The disclosure describes frame structure with downlink/uplink subframe configuration and channel hopping scheme for unlicensed narrowband Internet-of-Things (IoT) systems. An apparatus operable for unlicensed narrowband transmission to support IoT service is disclosed. The apparatus includes baseband circuitry to select a transmission channel within an unlicensed narrow band for downlink transmission of a discovery reference signal (DRS), and for channel hopping, to select, according to the DRS, a communication channel within the unlicensed narrow band for downlink data and uplink data. The DRS includes a primary synchronization signal (PSS), a secondary synchronization signal (SSS) and physical broadcast channel (PBCH) content. The baseband circuitry is further to demodulate a received signal received via radio frequency (RF) circuitry through the communication channel over an uplink frame, and to modulate a transmitting signal to be transmitted via the RF circuitry through the communication channel over a downlink frame.