Patent ID: 7733949
Filing Date: 2010-06-08
Classification: H04B

Abstract:
1. A wireless communications system comprising: at least one transmitter configured to modulate at least one input signal with a first carrier to generate a modulated output signal; and at least one receiver configured to receive the modulated output signal and to demodulate the modulated output signal received by the receiver with a second carrier that is at a frequency different from a frequency of the first carrier, wherein the at least one receiver is configured to generate at least one demodulated output signal comprising frequency components including a first carrier leakage component of the transmitter and a second carrier leakage component of the receiver, wherein a frequency of the first carrier leakage component of the transmitter and a frequency of the second carrier leakage component of the receiver are offset by a first value, and wherein the frequency components comprise a first sideband noise component of the transmitter corresponding to the input signal and a second sideband noise component of the receiver corresponding to the modulated output signal received by the receiver such that the first and second sideband noise components are at respective frequencies which are offset from one another by a second value; wherein at least one of the first and second carriers is adjusted such that a difference between the frequency of the first carrier and the frequency of the second carrier causes the carrier leakage components and the sideband noise components of the transmitter and receiver to fall uniformly in separate non-overlapping regions of frequency spectrum; wherein the transmitter is configured to perform a calibration procedure to suppress the first and second sideband noise components and the first and second carrier leakage components; and wherein the transmitter is configured to perform the calibration procedure in real-time at time instances during operation of the transmitter to adjust suppression of the first and second sideband noise components and the first and second carrier leakage components according to temporal changes in characteristics of imbalance and carrier leakage.