Patent ID: 8594158

Claim:
A base station—repeater station pair, comprising: a base station having an input for a broadcast signal and being arranged to transmit, in use, a transfer signal over a link using electromagnetic (EM) radiation; and a repeater station arranged to receive, in use and through EM radiation, the transfer signal from the base station and from the transfer signal broadcast the broadcast signal using EM radiation, in which the link between the base station and the repeater station over which the transfer signal is passed in use comprises a dual polarised link, whereby the base station is arranged to transmit the transfer signal over the link with two different polarisations, and the repeater station is arranged to receive the transfer signal from the link as two differently polarised versions, in which the base station comprises two differently polarised transfer antennas, which form part of the link and from which the transfer signal is transmitted in use, in which the repeater station comprises two differently polarised transfer antennas, which form part of the link and on each of which the repeater station is arranged to receive one of the versions of the transfer signal; and two broadcast antennas on which the broadcast signal is broadcast, in which the repeater station broadcast antennas are not differently polarized, in which the base station comprises two phase and/or amplitude modulators and is arranged so as to apply the broadcast signal to the two phase and/or amplitude modulators, the phase and/or amplitude modulators being arranged so as to, in use, apply different shifts in amplitude and/or phase to the broadcast signal, and to output the respective resultant signals to respective ones of the transfer antennas, in which the broadcast signal comprises two sub-signals, in which the phase and/or amplitude modulators are arranged to apply different shifts to the two sub-signals, and in which the shifts are such that each of the sub-signals is transmitted from a different broadcast antenna at the repeater station.