Methods and apparatuses for transmitting and detecting channel reservation preamble in a NR shared spectrum are described. An aspect may include determining whether a first reservation preamble of a first operator is received on a first time slot of multiple time slots of a downlink channel from a first network entity, and transmitting a second reservation preamble of the first operator on an uplink channel to the second network entity. Another aspect may include generating a first reservation preamble of a first operator based on at least one of a compressed representation in a signal space, a basis function of the signal space, or a CAZAC sequences; and transmitting, on a first timeslot of multiple time slots of a downlink channel, the first reservation preamble of the first operator to at least a UE. In another aspect, the SFN transmission of the first and second reservation preambles, and the low latency detection methods of the reservation preambles have been disclosed.