1. A method of wireless communication, comprising:performing, by a transmitter node, a listen before talk (LBT) procedure on a transmission channel shared by one or more synchronous or asynchronous network nodes;
transmitting, by the transmitter node, a fixed-length preamble in response to passing the LBT procedure;
transmitting, by the transmitter node, a dynamic length cyclic prefix after the preamble, wherein the dynamic length cyclic prefix includes a normal cyclic prefix plus a dynamic period; and
transmitting, by the transmitter node, a channel reservation message after the dynamic length cyclic prefix.