Aspects herein describe determining a channel format for transmitting uplink communications in a slot, wherein the channel format is selected from multiple channel formats based at least in part on a payload size of the uplink communications, determining a starting symbol and an ending symbol of an uplink channel duration of the slot for transmitting the uplink communications, determining, based at least in part on the starting symbol and the ending symbol, a portion of the channel format to utilize in transmitting the uplink communications in the slot, and transmitting the uplink communications in the slot, wherein transmitting the uplink communications is based on the portion of the channel format.