A wireless device receives configuration parameters indicating: a plurality of hybrid automatic repeat request (HARQ) processes of a cell; a subset of the plurality of HARQ processes; and a HARQ process identifier offset. A downlink control information (DCI) comprising a first HARQ process identifier and a resource assignment is received. The first HARQ process identifier indicates a HARQ process in the subset of the plurality of HARQ processes. A second HARQ process identifier is determined based on the first HARQ process identifier and the HARQ process identifier offset. The second HARQ process identifier indicates a second HARQ process of the plurality of HARQ processes. Based on the resource assignment, a transport block of a HARQ buffer associated with the second HARQ process is transmitted.