A radio base station and a method therein are provided for allocating measurement gaps within a MGRP to UEs currently being served by the base station, wherein consideration is taken to the impact a measurement gap has on the HARQ processes. A plurality of possible measurement gaps are identified within the MGRP with regards to their starting point and duration in time within the MGRP. A number of HARQ processes that would be affected due to the identified measurement gaps with regards to a starting point in time of the identified measurement gaps during the MGRP are determined for the identified measurement gaps. The identified measurement gaps are ranked depending on the number of HARQ processes which would be affected during the MGRP and the identified measurement gaps are allocated to the UEs based on the ranking.