Patent 7155216 was granted and assigned to Nokia on December, 2006 by the United States Patent and Trademark Office.
A base station in a radio system includes a transmitter that forms a signal to be transmitted by a transmission antenna of the base station, a mechanism forming a portion of the signal to be transmitted in a transmission frequency, a mechanism shifting the formed signal portion into a receiving frequency, where the separation between the receiving frequency and the transmission frequency differs from a frequency duplex used in the radio system, and a mechanism receiving the frequency-shifted signal portion.