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Traditional multiple-input multiple-output (MIMO) systems mostly consider only the azimuth dimension of the three-dimensional (3D) multipath propagation. Recently, there has been interests in extending MIMO techniques to exploit the elevation dimension in addition to the azimuth dimension. In this paper we developed a rank-restricted representation of MIMO channels. Based on the cascading structure...
This work exploits the benefits of adaptive downtilt and vertical sectorization schemes for Long Term Evolution Advanced (LTE-A) networks equipped with active antenna systems (AAS). We highlight how the additional control in the elevation domain (via AAS) enables use of adaptive downtilt and vertical sectorization techniques, thereby improving system spectrum efficiency. Our results, based on a full...
In this paper, we propose a radio frequency (RF) lens-embedded massive multiple-input multiple-output (MIMO) system. To analyze the characteristics of RF lens antennas, we first introduce the beam propagation method (BPM) and use it to construct a new channel model. We next design a low complexity codebook reflecting the characteristics of the RF lens antennas for limited feedback. Numerical results...
Three dimensional (3D) Multiple Input and Multiple Output (MIMO) is one of the most promising techniques for the 5th Generation (5G) mobile communication systems. Thus there is an urgent need for one reliable 3D MIMO channel model to research and evaluate 3D MIMO techniques. In this paper, we focus on the statistic characteristics of elevation angle in urban microcell (UMi) and propose a novel elevation...
A Cognitive Radio is a Software Defined Radio (SDR). The Cognitive radio network is capable to sense and analyze its surrounding environment as well as reconfigure its operation in accordance with this radio environment. In this way, based on the available Channel State Information (CSI), the cognitive radio network may dynamically access the spectrum. MIMO based cognitive radio system enabled dynamically...
A multiuser massive MIMO system with mutual coupling is investigated in finite-dimensional channel scenarios. The uplink ergodic achievable rate is analytically derived for a multiuser massive MIMO system equipped with a rectangular planar uniform antenna array at the base station (BS). Numerical results show that the mutual coupling effect reduces the uplink achievable rate of multiuser massive MIMO...
We propose a new hardware architecture for cost-and size-effective implementation of massive MIMO transmitters based on load modulation that is fully compatible with standard receiver architectures. With load modulation, a massive MIMO transmitter can be driven by a single power amplifier operating at constant envelope. The various data streams are modulated onto the antennas elements by varying the...
Multiple-input and multiple-output (MIMO) scheme can extend the transmission capacity for the light-emitting-diode (LED) visible light communication (VLC) system. The MIMO VLC system using the popular mobile-phone camera as the optical receiver (Rx) to receive MIMO signal from n × n Red-Green-Blue (RGB) LED array is desirable. The key step of decoding the received RGB LED array signals is detecting...
Color-Filter-Free wavelength division multiplexing (WDM) Multiple-input and multiple-output (MIMO) Red-Green-Blue (RGB)-light emitting diode (LED) visible light communication (VLC) system using mobile-phone camera is proposed and demonstrated. Neither color filter nor chromatic color information is required in the proposed receiver (Rx). All image signal processing is based on the grayscale image,...
Ground Penetrating Radar (GPR) with Ultra-Wideband (UWB) waveform has wide applications in numerous fields. Most of them utilize the conventional sensors configuration, which is either Single-Input Single-Output (SISO) or Single-Input Multiple-Output (SIMO). In this paper, we explore several potential applications of UWB GPR with Multiple-Input Multiple-Output (MIMO) configuration. Three sets of simulation...
A configurable, channel-adaptive K-best MIMO detector for multi-mode wireless communications that adapts computation to varying channel conditions to achieve high energy-efficiency is presented. An 8-stage configurable MIMO detector supporting up to a 4×4 MIMO array and BPSK to 16-QAM modulation schemes has been implemented and simulated in 0.80V, 22nm Tri-gate CMOS process. Dynamic clock gating and...
Compressed sensing is a topic that has recently gained much attention in high-speed underwater acoustic (UWA) communications. Combined the MIMO communication system with OFDM technology, they can realize high-speed data communication over UWA channels and overcome the fading problem efficiently. In this paper performance analysis of compressed sensing (CS) channel estimation algorithms for underwater...
This paper focuses on the target detection in low-grazing angle using Multiple-input Multiple-output (MIMO) radar systems with widely separated antennas in compound-Gaussian clutter, where the multipath effects are very abundant. The performance of detection can be improved via utilizing the multipath echoes. First, the reflection coefficient considering the curved earth effect is derived. Then, the...
A smart phone subscriber needs wide bandwidth services for more fast data communication on the internet. The conventional MIMO system is now developing to resolve these problems with limited device space for antenna and frequency band environment reserved. One of a way to make it practically is to add the number of antennas theoretically. But it is difficult to increase the antenna element as a limited...
Multiple-Input Multiple-Output (MIMO) radars represent a new class of sensors which combine orthogonal waveform transmissions and multichannel designs to improve specific performance of the system. Well known benefits are achieved in terms of either angular resolution, in the coherent MIMO scenario, or higher detection probability, in the statistical MIMO approach. In this paper the authors investigate...
Contrary to claims made Multiple Input and Multiple Output (MIMO) radars do not provide an order of magnitude or better angle resolution, accuracy and identifiability (the ability to resolve and identify targets) over conventional radars. This claim for MIMO results from making the wrong of a full/thin MIMO array to a full conventional array rather than to a conventional full/thin array. It is shown...
At present days the growing use of means of wireless communications in information transfer networks is present. One of the main problems of developing wireless systems is necessity to increase the capacity and improve the quality of service for users (reduce the probability of error). Capacity can be improved by expanding the frequency band or increasing the radiated power. Nevertheless, applicability...
Many multiple-input-multiple-output (MIMO) ultra-wideband (UWB) array systems are restricted to a limited array with limited antenna elements and thus suffer from the azimuth grating lobes. To combat the azimuth grating lobes, in this paper, firstly a simple analysis about the grating lobes in the sparse MIMO UWB array is performed. Then, an extended coherence factor (ECF) method taking advantage...
Considering the requirement of portability, the number of antennas used for the portable ultra-wideband (UWB) through wall imaging radar (TWIR) is limited. It is faced with challenges to take full advantage of antennas to obtain the optimal performance. In this paper, we study three kinds of array configuration modes (STR, SSIMO and MIMO) and compare their imaging performance based on two criterions...
High cost of millimeter wave (mmWave) hardware precludes the possibility to support each antenna element with a dedicated radio frequency (RF) chain in large-scale mmWave systems. It thus makes conventional baseband precoding, such as zero-forcing (ZF) which is deemed virtually optimal in the large array regime, impractical. In this paper, we consider the RF chain limitations present in large mmWave...
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