A method for mapping acknowledge/negative acknowledge, ACK/NACK, information to four antennas to transmit ACK/NACK information in a mobile communication system, the method comprising: generating the ACK/NACK information spread with an orthogonal sequence according to a spreading factor; and mapping the spread ACK/NACK information to the four antennas based on a physical HARQ indicator channel, PHICH, group index and a repetition index, r, of a code division multiplexing, CDM, segment, wherein the spread ACK/NACK information are mapped to the four antennas according to the following manner, depending on the PHICH group index: when r =0, 1, 2, antenna mapping pattern is A', B', A', respectively, or when r =0, 1, 2, antenna mapping pattern is B', A', B', respectively, wherein the spread ACK/NACK information is two consecutive ACK/NACK information corresponding to the spreading factor for ACK/NACK transmission in a time-frequency domain and the spreading factor is two, wherein pattern A' is a pattern for sequentially mapping the spread ACK/NACK information to a CDM segment of a first antenna (1702, 1802) in a frequency domain, and sequentially mapping complex conjugates or sign-reversed signals of the spread ACK/NACK information to a CDM segment of a third antenna (1706, 1806) in the frequency domain, wherein pattern B' is a pattern for sequentially mapping the spread ACK/NACK information to a CDM segment of a second antenna (1704, 1804) in the frequency domain, and sequentially mapping complex conjugates or sign-reversed signals of the spread ACK/NACK information to a CDM segment of a forth antenna (1708, 1808) in the frequency domain, and wherein the spread ACK/NACK information is mapped to the four antennas according to the following table: PHICH group index repetition index r OFDM symbol index Antenna mapping pattern 0 0 1 A' 0 1 0 B' 0 2 1 A' 1 0 1 A' 1 1 0 B' 1 2 1 A' 2 0 1 B' 2 1 0 A' 2 2 1 B' 3 0 1 B' 3 1 0 A' 3 2 1 B' 4 0 0 A' 4 1 1 B' 4 2 0 A' 5 0 0 A' 5 1 1 B' 5 2 0 A' 6 0 0 B' 6 1 1 A' 6 2 0 B' 7 0 0 B' 7 1 1 A' 7 2 0 B'............ generating the ACK/NACK information spread with an orthogonal sequence according to a spreading factor; and mapping the spread ACK/NACK information to the four antennas based on a physical HARQ indicator channel, PHICH, group index and a repetition index, r, of a code division multiplexing, CDM, segment, wherein the spread ACK/NACK information are mapped to the four antennas according to the following manner, depending on the PHICH group index: when r =0, 1, 2, antenna mapping pattern is A', B', A', respectively, or when r =0, 1, 2, antenna mapping pattern is B', A', B', respectively, wherein the spread ACK/NACK information is two consecutive ACK/NACK information corresponding to the spreading factor for ACK/NACK transmission in a time-frequency domain and the spreading factor is two, wherein pattern A' is a pattern for sequentially mapping the spread ACK/NACK information to a CDM segment of a first antenna (1702, 1802) in a frequency domain, and sequentially mapping complex conjugates or sign-reversed signals of the spread ACK/NACK information to a CDM segment of a third antenna (1706, 1806) in the frequency domain, wherein pattern B' is a pattern for sequentially mapping the spread ACK/NACK information to a CDM segment of a second antenna (1704, 1804) in the frequency domain, and sequentially mapping complex conjugates or sign-reversed signals of the spread ACK/NACK information to a CDM segment of a forth antenna (1708, 1808) in the frequency domain, and wherein the spread ACK/NACK information is mapped to the four antennas according to the following table: PHICH group index repetition index r OFDM symbol index Antenna mapping pattern 0 0 1 A' 0 1 0 B' 0 2 1 A' 1 0 1 A' 1 1 0 B' 1 2 1 A' 2 0 1 B' 2 1 0 A' 2 2 1 B' 3 0 1 B' 3 1 0 A' 3 2 1 B' 4 0 0 A' 4 1 1 B' 4 2 0 A' 5 0 0 A' 5 1 1 B' 5 2 0 A' 6 0 0 B' 6 1 1 A' 6 2 0 B' 7 0 0 B' 7 1 1 A' 7 2 0 B'............ when r =0, 1, 2, antenna mapping pattern is A', B', A', respectively, or when r =0, 1, 2, antenna mapping pattern is B', A', B', respectively, wherein the spread ACK/NACK information is two consecutive ACK/NACK information corresponding to the spreading factor for ACK/NACK transmission in a time-frequency domain and the spreading factor is two, wherein pattern A' is a pattern for sequentially mapping the spread ACK/NACK information to a CDM segment of a first antenna (1702, 1802) in a frequency domain, and sequentially mapping complex conjugates or sign-reversed signals of the spread ACK/NACK information to a CDM segment of a third antenna (1706, 1806) in the frequency domain, wherein pattern B' is a pattern for sequentially mapping the spread ACK/NACK information to a CDM segment of a second antenna (1704, 1804) in the frequency domain, and sequentially mapping complex conjugates or sign-reversed signals of the spread ACK/NACK information to a CDM segment of a forth antenna (1708, 1808) in the frequency domain, and wherein the spread ACK/NACK information is mapped to the four antennas according to the following table: PHICH group index repetition index r OFDM symbol index Antenna mapping pattern 0 0 1 A' 0 1 0 B' 0 2 1 A' 1 0 1 A' 1 1 0 B' 1 2 1 A' 2 0 1 B' 2 1 0 A' 2 2 1 B' 3 0 1 B' 3 1 0 A' 3 2 1 B' 4 0 0 A' 4 1 1 B' 4 2 0 A' 5 0 0 A' 5 1 1 B' 5 2 0 A' 6 0 0 B' 6 1 1 A' 6 2 0 B' 7 0 0 B' 7 1 1 A' 7 2 0 B'............