A multi-mode wireless transmit/receive unit (WTRU) includes at least one antenna, first and second communication mode receivers and a first communication mode transmitter. The first and second receivers simultaneously receive signals from the antenna. The first transmitter generates and sends a first type of signal to the antenna while, at the same time, the second receiver receives a second type of signal from the antenna. In a preferred embodiment, the WTRU further includes a vector multiplier configured to reduce or eliminate interference of signals received by the second receiver, the interference being caused by the first transmitter. The vector multiplier adjusts the phase and amplitude of noise (i.e., spurious in-band noise) measured by the second receiver. The WTRU may further include a second communication mode transmitter configured to generate and send a second type of signal to the antenna.