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The implementation of channel estimation procedures in modern wireless networks exposes them to the risk of pilot contamination attacks. To protect the system from such types of malicious intervention, a recently proposed method, based on legitimate pilots from shifted constellations, can be applied. In this paper, the detection capability of this method is studied in both the presence and absence...
Massive multiuser multi-input multi-output (MU-MIMO) system adopting large amount of antennas is a promising technique to improve spectral efficiency and energy efficiency for next generation wireless communication systems. In practice, the channels composed of pairs of transmit and receive antennas are often correlated and computational complexity is one of the critical concern in implementation...
In this paper, we investigate the power allocation algorithm for beam division multiple access (BDMA) transmission in massive multiple-input multiple-output (MIMO) communications under Rician fading. Based on the fact that eigenbasis at the base station (BS) become identical and independent of user equipment as the number of BS antennas goes to infinity, jointly correlated channel model is introduced...
Due to dense small cells deployment in a heterogeneous network, the backhaul links among the small cells and macro cell are band-limited when they share the same spectrum with the user equipments. To mitigate the intra- and inter-cell interference caused by the band-limited backhaul, we propose a recursive estimation-based zero-forcing beamforming (RE-ZFBF) scheme. Based on initial values obtained...
In this paper, we describe a 920 MHz band long range wireless SAW passive tag system (WSPTS) for vibration monitoring, which achieves more than 15 m reading distance. For the purpose of structural health monitoring (SHM) of aging infrastructures (e.g. bridge, building, and so forth), passive wireless sensor systems are an attractive option because they are operated battery-less and almost maintenance...
In recent years, the high resolution, high precision and high sensitivity telescopes have been widely developed for astronomical observation in the world, such as SKA, Arecibo, ALMA and MingantU SpEctral Radioheliograpy (Muser). Along with these newly developed modern telescopes, a “big data” challenge was raised for data storage and processing. For example, Muser produces about 4.3TB raw data for...
The performance of a rotating stirrer made of helically positioned paddles is experimentally analyzed. The statistically independent positions are computed as a function of the number of paddles, paddle separation and relative tilt angle. With respect to a traditional single paddle wheel stirrer, the structure combines a helical path and just a simple engine required for the rotation. The analysis...
Massive Multiple-Input Multiple-Output (MIMO) communications uses a large number of antennas at the base station to increase the data rate and user density in future wireless systems. For simulation, it has become common practice to use i.i.d. complex Gaussian matrix entries to obtain an average MIMO channel behavior. More refined models have been devised and proposed to standardization bodies; yet,...
The fifth-generation (5G) wireless communication systems envision the deployment of massive multiple-input multiple-output (MIMO) technology for enhanced network coverage and capacity. With frequency division duplex (FDD) being the prominent mode of operation, addressing the challenges for massive MIMO systems in FDD is extremely important. One such challenge is the downlink channel estimation, which...
Performance of safety applications of vehicular networks largely depends on the reliability of the communication channel. However the IEEE 802.11p channel is unreliable according to the previous measurement-based work, which reported that the whole communication range is a “gray-zone” and the packet inter-reception time suffered from blackouts with a relatively high probability. Besides the 5.9 GHz...
The problem of forming an FMICW signal for vertical-incidence single-antenna ionosonde based on the USRP platform using SDR technology was solved. We carried out studies aimed at getting a constant level of a received signal, unambiguous determining virtual reflection height in the required range as well as reducing interference and correlation noise during transmission and compression. The developed...
In this paper, we analyze uplink sum rate of multiple-input multiple-output (MIMO) systems with maximum-ratio combining (MRC) receivers. To be practical, receive correlation and different powers of users are assumed. Two novel approximate results on sum rate are derived in closed form. Based on the results, we also obtain the asymptotic results on sum rate when the number of base station antenna (M)...
This paper presents field experiments on the downlink throughput performance of a 5G centimeter wave radio access system employing higher rank MIMO in a shopping mall environment and a long corridor environment. The shopping mall has complex reflection paths within its non-line-of-sight areas. The long corridor environment exhibits line-of-sight propagation with many reflection paths. The results...
The first measured results for massive multiple-input, multiple-output (MIMO) performance in a line-of-sight (LOS) scenario with moderate mobility are presented, with 8 users served by a 100 antenna base Station (BS) at 3.7 GHz. When such a large number of channels dynamically change, the inherent propagation and processing delay has a critical relationship with the rate of change, as the use of outdated...
In this paper, we investigate wireless information and power transfer in full-duplex (FD) two-way massive MIMO amplify-and-forward (AF) relaying network. In the considered network, the relay is an energy demander and applies time switching scheme to harvest energy from the users for amplifying and forwarding the users'' signals. Different from prior studies, MIMO users and antenna correlation are...
We consider detection of spoofing relay attack in time-division duplex (TDD) multiple antenna systems where an adversary operating in a full-duplex mode, amplifies and forwards the training signal of the legitimate receiver. In TDD systems, the channel state information (CSI) can be acquired using reverse training. The spoofing relay attack contaminates the channel estimation phase. Consequently the...
This paper proposes a novel uplink power control scheme in a single cell for massive MIMO (Multiple-Input-Multiple-Output). The proposed algorithm exploits the spatial degrees of freedom provided by massive MIMO to achieve the highest signal to interference-plus-noise ratio (SINR) for each user by considering the mutual spatial correlation arising from other users. It also minimizes the required uplink...
Sets of waveform and mismatched filter pairs are used. On the contrary with Golays matched waveform filter pair the mismatched waveform filter pair does exist for all N (number pulses in waveform). Using corresponding shapes of filter good Doppler tolerance may be provided. This property together with a good range side-lobs level suppression makes it's attractable for use in marine radar.
Geometry-based stochastic model (GBSM) of multiple input multiple output (MIMO) channel describes the channel impulse response (CIR) in the sense of rays and clusters, which obey the empirical distributions. Thus, the correlation between MIMO sub-channels is not explicitly defined, which makes it difficult for GBSM to predict channel capacity accurately. Facing the increased antenna number of massive...
Hybrid preprocessing, where an analogue preprocessing matrix is used to feed a large antenna array to fewer up/down-conversion chains, helps reduce hardware cost of massive Multiple-Input-Multiple-Output systems. Here, we analyze a variant of hybrid preprocessing, namely hybrid preprocessing with selection (HPwS), as an attractive solution to reduce this hardware cost while retaining good performance...
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