Receiver Architecture for Frequency Offset Correction and I/Q Imbalance Compensation in Equal Bandwidth Contiguous Carrier Aggregation

A highly efficient receiver architecture for intraband contiguous carrier aggregation (CA) is described. The downconversion architecture is done in two stages; the first stage is done in the analog domain using a direct-conversion receiver, whereas the second stage is done in the digital domain using offset frequency digital mixing to separate the carriers. The novelty in the architecture stems from its ability to compensate for the different carrier frequency offsets (CFOs) between the two transmitted carriers, and unlike traditional approaches, the receiver uses a single complex digital mixer for baseband carrier separation. The receiver architecture also compensates for in-phase and quadrature gain and phase imbalance (IQI) inherent in direct-conversion receivers. It is shown that, in our new architecture, IQI compensation can be done post the digital mixer, thus enabling a low-power implementation to this impairment.