A radio base station for scheduling uplink transmissions for a user equipment, wherein at least one unlicensed cell is configured for communication between the user equipment and the radio base station, wherein the radio base station schedules an uplink transmission via the unlicensed cell according to one of at least the following different types of uplink transmissions: a first type of uplink transmission (Type A) which spans a complete subframe duration and starts and ends at subframe boundaries followed by the user equipment, and at least one of: a second type of uplink transmission (Type B) which spans a complete subframe duration, the uplink transmission being offset by a predetermined amount of time with respect to subframe boundaries followed by the user equipment such that the uplink transmission of the second type starts before/after a first subframe boundary and ends before/after a second subframe boundary being subsequent to the first subframe boundary, and a third type of uplink transmission (Type C) which spans less than a complete subframe duration, the uplink transmission being offset by a predetermined amount of time with respect to subframe boundaries followed by the user equipment, wherein the radio base station comprises a processor and transmitter, which, in operation, schedule uplink transmissions via the unlicensed cell to the at least one user equipment, wherein the radio base station comprises a receiver, which, in operation, receives the scheduled uplink transmissions from the at least one user equipment, wherein the radio base station schedules the uplink transmission such that the scheduled uplink transmission is performed by the at least one user equipment according to one of the different types of uplink transmissions in such a manner that at least between two directly-subsequent uplink transmissions a time gap with no uplink transmission occurs, and wherein the subframe boundaries followed by the user equipment are determined by the radio base station based on a timing advance procedure performed between the user equipment and the radio base station. wherein the radio base station schedules an uplink transmission via the unlicensed cell according to one of at least the following different types of uplink transmissions: a first type of uplink transmission (Type A) which spans a complete subframe duration and starts and ends at subframe boundaries followed by the user equipment, and at least one of: a second type of uplink transmission (Type B) which spans a complete subframe duration, the uplink transmission being offset by a predetermined amount of time with respect to subframe boundaries followed by the user equipment such that the uplink transmission of the second type starts before/after a first subframe boundary and ends before/after a second subframe boundary being subsequent to the first subframe boundary, and a third type of uplink transmission (Type C) which spans less than a complete subframe duration, the uplink transmission being offset by a predetermined amount of time with respect to subframe boundaries followed by the user equipment, a first type of uplink transmission (Type A) which spans a complete subframe duration and starts and ends at subframe boundaries followed by the user equipment, and at least one of: a second type of uplink transmission (Type B) which spans a complete subframe duration, the uplink transmission being offset by a predetermined amount of time with respect to subframe boundaries followed by the user equipment such that the uplink transmission of the second type starts before/after a first subframe boundary and ends before/after a second subframe boundary being subsequent to the first subframe boundary, and a third type of uplink transmission (Type C) which spans less than a complete subframe duration, the uplink transmission being offset by a predetermined amount of time with respect to subframe boundaries followed by the user equipment, a second type of uplink transmission (Type B) which spans a complete subframe duration, the uplink transmission being offset by a predetermined amount of time with respect to subframe boundaries followed by the user equipment such that the uplink transmission of the second type starts before/after a first subframe boundary and ends before/after a second subframe boundary being subsequent to the first subframe boundary, and a third type of uplink transmission (Type C) which spans less than a complete subframe duration, the uplink transmission being offset by a predetermined amount of time with respect to subframe boundaries followed by the user equipment, wherein the radio base station comprises a processor and transmitter, which, in operation, schedule uplink transmissions via the unlicensed cell to the at least one user equipment, wherein the radio base station comprises a receiver, which, in operation, receives the scheduled uplink transmissions from the at least one user equipment, wherein the radio base station schedules the uplink transmission such that the scheduled uplink transmission is performed by the at least one user equipment according to one of the different types of uplink transmissions in such a manner that at least between two directly-subsequent uplink transmissions a time gap with no uplink transmission occurs, and wherein the subframe boundaries followed by the user equipment are determined by the radio base station based on a timing advance procedure performed between the user equipment and the radio base station.