Patent ID: 7953169

Claim:
A method for transmitting a spread signal at a base station in a mobile communication system, the method comprising: spreading a signal using a plurality of spreading codes, wherein the plurality of spreading codes have a spreading factor of 4; coding the spread signal for multiple antenna transmission; multiplexing the coded spread signal by code division multiplexing for each antenna; transmitting the multiplexed signal via four neighboring frequency resources of one orthogonal frequency-division multiplexing (OFDM) symbol of a first antenna set comprising two antennas; and transmitting the same multiplexed signal via four neighboring frequency resources of one OFDM symbol of a second antenna set comprising two antennas, wherein the multiplexed signal transmitted via the first antenna set and the multiplexed signal transmitted via the second antenna set are transmitted via different OFDM symbols, wherein the multiplexed signal transmitted via the first antenna set and the multiplexed signal transmitted via the second antenna set are separated from each other by a plurality of subcarriers in a frequency domain, wherein the spread signal is coded between the two antennas in each of the first antenna set and the second antenna set as shown in Table 1: TABLE 1 neighboring frequency resources in one OFDM symbol antenna A f 1 (a 1 ) f 2 (a 2 ) f 1 (a 3 ) f 2 (a 4 ) antenna B f 3 (a 2 ) f 4 (a 1 ) f 3 (a 4 ) f 4 (a 3 ) wherein antenna A and antenna B represent the two antennas in each of the first antenna set and second antenna set, f 1 (x)=x, f 2 (x)=x, f 3 (x)=−x* and f 4 (x)=x*, and a 1 to a 4 represent each element of the spread signal, and wherein the spread signal is an ACK/NACK signal for indicating whether or not uplink signal is successfully received.