A method for handling a packet data convergence protocol, PDCP, duplication function in next generation wireless networks for a user equipment, UE, that is configured with a first cell group and a second cell group, the method comprising: receiving, from a base station, through radio resource control, RRC, signaling, a configuration for a PDCP entity, the configuration indicating: (i) an association between the PDCP entity and a plurality of radio link control, RLC, entities, each RLC entity associated with one of the first and second cell groups, wherein the plurality of RLC entities comprises at least three RLC entities; (ii) a first RLC entity in the plurality of RLC entities associated with the first cell group to be a primary RLC entity; and (iii) a second RLC entity in the plurality of RLC entities associated with the second cell group to be a secondary RLC entity; duplicating, by the PDCP entity, at least one of one or more PDCP protocol data units, PDUs; submitting, by the PDCP entity, the at least one and a duplicate of the at least one of the one or more PDCP PDUs to the primary RLC entity and at least another one of the plurality of RLC entities respectively, wherein a first subset of the plurality of RLC entities comprises one or more RLC entities indicated as active while a second subset of the plurality of RLC entities comprises one or more RLC entities indicated as inactive, and the at least another one of the plurality of RLC entities receiving the duplicated one or more PDCP PDUs is an RLC entity in the first subset of the plurality of RLC entities; deactivating the PDCP duplication function after receiving a medium access control, MAC, control element, CE, indicating to deactivate the PDCP duplication function; stopping duplication of subsequent PDCP PDUs after the PDCP duplication function is deactivated; selecting, for each of the subsequent PDCP PDUs, one of the primary and secondary RLC entities; and submitting each of the subsequent PDCP PDUs to the corresponding one of the selected one of the primary and secondary RLC entities. receiving, from a base station, through radio resource control, RRC, signaling, a configuration for a PDCP entity, the configuration indicating: (i) an association between the PDCP entity and a plurality of radio link control, RLC, entities, each RLC entity associated with one of the first and second cell groups, wherein the plurality of RLC entities comprises at least three RLC entities; (ii) a first RLC entity in the plurality of RLC entities associated with the first cell group to be a primary RLC entity; and (iii) a second RLC entity in the plurality of RLC entities associated with the second cell group to be a secondary RLC entity; (i) an association between the PDCP entity and a plurality of radio link control, RLC, entities, each RLC entity associated with one of the first and second cell groups, wherein the plurality of RLC entities comprises at least three RLC entities; (ii) a first RLC entity in the plurality of RLC entities associated with the first cell group to be a primary RLC entity; and (iii) a second RLC entity in the plurality of RLC entities associated with the second cell group to be a secondary RLC entity; duplicating, by the PDCP entity, at least one of one or more PDCP protocol data units, PDUs; submitting, by the PDCP entity, the at least one and a duplicate of the at least one of the one or more PDCP PDUs to the primary RLC entity and at least another one of the plurality of RLC entities respectively, wherein a first subset of the plurality of RLC entities comprises one or more RLC entities indicated as active while a second subset of the plurality of RLC entities comprises one or more RLC entities indicated as inactive, and the at least another one of the plurality of RLC entities receiving the duplicated one or more PDCP PDUs is an RLC entity in the first subset of the plurality of RLC entities; deactivating the PDCP duplication function after receiving a medium access control, MAC, control element, CE, indicating to deactivate the PDCP duplication function; stopping duplication of subsequent PDCP PDUs after the PDCP duplication function is deactivated; selecting, for each of the subsequent PDCP PDUs, one of the primary and secondary RLC entities; and submitting each of the subsequent PDCP PDUs to the corresponding one of the selected one of the primary and secondary RLC entities.