Yazar "Jaradat, Ahmad M." seçeneğine göre listele

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    Floating OFDM-SNM for PAPR and OOBE reduction
    (Institute of Electrical and Electronics Engineers Inc., 2021) Jaradat, Ahmad M.; Hamamreh, Jehad M.; Arslan, Hüseyin
    The novel orthogonal frequency division multiplexing with subcarrier number modulation (OFDM-SNM) transmission scheme offers high spectral and energy efficiency compared to the conventional OFDM; this is due to the extra information bits loaded over the active subcarriers. However, the OFDM-SNM scheme has a high and comparable peak-to-average power ratio (PAPR) performance to the classical OFDM. Besides the high PAPR in OFDM-SNM, out-of-band emission (OOBE) often happens between the adjacent blocks. To address the above-mentioned problems, we introduce an enhanced version of the classical OFDM-SNM, where the active subcarriers' positions are cleverly placed to reduce the PAPR and OOBE values. Power spectral density (PSD) and complementary cumulative distribution function (CCDF) of PAPR are used as performance metrics to assess the PAPR and OOBE performances of the proposed scheme. The obtained simulation results exhibit improved PAPR and OOBE performances of the proposed scheme along with almost similar bit error rate (BER) performance as compared to the classical OFDM.
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    Identification of the number of wireless channel taps using deep neural networks
    (Institute of Electrical and Electronics Engineers Inc., 2021) Jaradat, Ahmad M.; Elgammal, Khaled Walid; Özdemir, Mehmet Kemal; Arslan, Hüseyin
    In wireless communication systems, identifying the number of channel taps offers an enhanced estimation of the channel impulse response (CIR). In this work, efficient identification of the number of wireless channel taps has been achieved via deep neural networks (DNNs), where we modified an existing DNN and analyzed its convergence performance using only the transmitted and received signals of a wireless system. The displayed results demonstrate that the adopted DNN accomplishes superior performance in identifying the number of channel taps, as compared to an existing algorithm called Spectrum Weighted Identification of Signal Sources (SWISS).
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    Modulation options for OFDM-based waveforms: Classification, comparison, and future directions
    (IEEE-Inst Electrİcal Electronics Engineers Inc, 2019) Jaradat, Ahmad M.; Hamamreh, Jehad M.; Arslan, Hüseyin
    This paper provides a comparative study on the performance of different modulation options for orthogonal frequency division multiplexing (OFDM) in terms of their spectral efficiency, reliability, peak-to-average power ratio, power efficiency, out-of-band emission, and computational complexity. The modulation candidates are classified into two main categories based on the signal plane dimension they exploit. These categories are: 1) 2-D signal plane category including conventional OFDM with classical fixed or adaptive QAM modulation and OFDM with differential modulation, where information is conveyed in changes between two successive symbols in the same subcarrier or between two consecutive subcarriers in the same OFDM symbol and 2) 3-D signal plane category encompassing: a) index-based OFDM modulation schemes which include: i) spatial modulation OFDM, where information is sent by the indices of antennas along with conventional modulated symbols and ii) OFDM with index modulation, where the subcarriers' indices are used to send additional information; b) number-based OFDM modulation schemes which include OFDM with subcarrier number modulation, in which number of subcarriers is exploited to convey additional information; and c) shape-based OFDM modulation schemes which include OFDM with pulse superposition modulation, where the shape of pulses is introduced as a third new dimension to convey additional information. Based on the provided comparative study, the relationship and interaction between these different modulation options and the requirements of future 5G networks are discussed and explained. This paper is then concluded with some recommendations and future research directions.
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    OFDM with hybrid number and index modulation
    (IEEE - Institute of Electrical and Electronics Engineers, Inc., 2020) Jaradat, Ahmad M.; Hamamreh, Jehad M.; Arslan, Hüseyin
    A novel transmission scheme is introduced for efficient data transmission by conveying additional information bits through jointly changing the index and number of active subcarriers within each orthogonal frequency division multiplexing (OFDM) subblock. The proposed scheme is different from the conventional OFDM-subcarrier number modulation (OFDM-SNM) and OFDM-index modulation (OFDM-IM), in which data bits are transmitted using either number or index of active subcarriers. The proposed modulation technique offers superior spectral and energy efficiency compared to its counterparts OFDM-SNM and OFDM-IM, especially at low modulation orders such as binary phase shift keying (BPSK) that can provide high reliability and low complexity, thus making it very suitable for meeting the requirements of Internet of things (IoT) applications. Bit error rate (BER) performance analysis is provided for the proposed scheme, and Monte Carlo simulations are presented to prove the consistency of the simulated BER with the analyzed one. More importantly, it is demonstrated that the proposed scheme can offer much superior BER performance compared to that of OFDM-IM and classical OFDM under equivalent power and spectral efficiency values.
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    Service-based resource scheduling optimization for multi-user otfs-based systems
    (2024) Jaradat, Ahmad M.; Alayedi, Mohanad; Arslan, Hüseyin
    In this letter, we investigate a flexible resource allocation (RA) in the delay and Doppler domains to accommodate services with varying requirements. We demonstrate that our problem is NP-hard and propose an optimization method based on linear programming (LP) and Lagrangian dual (LD). The adoption of flexibility in the delay and Doppler domains for capacity enhancement and addressing the needs of mission-critical services has considerable advantages, according to the obtained numerical results. They show that the new scheduling method outperforms conventional time-frequency (TF) domains in terms of bit rate and latency per user, making it valuable for fifth generation (5G) applications and beyond.