=exp(j2π

(i+1/4)/N_t), i=0, 1, 2, . . . , N_t/2-1.

37. A reception method in a mobile communication system using a space-time coding scheme with an even number of (N_t) transmit antennas, comprising the steps of:

multiplying a channel response matrix H by a pre-coding matrix Θ and

calculating a Hermitian matrix (HΘ

)^H of the product matrix;

calculating a vector of size N_t by multiplying a signal received through at least one receive antenna and the Hermitian matrix (HΘ

)^H and dividing the vector into two vectors; and

estimating symbols transmitted from a transmitter by decoding each of the two vectors received from the signal combiner according to a decoding method.

38. The reception method of claim 37, wherein the decoding method is maximum likelihood (ML) decoding.

39. The reception method of claim 37, wherein the pre-coding matrix is produced by puncturing N_t/2 columns in an N_t×

N_t Vandermonde matrix, sequentially grouping the rows of the punctured matrix by twos, and shifting one row of each group.

40. The reception method of claim 37, wherein if the number of transmit antennas is 4 (N_t=4), the pre-coding matrix is

$\Theta$

= 1 2 ⁡

[ 1 ⅇ

- j ⁢

 

⁢

θ

0 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

θ

0 1 ⅇ

- j ⁢

 

⁢

θ

1 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

θ

1 ]

where 0≦

θ

₀, θ

₁≦

2π

, and |θ

₁-θ

₂|=180°

.

41. The reception method of claim 37, wherein if the number of transmit antennas is 6 (N_t=6), the pre-coding matrix is

$\Theta$

= 1 3 ⁡

[ 1 ⅇ

- j ⁢

 

⁢

5 9 ⁢

π

ⅇ

- j ⁢

 

⁢

10 9 ⁢

π

0 0 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

5 9 ⁢

π

ⅇ

- j ⁢

 

⁢

10 9 ⁢

π

1 ⅇ

- j ⁢

 

⁢

11 9 ⁢

π

ⅇ

- j ⁢

 

⁢

4 9 ⁢

π

0 0 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

11 9 ⁢

π

ⅇ

- j ⁢

 

⁢

4 9 ⁢

π

1 ⅇ

- j ⁢

 

⁢

17 9 ⁢

π

ⅇ

- j ⁢

 

⁢

16 9 ⁢

π

0 0 0 0 0 0 1 ⅇ

- j ⁢

 

⁢

17 9 ⁢

π

ⅇ

- j ⁢

 

⁢

16 9 ⁢

π

]

42. The reception method of claim 37, wherein for an even number of transmit antennas (N_teven number), the pre-codding matrix is

$\Theta$

= 1 N t / 2 ⁡

[ 1 α

0 1 ⋯

α

0 N t / 2 - 1 0 0 ⋯

0 0 0 ⋯

0 1 α

0 1 ⋯

α

0 N t / 2 - 1 ⋮

⋮

⋰

⋯

⋯

⋰

⋮

⋮

1 α

N t - 2 1 ⋯

α

N t - 2 N t / 2 - 1 0 0 ⋯

0 0 0 ⋯

0 1 α

N t - 2 1 ⋯

α

N t - 2 N t / 2 - 1 ]

where α

_i=exp(j2π

(i+1/4)/N_t), i=0, 1, 2, . . . , N_t/2-1.

43. The reception method of claim 37, further comprising the steps of:

calculating the channel response matrix, H using the signal received through the at least one antenna;

demodulating the estimated symbols; and

recovering original information data by decoding the demodulated symbols.