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Device-to-device communication is a cellular network communication technique in which cellular user devices directly communicate with each other without a base station. In the present work, resource sharing methods of device device users and cellular users are examined in terms of channel capacity gain. For this purpose, the problem of determining the transmit power values that provide the best data...
We consider an interference network tapped by external eavesdropper(s) in which each legitimate transmit-receive pair conceals its communications by using joint transmit-based friendly jamming (TxFJ) and receiver-based friendly jamming (RxFJ). Specifically, TxFJ is realized at the transmit side using MIMO precoding while RxFJ is achieved at the receiver side of each link by leveraging the state-of-the-art...
In this paper, we propose a new full-duplex relay-assisted cognitive radio system model with an adaptive decoding algorithm at the secondary user, in order to maximize both primary and secondary achievable rates. We consider the uplink transmission and we compare the system's achievable rates obtained with both amplify-and-forward and decode-and-forward relaying in the single-carrier case. Then, we...
The concept of the wireless dynamic network architecture (DNA) stands for a system design, which allows terminals to convert into temporary access points (APs) when necessary. In this paper, we propose a framework to solve the problem of load balancing in DNA. Particularly, the user association in DNAs is optimized to minimize the number of active APs and the network cost in terms of tradeoff between...
Results are presented for optimizing device-to-device communications in cellular networks, while maintaining spectral efficiency of the base-station-to-device downlink channel. We build upon established and tested stochastic geometry models of signal-to-interference ratio in wireless networks based on the Poisson point process, which incorporate random propagation effects such as fading and shadowing...
Wireless channels in millimeter wave based wearable networks are particularly susceptible to environmental blockages and dynamics when there are humans/objects in motion. Such dynamics imply, not only physical layer overheads to discover and track viable transmission paths, but also MAC overheads to keep track of neighboring interferers, perform clustering and enable proper scheduling of transmissions...
We state and solve a problem of the optimal geographic caching of content in cellular networks, where linear combinations of contents are stored in the caches of base stations. We consider a general content popularity distribution and a general distribution of the number of stations covering the typical location in the network. We are looking for a policy of content caching maximizing the probability...
Ultra Dense network (UDN) is considered as one of the promising and efficient communication solution for high throughput and large connection numbers scenarios. Due to the densification of the users perspective and massive-access opportunities, how to optimize the multiple users access in UDN is an important and complicated problem. The traditional multi-user access schemes may be no longer suitable...
Consider an orthogonal frequency division multiple access (OFDMA)-based heterogeneous cellular network (HetNet) in which a macrocell is underlaid with several small cells overheard by eavesdropper and jamming by jammer. In this paper, our goal is to design a transmission strategy, such that the achievable secrecy rate is maximized subject to the individual transmit power constraints for the macrocell...
To meet 1000x wireless traffic volume increment in the next decade, a larger number of small base stations (SBSs) have to be densely deployed for 5G cellular networks. Analyzing the optimal density of small base station from the perspective of energy efficiency is very meaningful for green 5G mobile networks. In this paper, we analyze the SBS density for energy efficiency in ultra-dense heterogeneous...
In this paper, power allocation for device-to-device (D2D) communication underlaying cellular networks is investigated. Our optimization task is to maximize the sum rate of the cellular link and the D2D link subject to the maximum power budget and intercell interference constraints. An efficient iterative algorithm is proposed to address the formulated intractable problem, to which the global optimum...
Filter optimization of out-of-band emission plays an important role for FBMC-OQAM system. The main idea of this paper is to minimize the stopband energy with constraints of sidelobe and interchannel interference (ICI)/intersymbol interference (ISI) by optimizing the filter coefficients. The main contribution is that the improved approach reduces the stopband energy and suppresses the sidelobe simultaneously...
Nowadays, various types of access-points (APs) and hosts such as dedicated APs, laptop personal computers, and mobile terminals have been used in IEEE802.11 wireless local-area networks (WLANs). As a result, the optimal assignment of holding APs into the network field depending on the host type distribution has become very important to improve the network performance. In this paper, we formulate this...
Frequency Hopping (FH) systems are increasingly popular in contemporary wireless communications, especially in military communications and electronic confrontations. The key performance of FH systems includes robustness, continuation, and resilience. To measure these factors, additional interference is introduced into FH systems, and a large number of algorithms and schemes have been proposed to maximize...
In this work, we investigate the routing and channel assignment problem in Self-Interference Suppression (SIS)-enabled CRNs, where FD communication is possible. Specifically, we propose a novel metric called “Path Capacity” that reflects the number of links that can be simultaneously activated across a given path while using the minimum possible spectrum resources. Accordingly, we develop a novel...
Cognitive Radio is a promising technology to improve the spectrum exploitation and spectrum sensing is one of the key functionality for cognitive radio (CR) systems to operate in the available spectrum holes. To guard the primary users present in any spectrum from any interference, the CR should be able enough detect incumbent signals even at very low signal-to-noise ratio (SNR). In this paper, different...
Aiming at further increasing the data-storage density beyond 1Tb/in2[1–3], bit-patterned media recording (BPMR), shingled writing (SW)/two-dimensional magnetic recording (TDMR) have emerged as new promising technologies.
Based on the tapped delay-lines (TDL) wideband model, the response variation (RV) constraint is applied to improve the frequency response consistency of the wideband beamforming. The optimization criterion of the proposed algorithm is minimizing the designed sidelobe level utmost and the constraints of the sidelobe level, interference suppression and the response variation while making the direction...
This paper investigates the physical layer security in a multibeam satellite communication system, where each legitimate user is surrounded by one eavesdropper. First of all, an optimization problem is formulated to maximize the sum of achievable secrecy rate, while satisfying the on-board satellite transmit power constraint. Then, two transmit beamforming(BF) schemes, namely, the zero-forcing (ZF)...
Neighbouring cells deteriorates the performance of Orthogonal Frequency Division Multiplexing Access (OFDMA) cellular networks particularly for edge users due to Inter Cell Interference (ICI). In this paper, subcarrier integration with suitable links is proposed for minimizing ICI after Self Organized Resource Allocation (SORA) and Link Grouping Algorithm (LGA) is used to selects the satisfactory...
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