A method for receiving downlink control information, DCI, by a user equipment, UE,, the method comprising: receiving the DCI in a search space of an aggregation level L in a control region of a transmission time interval, TTI; and receiving downlink data based on the DCI, wherein the TTI is divided into the control region and a data region in a time domain, wherein the TTI consists of 14 orthogonal frequency division multiplexing, OFDM, symbols in the time domain, wherein the control region spans a maximum of 3 OFDM symbols located in a front part of the TTI, wherein the control region includes multiple search spaces, wherein the multiple search spaces have different aggregation levels, wherein the search space of the aggregation level L consists of N_L decoding candidates, wherein the data region includes short TTIs #0 to M-1 in the time domain, wherein each of the short TTIs #0 to M-1 includes more than one OFDM symbols in the time domain, where M is an integer larger than 1, wherein each of the short TTIs #1 to M-1 is divided into a short control region for a short data region and the short data region in the time domain, wherein if the DCI is received in one of first X decoding candidates among the N_L decoding candidates in the search space of the aggregation level L, where X is a positive integer smaller than N_L, the downlink data is received on a first downlink data channel allocated across the entire data region of the TTI in the time domain, and wherein if the DCI is received in one of remaining decoding candidates other than the first X decoding candidates among the N_L decoding candidates, the downlink data is received on a second downlink data channel allocated across the short data region of the short TTI #0. receiving the DCI in a search space of an aggregation level L in a control region of a transmission time interval, TTI; and receiving downlink data based on the DCI, wherein the TTI is divided into the control region and a data region in a time domain, wherein the TTI consists of 14 orthogonal frequency division multiplexing, OFDM, symbols in the time domain, wherein the control region spans a maximum of 3 OFDM symbols located in a front part of the TTI, wherein the control region includes multiple search spaces, wherein the multiple search spaces have different aggregation levels, wherein the search space of the aggregation level L consists of N_L decoding candidates, wherein the data region includes short TTIs #0 to M-1 in the time domain, wherein each of the short TTIs #0 to M-1 includes more than one OFDM symbols in the time domain, where M is an integer larger than 1, wherein each of the short TTIs #1 to M-1 is divided into a short control region for a short data region and the short data region in the time domain, wherein if the DCI is received in one of first X decoding candidates among the N_L decoding candidates in the search space of the aggregation level L, where X is a positive integer smaller than N_L, the downlink data is received on a first downlink data channel allocated across the entire data region of the TTI in the time domain, and wherein if the DCI is received in one of remaining decoding candidates other than the first X decoding candidates among the N_L decoding candidates, the downlink data is received on a second downlink data channel allocated across the short data region of the short TTI #0.