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Spectrum Sensing (SS) constitutes the most critical task in Cognitive Radio ( CR) systems for Primary User (PU) detection. Cooperative Spectrum Sensing (CSS) is introduced to enhance the detection reliability of the PU in fading environments. In this paper, we propose a soft decision based CSS algorithm using energy detection by taking into account the noise uncertainty effect. In the proposed algorithm,...
Cognitive radio is able to effectively increase spectral utilization. However, cooperative spectrum sensing gives malicious users chances to interfere with its decision processes. If a mobile secondary user's energy detection results become unreliable, conventional trust-value based cooperative spectrum sensing algorithms, which are used to resist malicious attacks, cannot distinguish whether it's...
For massive MIMO system, few research has been done for multipath frequency selective fading model among all literatures. Hence, in this paper we propose a 2-stage multibranch linear MOE (minimum output energy) receiver which collects symbols from different paths to deal with frequency selective fading environment. Due to the big number of antennas, we are using sample covariance matrix other than...
In this work, we propose a scheme, named LECRAD, for the re-construction of temporarily lost connectivity in the presence of dumb nodes in stationary wireless sensor networks. A sensor node is termed as “dumb”, when it continues its physical sensing, but fails to communicate due to shrinkage in communication range, typically attributed to adverse environmental effects such as rainfall, fog and high...
This paper proposed an optimized packet scheduling algorithm for live peer-to-peer streaming system, where network coding technique is extended to improve the efficiency in bandwidth utilization. We identify a problem of undesirable non-innovative packet transmission due to the latency of buffer-map update among peers, which, with many previous proposed techniques, yields to bandwidth inefficiencies...
The Stream Control Transmission Protocol (SCTP) is a relatively new transport protocol. It has several underlying mechanisms that are similar to the Transmission Control Protocol (TCP), as well as several improvements that are important in certain classes of applications. The timeout scheme of SCTP, however, is almost identical to that used in TCP. With dynamics of today's Internet, that timeout scheme...
Full-duplex (FD) technology has been regarded as a promising solution to improve the spectral efficiency of the 5th generation (5G) wireless communication system. In this paper, we focus on a small-area radio system, where a FD base-station serves two half-duplex users simultaneously with one in the uplink and the other one in downlink direction. However, the self-interference (SI) and the inter-user...
As machine-type communications (MTC) penetrate deeper into our everyday life, alternative access models are considered for them. In particular, instead of a traditional multi-hop mesh topology (a.k.a. capillary network), recent works have suggested the use of a cellular network to cover massive numbers of MTC devices with a one-hop deployment (specifically, 3GPP LTE). This significantly reduces the...
Compressive Sensing (CS) enables us to exactly reconstruct a signal from a small number of observations if it has a sparse representation in a known basis. But in the situation where the sparsity is not strictly satisfied as the signal contains Gaussian noise, the general practice tries to directly recover the noisy signal, and then filters out the noise from the recovered signal. Because the existence...
When the Global Positioning System is unavailable, cellular networks become the dominant vehicle for positioning. However, no tractable approach exists for gaining general insights into localization performance in such networks. Instead, analysis is often done using deterministic network models or with complex system-level simulations, resulting in highly context-specific insights, which do not translate...
Nonparametric belief propagation (NBP) algorithm is a popular probabilistic localization method in wireless sensor networks. It is particle-based and can be applied in nonlinear and non-Gaussian inference problems. However, NBP has practical limitations in dense networks due to the high computational complexity and network traffic resulting from the ranging and information exchanges with neighboring...
Multipath-assisted localization is a promising concept for cooperative agent networks to guarantee robust and accurate positioning in indoor environments with harsh radio channel characteristics. It uses two types of measurements: (i) bistatic measurements between agents and (ii) monostatic (bat-like) measurements by the individual agents. This paper presents an in-depth analysis of the position-related...
Fluctuations in the Received Signal Strength, caused for example by temporal propagation dynamics or various mobile types, can decrease the positioning accuracy in WLAN-based indoor fingerprinting. In this paper, the effect of an offset between Received Signal Strength values in the training and estimation phases is investigated. Our study is based on a huge measurement campaign that covers in total...
In this paper, we introduce a novel multiple access scheme for aerial sensor networks employing adaptive antenna arrays with spatial reuse. Spatial reuse has been adopted to enable simultaneous data transmission among unmanned aerial vehicles in a context of spatial diversity. This work introduces two types of UAV: a single main actor UAV and multiple actor UAVs. Since these UAVs cooperatively perform...
Virtual Private LAN Services (VPLS) is a widely utilized Layer 2 (L2) Virtual Private Network (VPN) architecture in industrial networks. In the last few years, VPLS networks gained an immense popularity as an ideal network architecture to interconnect industrial legacy SCADA (Supervisory Control and Data Acquisition) and process control devices over a shared network. However, legacy VPLS architectures...
The combined bulk/per-tone transmit antenna selection strategy has been shown to achieve optimal diversity and coding gains for single-hop systems with multiple transmit and receive antennas. In this paper, we extend this strategy to the case in which a set of user pairs communicate via a cluster of intermediary amplify-and-forward relaying nodes. We obtain an upper bound on the outage probability...
In this paper we consider strategies for MIMO interference channels which combine the notions of interference alignment and channel pre-inversion. Users collaborate to form data-sharing groups, enabling them to clear interference within a group, while interference alignment is employed to clear interference between groups. To improve the capacity of our schemes at finite SNR, we propose that the groups...
A wireless relay node employing Wireless Physical Layer Network Coding (WPLNC) must use a specific mapping in order to combine incoming signals. This mapping, however, cannot be selected arbitrarily. Together with the signals from the other network relays, it has to allow the destinations to be able to recover the source data from the available observations. Moreover the mapping should optimize a...
In this paper the error rate of irregular repetition slotted ALOHA (IRSA) access protocols, under successive interference cancellation decoding, is analyzed for a finite number of active users and in a finite frame length setting. The considered channel model is a collision channel where collisions are destructive and where packets not experiencing collisions are always correctly received. An expression...
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