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We examine the upper and lower bound of the secrecy outage probability of primary links in cognitive wireless sensor networks employing power control scheme. The power control law is adopted in order to govern the transmission power of a cognitive radio node and there by limit interference incurred to the neighboring cognitive radio user. An accurate expressions for the probability density function...
We evaluate the secrecy performance of a cooperative network where the destination node is wiretapped by a malicious and passive eavesdropper. We propose the application of the network coding technique as an alternative to increase the secrecy at the destination node, in a scenario without channel state information (CSI) at the transmitter side. Network coding is leveraged by assuming that the legitimate...
This paper presents a system-level simulation approach developed at the Poznan University of Technology for the evaluation of selected aspects of next generation wireless systems. The details of the considered environment and propagation models are given, as well as several important aspects of the simulator implementation methodology. Selected use cases of the presented simulation platform are demonstrated...
We introduce an algorithm minimizing the consumed energy of a cooperative spectrum sensing-based cognitive radio network. The energy is minimized, while satisfying requirements for primary user protection and for secondary user data rate simultaneously, with respect to the powers for transmitting on control and data channels, the number of reported bits, and the thresholds of the global sensing test...
This paper proposes a real-time detector of rectilinearity of signals received by an antenna array. A rectilinear source is characterised by having a circularity coefficient of unity and it represents a real-valued source with an arbitrary phase shift. Real-time detection of rectilinearity has been introduced as a new challenge in communications since identifying the rectilinearity of the sources...
Quality of service (QoS) routing in mobile ad hoc networks (MANETs) is a big challenge because of dynamically varying network topology and the limited availability of resources. Many techniques for solving the QoS routing problem in MANETs are available. Ant colony optimization is a promising solution that can be applied in wireless ad hoc networks. However, existing routing protocols that require...
This paper investigates downlink channel estimation in a distributed MIMO context employing Filter Bank-based Multi-Carrier Offset QAM (FBMC-OQAM) modulation. Training preambles are constructed based on two different subcarriers assignment schemes (SAS), with the aim of freeing the estimation procedure from the effects of the multi-stream interference (MSI). The Linear Minimum Mean Squared Error (LMMSE)...
In backscatter radio systems, a passive (i.e., battery-free) device (so-called tag) is able to transmit information by harvesting energy from a carrier transmitted by an access point or base station (so-called reader), thus enabling significant power savings compared to traditional wireless communication schemes. In this paper, the physical layer of a backscatter system is revisited to develop a design...
In this work, we revisit the structure of weight matrices for Linear Dispersion STBCs to admit ML decoding with low-complexity. We first propose novel sufficient design criteria for linear STBCs considering an arbitrary number of antennas and an arbitrary coding rate. Then we apply the derived criteria to three families of codes, multi-group decodable, fast decodable, and fast-group decodable codes...
The presence of unwanted transmission out of the nominal signal band belongs to the crucial problems in the context of coexisting wireless communication systems. The effective reduction of out-of-band emission (OOBE) requires the application of algorithms for, e.g., sidelobes suppression or intermodulation product removal. Moreover, the predistortion of the power amplifier (PA) can be considered....
This paper considers the jointly optimal pilot and data power allocation in single cell uplink massive MIMO systems. A closed form solution for the optimal length of the training interval is derived. Using the spectral efficiency (SE) as performance metric and setting a total energy budget per coherence interval the power control is formulated as optimization problems for two different objective functions:...
Area coverage, which reflects how well each point in the sensing field is monitored, is one of the most important performance metrics to measure sensor networks. However, it requires the activation of many redundant sensors. The sleep/wake scheduling mechanism is used to schedule sensors to be activated alternatively. Nevertheless, the repeated redundancy checks due to the frequent switching between...
The presence of void area in the routing path is perhaps the most challenging issue from the routing protocol perspective in 3D acoustic Under-Water Sensor Networks (UWSN). In this paper, we propose a new routing protocol, called Inherently Void-Avoidance Routing (IVAR), to address the void problem without relying on any positioning system. IVAR is able to efficiently bypass void areas by properly...
Inspired by the success in sparse signal recovery, compressive sensing has already been applied for the pilot-based channel estimation in massive multiple input multiple output (MIMO) orthogonal frequency division multiplexing (OFDM) systems. However, little attention has been paid to the pilot design in the massive MIMO system. To obtain the near-optimal pilot placement, two efficient schemes based...
Noncoherent multi-user detection schemes are attractive in multi-user massive MIMO uplink systems. In particular, sorted decision-feedback differential detection (DFDD) in combination with noncoherent decision-feedback equalization (nDFE) over the users has been shown to perform well though avoids the need for channel estimation. Up to now, in all studies a uniform linear receiver array employing...
We designed and developed a test bed of infrastructure independent wireless network that connects end devices directly without centralized coordination. Various types of end devices are implemented and used for different scenarios. There is neither base station nor access point, so as to avoid the single-point-of-failure. The developed test bed has been deployed successfully in two real fields. It...
This work proposes a distributed power allocation scheme to maximize energy efficiency in the uplink of multi-cell massive MIMO systems with hardware impairments at the user equipments (UEs) and imperfect channel state information at the base stations (BSs). Each UE in the network is modeled as a rational agent that engages in a generalized non-cooperative game and allocates its available transmit...
This paper concerns the performance of two-way point-to-point multiple-input multiple-output (MIMO) links. In particular, the system of interest comprises a pair of multiantenna full-duplex terminals that communicate with each other through a MIMO radio channel under residual self-interference from imperfect mitigation using joint decoding for reception. The new theoretical result underlying this...
To facilitate the demand for a higher spectrum and power efficiency, relay-aided cooperative communication is considered as one of the most efficient techniques for achieving high data rate and coverage. In this work, we consider a scenario where the relays are not equipped with fixed batteries but collect the required energy (for processing and transmission purposes) via simultaneous wireless information...
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