Elektronik ve Haberleşme Mühendisliği Bölümü Yayın Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/260

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Department: search.filters.department.Çankaya Üniversitesi, Mühendislik Fakültesi, Elektronik ve Haberleşme Mühendisliği Bölümü

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Now showing 1 - 10 of 27
  • Article
    The Research and Design of Multi Relays in Cooperative Communication System Based on Polar Codes
    (2021) Hadi Hadı, Ali Sameer; Gazi, Orhan
    In this paper, we propose a method to increase the performance of cooperative communication using polar codes. For this purpose, we consider non-line-of sight (NLOS) cooperative communication scheme where destination node does not receive signal from source directly. The relay nodes use decodes and forward approach. We propose a voting scheme for the relay nodes, which share information among them. It is shown by the simulation results that the proposed approach significantly improves the performance of relayed communication.
  • Article
    Prunable collision free random interleaver design
    (Springer, 2012) Gazi, Orhan
    In this article we introduce a new collision free prunable random interleaver. The suggested interleaver is a joint structure involving rectangular and S-random interleaver. It comprises a general model for all kind of collision free prunable random interleavers. In addition, it can be designed for any number of parallel processors and any length of information sequence vector and can be considered also as a template for collision free prunable interleavers. The proposed interleaver can be used with all kind of turbo-like codes. The performance of the proposed interleaver is measured with parallel decodable serially concatenated convolutional codes (PDSCCCs) and compared to the PDSCCCs' performance with collision full S-random interleaver.
  • Book
    Dijital Mantık Devrelerinin Tasarımı
    (Seçkin Yayıncılık, 2018) Gazi, Orhan
  • Conference Object
    The Performance of Turbo Equalization Using Blind and Non-blind Channel Estimation Technique
    (2014) Ali AL_Isawi, Ahmed Sami; Gazi, Orhan
    This article presents, we measure the performance of turbo equalizers under channel estimation .Channel estimation is performed via two different approaches, one is based on the use of training sequences ,and the other on the other hand is a blind estimation technique .We have used per-survivor approach for the blind channel estimation . From the simulation results we see that per survivor based approach performs as well as training sequence based approach
  • Article
    Fast Calculation of Polar Code Bits and Frozen-Bit Locations
    (2021) Genç, Fatih; Gazi, Orhan
    In this paper, we show that encoding operation for the polar codes can be achieved without the employment of the generator matrix, and all the polar code bits can be generated at the same time using a number of tree-encoding structures running in parallel. Since encoding matrix is not used in the implementation of the polar encoders in digital electronic devices, hardware space is saved, and low complexity hardware applications are achieved. Besides, we also proposed a method for the calculation of split channel parameters, such as Bhattacharyya bounds or average-bit-error probabilities of the transmitted bits using a tree-based structure. Moreover, the proposed structure enables to calculate the probability of bit-error values of all the transmitted bits at the same time in a parallel manner and decide the locations of data and frozen bits very rapidly.
  • Article
    High Performance Low Latency Parallel Successive Cancelation Decoder Structures for Polar Codes
    (2020) Alrataim, Abdelkareim; Gazi, Orhan
    Polar codes are decoded using successive cancellation (SC) algorithm where likelihood ratios (LRs) for data bits are calculated in a sequential manner, and decisions are made using the calculated LRs. During the decoding of an information bit, the decision results for the predecessor bits are used, and a wrongly decided predecessor bit has negative effect on the accurate calculation of the LR for the information bit being decoded. In SC algorithm, when LR=1, the information bit is decoded as u ̂_i=0, however, such a decision has 50% of chance of being correct. In this paper, we propose improved polar decoders utilizing a number of SC decoders. We consider the case of LR=1, and propose polar decoder structures for the more accurate calculation of the LRs of the successor bits
  • Article
    Diffraction Theory of Waves by Resistive Surfaces
    (2010) Umul, Yusuf Ziya; Yalçın, Uğur
    Diffraction of scalar plane waves by resistive surfaces are investigated by defining a new boundary condition in terms of the Dirichlet and Neumann conditions. The scattering problems of waves by a resistive half-plane and the interface between resistive and perfectly magnetic conducting half-planes are examined with the developed method. The resulting fields are plotted numerically. The numerical results show that the evaluated field expressions are in harmony with the theory.
  • Article
    Comparative Analysis of Early Studies on Turkish Whistle Language and a Case Study on Test Conditions
    (2018) Özaydın, Selma
    This paper examines the early studies on Turkish Whistle Language and it argues that they have some controversial results. The study considers these issues need to be discussed and searched again in terms of linguistic and phonetic form. Unfortunately, there are few research studies on Turkish whistle language and most of them were performed nearly fifty years ago despite the fact that this language still has been used in Kuskoy region. Therefore, the findings of these early research studies could give valuable information to start to a new research study on the subject. The first scientific study on Turkish Whistle language was performed by a French scientist R.G. Busnel with his multidisciplinary research team in 1967. Some of this research’s results were published in the book. A Turkish scientist O. Baskan also participated in Busnel’s research group and published a paper on TWsL in 1968. However, some assertions such as people having a tendency to understand the Turkish whistle language with three vowels and three consonants have not been in the research results of R.G. Busnel. In addition, a Turkish scientist D. Aksan in Turkey had performed another research at Kuskoy region with his own team. Their test methods were different from the previous ones. This paper analyzes these research results on a comparative basis and presents the common and conflicted issues to discuss the uncertain points. The comparative evaluation of these past research studies aims to highlight the controversial position of the results on Turkish Whistle Language. In this scope, this paper opens a discussion about the selection of test conditions for an acoustic and linguistic analysis of the Turkish whistle language.
  • Article
    Acoustic and Linguistic Properties of Turkish Whistle Language
    (2018) Özaydın, Selma
    This paper presents the acoustic and linguistic properties of Turkish Whistle Language. Whistle Language is a natural communication method usually used for far-distance interaction in some regions in the world. In a whistled speech, auditory features of spoken languages are transposed. Therefore, whistle languages carry some properties of vocal speech with its own vocabulary, grammar, phonology and prosodic features. There are a few places in the world using this whistled communication style and Kuskoy region in Turkey is one of them. Although there are some researches on Turkish Whistle Language, unfortunately there have been a limited number of scientific publications in the literature. On the other hand, the research results present very stunning results such as people can still continue articulating some words while whistling and there is a high understandability rate while communicating. Therefore, it is described as an incomplete form of Turkish Language. The research results also indicate that Turkish Whistle Language is a non-tonal language transposing formants and therefore it can be used to evaluate the formant changes in the transform of a language. These research results indicate many other valuable properties of Turkish whistle language. But, unfortunately there has not been a collective study combining all these properties. Besides, there are still unclear and conflicted points in the literature as can be implied in this paper. This study aims to bring together the research results to underline the distinct features of Turkish Whistle Language and to motivate researchers to go forward on this subject. The paper is mainly focused on acoustic and phonetic properties of Turkish Whistle Language. Historical or cultural based details are out of the scope of this study.
  • Book Part
    Citation - Scopus: 1
    Information theory perspective of polar codes and polar encoding
    (Springer Science and Business Media B.V., 2019) Gazi, Orhan
    Polar codes are one of the recently discovered capacity achieving channel codes. What makes the polar codes different from other channel codes is that polar codes are designed mathematically and their performance are mathematically proven. © Springer Nature Singapore Pte Ltd. 2019.