A method for performing a random access by a user equipment in a wireless communication system using an mmWave band, the method comprising: obtaining (S910, S1310) information on a sequence set and information on a phase pattern vector set among a plurality of phase pattern vector sets, wherein the sequence set and the phase pattern vector set comprise a plurality of sequences and a plurality of phase pattern vectors, respectively, and wherein respective phase pattern vector set among the plurality of phase pattern vector sets is pre-configured differently according to respective repetitive transmission count among a plurality of repetitive transmission counts for a random access channel, RACH, signal; selecting (S920, S1320) a phase pattern vector among the plurality of phase pattern vectors, wherein the phase pattern vector denotes a matrix applied to a sequence selected among the plurality of sequences; obtaining the RACH signal based on the sequence and the selected phase pattern vector, wherein a phase of the sequence is changed by applying the selected phase pattern vector to the sequence; transmitting (S930, S1330), to a base station, the RACH signal repeatedly as many times as a repetitive transmission count, included in the plurality of repetitive transmission counts, at a specific transmission timing in a whole time interval corresponding to a maximum repetitive transmission count; and receiving (S950, 1350), from the base station, a RACH response signal comprising information on an estimated sequence, information on an estimated phase pattern vector and information on an estimated transmission timing, wherein the specific transmission timing denotes a specific orthogonal frequency division multiplexing, OFDM, symbol with an index, and determined based on the maximum repetitive transmission count. obtaining (S910, S1310) information on a sequence set and information on a phase pattern vector set among a plurality of phase pattern vector sets, wherein the sequence set and the phase pattern vector set comprise a plurality of sequences and a plurality of phase pattern vectors, respectively, and wherein respective phase pattern vector set among the plurality of phase pattern vector sets is pre-configured differently according to respective repetitive transmission count among a plurality of repetitive transmission counts for a random access channel, RACH, signal; selecting (S920, S1320) a phase pattern vector among the plurality of phase pattern vectors, wherein the phase pattern vector denotes a matrix applied to a sequence selected among the plurality of sequences; obtaining the RACH signal based on the sequence and the selected phase pattern vector, wherein a phase of the sequence is changed by applying the selected phase pattern vector to the sequence; transmitting (S930, S1330), to a base station, the RACH signal repeatedly as many times as a repetitive transmission count, included in the plurality of repetitive transmission counts, at a specific transmission timing in a whole time interval corresponding to a maximum repetitive transmission count; and receiving (S950, 1350), from the base station, a RACH response signal comprising information on an estimated sequence, information on an estimated phase pattern vector and information on an estimated transmission timing, wherein the specific transmission timing denotes a specific orthogonal frequency division multiplexing, OFDM, symbol with an index, and determined based on the maximum repetitive transmission count.