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This paper analyzes a self-backhauling inband full-duplex access node that has massive antenna arrays for transmission and reception. In particular, the optimal transmit powers for such a system are solved in a closed form, taking into account the self-interference as well as backhaul capacity requirements and incorporating the role of downlink-uplink traffic ratio in sum-rate maximization. Numerical...
For Global Navigation Satellite System (GNSS) receivers, adaptive antenna arrays are the most effective techniques for interference suppression. Unfortunately, adaptive antenna arrays may distort the GNSS signals and induce measurement biases on both code phase and carrier phase, which are unacceptable for precision applications. In this paper, the measurement errors induced by space-time anti-jamming...
In communication systems with interference, the performance of traditional adaptive beamforming to search the direction of angle (DOA) of incoming desired signal degrades because of mismatch between the true array response and the assumed array response of desired signal in a receiver antenna array. In this paper, we approach the method of maximum output Signal-to-Interference-plus-Noise Ratio (SINR)...
The emerging 5G cellular networks will operate at millimeter wave (mmWave) frequency bands to enhance the cell capacity. Massive MIMO antenna array and beamforming technology are used in order to overcome propagation limitations of mmWave band. Multi-beam based communication system is considered as the basic structure for 5G mobile network. However, to optimize the cell capacity, the question of how...
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...
The trade-off between the achievable sum rate and harvested energy is investigated for multi-user/multi-cell massive multiple-input multiple-output (MIMO) relay networks. To this end, the antenna array at the relay is switched periodically between the energy harvesting and information processing modes, and the harvested energy is utilized for the relay's transmissions. Closed-form expressions for...
Millimeter wave (mmWave) systems will likely employ large antenna arrays at both the transmitters and receivers. A natural application of antenna arrays is simultaneous transmission to multiple user equipments (UEs), which requires multi-user precoding at the transmitter. However, hardware constraints and operation loads make it challenging to apply conventional pure MIMO digital precoding or even...
This paper addresses the problem of initial synchronization of users in an indoor mm-Wave scenario. By using a massive number of antenna elements at access nodes, the resulting beams have narrow beamwidth. However, the transmission of individual narrow beams may cause poor coverage in some areas as the energy is concentrated over the direction of their main lobes. To cope with that, a beam sweep procedure...
A multimode configuration of concentric TMn1 mode circular microstrip antennas is proposed for anti-jamming in GPS receivers. By calculating the performance of a five-element configuration in terms of availability of service in the presence of jammers, it is shown that theoretically, it provides improvement when compared to a planar and a spherical arrays with the same number of elements.
We present a new multiple-input-multiple-output (MIMO) transmission scheme for generic phase-shift-keying (PSK) modulations in the multi-user (MU) downlink channel, where Constant Envelope Precoding (CEP) is combined with concepts of interference exploitation. In the proposed approach, multi-user-interference (MUI) is treated as a resource for increasing the signal-to-interference-and-noise-ratio...
This paper deals with the problem of hybrid analog-digital transmit beamforming under spectrum sharing constraints. Hybrid multiantenna architectures are ideal for high throughput wireless links, where full-digital solutions are extremely expensive due to their the high number of radiofrequency chains and full-analog architectures require complex and lossy beamforming networks. In contrast to the...
Usually, the stray signals from antenna test environment and compact antenna test range (CATR) system may cause errors in the measured patterns. In order to improve the measurement accuracy of a specific antenna test system, the techniques about antenna pattern correction for mitigating the effects of these stray signals are required. In this paper, a two-unit virtual array method and its extended...
A two-element antenna array with a 1/40-wavelength interval is proposed, and analysed using the method of moments (MoM). Based on the time reversal (TR) technique, the two antenna elements can work simultaneously with little interference when metal-wire resonators are loaded controllably. It shows that the resonators can be used to design multi-frequency sub-wavelength antenna arrays efficiently.
While spectrum at millimeter wave (mmWave) frequencies is less scarce than at traditional frequencies below 6 GHz, still it is not unlimited, in particular if we consider the requirements from other services using the same band and the need to license mmWave bands to multiple mobile operators. Therefore, an efficient spectrum access scheme is critical to harvest the maximum benefit from emerging mmWave...
The broadband concentric circular antenna array beamformer with convolution constraints and efficient realization techniques are addressed in this paper. The concentric circular array processor is competent to scan a beam azimuthally through 360 degree and inherently cover up the entire breathing space. The behavior of the time domain element space array processor is appraised by comparing its recital,...
In this paper, we analyze the spectral efficiency (SE) and energy efficiency (EE) of multi-user (MU) multiple-input and multiple-output (MIMO) in multi-cell downlink networks. We first analyze the achievable sum-rate, i.e., the SE, of MU-MIMO systems with maximal ratio transmission (MRT) and zero-forcing (ZF) precoders in downlink cellular networks. Different from the conventional analysis, we derive...
Multiuser multiplexing is an attractive research topic for wireless communication system, since it can increase the sum channel capacity dramatically. The multiuser multiplexing is realized based on the independent channel influences of different users. However, the multiplexing gain will be reduced, when the channels are correlated among different users, due to the destroyed independent statistics...
The massively dense distributed antenna system (md-DAS) with virtual cells (VCs) has drawn increasing interests recently. In this paper, we develop an energy-efficiency-oriented coordinated power allocation (PA) scheme considering the inter-VC interference in a downlink md-DAS. The problem can be formulated as a complicated non-convex fractional programming problem. To make it tractable, we recast...
The present work is going to investigate the potential benefits obtainable by taking advantage of the polarization diversity in a Passive Bistatic Radar (PBR) system exploiting Digital Video Broadcasting — Terrestrial (DVB-T) signals. In particular, a PBR demonstrator equipped with a surveillance array antenna able of simultaneously receiving both horizontal and vertical polarizations has been used...
The physical layer security in a multi-user massive multiple-input multiple-output (MU-Massive-MIMO) system is considered in this paper, where a hidden eavesdropper (Eve) may eavesdrop the information signal of any legitimate user. Two distributed antenna system (DAS) aided power-saving transmit strategies are evaluated: 1) the autonomous full (AF) transmission with explicit artificial noise (AN),...
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