Methods, systems, and devices for wireless communication are described. A transmitting wireless device may select a direction for a wireless transmission over a channel The transmitting wireless device may monitor an availability of the channel in the selected direction for a duration of a first channel listening time corresponding to the selected direction. The transmitting wireless device may determine that the channel is available in the selected direction based on either an absence of channel reservation messages during the monitoring, or a first channel reservation message received during the monitoring. The first channel reservation message may indicate a permissibility of a simultaneous transmission in the selected direction. The transmitting wireless device may transmit a second channel reservation message to a receiving wireless device over the channel in the selected direction based on the determination that the channel is available in the selected direction.
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