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Search Results: 1 - 10 of 159 matches for " Maged Elkashlan "
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Cooperative Non-Orthogonal Multiple Access with Simultaneous Wireless Information and Power Transfer
Yuanwei Liu,Zhiguo Ding,Maged Elkashlan,H. Vincent Poor
Mathematics , 2015,
Abstract: In this paper, the application of simultaneous wireless information and power transfer (SWIPT) to non-orthogonal multiple access (NOMA) networks in which users are spatially randomly located is investigated. A new cooperative SWIPT NOMA protocol is proposed, in which near NOMA users that are close to the source act as energy harvesting relays to help far NOMA users. Since the locations of users have a significant impact on the performance, three user selection schemes based on the user distances from the base station are proposed. To characterize the performance of the proposed selection schemes, closed-form expressions for the outage probability and system throughput are derived. These analytical results demonstrate that the use of SWIPT will not jeopardize the diversity gain compared to the conventional NOMA. The proposed results confirm that the opportunistic use of node locations for user selection can achieve low outage probability and deliver superior throughput in comparison to the random selection scheme.
Variance-Constrained Capacity of the Molecular Timing Channel with Synchronization Error
Malcolm Egan,Yansha Deng,Maged Elkashlan,Trung Q. Duong
Mathematics , 2014,
Abstract: Molecular communication is set to play an important role in the design of complex biological and chemical systems. An important class of molecular communication systems is based on the timing channel, where information is encoded in the delay of the transmitted molecule---a synchronous approach. At present, a widely used modeling assumption is the perfect synchronization between the transmitter and the receiver. Unfortunately, this assumption is unlikely to hold in most practical molecular systems. To remedy this, we introduce a clock into the model---leading to the molecular timing channel with synchronization error. To quantify the behavior of this new system, we derive upper and lower bounds on the variance-constrained capacity, which we view as the step between the mean-delay and the peak-delay constrained capacity. By numerically evaluating our bounds, we obtain a key practical insight: the drift velocity of the clock links does not need to be significantly larger than the drift velocity of the information link, in order to achieve the variance-constrained capacity with perfect synchronization.
Safeguarding Massive MIMO Aided HetNets Using Physical Layer Security
Yansha Deng,Lifeng Wang,Kai-Kit Wong,Arumugam Nallanathan,Maged Elkashlan
Mathematics , 2015,
Abstract: This paper exploits the potential of physical layer security in massive multiple-input multiple-output (MIMO) aided two-tier heterogeneous networks (HetNets). We focus on the downlink secure transmission in the presence of multiple eavesdroppers. We first address the impact of massive MIMO on the maximum receive power based user association. We then derive the tractable upper bound expressions for the secrecy outage probability of a HetNets user.We show that the implementation of massive MIMO significantly improves the secrecy performance, which indicates that physical layer security could be a promising solution for safeguarding massive MIMO HetNets. Furthermore, we show that the secrecy outage probability of HetNets user first degrades and then improves with increasing the density of PBSs.
Millimeter Wave Power Transfer and Information Transmission
Lifeng Wang,Maged Elkashlan,Robert W. Heath, Jr.,Marco Di Renzo,Kai-Kit Wong
Mathematics , 2015,
Abstract: Compared to the existing lower frequency wireless power transfer, millimeter wave (mmWave) power transfer takes advantage of the high-dimensional multi-antenna and narrow beam transmission. In this paper we introduce wireless power transfer for mmWave cellular networks. Here, we consider users with large energy storage that are recharged by the mmWave base stations prior to uplink information transmission, and analyze the average harvested energy and average achievable rate. Numerical results corroborate our analysis and show that the serving base station plays a dominant role in wireless power transfer, and the contribution of the interference power from the interfering base stations is negligible, even when the interfering base stations are dense. By examining the average achievable rate in the uplink, when increasing the base station density, a transition from a noise-limited regime to an interference-limited regime is observed.
Molecular Communication with a Reversible Adsorption Receiver
Yansha Deng,Adam Noel,Maged Elkashlan,Arumugam Nallanathan,Karen C. Cheung
Mathematics , 2015,
Abstract: In this paper, we present an analytical model for a diffusive molecular communication (MC) system with a reversible adsorption receiver in a fluid environment. The time-varying spatial distribution of the information molecules under the reversible adsorption and desorption reaction at the surface of a bio-receiver is analytically characterized. Based on the spatial distribution, we derive the number of newly-adsorbed information molecules expected in any time duration. Importantly, we present a simulation framework for the proposed model that accounts for the diffusion and reversible reaction. Simulation results show the accuracy of our derived expressions, and demonstrate the positive effect of the adsorption rate and the negative effect of the desorption rate on the net number of newly-adsorbed information molecules expected. Moreover, our analytical results simplify to the special case of an absorbing receiver.
User Association in 5G Networks: A Survey and an Outlook
Dantong Liu,Lifeng Wang,Yue Chen,Maged Elkashlan,Kai-Kit Wong,Robert Schober,Lajos Hanzo
Computer Science , 2015,
Abstract: The fifth generation (5G) mobile networks are envisioned to support the deluge of data traffic with reduced energy consumption and improved quality of service (QoS) provision. To this end, the key enabling technologies, such as heterogeneous networks (HetNets), massive multiple-input multiple-output (MIMO) and millimeter wave (mmWave) techniques, are identified to bring 5G to fruition. Regardless of the technology adopted, a user association mechanism is needed to determine whether a user is associated with a particular base station (BS) before the data transmission commences. User association plays a pivotal role in enhancing the load balancing, the spectrum efficiency and the energy efficiency of networks. The emerging 5G networks introduce numerous challenges and opportunities for the design of sophisticated user association mechanisms. Hence, substantial research efforts are dedicated to the issues of user association in HetNets, massive MIMO networks, mmWave networks and energy harvesting networks. We introduce a taxonomy as a framework for systematically studying the existing user association algorithms. Based on the proposed taxonomy, we then proceed to present an extensive overview of the state-of-the-art in user association conceived for HetNets, massive MIMO, mmWave and energy harvesting networks. Finally, we summarize the challenges as well as opportunities of user association in 5G and provide design guidelines and potential solutions for sophisticated user association mechanisms.
The Unreasonable Effectiveness of Blood Pressure Measurement: Molecular Communication in Biological Systems
Malcolm Egan,Adam Noel,Yansha Deng,Maged Elkashlan,Trung Q. Duong
Quantitative Biology , 2014,
Abstract: Arterial blood pressure is a key vital sign for the health of the human body. As such, accurate and reproducible measurement techniques are necessary for successful diagnosis. Blood pressure measurement is an example of molecular communication in regulated biological systems. In general, communication in regulated biological systems is difficult because the act of encoding information about the state of the system can corrupt the message itself. In this paper, we propose three strategies to cope with this problem to facilitate reliable molecular communication links: communicate from the outskirts; build it in; and leave a small footprint. Our strategies---inspired by communication in natural biological systems---provide a classification to guide the design of molecular communication mechanisms in synthetic biological systems. We illustrate our classification using examples of the first two strategies in natural systems. We then consider a molecular link within a model based on the Michaelis-Menten kinetics. In particular, we compute the capacity of the link, which reveals the potential of communicating using our leave a small footprint strategy. This provides a way of identifying whether the molecular link can be improved without affecting the function, and a guide to the design of synthetic biological systems.
Application of Non-orthogonal Multiple Access in LTE and 5G Networks
Zhiguo Ding,Yuanwei Liu,Jinho Choi,Qi Sun,Maged Elkashlan,Chih-Lin I,H. Vincent Poor
Mathematics , 2015,
Abstract: As the latest member of the multiple access family, non-orthogonal multiple access (NOMA) has been recently proposed for 3GPP Long Term Evolution (LTE) and envisioned to be an essential component of 5th generation (5G) mobile networks. The key feature of NOMA is to serve multiple users at the same time/frequency/code, but with different power levels, which yields a significant spectral efficiency gain over conventional orthogonal MA. This article provides a systematic treatment of this newly emerging technology, from its combination with multiple-input multiple-output (MIMO) technologies, to cooperative NOMA, as well as the interplay between NOMA and cognitive radio. This article also reviews the state of the art in the standardization activities concerning the implementation of NOMA in LTE and 5G networks.
Relationships between Hydraulic Parameters of the Nubian Aquifer and Wells in El Shab Area, South Western Desert, Egypt (A Case Study)  [PDF]
Maged El Osta
International Journal of Geosciences (IJG) , 2012, DOI: 10.4236/ijg.2012.35112
Abstract: For proper water management in the new reclaimed areas, hydraulic parameters of both aquifer and wells related to transmissivity, specific capacity, well loss, formation loss, and water entrance velocity, as well as the relationship between these parameters are the main target after construction of production wells. In El Shab area, the Nubian Sandstone aquifer has a large range of transmissivity (from 483.12 to 1489.24 m2/day) and, also, specific capacity (from 203 to 486.32 m2/day). Relationship of specific capacity and transmissivity is constructed and the established empirical equations can be used to predict the transmissivity of the Nubian aquifer in all new proposed sites for well drilling at which the specific capacity measured without performing pumping tests. On the other hand, the drilled wells in El Shab area exhibit relatively high well losses (25%). The causes for high well losses (entrance velocity (Vn) through water well screen and the distance from the point of water entrance in the well to the point of intake in the pump) are discussed and the relationships are constructed, which seem a positive linear correlation. Relationships between well losses constant for 30 wells with transmissivity and specific capacity, are constructed. These relationships are useful for estimating hydraulic characteristics that are needed for the designs of wells and well fields and for preliminary water-resources management.
Discordant tumor response in the treatment of ALK-rearranged non-small cell lung cancer leads to the diagnosis of synchronous multiple primary lung cancer  [PDF]
Benny Johnson, Maged Khalil
Case Reports in Clinical Medicine (CRCM) , 2013, DOI: 10.4236/crcm.2013.21005
Abstract:


The advent of targeted molecular therapy against the EML4-ALK fusion gene is the latest therapeutic intervention for a subset of patients with non-small cell lung cancer (NSCLC). Crizotinib (Xalkori) is an orally available small molecule tyrosine kinase inhibitor proven in clinical trials to significantly impact progression free survival and overall response rate. We present a case of a 56-year-old male with NSCLC whose lack of a positive treatment response to this therapy led to the clinical suspicion and identification of the underdiagnosed entity known as synchronous multiple primary lung cancer (SMPLC).


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