A method for adjusting a Time Advance, TA, performed by a Coordinated Multi-Point transmission, CoMP, system comprising a user equipment, UE, an eNodeB and multiple access points, APs, each connected to the eNodeB, the multiple APs covering multiple serving cells serving the UE, the method comprising: a.) measuring, by the UE, an arrival time of a first downlink signal of a first cell selected by the UE among the multiple serving cells and measuring, by the UE, an arrival time of a second downlink signal of a synchronization cell of the multiple serving cells configured by the eNodeB, and determining, by the UE, a time difference between the arrival time of the first downlink signal of the first cell and the arrival time of the second downlink signal of the synchronization cell by subtracting the arrival time of the second downlink signal from the arrival time of the first downlink signal, wherein the synchronization cell is a cell at which an arrival time of any signal sent from the UE to the synchronization cell falls within a Cyclic Prefix, CP, of an Orthogonal Frequency Division Multiplexing, OFDM, receiving window of the synchronization cell, thereby arriving at a synchronization between the synchronization cell and the UE, wherein the OFDM receiving window comprises the CP and a data part, wherein furthermore the synchronization cell and the first cell are synchronized, so that a sending time point of the first and second downlink signal is a same, b.) determining, by the UE, whether one of a first or a second preset event is satisfied, wherein the first preset event is that the time difference is greater than an offset value, and the second preset event is that the time difference is less than (-1) × the offset value, wherein the offset value is the CP, c.) in case of yes in step b.), reporting, by the UE, an identifier, ID, of the satisfied event and an absolute value of the time difference to the eNodeB, d.) if the received ID of the satisfied event is an ID of the first preset event, determining, by the eNodeB, to increase the TA provided by the synchronization cell by the absolute value of the time difference, thereby arriving at an increased TA, so that uplink signals sent from the UE to an AP of the first cell arrive at the AP of the first cell within the CP, if the received ID of the satisfied event is an ID of the second preset event, determining, by the eNodeB, to decrease the TA provided by the synchronization cell by the absolute value of the time difference, thereby arriving at a decreased TA, so that the uplink signals sent from the UE to the AP of the first cell arrive at the AP of the first cell within the CP, e.) receiving, by the UE, an TA determined in step d.) from the eNodeB, and determining, by the UE, the received TA as a TA for sending uplink data to the first cell. a.) measuring, by the UE, an arrival time of a first downlink signal of a first cell selected by the UE among the multiple serving cells and measuring, by the UE, an arrival time of a second downlink signal of a synchronization cell of the multiple serving cells configured by the eNodeB, and determining, by the UE, a time difference between the arrival time of the first downlink signal of the first cell and the arrival time of the second downlink signal of the synchronization cell by subtracting the arrival time of the second downlink signal from the arrival time of the first downlink signal, wherein the synchronization cell is a cell at which an arrival time of any signal sent from the UE to the synchronization cell falls within a Cyclic Prefix, CP, of an Orthogonal Frequency Division Multiplexing, OFDM, receiving window of the synchronization cell, thereby arriving at a synchronization between the synchronization cell and the UE, wherein the OFDM receiving window comprises the CP and a data part, wherein furthermore the synchronization cell and the first cell are synchronized, so that a sending time point of the first and second downlink signal is a same, b.) determining, by the UE, whether one of a first or a second preset event is satisfied, wherein the first preset event is that the time difference is greater than an offset value, and the second preset event is that the time difference is less than (-1) × the offset value, wherein the offset value is the CP, c.) in case of yes in step b.), reporting, by the UE, an identifier, ID, of the satisfied event and an absolute value of the time difference to the eNodeB, d.) if the received ID of the satisfied event is an ID of the first preset event, determining, by the eNodeB, to increase the TA provided by the synchronization cell by the absolute value of the time difference, thereby arriving at an increased TA, so that uplink signals sent from the UE to an AP of the first cell arrive at the AP of the first cell within the CP, if the received ID of the satisfied event is an ID of the second preset event, determining, by the eNodeB, to decrease the TA provided by the synchronization cell by the absolute value of the time difference, thereby arriving at a decreased TA, so that the uplink signals sent from the UE to the AP of the first cell arrive at the AP of the first cell within the CP, e.) receiving, by the UE, an TA determined in step d.) from the eNodeB, and determining, by the UE, the received TA as a TA for sending uplink data to the first cell.