Massive multiuser (MU) multiple-input multiple-output (MIMO) is foreseen to be one of the key technologies in fifth-generation wireless communication systems. In this paper, we investigate problem downlink precoding for a narrowband massive MU-MIMO system with low-resolution digital-to-analog converters (DACs) at base station (BS). We analyze performance linear precoders, such as maximal-ratio transmission and zero-forcing, subject coarse quantization. Using Bussgang's theorem, derive...

We investigate the uplink throughput achievable by a multiple-user (MU) massive multiple-input multiple-output (MIMO) system in which base station is equipped with large number of low-resolution analog-to-digital converters (ADCs). Our focus on case where neither transmitter nor receiver have any priori channel state information. This implies that fading realizations to be learned through pilot transmission followed estimation at receiver, based coarsely quantized observations. propose novel...

We investigate the information-theoretic throughout achievable on a fading communication link when receiver is equipped with one-bit analog-to-digital converters (ADCs). The analysis conducted for setting where neither transmitter nor have priori information realization of channels. This means that channel-state needs to be acquired at basis quantized channel outputs. show least-squares (LS) estimation combined joint pilot and data processing capacity achieving in single-user,...

Massive multi-user (MU) multiple-input multiple-output (MIMO) will be a core technology in fifth-generation (5G) wireless systems as it offers significant improvements spectral efficiency compared to existing multi-antenna technologies. The presence of hundreds antenna elements at the base station (BS), however, results excessively high hardware costs and power consumption, requires interconnect throughput between baseband-processing unit radio unit. MU-MIMO that uses low-resolution...

We consider the downlink of a massive multiuser (MU) multiple-input multiple-output (MIMO) system in which base station (BS) is equipped with low-resolution digital-to-analog converters (DACs). In contrast to most existing results, we assume that operates over frequency-selective wideband channel and uses orthogonal frequency division multiplexing (OFDM) simplify equalization at user equipments (UEs). Furthermore, practically relevant case oversampling DACs. theoretically analyze uncoded bit...

Full-duplex relays can provide cost-effective cover-age extension and throughput enhancement. However, the main limiting factor is resulting self-interference signal which deteriorates relay performance. In this paper, we propose a novel technique for suppression in full-duplex Multiple-Input Multiple-Output (MIMO) relays. The employs transmit receive weight filters suppressing signal. Unlike existing techniques that are based on zero forcing of self-interference, aim at maximizing ratio...

In this work the modeling and capacity of a dual polarized (DP) MIMO channel is addressed. The includes parameters such as receive transmit correlation, cross-polarization discrimination (XPD), antenna polarization state, parallelity coupling. DP evaluated compared to single (SP) system. SP system with spatially separated sensors has advantage that it also offers array gain will therefore during idealized conditions outperform However, in found often reduced sometimes even lost when...

In this paper, we make a performance comparison between two different training-based schemes for multiple-input multiple-output (MIMO) channel estimation. The are the conventional time-multiplexed pilot (CP) scheme and more recently suggested superimposed (SIP) scheme. Unlike previous comparisons found in literature, which mostly based on estimation error performances, paper is made by deriving comparing maximum data rate (or rather tight lower bound mutual information) achieved each By...

Radio-frequency (RF) impairments, which intimately exist in wireless communication systems, can severely limit the performance of multiple-input-multiple-output (MIMO) systems. Although we resort to compensation schemes mitigate some these a certain amount residual impairments always persists. In this paper, consider training-based point-to-point MIMO system with transmit RF (RTRI) using spatial multiplexing transmission. Specifically, derive new linear channel estimator for proposed model,...

Radio-frequency (RF) impairments, that exist intimately in wireless communications systems, can severely degrade the performance of traditional multiple-input multiple-output (MIMO) systems. Although compensation schemes cancel out part these RF there still remains a certain amount impairments. These residual impairments have fundamental impact on MIMO system performance. However, most previous works neglected this factor. In paper, training-based with transmit (RTRI) is considered....

Massive multi-user (MU) multiple-input multiple-output (MIMO) is widely believed to be a core technology for the upcoming fifth-generation (5G) wireless communication standards. The use of low-precision digital-to-analog converters (DACs) in MU-MIMO base stations interest because it reduces power consumption, system costs, and raw baseband data rates. In this paper, we develop novel algorithms downlink precoding massive systems with 1-bit DACs that support higher-order modulation schemes...

In this article we discuss different technology alternatives for small cell backhaul, and present high-frequency microwave as a very interesting alternative wireless backhauling of cells. fact, demonstrate that can be used NLOS cells, which opens up new applications technology. We urban channel propagation at high frequencies, show both measurement simulation results to validate the use backhaul.

We consider downlink transmission in a cellular network consisting of multi-antenna base stations (BSs), single-antenna mobile users, directional antennas each with vertically adjustable beam, and control signaling delays feedback backhaul links. propose novel technique which intercell interference management is performed via coordinating the beamforming jointly horizontal vertical planes wireless channel, denoted as coordinated 3D beamforming. In plane, we focus on cancelation (ICIC)...

Radio-frequency (RF) impairments in the transceiver hardware of communication systems (e.g., phase noise (PN), high power amplifier (HPA) nonlinearities, or in-phase/quadrature-phase (I/Q) imbalance) can severely degrade performance traditional multiple-input multiple-output (MIMO) systems. Although calibration algorithms partially compensate these impairments, remaining distortion still has substantial impact. Despite this, most prior works have not analyzed this type distortion. In paper,...

In this paper, we consider the uplink of a single-cell multi-user single-input multiple-output (MU-SIMO) system with in-phase and quadrature-phase imbalance (IQI). particular, investigate effect receive (RX) IQI on performance MU-SIMO systems large antenna arrays employing maximum-ratio combining receivers. order to study how affects channel estimation, derive new estimator for IQI-impaired model show that higher value signal-to-noise ratio, impact spectral efficiency (SE). Moreover, novel...

Massive multiuser (MU) multiple-input multiple- output (MIMO) is foreseen to be a key technology in future wireless communication systems. In this paper, we analyze the downlink performance of an orthogonal frequency division multiplexing (OFDM)-based massive MU-MIMO system which base station (BS) equipped with 1-bit digital-to-analog converters (DACs). Using Bussgang's theorem, characterize achievable linear precoders (such as maximal-ratio transmission and zero forcing) terms bit error...

Distributed multiple-input-multiple-output (DMIMO) is a very promising technique to improve capacity and quality of service for emerging 5G systems. In this paper, we propose flexible low-cost testbed D-MIMO systems, where sigma-delta over fiber (SDoF) solution proposed address the fundamental challenge phase-coherent transmission between multiple distributed access points (APs) from central unit (CU). Employing standardized optical data interconnects, SDoF, brings software controlled RF...

In this paper, we study the impact of in-phase and quadrature imbalance (IQI) on single-cell multiuser multiple-input multiple-output systems with large antenna arrays. Moreover, consider a time-division duplex system, where assume uplink/downlink channel reciprocity in downlink precoding design. First, investigate effect transceiver IQI uplink estimation by deriving linear minimum-mean-square-error estimator for IQ-impaired model prove that only receiver at base station (BS) limits...

In this paper we investigate the feasibility of using microwave frequencies for fixed non-line-of-sight wireless backhauling connecting small-cell radio base stations with an aggregation node in outdoor urban environment, i.e. a typical heterogeneous network scenario. We study system level simulations point-to-point where wave propagation is based on diffraction over rooftops. further effects carrier frequency, interference, antenna height, rain, and tolerance to alignment errors. It found...

In this paper, we present a channel estimation scheme for Amplify-and-Forward (AF) relaying systems, using measurements at the destination only. A Least-Squares (LS) based algorithm is developed, that provides with full knowledge of all responses involved in transmission. To investigate performance, Cramer-Rao lower bound (CRB) analytically computed and compared asymptotic covariance proposed estimator. Since existing estimator does not reach CRB, also propose analyze an improved by taking...

In this letter, we propose a novel framework to enhance the throughput in multiple-input single-output (MISO) mutually interfering channels via selecting tilt angles at all base stations (BSs) coordinated fashion. proposed framework, multiple BSs adjust their jointly maximize sum of scheduled users, denoted as user-specific tilting. Assuming availability location information users BSs, accurate analytical expression for user ergodic rate is provided, which enables decentralized deployment...

We consider a cellular network with multiantenna base stations (BSs) and single-antenna users, multicell cooperation, imperfect channel state information (CSI), directional antennas, each vertically adjustable beam. investigate the impact of elevation angle BS antenna pattern, which is denoted as tilt, on performance considered when employing either traditional single-cell transmission or fully cooperative transmission. Using results this investigation, we propose novel hybrid cooperation...

In this paper, the maximum achievable data rate performance is addressed for MIMO systems that employ transmission of known training sequences channel estimation. Part I it was found based on superimposed pilots (SIP) offer an increased over conventional time-multiplexed fast fading channels. other cases, gain lost due poor estimates are attained when there interfering power present during estimation process. By allowing reestimation using a decision-directed approach, can instead be...

In this paper, we propose a novel framework to enhance the throughput in single-cell multiuser multiple-input multiple-output (MU-MIMO) system via adaptive base station (BS) antenna tilting. The key idea is partition cell into so-called vertical regions and apply one out of finite number tilt half-power beamwidth (HPBW) pairs at BS when serving each region. This strategy results an increased average received signal-to-noise ratio (SNR) over coverage area. A scheduler then employed schedule...

We present the uplink and downlink of a time-division duplex distributed multiple-input multiple-output (D-MIMO) testbed, based on 1-bit radio-over-fiber architecture, which is low cost scalable. The proposed architecture involves central unit (CU) that equipped with digital-to-analog analog-to-digital converters, operating at 10 GS/s. CU connected to multiple single-antenna remote radio heads (RRHs) via optical fibers, over binary frequency (RF) waveform transmitted. In uplink, RF generated...