A communication device , comprising: - a receiver circuit configured to receive a signal, wherein the signal is an ultra-wideband, UWB, pulse signal; - a controller configured to control said receiver circuit , wherein said controller is configured to cause said receiver circuit to operate either in a complex receiver mode or in a real receiver mode; wherein the controller is configured to cause said receiver circuit to operate in the real receiver mode until the signal is successfully acquired; characterized in that the controller is further configured to cause the receiver circuit to use, in the complex receiver mode, an I-channel and a Q-channel of the received signal; wherein the controller is further configured to cause the receiver circuit to use, in the real receiver mode, only said I-channel of the received signal or only said Q-channel of the received signal; wherein the controller is further configured to apply, when the receiver circuit operates in the real receiver mode, a local oscillator frequency which is different from the local oscillator frequency applied when the receiver circuit operates in the complex receiver mode, and wherein the controller is configured to offset, when the receiver circuit operates in the real receiver mode, the local oscillator frequency of the receiver circuit by a fraction of the pulse rate. - a receiver circuit configured to receive a signal, wherein the signal is an ultra-wideband, UWB, pulse signal; - a controller configured to control said receiver circuit , wherein said controller is configured to cause said receiver circuit to operate either in a complex receiver mode or in a real receiver mode; wherein the controller is configured to cause said receiver circuit to operate in the real receiver mode until the signal is successfully acquired; characterized in that the controller is further configured to cause the receiver circuit to use, in the complex receiver mode, an I-channel and a Q-channel of the received signal; wherein the controller is further configured to cause the receiver circuit to use, in the real receiver mode, only said I-channel of the received signal or only said Q-channel of the received signal; wherein the controller is further configured to apply, when the receiver circuit operates in the real receiver mode, a local oscillator frequency which is different from the local oscillator frequency applied when the receiver circuit operates in the complex receiver mode, and wherein the controller is configured to offset, when the receiver circuit operates in the real receiver mode, the local oscillator frequency of the receiver circuit by a fraction of the pulse rate. wherein the controller is configured to cause said receiver circuit to operate in the real receiver mode until the signal is successfully acquired; characterized in that the controller is further configured to cause the receiver circuit to use, in the complex receiver mode, an I-channel and a Q-channel of the received signal; wherein the controller is further configured to cause the receiver circuit to use, in the real receiver mode, only said I-channel of the received signal or only said Q-channel of the received signal; wherein the controller is further configured to apply, when the receiver circuit operates in the real receiver mode, a local oscillator frequency which is different from the local oscillator frequency applied when the receiver circuit operates in the complex receiver mode, and wherein the controller is configured to offset, when the receiver circuit operates in the real receiver mode, the local oscillator frequency of the receiver circuit by a fraction of the pulse rate. <EOS>