Apparatus and method for transmitting/receiving the hybrid-ARQ ACK/NACK signal in mobile communication system

1. A method for transmitting a symbol group in a mobile communication system, the method comprising:

generating the symbol group to which an orthogonal sequence is applied;

mapping the generated symbol group to an Orthogonal Frequency Division Multiple (OFDM) symbol based on a symbol group index and a Physical HARQ Indicator Channel (PHICH) group index; and

transmitting the mapped symbol group,

wherein the generated symbol group is mapped to the OFDM symbol in an alternating pattern in accordance with the symbol group index.

2. The method of claim 1 , wherein the generated symbol group is alternately mapped to a first OFDM symbol and a second OFDM symbol in order to be mapped to the OFDM symbol.

3. The method of claim 1 , wherein a size of the symbol group index is three (3).

4. The method of claim 1 , further comprising mapping the generated symbol group to a multi-antenna array in an alternating pattern based on the symbol group index and the PHICH group index;

wherein the multi-antenna array includes four antennas.

5. The method of claim 4 , wherein at least one of complex conjugation and sign reversal is applied to map the generated symbol group to the multi-antenna array.

6. The method of claim 4 , wherein the generated symbol group is mapped to the OFDM symbol according to:

PHICH

Symbol Group

Symbol

Antenna Mapping

Group g

Index r

Index n

Pattern

0

0

0

A

0

1

1

B

0

2

0

A

1

0

0

B

1

1

1

A

1

2

0

B

2

0

1

A

2

1

0

B

2

2

1

A

3

0

1

B

3

1

0

A

3

2

1

B

. . .

. . .

. . .

. . ..

7. The method of claim 1 , wherein the symbol group, to which an orthogonal sequence is applied, includes a symbol group generated by spreading a symbol group with an orthogonal sequence according to a spreading factor, and

wherein the spreading factor is four (4).

8. The method of claim 1 , further comprising mapping the generated symbol group to four consecutive resource elements in a frequency domain, in order to map the generated symbol group to the OFDM symbol.

9. The method of claim 1 , wherein if a start symbol of an OFDM symbol, to which the symbol group is mapped, is defined as n=0, a symbol index n for the transmission of the symbol group is mapped in the order [010].

10. The method of claim 1 , wherein if a start symbol of an OFDM symbol, to which the symbol group is mapped, is defined as n=1, a symbol index n for the transmission of the symbol group is mapped in the order [101].

11. The method of claim 1 , wherein an alternating pattern based on the symbol index is changed for every at least two consecutive PHICH groups among a plurality of PHICH groups.

12. The method of claim 1 , wherein the generated symbol group is mapped to the OFDM symbol according to:

PHICH

Symbol Group

Symbol

Group g

Index r

Index n

0

0

0

0

1

1

0

2

0

1

0

0

1

1

1

1

2

0

2

0

1

2

1

0

2

2

1

3

0

1

3

1

0

3

2

1

. . .

. . .

. . ..

13. An apparatus for transmitting a symbol group in a mobile communication system, the apparatus comprising:

a processor for generating the symbol group to which an orthogonal sequence is applied, and mapping the generated symbol group to an Orthogonal Frequency Division Multiple (OFDM) symbol based on a symbol group index and a Physical HARQ Indicator Channel (PHICH) group index; and

a transmitter for transmitting the mapped symbol group,

wherein the generated symbol group is mapped to the OFDM symbol in an alternating pattern in accordance with the symbol group index.

14. The apparatus of claim 13 , wherein the generated symbol group is alternately mapped to a first OFDM symbol and a second OFDM symbol in order to be mapped to the OFDM symbol.

15. The apparatus of claim 13 , wherein a size of the symbol group index is three (3).

16. The apparatus of claim 13 , wherein the processor maps the generated symbol group to a multi-antenna array in an alternating pattern based on the symbol group index and the PHICH group index,

wherein the multi-antenna array includes four antennas.

17. The apparatus of claim 16 , wherein the generated symbol group is mapped to the OFDM symbol according to:

PHICH

Symbol Group

Symbol

Antenna Mapping

Group g

Index r

Index n

Pattern

0

0

0

A

0

1

1

B

0

2

0

A

1

0

0

B

1

1

1

A

1

2

0

B

2

0

1

A

2

1

0

B

2

2

1

A

3

0

1

B

3

1

0

A

3

2

1

B

. . .

. . .

. . .

. . ..

18. The apparatus of claim 16 , wherein at least one of complex conjugation and sign reversal is applied to map the generated symbol group to the multi-antenna array.

19. The apparatus of claim 13 , wherein the symbol group, to which an orthogonal sequence is applied, includes a symbol group generated by spreading a symbol group with an orthogonal sequence according to a spreading factor, and

wherein the spreading factor is four (4).

20. The apparatus of claim 13 , wherein the processor maps the generated symbol group to four consecutive resource elements in a frequency domain, in order to map the generated symbol group to the OFDM symbol.

21. The apparatus of claim 13 , wherein if a start symbol of an OFDM symbol, to which the symbol group is mapped, is defined as n=0, a symbol index n for the transmission of the symbol group is mapped in the order [010].

22. The apparatus of claim 13 , wherein if a start symbol of an OFDM symbol, to which the symbol group is mapped, is defined as n=1, a symbol index n for the transmission of the symbol group is mapped in the order [101].

23. The apparatus of claim 13 , wherein an alternating pattern based on the symbol index is changed for every at least two consecutive PHICH groups among a plurality of PHICH groups.

24. The apparatus of claim 13 , wherein the generated symbol group is mapped to the OFDM symbol according to:

PHICH

Symbol Group

Symbol

Group g

Index r

Index n

0

0

0

0

1

1

0

2

0

1

0

0

1

1

1

1

2

0

2

0

1

2

1

0

2

2

1

3

0

1

3

1

0

3

2

1

. . .

. . .

. . ..

25. A method for receiving a symbol group in a mobile communication system, the method comprising:

receiving a signal;

determining location information of the symbol group; and

acquiring the symbol group, to which an orthogonal sequence is applied, from the signal based on the location information,

wherein the symbol group is mapped to an Orthogonal Frequency Division Multiple (OFDM) symbol based on a symbol group index and a Physical HARQ Indicator Channel (PHICH) group index, and

wherein the symbol group is mapped to the OFDM symbol in an alternating pattern in accordance with the symbol group index.

26. The method of claim 25 , wherein the symbol group is alternately mapped to a first OFDM symbol and a second OFDM symbol in order to be mapped to the OFDM symbol.

27. The method of claim 25 , wherein a size of the symbol group index is three (3).

28. The method of claim 25 , wherein the symbol group is mapped to a multi-antenna array in an alternating pattern based on the symbol group index and the PHICH group index, and

wherein the multi-antenna array includes four antennas.

29. The method of claim 28 , wherein at least one of complex conjugation and sign reversal is applied to map the symbol group to the multi-antenna array.

30. The method of claim 28 , wherein the symbol group is mapped to the OFDM symbol according to:

PHICH

Symbol Group

Symbol

Antenna Mapping

Group g

Index r

Index n

Pattern

0

0

0

A

0

1

1

B

0

2

0

A

1

0

0

B

1

1

1

A

1

2

0

B

2

0

1

A

2

1

0

B

2

2

1

A

3

0

1

B

3

1

0

A

3

2

1

B

. . .

. . .

. . .

. . ..

31. The method of claim 25 , wherein the symbol group, to which an orthogonal sequence is applied, includes a symbol group generated by spreading a symbol group with an orthogonal sequence according to a spreading factor, and

wherein the spreading factor is four (4).

32. The method of claim 25 , wherein the symbol group is mapped to four consecutive resource elements in a frequency domain, in order to be mapped to the OFDM symbol.

33. The method of claim 25 , wherein if a start symbol of an OFDM symbol, to which the symbol group is mapped, is defined as n=0, a symbol index n for the transmission of the symbol group is mapped in the order [010].

34. The method of claim 25 , wherein if a start symbol of an OFDM symbol, to which the symbol group is mapped, is defined as n=1, a symbol index n for the transmission of the symbol group is mapped in the order [101].

35. The method of claim 25 , wherein an alternating pattern based on the symbol index is changed for every at least two consecutive PHICH groups among a plurality of PHICH groups.

36. The method of claim 25 , wherein the symbol group is mapped to the OFDM symbol according to:

PHICH

Symbol Group

Symbol

Group g

Index r

Index n

0

0

0

0

1

1

0

2

0

1

0

0

1

1

1

1

2

0

2

0

1

2

1

0

2

2

1

3

0

1

3

1

0

3

2

1

. . .

. . .

. . ..

37. An apparatus for receiving a symbol group in a mobile communication system, the apparatus comprising:

a receiver for receiving a signal; and

a controller for determining location information of the symbol group, and acquiring the symbol group, to which an orthogonal sequence is applied, from the signal based on the location information,

wherein the symbol group is mapped to an Orthogonal Frequency Division Multiple (OFDM) symbol based on a symbol group index and a Physical HARQ Indicator Channel (PHICH) group index, and

wherein the symbol group is mapped to the OFDM symbol in an alternating pattern in accordance with the symbol group index.

38. The apparatus of claim 37 , wherein the symbol group is alternately mapped to a first OFDM symbol and a second OFDM symbol in order to be mapped to the OFDM symbol.

39. The apparatus of claim 37 , wherein a size of the symbol group index is three (3).

40. The apparatus of claim 37 , wherein the symbol group is mapped to a multi-antenna array in an alternating pattern based on the symbol group index and the PHICH group index, and

wherein the multi-antenna array includes four antennas.

41. The apparatus of claim 40 , wherein at least one of complex conjugation and sign reversal is applied to map the symbol group to the multi-antenna array.

42. The apparatus of claim 40 , wherein the symbol group is mapped to the OFDM symbol according to:

PHICH

Symbol Group

Symbol

Antenna Mapping

Group g

Index r

Index n

Pattern

0

0

0

A

0

1

1

B

0

2

0

A

1

0

0

B

1

1

1

A

1

2

0

B

2

0

1

A

2

1

0

B

2

2

1

A

3

0

1

B

3

1

0

A

3

2

1

B

. . .

. . .

. . .

. . ..

43. The apparatus of claim 37 , wherein the symbol group, to which an orthogonal sequence is applied, includes a symbol group generated by spreading a symbol group with an orthogonal sequence according to a spreading factor, and

wherein the spreading factor is four (4).

44. The apparatus of claim 37 , wherein the symbol group is mapped to four consecutive resource elements in a frequency domain, in order to be mapped to the OFDM symbol.

45. The apparatus of claim 37 , wherein if a start symbol of an OFDM symbol, to which the symbol group is mapped, is defined as n=0, a symbol index n for the transmission of the symbol group is mapped in the order [010].

46. The apparatus of claim 37 , wherein if a start symbol of an OFDM symbol, to which the symbol group is mapped, is defined as n=1, a symbol index n for the transmission of the symbol group is mapped in the order [101].

47. The apparatus of claim 37 , wherein an alternating pattern based on the symbol index is changed for every at least two consecutive PHICH groups among a plurality of PHICH groups.

48. The apparatus of claim 37 , wherein the symbol group is mapped to the OFDM symbol according to:

PHICH

Symbol Group

Symbol

Group g

Index r

Index n

0

0

0

0

1

1

0

2

0

1

0

0

1

1

1

1

2

0

2

0

1

2

1

0

2

2

1

3

0

1

3

1

0

3

2

1

. . .

. . .

. . ..