This paper discusses different approaches used for millimeter wave imaging of 2D objects. Imaging of a 2D object requires reflected wave data to be collected across two distinct dimensions. In this paper, we propose a reconstruction method that uses narrowband waveforms along with 2D beam steering. The beam is steered in azimuthal and elevation direction, which forms the two distinct dimensions required for the reconstruction. The reconstruction technique uses inverse Fourier transform along with amplitude and phase correction factors. In addition, this reconstruction technique does not require interpolation of the data in either wavenumber or spatial domain. Use of the 2D beam steering offers better performance in the presence of noise compared with the existing methods, such as switched array imaging system. Effects of radio-frequency impairments such as quantization of the phase of beam steering weights and timing jitter, which add to phase noise, are analyzed.
For massive MIMO system, few research has been done for multipath frequency selective fading model among all literatures. Hence, in this paper we propose a 2-stage multibranch linear MOE (minimum output energy) receiver which collects symbols from different paths to deal with frequency selective fading environment. Due to the big number of antennas, we are using sample covariance matrix other than estimating all channels. To avoid collecting large number of samples (which requires additional storage resources and may cause significant system delay), we are focusing on detection methods which use less samples. With the aid of a new method of singular matrix preconditioning and efficient series expansion, we are able to show that this implementation not only achieves lower computational complexity but also outperforms the conventional reduced-rank receiver and the single branch MOE receiver as well.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.