Methods, systems, and devices for wireless communication are described. In some examples, a wireless system may use a staggered uplink/downlink (UL/DL) format in which the symbol periods of the downlink are offset from the symbol periods of the uplink. Thus, if a user equipment (UE) receives a transmission in a first symbol period, it may decode the transmission and transmit a response in a staggered symbol period (e.g., in a UL control channel symbol period beginning one half of a symbol period after the first symbol period). A base station may then receive the response and, if it is a negative acknowledgement (NACK), retransmit during the third symbol period following the first symbol period. In another example, thin control channels may be used to reduce the round trip time between receiving a transmission and a retransmission.