Methods, systems, and devices are described for indexing control channel elements to determine uplink channel resources. Downlink control messages may be monitored in a set of downlink subframes. The monitoring may include monitoring physical downlink control channel (PDCCH) messages in at least one of the subframes and monitoring enhanced physical downlink control channel (EPDCCH) messages in at least one of the subframes. A downlink control message may be received in at least one subframe. The downlink control message may include an EPDCCH message. An index for enhanced control channel elements (ECCEs) may be determined based at least in part on the set of downlink subframes. The determined index of the ECCEs may be used to identify uplink control channel resources. The ECCEs may be indexed in a manner that is specific to a cell in a wireless communication system, or which is configured for a particular mobile device.