A terminal device comprising: • a receiver configured to receive cell load information of a plurality of cells in a first wireless communications system, cell interference information of the plurality of cells, cell data transmission delay information of the plurality of cells, and cell backhaul link capacity information of the plurality of cells from a second network device in a second wireless communications system, wherein the first wireless communications system uses a different access technology than the second wireless communications system, wherein the terminal device is further configured to perform a first wireless measurement process in which received signal strength information, RSRP, of the plurality of cells in the first wireless communications system is measured and is further configured to perform a second wireless measurement process in which a received signal quality information, RSRQ, of the plurality of cells in the first wireless communications system is measured, • a processor configured to select a target cell in the first wireless communications system among the plurality of cells in the first wireless communications system based on one or more types of the following information: ∘ the RSRP of the plurality of cells, ∘ the RSRQ of the plurality of cells, ∘ the cell load information of the plurality of cells, ∘ the cell interference information of the plurality of cells, ∘ the cell data transmission delay information of the plurality of cells, ∘ the cell backhaul link capacity information of the plurality of cells, • a transmitter configured to send cell identity information of the target cell selected by the processor to the second network device in the second wireless communications system, wherein • the receiver is configured to receive from the second network device, after the transmitter sends the cell identity information of the target cell selected by the processor to the second network device in the second wireless communications system, access information that is configured by a first network device to which the target cell belongs and that is used when the terminal device accesses the target cell, wherein the first and second network devices are base stations, and • the processor is further configured to control, according to the access information received by the receiver, the terminal device to access the target cell, thereby also accessing a core network in the first wireless communications system by using the first network device. • a receiver configured to receive cell load information of a plurality of cells in a first wireless communications system, cell interference information of the plurality of cells, cell data transmission delay information of the plurality of cells, and cell backhaul link capacity information of the plurality of cells from a second network device in a second wireless communications system, wherein the first wireless communications system uses a different access technology than the second wireless communications system, wherein the terminal device is further configured to perform a first wireless measurement process in which received signal strength information, RSRP, of the plurality of cells in the first wireless communications system is measured and is further configured to perform a second wireless measurement process in which a received signal quality information, RSRQ, of the plurality of cells in the first wireless communications system is measured, • a processor configured to select a target cell in the first wireless communications system among the plurality of cells in the first wireless communications system based on one or more types of the following information: ∘ the RSRP of the plurality of cells, ∘ the RSRQ of the plurality of cells, ∘ the cell load information of the plurality of cells, ∘ the cell interference information of the plurality of cells, ∘ the cell data transmission delay information of the plurality of cells, ∘ the cell backhaul link capacity information of the plurality of cells, ∘ the RSRP of the plurality of cells, ∘ the RSRQ of the plurality of cells, ∘ the cell load information of the plurality of cells, ∘ the cell interference information of the plurality of cells, ∘ the cell data transmission delay information of the plurality of cells, ∘ the cell backhaul link capacity information of the plurality of cells, • a transmitter configured to send cell identity information of the target cell selected by the processor to the second network device in the second wireless communications system, wherein • the receiver is configured to receive from the second network device, after the transmitter sends the cell identity information of the target cell selected by the processor to the second network device in the second wireless communications system, access information that is configured by a first network device to which the target cell belongs and that is used when the terminal device accesses the target cell, wherein the first and second network devices are base stations, and • the processor is further configured to control, according to the access information received by the receiver, the terminal device to access the target cell, thereby also accessing a core network in the first wireless communications system by using the first network device.