Apparatus for transmitting and receiving signals in a wireless communication network comprises a transmit antenna configured to transmit signals to the wireless communication network, a receive antenna configured to receive signals from the wireless communication network, and an energy harvesting unit. The energy harvesting unit is configured to harvest electrical energy from self-signal received at the receive antenna while a signal is being transmitted by the transmit antenna. In some embodiments, a signal splitter can be used to additionally harvest energy received from another device in the wireless communication network. In some embodiments the transmit and receive antennas can be the same physical antenna, and the apparatus can further comprise a fixed or reconfigurable coupling component to separate signals received and transmitted via said antenna. In some embodiments, the apparatus can be further configured to perform co-operative energy harvesting by harvesting electrical energy from one or more other devices, in addition to harvesting electrical energy from the self-signal.