The application relates to a mobile terminal radio stack for D2D single channel (308) and a cellular uplink single channel (324). A D2D connection is a direct connection formed between a first mobile terminal and a second mobile terminal over the cellular radio spectrum. The D2D connection is a local communication link and is generally enabled for use over short distances. Because the D2D connection could be lost quite rapidly, handover (e.g. bearer establishment) of the D2D communications to traditional cellular communications e.g. Evolved Universal Mobile Telecommunications System Terrestrial Radio Access Network (E-UTRAN)) may not occur in time to synchronize the multiple mobile terminals. As a result, multiple protocol data units between the mobile terminals may be lost. This problem is solved in that in response to a handover indication, the mobile terminal may then cause a PDCP entity (318) that is associated with the D2D bearer that is undergoing handover to be associated with an additional RLC entity, such as an RLC entity associated with a cellular bearer, e.g. an Evolved Packet System EPS bearer (334). SDUs received via the logical channel related to the D2D connection (314) and SDUs received via the logical channel related to the cellular connection (334) are then transmitted via the same cellular bearer (330).