An apparatus of an evolved Node B or a Fifth Generation Node B comprises one or more baseband processors to generate an RRCConnectionReconfiguration message to include an information element (IE) to configure a user equipment (UE) to receive data from a Long-Term Evolution node and from a New Radio node in a unified split bearer configuration and encode data to be transmitted to the UE via a master cell group bearer, a secondary cell group bearer, or a unified split bearer. The baseband processors further are to encode an IE of an RRCReconfiguration message to configure a data radio bearer as a Packet Data Convergence Protocol and higher layers configuration coupled with one or more logical channels of radio link control and below, and to configure a change between a single connectivity bearer to multi-connectivity bearer by configuring or releasing one or more of the logical channels.