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Massive MIMO is a multi-user technology, where radio base stations (BSs) are equipped with a large number of antennas to simultaneously serve many terminals in the same time-frequency resource. Performance evaluation of such large-scale antenna systems in the design and development stage is challenging. In this paper, we propose to evaluate massive MIMO BSs with a sectorized multi-probe anechoic chamber...
A realistic stochastic multiple-input multiple-output (MIMO) channel is presented in this paper. It is shown that the spatial correlation depends on the statistical properties of the channel, the antenna pattern, the inter-element spacing and the array configuration. Furthermore, the total spatial correlation matrix is equal to the Kronecker product of the transmit and receive correlation matrices...
The authors have proposed a method of estimating the location of the receiving terminal by a triangulation technique using DOD information from the multiple transmitters, which is calculated only from the Received Signal Strength Indicator (RSSI). In our previous study, DODs are calculated using four beacon signals, but the number of the antennas for each array is limited to two, which offers insufficient...
The cyclic method performs the direction-of-arrival (DOA) estimation of the desired signals by using cyclic correlations of digital-modulation signals. This paper proposes a cyclic method which uses in-phase combining of multiple cyclic correlations (MCC) and the forward and backward spatial smoothing processing (FB-SSP). Also, the way of reducing the computation load in FB-SSP is provided. Computer...
A low-density spatial downlink reference signal (LDS-RS) design is proposed for frequency-division duplex (FDD) massive full-dimensional multiple-input multiple-output (FD-MIMO) systems. By exploiting the spatial correlation between the channels of different antennas, this scheme can efficiently reduce the downlink RS overhead and therefore enhances the achievable spectral efficiency significantly...
Elevation beamforming and Full Dimension MIMO (FD-MIMO) are currently active areas of research and standardization in 3GPP LTE-Advanced. FD-MIMO utilizes an active antenna array system (AAS), that provides the ability of adaptive electronic beam control over the elevation dimension, resulting in a better system performance as compared to the conventional 2D MIMO systems. FD-MIMO is more advantageous...
Channel estimation is a major overhead factor in large-scale multiple-input multiple-output \mbox{(MIMO)} systems, especially under the high- speed railway scenarios. This paper proposes a position-aided channel estimation scheme for high- speed railway communication systems, where both the transmitter and the receiver are equipped with large-scale antenna linear arrays. By joint spatio- temporal...
The large number of analog received signals to be processed in massive MIMO systems renders conventional high-precision analog-to-digital conversion (ADC) not feasible in terms of cost- and power-efficiency. In this paper we present a novel ADC architecture inspired by the principles of integer-forcing source coding, which jointly reconstructs the received signals in the digital domain. This scheme...
This paper presents a novel array configuration based on the combination of the sum and difference co-arrays. There have been many studies on the array antenna configurations which enhances the array degree of freedom (DOF), however the maximum DOF of the configurations based on the difference co-array is often limited. We try to further enhance the DOF by combining the concepts of the sum coarray...
Massive multiple-input multiple-output (MIMO) as a promising air interface technology refers to the idea of equipping cellular base stations (BSs) with a huge number of antenna elements. Massive MIMO technology allows for orders of magnitude enhancement in spectral and energy efficiency requirement demanded by the fifth generation (5G) wireless communications. Accurate channel models that reflect...
Reconfigurable antenna arrays provide important advantages such as reduction on the number of the physical antennas or reduced hardware complexity in terms of receiving radio frequency chains. Both these properties are critical in vehicle-to-vehicle (V2V) communication systems, which are characterized by inflexible dimensions and cost constraints. In this paper, a new pattern reconfigurable antenna...
A presented paper deals with a theoretical base of the localization of electromagnetic sources. There are presented a mathematical model of localization of electromagnetic sources in near-field region and the mathematical model in far-field region. The localization in far-field region is introduced by covariance matrix and the localization in near-field region is introduced by cross-correlation matrix...
This paper presents experimental results of our proposed null-space expansion scheme for multiuser massive MIMO in time varying channel. Multiuser MIMO transmission with proposed scheme can suppress inter-user interference (IUI) caused by outdated channel state information (CSI). The excess degrees of freedom (DoFs) of massive MIMO is exploited to perform additional null-steering...
In this paper, we present a close-form expression for the downlink throughput of a massive MIMO system with finite antenna elements in a multi-celluar systems. In practice, the performance of massive MIMO system is limited by the number of antenna elements. From the operator aspect, the cost of massive MIMO is a major concern. Thus, a massive MIMO system with finite antenna elements is of interest...
Recent achievements in hyperspectral imaging (HSI) demonstrated successfully a novel snapshot mosaic sensor architecture, enabling spectral imaging in a truly compact way. Integration of this new technology in handheld devices necessitates efficient compression of HSI data. However, due to the specific mosaic structure of the acquired images, traditional compression methods tailored to full-resolution...
Massive Multi Input and Multi Output (M-MIMO) is the most prominent technology to improve the spectral and energy efficiency of future wireless systems by deploying multiple number of antennas at the base station. In this letter, we considered the impact of spatially correlation on massive MIMO downlink systems with achievable data rate in the block fading environment. The proposed schemes exploit...
Mirrored Aperture Synthesis (MAS) was proposed to improve spatial resolution with fewer antennas for passive microwave remote sensing. In this paper, an Experiment System of MAS (ESMAS) at 36.4GHz is introduced, which is designed for verifying the principle and performance of MAS. ESMAS is composed of an antenna array, four reflectors, a receiving channel array, a synchronous acquisition subsystem,...
For preventing the effects of sea ice bring the serious negative impact on the maritime transport, a full-scale detection of sea ice should be performed. The BeiDou GEO satellites could provide stable geometry and better coverage in mid- and low-latitude region where most of the sea ice occur. Based on this consideration, this paper evaluates the usage of BeiDou GEO Satellites reflected signals for...
Mirrored aperture synthesis (MAS) can improve spatial resolution compared with conventional aperture synthesis (AS). In this paper, for 1D MAS and 2D MAS, the array optimization models with the autocorrelation are established. The optimal array configurations based on the models are presented. The simulation results demonstrate that the optimal array configurations have good performance in imaging...
In this paper, we consider a uniform circular array (UCA) of directional antennas at the base station (BS) and the mobile station (MS) and derive an exact closed-form expression for the spatial correlation present in the 3D multiple-input multiple-output (MIMO) channel constituted by these arrays. The underlying method leverages the mathematical convenience of the spherical harmonic expansion (SHE)...
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