Method and apparatus for preventing transmitter leakage

Abstract

Method and transceiver arrangements for reducing a leakage signal's impact on a receiver partof the transceiver arrangement. The leakage signal originates from a transmitter partof the transceiver arrangement. The radio base station is adapted to communicate in a Time Division Duplex, TDD mode in a cellular network. The method comprises frequency shifting, by the transmitter part, a downlink, DL, baseband by an offset frequency, f, the DL baseband comprising DL data. Furthermore, the method comprises to mixing, by the transmitter part (), the frequency shifted DL baseband with a Transmitter Local Oscillator, TX LO, frequency, fto produce a DL signal spectrum. The offset frequency, f, and the TX LO frequency fis selected such that f=f−f, or f=f+fwhere fis the center frequency of the DL signal spectrum, such that the TX LO leakage signal reachingthe receiver partis located outside, or on an edge of a UL signal spectrum when received by the receiver part. By frequency shifting an output frequency of a transmitter local oscillator with an offset frequency, and frequency shifting a transmitter baseband with the offset frequency, but in a reverse direction, leakage signals originating from the transmitter local oscillator may be prevented from affecting a receiver RF spectrum, without affecting the transmitter RF spectrum.