Methods, systems, and devices for wireless communication are described. A base station may communicate with multiple user equipments (UEs) in a wireless system supporting directional transmission in shared spectrum (e.g., in millimeter wave (mmW) spectrum). The base station may contend for the channel (e.g., using a listen-before-talk (LBT) procedure) and, upon success, transmit a directional channel reservation (CR) signal to each of the multiple UEs. The CR signal may reserve the channel for a specific time period and indicate a start time, an end time, or both. The UE may respond with another CR transmission. In some examples, the base station may transmit CR signals to each of the UEs in a single burst transmission. In other examples, the base station may transmit CR signals to the UEs sequentially, so that if a UE does not respond, the reserved time may be allotted to another UE.