Carrier Aggregation Receiver with Beamformer and Compensation of Doppler Effects and Timing Offset

Abstract

Due to limitations in sampling capabilities for high frequency systems, the universal receiver at this time cannot sample the incoming signals just after a RF stage process. As one way, using sub-sampling technique can convert multi-band signals from RF band to IF band without oscillators. But as the filter performance in RF bands, signals converted to low bands possibly cause interference and degrade performances. In this paper, we extend a sub-sampling method to the case of multi-band receiver using pre-FFT beamformer, and a new approach is proposed to avoid interference by TDM method. The purpose of designing the pre-FFT beamformer is to coherently combine the desired signals and suppress the undesired signals so that it is able to provide medium to high gains in a mobile environment. Simulation results show that after compensating the Doppler effects and timing offset the approach works effectively and we can get optimal performances in the multi-band receiver.