Methods, systems, and devices for wireless communications are described. A base station may transmit control information to a UE in a shortened physical downlink control channel (sPDCCH). The sPDCCH may be included in shortened resource element groups (sREGs) of shortened channel control elements (sCCEs), which may be indexed in resource block (RB) sets by using localized or distributed mapping schemes. Updated sREG mapping schemes may result in a uniform distribution of sREGs within available symbols (and, as a result, a uniform distribution of unused resource blocks within the available symbols) and may ensure that sREGs within an sCCE are indexed into only one symbol.