Patent ID: 8243851

Claim:
A radio system for relaying radio signals, the radio system comprising: at least one transmit path adapted to forward a payload signal as a transmit signal, at least one amplifier adapted to amplify the transmit signal, at least one duplex filter adapted to separate the transmit signal as a relayed transmit signal from a receive signal, a digital predistortion unit adapted to apply a digital predistortion to the payload signal for linearising a transfer characteristic of the radio system, a calibration unit adapted to apply phase and amplitude changes to the at least one transmit path, at least one coupler to extract coupled transmit signals extracted from the transmit signal, a feedback path commonly used by the digital predistortion unit and the calibration unit for feeding back a selected one of the coupled transmit signals as a feedback signal, at least one switch located in close proximity to an output of the at least one amplifier, the at least one switch being configured to switch between the coupled transmit signals and the relayed transmit signal relayed by the at least one duplex filter, thereby forwarding a selected one of the coupled transmit signals and the relayed transmit signal, a multi-way switch located at a distance from the at least one transmit path, the multi-way switch being adapted to select said selected one of the coupled transmit signals and the relayed transmit signal as a feedback signal, wherein at least one of: the phase and amplitude changes and the digital predistortion is adaptable using the feedback signal.