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The performance of an optical wireless communication (OWC) system subjected to atmospheric turbulence induced fading can be significantly improved by using spatial diversity reception. Diversity reception also suffers from correlation among diversity branches due to insufficient spacing between multiple photodetectors at the receiver. In this paper, average channel capacity of OWC system employing...
Wi-Fi has been widely deployed with the rapid development of wireless communication technique. Wi-Fi hotspots are popular in campus, making convenient wireless network access possible. However, during class teaching, in order to avoid students browsing the web based on Wi-Fi hotspots and distracting, we hope Wi-Fi hotspots adaptively shield network access to students in the classroom, while grant...
The statistical properties of traffic in Internet access networks have long been of interest to networking researchers and practitioners. In this paper, we analyse network traffic originating and terminating from various types of Internet access networks (Ethernet, Digital Subscriber Line, Wireless hotspot and their next tier Internet Service Provider's core network) and show that renewal processes...
Average travel speed for road sections is important information for traffic condition evaluation, transportation management, and so on. Vehicular crowdsensing can be used to collect data including real-time locations and velocities of vehicles, which can be further utilized to estimate travel speed. However, due to the uneven spatial-temporal distribution of vehicles and the variation of data-offering...
This paper analyzes the performance of energy beamforming in spatially correlated multiple-input multiple-output (MIMO) relaying systems, where the source and destination nodes are equipped with multiple spatially correlated antennas and communicating via a dual-hop amplify-and-forward (AF) single antenna energy-constrained relay. To maximize the overall harvested energy so as to enable long-distance...
Sparse channel estimation (SCE) in orthogonal frequency division multiplexing (OFDM) systems with large number of virtual sub-carriers and regularly spaced pilots is studied in this paper. Such OFDM systems are present in wireless standards like long term evolution (LTE). We numerically evaluate the performance of popular compressive sensing (CS) algorithms and shows that low complexity CS algorithms...
We examine for the first time the impact of transmitter-side correlation on the secure transmission with artificial noise (AN), based on which a new power allocation strategy for AN is devised for physical layer security enhancement. Specifically, we design a correlation-based power allocation (CPA) for AN, of which the optimality in terms of achieving the minimum secrecy outage probability is analytically...
Abstract-In this article, the authors focus on a correlated channel model for secure relay beamforming in the relayeavesdropper network. In this network, a single-antenna sourcedestination pair transmits secure information with the help of a amplify-and-forward (AF) relay equipped with multiple antennas. The relay cannot obtain the instantaneous channel state information (CSI) of the eavesdropper...
This paper investigates the impact of antenna correlation on wireless powered dual-hop multi-antenna relaying systems with instantaneous channel state information (CSI) or statistical CSI at the relay. Considering the power-splitting architecture, we study the outage probability as well as the achievable diversity order of the system for amplify-and-forward protocol. Our results show that, antenna...
Recently, DCS-cast has shown an advantage in accommodating heterogeneous users over wireless networks by combining SoftCast and Distributed Compressed Sensing (DCS). However, DCS-cast's efficiency is not actually high due to its ignorance of the temporal correlation in each packet at the encoder. This paper proposes an improved scheme named DCT-DCS-cast that removes such temporal correlation through...
Wireless telemonitoring of physiological signals is an evolving direction in personalized medicine and home-based e-Health. There are several constraints in designing such systems. The three important constraints are energy consumption, data compression and device cost. Compressive Sensing (CS) is an emerging data compression technique that overcomes those constraints. Nevertheless, the non-sparsity...
The method of key sharing between a mobile unit and a base station through a wireless MIMO-based fading channel is investigated. The description of a key distribution protocol is given. The expression to estimate the correct key bit agreement based on the use of guard interval is proved. Statistical properties of the key string are tested using the NIST criteria. Impossibility of key string eavesdropping...
Practical generation of secret bits using wireless channel measurements between two terminals is presented in this paper. The model used for this implementation assumes imperfect reciprocity between the channel measurements made by the two terminals in the presence of a passive eavesdropper. The channel measurements (e.g., received signal strength values) are used to estimate the secret key rate in...
Accurate channel state information (CSI) at transmitter is of importance to sufficiently exploit the merits of massive multiple input multiple output (MIMO). Because of the large amount of antennas at base station (BS), the pilot overhead becomes unaffordable, especially in frequency-division duplexing (FDD) massive MIMO systems. To alleviate the overwhelming pilot overhead, a novel channel estimation...
A multi-stage temporal pooling mechanism is proposed in this paper for improving the prediction capability of an objective quality metric for video quality assessment. The performance of the proposed pooling mechanism is evaluated along with that of traditional pooling mechanisms in terms of linear correlation coefficient and Spearman rank order correlation coefficient on four publicly available video...
This paper examines the low-probability-of-exploitation (LPE) characteristics of a noncontiguous orthogonal frequency division multiplexing (NC-OFDM) system. NC-OFDM transmission is similar to OFDM transmission but only uses a subset of the frequencies either to avoid incumbent transmissions or due to tactical considerations. This paper considers an NC-OFDM transmission with a given set of active...
Reconfigurable antenna arrays provide important advantages such as reduction on the number of the physical antennas or reduced hardware complexity in terms of receiving radio frequency chains. Both these properties are critical in vehicle-to-vehicle (V2V) communication systems, which are characterized by inflexible dimensions and cost constraints. In this paper, a new pattern reconfigurable antenna...
The problem of the centralized caching is studied in a two-layer network. The first layer of the network is constructed by a server and K1 helpers, and the second layer consists of K1 orthogonal sub-networks, each of which contains a helper and K2 users. The pioneer caching design in the two-layer network is to directly apply the Maddah-Ali & Niesen (MAU) centralized caching [1] into individual...
We study a multi-user up-link scenario where an attacker tries to impersonate the legitimate transmitters. We present a new framework for deriving a posteriori attack proba- bilities from the channel observations at the access point, which enables fast intrusion detection and authentication at the physical layer and can be exploited to reduce the security overhead by offloading higher-layer authentication...
Communication in industrial applications like factory automation (FA) demands very low latency combined with high reliability. Since state of the art wireless technologies are not entirely fulfilling FA requirements, novel approaches are being developed.
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