Electrical - Electronic Engineering / Elektrik - Elektronik Mühendisliği

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  • Conference Object
    Adaptive Limited Feedback Scheme for Stream Selection Based Interference Alignment in Heterogeneous Networks
    (IEEE, 2016) Beyazıt, Esra Aycan; Özbek, Berna; Le Ruyet,D.
    This paper presents a stream selection based interference alignment approach with imperfect channel state information for heterogeneous networks. The proposed algorithm performs the selection of a stream sequence among a predetermined set of sequences. Those selected sequences are the ones that mostly contribute to the sum rate when performing the exhaustive search. These stream sequences form a regular structure where the first stream is associated to a pico user. The effect of imperfect channel state information on the proposed algorithm is analyzed and a bit allocation scheme is proposed by deriving an upper bound on the rate loss due to quantization. © 2016 IEEE.
  • Article
    Citation - WoS: 12
    Citation - Scopus: 14
    A Molecular Communication Perspective on Airborne Pathogen Transmission and Reception Via Droplets Generated by Coughing and Sneezing
    (IEEE, 2021) Güleç, Fatih; Atakan, Barış
    Infectious diseases spread via pathogens such as viruses and bacteria. Airborne pathogen transmission via droplets is an important mode for infectious diseases. In this paper, the spreading mechanism of infectious diseases by airborne pathogen transmission between two humans is modeled with a molecular communication perspective. An end-to-end system model which considers the pathogen-laden cough/sneeze droplets as the input and the infection state of the human as the output is proposed. This model uses the gravity, initial velocity and buoyancy for the propagation of droplets and a receiver model which considers the central part of the human face as the reception interface is proposed. Furthermore, the probability of infection for an uninfected human is derived by modeling the number of propagating droplets as a random process. The numerical results reveal that exposure time affects the probability of infection. In addition, the social distance for a horizontal cough should be at least 1.7 m and the safe coughing angle of a coughing human to infect less people should be less than -25 degrees.
  • Conference Object
    Citation - Scopus: 1
    Interference Management for Multiuser Multiantenna Ofdma Underlaying Device-To Communications
    (IEEE, 2017) Özbek, Berna; Pischella, Mylene; Le Ruyet, Didier
    Underlaying device-to-device (D2D) transmission in cellular wireless systems is one of the promising transmission techniques for fifth generation (5G) and beyond 5G applications. Nevertheless, the interference between the D2D pairs, the interference from cellular users to D2D receivers and the interference that affects the cellular communications should be mitigated to increase the overall system performance. In this paper, we propose interference management techniques for D2D underlaying communications in multiuser multiantenna orthogonal frequency division multiple access (OFDMA) systems. Our goal is to increase the data rate of both the cellular users and D2D pairs by performing interference management in frequency, power and spatial dimensions. The performance evaluations illustrate the effectiveness of the proposed algorithm in terms of average data rate and average transmitted power for both cellular users and D2D pairs.
  • Conference Object
    Citation - WoS: 3
    Citation - Scopus: 3
    Space-Frequency Grouping Based Key Extraction for Mimo-Ofdm Systems
    (IEEE, 2017) Topal, Ozan Alp; Karabulut Kurt, Güneş; Özbek, Berna
    Latest developments in wireless communication networks push the limits of conventional security methods. Security can be improved with a secret key that is dynamically generated based on the surrounding physical environment. With this objective, physical layer security approaches can be implemented by means of simple signal processing methods. In this paper, we propose novel key extraction approaches based on spatial and frequency characteristics of the wireless environment. In a 2x2 MIMO-OFDM system, low key disagreement rates and key error rates are observed, proving the potential of physical layer key extraction techniques.
  • Conference Object
    Citation - Scopus: 2
    Message-Passing Algorithm for Sum-Rate Maximization in Multi-Antenna Underlay D2d Communications
    (IEEE, 2018) Özbek, Berna; Pischella, Mylene; Le Ruyet, Didier
    In this paper, we propose a resource allocation of device-to-device (D2D) communications underlaying multiantenna cellular systems by employing message-passing algorithm. It is possible to construct the factor graph of the D2D pairs by considering the interference power at the base station and among the D2D pairs. The goal is to avoid interfering the cellular transmission while increasing the sum data rate of D2D pairs. We show that the proposed resource allocation based on message passing algorithm allow us to almost reach the performance of the exhaustive search and outperforms the random allocation. Since the associated factor graph is not fully connected, the complexity of the algorithm is significantly reduced compared to the exhaustive search. © 2018 IEEE.