A technique includes receiving, by a first user device from a base station, control information indicating an assignment of the first user device to a first scheduling request sub-pool of resources of one or more scheduling request sub-pools, and an assignment of the first user device to a first data sub-pool of resources of one or more data sub-pools, wherein the sub-pools assigned to the first user device allow a contention-based grant-free mode transmission from the first user device of both a data and a scheduling request at the same time via different resources, wherein for at least a plurality of user devices no two user devices are assigned to both a same data sub-pool and a same scheduling request sub-pool.