Yazar "Uysal, Elif" seçeneğine göre listele

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    Age of Information in Practice
    (Cambridge University Press, 2023) Uysal, Elif; Kaya, Onur; Baghaee, Sajjad; Beytur, Hasan Burhan
    While age of Information (AoI) has gained importance as a metric characterizing the freshness of information in information-update systems and time-critical applications, most previous studies on AoI have been theoretical. In this chapter, we compile a set of recent works reporting AoI measurements in real-life networks and experimental testbeds, and investigating practical issues such as synchronization, the role of various transport layer protocols, congestion control mechanisms, application of machine learning for adaptation to network conditions, and device related bottlenecks such as limited processing power.
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    Improving age of information in random access channels
    (Institute of Electrical and Electronics Engineers Inc., 2020-07) Atabay, Doğa Can; Uysal, Elif; Kaya, Onur
    We study Age of Information (AoI) in a random access channel where a number of devices try to send status updates over a common medium. Assuming a time-slotted scenario where multiple transmissions result in collision, we propose a threshold-based lazy version of Slotted ALOHA and derive the time average AoI achieved by this policy. We demonstrate that the average AoI performance of the lazy policy is significantly better than Slotted ALOHA, and close to the ideal round robin benchmark.
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    Resource allocation in the finite blocklength regime under PAoI and delay violation constraints
    (IEEE, 2023-08-27) Kartal, Özkan Tuğberk; Kaya, Onur; Uysal, Elif
    URLLC (Ultra-reliable low-latency communication) is one of the more challenging modes for 5G for resource allocation (RA). Most of the previous studies for RA for wireless access in URLLC assumed known packet arrival processes, and focused on maximizing average rates or throughput. The objective of this paper is to present a formulation of allocating resource blocks, modulation and coding rates to multiple short packet machine-type information flows to provide information age and delay violation guarantees. The scenario is motivated by the scheduling of URLLC flows among users served by a common 5G base station. The problem involves the selections of frequency allocation policy and modulation and coding scheme (MCS) under estimated CSI. Moreover, the sensitivity of the information packet size on the choice of modulation and coding parameters as well as the number of resource blocks and the choice of the number of pilot symbols is demonstrated. The results of this formulation are compared with resource allocation algorithms in the literature.
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    Semantic communications in networked systems: a data significance perspective
    (IEEE, 2022-07-01) Uysal, Elif; Kaya, Onur; Ephremides, Anthony; Gross, James; Codreanu, Marian; Popovski, Petar; Assaad, Mohamad; Liva, Gianluigi; Munari, Andrea; Soret, Beatriz; Soleymani, Touraj; Johansson, Karl Henrik
    We present our vision for a departure from the established way of architecting and assessing communication networks, by incorporating the semantics of information for communications and control in networked systems. We define semantics of information, not as the meaning of the messages, but as their significance, possibly within a real time constraint, relative to the purpose of the data exchange. We argue that research efforts must focus on laying the theoretical foundations of a redesign of the entire process of information generation, transmission and usage in unison by developing: advanced semantic metrics for communications and control systems; an optimal sampling theory combining signal sparsity and semantics, for real-time prediction, reconstruction and control under communication constraints and delays; semantic compressed sensing techniques for decision making and inference directly in the compressed domain; semantic-aware data generation, channel coding, feedback, multiple and random access schemes that reduce the volume of data and the energy consumption, increasing the number of supportable devices. This paradigm shift targets jointly optimal information gathering, information dissemination, and decision making policies in networked systems.
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    When to pull data for minimum age penalty
    (IEEE, 2021-10-18) Yavaşcan, Orhan Tahir; Ceran, Elif Tuğçe; Cakir, Zeynep; Uysal, Elif; Kaya, Onur
    A communication receiver that wants to pull data from a remote sensor by exploiting wireless energy transfer is considered. The receiver has a long-term average energy budget for this operation, and its goal is to keep the time average of a general age penalty function as small as possible. The channel from the source to the receiver is a two-state (ON/OFF) communication link whose state is IID or Markovian, and known instantaneously by the receiver. Modeling the problem as a constrained Markov decision problem, we obtain a randomized threshold-based decision policy that achieves the minimum possible average age penalty. We determine the optimal time average Age of Information and age violation probabilities by exploiting the optimality of the derived policy.