A retransmission control method in a Multiple User Shared Access, MUSA, process, wherein the MUSA process comprises: multiple User Equipment, UEs, utilize an orthogonal or quasi-orthogonal spreading sequence having low correlation characteristics to spread data and transmit the data on an Orthogonal Frequency Division Multiplexing, OFDM, channel, the method comprising: allocating, by a Mobility Management Entity, MME, an MUSA number to each one of the multiple UEs; receiving, by a base station, a data packet sent by one of the multiple UEs within an uplink MUSA resource range instructed by the base station; indicating, by the base station, by using an MUSA Radio Network Temporary Identity, MUSA-RNTI, a radio resource block for transmitting Acknowledgement, ACK, information; and broadcasting, by the base station, in the indicated radio resource block, the MUSA number of a UE having sent a data packet that is correctly received or the MUSA number of a UE having sent a data packet that is not correctly received, the broadcasting of the MUSA number enabling the UE to determine whether to retransmit the data packet that has been sent; characterized in that the method further comprises: receiving, by the base station, an MUSA number update request message sent by the UE; and sending, by the base station, an MUSA number update accepting message to the UE, the MUSA number update accepting message comprising: a new allocated MUSA number, an effective range of a new MUSA number, an MUSA capability indicator of the UE, and an MUSA service demand indicator of the UE, wherein the effective range is a cell or a tracking region, or a group of cells or tracking regions; and wherein the MUSA number update accepting message enables the UE to update the MUSA number. allocating, by a Mobility Management Entity, MME, an MUSA number to each one of the multiple UEs; receiving, by a base station, a data packet sent by one of the multiple UEs within an uplink MUSA resource range instructed by the base station; indicating, by the base station, by using an MUSA Radio Network Temporary Identity, MUSA-RNTI, a radio resource block for transmitting Acknowledgement, ACK, information; and broadcasting, by the base station, in the indicated radio resource block, the MUSA number of a UE having sent a data packet that is correctly received or the MUSA number of a UE having sent a data packet that is not correctly received, the broadcasting of the MUSA number enabling the UE to determine whether to retransmit the data packet that has been sent; characterized in that the method further comprises: receiving, by the base station, an MUSA number update request message sent by the UE; and sending, by the base station, an MUSA number update accepting message to the UE, the MUSA number update accepting message comprising: a new allocated MUSA number, an effective range of a new MUSA number, an MUSA capability indicator of the UE, and an MUSA service demand indicator of the UE, wherein the effective range is a cell or a tracking region, or a group of cells or tracking regions; and wherein the MUSA number update accepting message enables the UE to update the MUSA number. receiving, by the base station, an MUSA number update request message sent by the UE; and sending, by the base station, an MUSA number update accepting message to the UE, the MUSA number update accepting message comprising: a new allocated MUSA number, an effective range of a new MUSA number, an MUSA capability indicator of the UE, and an MUSA service demand indicator of the UE, wherein the effective range is a cell or a tracking region, or a group of cells or tracking regions; and wherein the MUSA number update accepting message enables the UE to update the MUSA number.