The present invention discloses a communication method, a network device, user equipment, and a communications system. The communication method includes: determining, by a network device, to allocate a first secondary cell group to user equipment; and sending, by the network device, first configuration indication information to the user equipment, where the first configuration indication information is used to indicate at least one type of the following configuration: transmitting uplink control information related to a cell in the first secondary cell group by using a physical uplink control channel of a first cell, where the first cell belongs to a second secondary cell group of the user equipment; or processing data transmission on at least one cell in the first secondary cell group by using a layer 2 functional entity located in the second secondary cell group. The communication method disclosed in the present invention can reduce complexity of UE.
