There is provided mechanisms for transmitting reference signals. A method is performed by a first network device. The method comprises transmitting, in a single orthogonal frequency-division multiplexing (OFDM) symbol, a composite reference signal to a second network device. The composite reference signal is a time domain concatenation of at least a first reference signal and a last reference signal. The composite reference signal has a single cyclic prefix. The cyclic prefix is determined according to a last part of the single OFDM symbol. There is also provided mechanisms for receiving such reference signals.