The potential benefits of massive multiple-input multiple-output (MIMO) make it possible to achieve high-quality underwater acoustic (UWA) communications. Nevertheless, due the wideband nature UWA channels, existing MIMO techniques for radio frequency cannot be directly applied This paper investigates a system in shallow-water environment, deploying large array apertures at both transmitter and...

Abstract Massive MIMO will improve the performance of future 5G systems in terms data rate and spectral efficiency, while accommodating a large number users. Furthermore, it allows for 3D beamforming order to provide more degrees freedom increase high-throughput is expected advantages compared other solutions energy efficiency. This be achieved by focusing radiation towards direction intended u...

Massive multiple-input multiple-output (MIMO) is becoming a key technology for future 5G wireless communications. Channel feedback for massive MIMO is challenging due to the substantially increased dimension of MIMO channel matrix. In this letter, we propose a compressive sensing (CS) based differential channel feedback scheme to reduce the feedback overhead. Specifically, the temporal correlat...

In this paper we introduce a new 2D modulation technique called OTFS (Orthogonal Time Frequency & Space) that transforms information carried in the Delay-Doppler coordinate system to the familiar time-frequency domain utilized by traditional modulation schemes such as OFDM, CDMA and TDMA. OTFS converts the fading, time-varying wireless channel into a non-fading, time-independent interaction rev...

Due to the low per-antenna SNR and high signaling overhead, channel estimation is a major bottleneck in Massive MIMO systems. Spatial constraints can improve estimation performance by exploiting sparsity. Solutions exist for far field beam domain channel estimation based on angle of arrival estimation. However, there is no equivalent solution for near field and distributed MIMO spatial channel ...

Compared with the traditional multiple-input multiple-output (MIMO) systems, the large number of the transmit antennas of massive MIMO makes it more dependent on the limited feedback in practical systems. In this paper, we study the problem of precoding design for a massive MIMO system with limited feedback via minimizing mean square error (MSE). The feedback from mobile users to the base stati...

Modern wireless communication systems demanding high data rate operating in bandwidth deficient world is using Multiple Input Multiple Output (MIMO) antenna arrangement. MIMO arrangement helping achieving high data rates with a technique of special multiplexing saves bandwidth but needs efficient receivers with manageable hardware. The receivers employing linear equalizers or Decision Feedback ...