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In the past decades, physical layer security has been extensively studied to exploit fundamental capabilities of physical layer such as randomness in wireless channels, signal-to-noise ratio gap, intended jamming, etc., for secure wireless communications. The notion of secrecy rate plays a crucial role in quantifying the transmission rate for secure communications in the presence of an eavesdropper...
Massive multiple-input multiple-output (MIMO) systems, where the base station (BS) is equipped with a large number of antennas and the mobile devices have a single antenna, can significantly enhance the system performance. In many wireless systems inter symbol interference (ISI) due to delay dispersion of the channel can dramatically affect the demodulation process of the received signals. Precoding...
Existing methods of self-interference cancellation have greatly reduced the strong self-interference signal for the practical design of Full-Duplex (FuDu) wireless systems. However, current FuDu wireless is hard to be put into practice due to the reason that residual self-interference after interference cancellation is still much stronger than the thermal noise. In this paper, a wideband FuDu OFDM...
In this paper, transmission performance for wireless harness systems is evaluated using propagation models which include pathloss and power delay profile in an automobile engine compartment. In the wireless harness system in vehicles, it is assumed that an electronic control unit has a wireless access point (AP) and each sensor has a wireless station terminal (ST). First, pathloss and power delay...
This paper proposes a cluster-based optimal relay and jammer selection (CB-ORJ) scheme to deal with interception and improve the secrecy rate in wireless multi-hop networks in the presence of both intra-cluster and inter-cluster eavesdroppers. We first present a novel mathematical model of cluster-based secure transmission. Furthermore, we propose an on-demand relay and jammer selection approach based...
We study the problem of interference management for device-to-device (D2D) communications where multiple D2D users may coexist with one cellular user. The problem is to optimize the transmit power levels of D2D users to maximize the cell throughput while preserving the signal-to-noise-plus-interference ratio (SINR) performance for the cellular user. This is the so-called multi rate power control problem...
In this paper, a ray-tracing technique taking into consideration the effects of user-body shadowing is investigated. With the rapid growth in the applicability of mobile devices, accurate received signal predictions are increasingly important. The user's body especially has a great impact on the received signals, because it is nearly always located close to the mobile device. We consider two deterministic...
We develop a novel approach to source localization in mobile wireless sensor networks. Standard approaches make explicit assumptions relating to the statistical characteristics of the physical process and propagation environments which result from distributional model assumptions in a likelihood-based inference method. In contrast, we adopt an approach known in statistics as a non-parametric modeling...
This paper considers relay positioning in wireless butterfly networks consisting of two source nodes, a relay node and two destination nodes. The relay-assisted data transmission from two source nodes to two destination nodes is carried out based on either physical-layer network coding (PLNC) or analog network coding (ANC) techniques. The reliability of communications in wireless network-coded butterfly...
Heterogeneous wireless systems such as a combination of mobile broadband wireless access (MBWA) and wireless local area network (WLAN) are candidates to attain higher throughput and wide coverage in the next generation mobile communication systems. A multimode receiver to demodulate signals with multiple air interfaces is required in the heterogeneous systems. In this paper, we discuss an implementation...
Optimization of transmit strategies with linear transceivers in multiple-input multiple-output (MIMO) broadcast channels generally leads to nonconvex problems, which cannot be solved efficiently in a globally optimal manner. Instead, it is necessary to resort to suboptimal algorithms. In this paper, we evaluate the application of a gradient descent algorithm for the optimization of the energy efficiency...
This paper investigates the secrecy performance of multiple-input single-output (MISO) wiretap channels with transmit antenna selection (TAS) and subject to an interference-limited eavesdropper. By considering NA antennas at the transmitter, a single antenna at the legitimate receiver and eavesdropper, and multiple arbitrary co-channel interferers M at the eavesdropper, an exact closed-form expression...
Exploiting the idea of cooperative communications is an efficient way to improve the physical-layer security of a wireless transmission in the presence of passive eavesdroppers. In this paper, we propose a hybrid cooperative relaying and jamming scheme to enhance the security of a two-way relay network, where some intermediate nodes help to relay the signal to the legitimate terminals via distributed...
This paper is oriented in the area of wireless device identification through the analysis of emitted signals corrupted by radio frequency transmitter impairments. These impairments (such as power amplifier nonlinearity, IQ modulator imbalance, DC offset, phase noise, carrier frequency offset, shaping filter length and its shape) represent a unique characterization of any radio wireless transmitting...
In this paper, we present and analyze utilizing generalized selection combining (GSC) scheme to enhance the physical layer (PHY) security of a wireless communication system consisting of a single antenna transmitter, a multi-antennas receiver and a multi-antennas eavesdropper. We consider a practical scenario where GSC scheme is applied to the receiver considering both the complexity and the energy...
This paper investigates the optimal resource allocation for a Gaussian multiple access channel (MAC) with two transmitters powered by a shared energy harvester. A deterministic energy-harvesting (EH) model is adopted, which assumes that the energy arrival amounts and timing are non-causally known before transmissions. Besides, packets for both transmitters are assumed always ready before transmissions...
RF energy scavenging enables batteryless operation of wireless sensors. In particular, a system with a central controller that transfers wireless energy to and exchanges information with RF energy scavenging sensors is very suitable for a wide range of applications. State-of-the-art analysis of RF energy scavenging is mostly based on RF-DC rectifier models operating with relatively high input power...
Batteries of field nodes in a wireless sensor network pose an upper limit on the network lifetime. Energy harvesting and harvesting aware medium access control protocols have the potential to provide uninterrupted network operation, as they aim to replenish the lost energy so that energy neutral operation of the energy harvesting nodes can be achieved. To further improve the energy harvesting process,...
This paper tackles the four-level hypothesis problem for spectrum sharing between primary users (PUs) and secondary users (SUs). The considered hypotheses are as follows; the studied frequency band is vacant (hypothesis H0), the studied frequency band is occupied only by a PU (hypothesis H1), the studied frequency band is occupied only by another SU (hypothesis H2) and the studied frequency band is...
Fractional Frequency Reuse (FFR) is an efficient method to mitigate Inter Cell Interference in multicellular Orthogonal Frequency Division Multiple Access (OFDMA) systems. In this paper, we analyze the downlink worst case Signal to Interference Ratio for FFR schemes. A closed form expression is derived analytically for the worst SIR, outage probability, and Spectral Efficiency (SE). The proposed analytical...
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