METHOD AND APPARATUS FOR TRANSMITTING PILOT SYMBOLS IN WIRELESS COMMUNICATION SYSTEM

• US 20090147868A1
• Filed: 07/14/2006
• Published: 06/11/2009
• Est. Priority Date: 07/15/2005
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation), Zhe Jiang Cell Biomedical Research Co., Ltd.
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Kim, Jae Wan, Jung, Jin Hyuk, Ihm, Bin Chul, Lee, Moon Il, Chun, Jin Young, Lee, Wook Bong, Chang, Jae Won
• Granted Patent: US 7,995,664 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04B 7/0669 using different channel coding between antennas space-time coding H04L1/0618
• CPC Class Codes: H04B 7/0684 using different training sequences per antenna
• CPC Class Codes: H04J 13/004 Orthogonal
• CPC Class Codes: H04J 13/18 Allocation of orthogonal codes
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0226 sounding signals per se
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver

Abstract

A method of transmitting pilot symbols is disclosed. In a communication system performing communications using a plurality of antennas and multiple carriers, the present invention includes the steps of generating a plurality of pilot symbol sequences based on a basic code sequence, data-processing a plurality of the pilot symbol sequences by allocating each of a plurality of the pilot symbol sequences to the multiple carriers, and transmitting each of a plurality of the data-processed pilot symbol sequences via a corresponding one of a plurality of the antennas.

Claims

1. A method of transmitting pilot symbols in a communication system using a plurality of antennas and multiple carriers, comprising the steps of:

generating a plurality of pilot symbol sequences based on a basic code sequence;

data-processing the plurality of pilot symbol sequences by allocating each of the plurality of pilot symbol sequences to the multiple carriers; and

transmitting each of the plurality of data-processed pilot symbol sequences via a corresponding one of the plurality of antennas.

2. The method of claim 1, wherein the plurality of pilot symbol sequences are generated by performing encoding using an orthogonal code on the basic code sequence.

3. The method of claim 2, wherein the encoding using the orthogonal code is carried out in a manner of a multiplication of the orthogonal code in a frequency-space.

4. The method of claim 2, wherein the encoding using the orthogonal code is carried out in a manner of a multiplication of the orthogonal code in a time-frequency-space.

5. The method of claim 3, wherein the orthogonal code is an Alamouti code.

6. The method of claim 1, wherein assuming that an n^th symbol of the basic code sequence is represented as x_n(n=0, 1, 2, 3, . . . ), n^th symbols of the pilot symbol sequences allocated to 0^th and 1^st time symbols of 0^th and 1^st antennas are x_n, x_n*, x_n and −

x_n*, respectively.

7. The method of claim 6, wherein a symbol interval of the pilot symbol sequence allocated to a 0^th time symbol of a random antenna is twice greater than a symbol-to-symbol interval in case of transmitting the basic code sequence via a single transmitting antenna.

8. The method of claim 7, wherein each symbol of the pilot symbol sequence allocated to a 1^st time symbol of the random antenna is allocated between symbols of the pilot symbol sequence allocated to the 0^th time symbol of the random antenna on a frequency axis.

9. The method of claim 7, wherein the pilot symbol sequences allocated to 0^th and 1^st time symbols of 2(m+1)^th and {2(m+1)+1}^th antennas are allocated to subcarriers resulting from shifting the pilot symbol sequences allocated to 0^th and 1^st time symbols of 2m^th and (2m+1)^th antennas by one subcarrier interval each on a frequency axis, respectively.

10. The method of claim 7, wherein the pilot symbol sequence allocated to a 0^th time symbol of a 2(m+1)^th antenna is allocated to a same subcarrier of the pilot symbol sequence allocated to a 0^th time symbol of a 2m^th antenna.

11. The method of claim 10, wherein symbols of the pilot symbol sequences allocated to 1^st time symbols of 0^th and 1^st antennas are allocated between symbols of the pilot symbol sequences allocated to 0^th time symbols of the 0^th and 1^st antennas on a frequency axis, respectively.

12. The method of claim 11, wherein the pilot symbol sequence allocated to a 1^st time symbol of a {2(m+1)+1}^th antenna is allocated by shifting the pilot symbol sequence allocated to a 1^st time symbol of a (2m+1)^th antenna by one subcarrier on the frequency axis.

13. The method of claim 1, the data-processing step comprising the steps of:

converting each of the pilot symbol sequences to time domain signals; and

inserting a guard interval (CP) in a prefix converted to the time domain signals.

14. The method of claim 13, wherein if there is an overlapped part in the time-domain signal in which the guard interval is inserted, a portion of the time-domain signal is transmitted via each of a plurality of the transmitting antennas.

15. The method of claim 13, wherein in the step of inserting the guard interval, the guard interval is inserted in both a 0^th time symbol and a 1^st time symbol.

16. The method of claim 13, wherein in the step of inserting the guard interval, the guard interval is inserted in a 0^th time symbol only.

17. The method of claim 1, wherein the plurality of pilot symbol sequences are generated by shifting a phase of the basic code sequence differently.

18. The method of claim 17, wherein each symbol (Pilot_p) of a plurality of the pilot symbol sequences is found by

$\begin{array}{c}{\mathrm{Pilot}}_p=\end{array}$

a p 



- j 



2 

π





np 

( P / N t ) / P = 

a p 



- j 



2 

π





np / N t ,

where a_p is a basic code sequence, n is an index of a transmitting antenna corresponding to n=0, 1, . . . , (N_t−

1), p is an index of a pilot symbol corresponding to p=0, 1, . . . , (P−

1), and N_i is the total number of transmitting antennas.

19. The method of claim 18, wherein corresponding symbols of the plurality of pilot symbol sequences are allocated to identical subcarriers, respectively.

20. The method of claim 17, further comprising the step of scrambling each of the plurality of pilot symbol sequences by a specific scrambling code.

21. A method of transmitting pilot symbols in a communication system using a plurality of antennas and multiple carriers, comprising the steps of:

data-processing a plurality of pilot symbol sequences generated based on a basic code sequence in a manner of allocating each of the plurality of pilot symbol sequences to the multiple carriers; and

transmitting each of the plurality of data-processed pilot symbol sequences via a corresponding one of a plurality of the antennas.

22. An apparatus for transmitting data in a communication system using a plurality of antennas and multiple carriers, comprising:

a subcarrier allocating module allocating each of a plurality of pilot symbol sequences generated based on a basic code sequence to the multiple carriers; and

a data processing module performing a data processing on each of the plurality of pilot symbol sequences allocated to the multiplexing subcarrier to be transmitted via a random transmitting antenna.

23. The apparatus of claim 22, wherein the plurality of pilot symbol sequences are generated from the basic code sequence.

24. The apparatus of claim 22, wherein the plurality of pilot symbol sequences are generated by performing encoding using an orthogonal code on the basic code sequence.

25. The apparatus of claim 24, wherein the orthogonal code is Alamouti code.

26. The apparatus of claim 24, wherein assuming that an n^th symbol of the basic code sequence is represented as x_n (n=0, 1, 2, 3, . . . ), n^th symbols of the pilot symbol sequences allocated to 0^th and 1^st time symbols of 0^th and 1^st antennas are x_n, x_n*, x_n and −

x_n*, respectively.

27. The apparatus of claim 22, the data processing module comprising:

an IFFT unit converting each of the plurality of pilot symbol sequences allocated to the multiple carriers to time domain signals; and

a CP inserting unit inserting a guard interval (CP) in the pilot symbol sequence converted to the time domain signals.

28. The apparatus of claim 22 or claim 23, wherein the plurality of pilot symbol sequences are generated by shifting a phase of the basic code sequence differently.

29. The apparatus of claim 28, wherein each symbol (Pilot_p) of a plurality of the pilot symbol sequences is calculated by

$\begin{array}{c}{\mathrm{Pilot}}_p=\end{array}$

a p 



- j 



2 

π





np 

( P / N t ) / P = 

a p 



- j 



2 

π





np / N t ,

where a_p is a basic code sequence, n is an index of a transmitting antenna to correspond to n=0, 1, . . . , (N−

1), p is an index of a pilot symbol to correspond to p=0, 1, . . . , (−

1), and N_i is the total number of transmitting antennas.

30. The apparatus of claim 29, wherein corresponding symbols of the plurality of pilot symbol sequences are allocated to identical subcarriers, respectively.

31. The apparatus of claim 28, further comprising a scrambling module scrambling each of the plurality of pilot symbol sequences by a specific scrambling code.