Methods, systems, and devices for wireless communications are described. In some systems (e.g., new radio (NR) wireless communications systems), a base station may serve a large number of user equipment (UEs). The base station may allocate uplink control channel resources to the UEs using a limited number of bits by implementing explicit and implicit resource mapping. Explicit mapping may involve determining certain indicated resources based on a received set of bits, and implicit mapping may involve determining a resource indication from a characteristic of a transmission (e.g., a starting control channel element (CCE) for a downlink control information (DCI) transmission). A UE may determine an allocated uplink control channel resource for transmission based on the combination of the two types of indications. Additionally, the UE may implement one or more techniques for handling colliding resource allocations (e.g., acknowledgement (ACK), channel quality indicator (CQI), or scheduling request (SR) resource allocations).