A method for pre-correcting a downlink signal characterized in: obtaining uplink frequency shifts of a first Remote Radio Unit, RRU, and a second RRU corresponding to each client respectively, wherein the first RRU is an RRU of the client operating at the highest power, and the second RRU is an RRU of the client operating at the second highest power; determining a set of uplink frequency shifts corresponding to each RRU respectively based upon the uplink frequency shifts of the first RRU and the second RRU corresponding to each client, wherein the set of uplink frequency shifts corresponding to an RRU comprises uplink frequency shifts of the first RRUs or the second RRUs corresponding to all clients operating with the RRU; and upon determining that a downlink pre-correction periodicity arrives, performing respectively for each RRU the operations of: calculating an average uplink frequency shift of the RRU based upon the uplink frequency shifts, of the first RRUs or the second RRUs corresponding to all clients operating with the RRU, in the set of frequency shifts of the RRU, and obtaining a downlink pre-correction value of the RRU in a last pre-correction periodicity; and determining a downlink pre-correction value of the RRU in a current downlink pre-correction periodicity based upon the average uplink frequency shift of the RRU and the downlink pre-correction value of the RRU in the last pre-correction periodicity. obtaining uplink frequency shifts of a first Remote Radio Unit, RRU, and a second RRU corresponding to each client respectively, wherein the first RRU is an RRU of the client operating at the highest power, and the second RRU is an RRU of the client operating at the second highest power; determining a set of uplink frequency shifts corresponding to each RRU respectively based upon the uplink frequency shifts of the first RRU and the second RRU corresponding to each client, wherein the set of uplink frequency shifts corresponding to an RRU comprises uplink frequency shifts of the first RRUs or the second RRUs corresponding to all clients operating with the RRU; and upon determining that a downlink pre-correction periodicity arrives, performing respectively for each RRU the operations of: calculating an average uplink frequency shift of the RRU based upon the uplink frequency shifts, of the first RRUs or the second RRUs corresponding to all clients operating with the RRU, in the set of frequency shifts of the RRU, and obtaining a downlink pre-correction value of the RRU in a last pre-correction periodicity; and determining a downlink pre-correction value of the RRU in a current downlink pre-correction periodicity based upon the average uplink frequency shift of the RRU and the downlink pre-correction value of the RRU in the last pre-correction periodicity. calculating an average uplink frequency shift of the RRU based upon the uplink frequency shifts, of the first RRUs or the second RRUs corresponding to all clients operating with the RRU, in the set of frequency shifts of the RRU, and obtaining a downlink pre-correction value of the RRU in a last pre-correction periodicity; and determining a downlink pre-correction value of the RRU in a current downlink pre-correction periodicity based upon the average uplink frequency shift of the RRU and the downlink pre-correction value of the RRU in the last pre-correction periodicity.