This disclosure relates to techniques for supporting narrowband device-to-device wireless communication, including possible techniques for performing discovery in an off grid radio system. According to some embodiments, a wireless device may determine a number of synchronization signal repetitions to use for a narrowband device-to-device transmission. The wireless device may perform the transmission, including transmitting the determined number of synchronization signal repetitions. The transmission may include an indication of the number of synchronization signal repetitions used in the transmission.