Transmitter Chain Research Articles

Эпосы про Идегея и его родственников в эпическом цикле «Сорок батыров Крыма»

Objective of the study: The aim of the research is to examine the content, origin, and chain of transmitters of the epics dedicated to the dynasty of the Golden Horde's beglerbeg, Idegei, included in the cycle of heroic epics, “Forty Heroes of Crimea”. A comparative analysis of each epic with available information about historical figures mentioned in the epics is carried out to identify the main characters. The study also seeks to determine the author of the entire cycle, “Forty Heroes of Crimea,” and establish the time and circumstances of the creation of these epics among the Kazakhs of the Junior Zhuz. Materials of the study: The primary source of this research is the cycle of epics, “Forty Heroes of Crimea,” recorded from the oral tradition of Muryn Sengirbekuly and published as part of the “Madenі Mura” ("Cultural Heritage”) project in the 50th and 51st volumes of the “Babalar Sözi” (“Words of Ancestors”) series. Results of the study: The author of the cycle “Forty Heroes of Crimea” has been identified as Kazytugan-zhyrau, a descendant of Idegei. The cycle of epics was composed in the last quarter of the 17th century. The circumstances of the creation of the cycle were related to Kazytugan's migration to the Kuban who were the descendants of Karasai. It has been established that the cycle of epics was introduced by fugitive Kuban Nogais into the Junior Zhuz Kazakh environment in 1745 under the rule of Nuraly Khan who settled them among the Kazakhs of the Berish clan of the Alshin tribe. These Nogais later formed the Besskaska-Berish branch from which the spread of the “Forty Heroes of Crimea” epics among the Kazakhs began. The first known Kazakh zhyrau to transmit the entire cycle was Abyl-zhyrau, followed by his students Nurym-zhyrau, Murat-akyn, and Kashagan-zhyrau. From these latter figures, Muryn-zhyrau Sengirbekuly learned the epics. The entire cycle of epics was recorded and published from his oral account.

CMOS IC Solutions for the 77 GHz Radar Sensor in Automotive Applications

This paper presents recent results on CMOS integrated circuits for automotive radar sensor applications in the 77 GHz frequency band. It is well demonstrated that nano-scale CMOS technologies are the best solution for the implementation of low-cost and high-performance mm-wave radar sensors since they provide high integration level besides supporting high-speed digital processing. The present work is mainly focused on the RF front-end and summarizes the most stringent requirements of both short/medium- and long-range radar applications. After a brief introduction of the adopted technology, the paper addresses the critical building blocks of the receiver and transmitter chain while discussing crucial design aspects to meet the final performance. Specifically, effective circuit topologies are presented, which concern mixer, variable-gain amplifier, and filter for the receiver, as well as frequency doubler and power amplifier for the transmitter. Moreover, a voltage-controlled oscillator for a PLL efficiently covering the two radar bands is described. Finally, the circuit description is accompanied by experimental results of an integrated implementation in a 28 nm fully depleted silicon-on-insulator CMOS technology.

Beyond Fictionality

According to Gérard Genette, frame narratives are one of few reliable textual markers of fictionality. While very different from the corpus studied by Genette, al-Tanūkhī’s (d. 384/994) compilation al-Faraj baʿd al-shidda includes many anecdotes featuring at least one instance of narrative framing, as well as many more anecdotes told on a single narrative level (after the usual introductory chain of transmitters). As such, the compilation presents a good case study for the link between fictionality and narrative levels in a premodern Arabic context. On the strength of many examples drawn from the compilation, this article describes three uses of frame narratives in the Faraj and argues that even if some of the compiled material thematizes questions of reports’ plausibility (rather than “fictionality”), narrative levels are not a reliable marker of stories considered to be more implausible. One use of the frame narrative in the Faraj is indeed in addressing a report’s plausibility (1), but other anecdotes achieve this without any such framing. Moreover, frame narratives also take on other functions whereby they neither flag nor are reliably associated with a story’s lesser plausibility. Such functions include anchoring a story’s narration within a familiar situation and highlighting the message of a narrative by setting up parallels between its different levels (2). Another function is to negotiate the incorporation of less familiar voices and content, remote in social milieu or geography from al-Tanūkhī’s life, into the world of the compilation (3). These different uses show that frame narratives are not reliable markers of fictionality in the Faraj, and that they were not artificially affixed onto the Faraj’s less plausible plots. Instead, they served different functions, introducing a wide variety of content and shaping the reception of stories by questioning their plausibility, yes, but also by exploiting and manipulating readers’ expectations, and by pushing the limits of spaces and perspectives incorporated into the Faraj’s overall message of deliverance after hardship. Key words: Frame narratives, fictionality, plausibility, foreignness, al-Tanūkhī, al-Faraj baʿd al-shidda, compilation, Abbasid literature.

Problems of interpreting the main types of hadith in terms of their correct understanding

Relevance. This study provides traditional insights into the hadith and Sunnah of the Prophet Muhammad as an important source of Islamic religion and Muslim culture in general. All the Prophet's activities are covered by the Sunnah, which was, remains and will remain one of the main sources of Muslim law, secondary solely to the Holy Koran.Purpose. The purpose of the study was to conduct a systematic analysis of the stages of hadith study based on Sheikh Abdullah Harare's theology and to draw attention to the complexity of the science of hadith.Methodology. The methodology for analysing the veracity and accuracy of the hadith of the Prophet Muhammad involves a set of specific procedures and activities.Results. This study covers topics such as the concept of hadith, its meaning, hadith teaching and distribution, recording, the Isnad system, criticism of hadith, the classification of scholars and its impact on the classification of hadith, fabrication of hadith, etc. The types of hadith in terms of the credibility of the chain of transmitters and the authenticity of the texts were investigated. Each type of hadith is unique. Thus, every scholar, theologian, orientalist and ordinary reader of the hadith before diving into this science must be more or less familiar with it unless he wants to go down the wrong path.Conclusions. People have always distorted texts when passing them on or translating them to one another. Sometimes these distortions occurred unintentionally and sometimes deliberately. The science of hadith helps to clearly assess each individual expression attributed to the Prophet Muhammad in terms of its veracity. The task of hadith scholars is to determine the truth of hadith. Only after examining the biographies of the people mentioned in the Isnad (chain of transmissions) to convince them of their positive moral and intellectual qualities it is possible to judge the authenticity of a particular hadith.

المنهجية التي اعتمدها الشيخ الشنقيطي في بيان الاعتضاد للأحاديث في تفسيره "أضواء البيان" دراسة تحليلية

Shaikh Shanqīṭī has been well known for his Encyclopedic, versatile, and scholarly personality. He has contributed in almost every field of Islamic studies, from Tafsīr, ʾUṣūl al-Tafsīr, Ḥadīth, Muṣṭalah al-Ḥadīth, Fiqh and ʾUṣūl al-Fiqh to ʿIlm al-Kalām. He has been famously known for His commentary on Quran named: “ʾAḍwāʿ al-Bayān fī Tafsīr al-Quran bi al-Quran” which is considered one of the best commentaries on the interpretation of Quran with the Quran. Although, this aspect has been considered by other commentators, interpreting every ʾāyah being restricted within the Quranic context, is the salient feature of this commentary. Another aspect that needs to be highlighted from this Tafsīr is the approach of Shaikh Shanqīṭī to consider a Ḥadīth reliable. He is the unique in applying this method in a way that he considers many things to strengthen a Ḍaʿīf Ḥadīth (weak) so be reliable. by doing this, he considers other branches of Islamic Studies playing their role in the process of Ḥadīth authentication. In fact, this approach is different from Muḥaddithīn (Ḥadīth scholars), who usually consider only ʾIsnād (chain of transmitters) to strengthen a Ḍaʿīf Ḥadīth. In this article, we will be trying to explore this aspect and highlight all those standards that can be considered to strengthen a Ḍaʿīf Ḥadīth from the perspective of Shaikh Shanqīṭī.

From Mustalah al Hadith to Mustalah al Ta’rikh: Transmission and Contents Criticism in Afrabic Historiography

Drawing from this same concept, Afrabic is employed considering the fact that most of the ideas therein fall within the purview of the relationship between Africa and Arabic. The task of screening and documenting authentic prophetic traditions and discarding fabricated information attributed to the Prophet of Islam resulted in the evolution of the critical study of Ḥadīth literature, technically referred to as Muṣṭalaḥ al Ḥadīth. Scholars of Ḥadīth employed a method of validating matn (text) by subjecting the isnād (chain of transmitters) to tests of reliability. Considering the similarity of the process of Ḥadīth verification and the methodology of establishing facts in historiography, which involves Heuristik (identification of sources), Kritik (testing sources for reliability), and Hermeneutik (interpretation of reliable sources for constructing a connected and significant narrative), there is a high potential for a symbiotic relationship between Ḥadīth studies and historiography. This paper makes a case for the specific application of the method of validation of information in Ḥadīth for obtaining authentic historical facts. For illustrative purposes and ascertainig the efficacy of this method and approach, two Arabic works on Medieval African Historiography, viz; Infāq al Maysūr of Muḥammad Bello and Tārikh Mai Idrīs Alūma waghazawātuh of Ibn Fartuwa were subjected to the mechanism of information validation hereby technically referred to as Muṣṭalaḥ al Tārīkh. The outcome revealed significant strengths and weaknesses of the two works. While they both subsist as useful sources of history, various dimensions of inaccurate information were detected in the accounts of the authors.

FPGA implementation of a sub-400ns 6G free-space optical wireless communications transmitter.

Future wireless networks are planned to service many applications with an Ultra Low-Latency (ULL) requirement. Numerous 6G systems have been proposed including more traditional electro-magnetic (EM) antenna transmissions and optical wireless communications (OWC). For extremely wide-band operation, the traditional approaches require digital pre-distortion and other processing techniques which, in turn, require more computational resources and processing times thus increasing latency. Alternatively, OWC has the potential for extremely wide bandwidths in 6G without the need for as much digital signal processing. In order to realise ULL performance, a minimum number of digital signal processing (DSP) blocks is required, as well as an optimal design of each of these. In this letter, we propose a DSP solution for ULL and peak to average power ratio (PAPR) reduction for OWC systems. Unitary checkerboard precoding - orthogonal frequency division multiplexing (UCP-OFDM) is chosen as the modulation scheme and has been implemented within a single digital block avoiding the use of standard OFDM which would otherwise require multiple digital blocks. Experimentally validated results successfully demonstrate a 2.21184 GSps wireless link at distances of up to 2m in noisy daylight settings. Bit error rates (BER) of 0 at root mean square (RMS) error vector magnitude (EVM) of 4.09% are achieved. A complete digital line-up of an OWC transmitter chain for this work contains only three core blocks and ULL of less than 400 ns.

A New Varactor-Tuned 5.8 GHz Dielectric Resonator Band-Stop Filter for ITS and C-V2X Coexistence with Vehicular DSRC

In this paper, we introduce an electronically tuneable band-stop filter based on a dielectric resonator, along with its design principles and equivalent circuit model aimed at the coexistence of intelligent transport systems (ITS) and cellular vehicle-to-everything (C-V2X) communications operating at 5.9 GHz, with the widely spread vehicular dedicated short range communications (DSRC) at 5.8 GHz. The proposed architecture involves a dielectric resonator coupled via a microstrip transmission line to a planar ring resonator. The resonance is electronically tuned by varying the bias voltage of a varactor diode placed in the ring. This design is analyzed theoretically and experimentally. For validation, a filter operating at 5.8 GHz was designed. The prototype is capable of enhancing coexistence exhibiting to features. First, when inserted into the ITS transmitter chain, it reduces unwanted transmitter emissions in the out-of-band spectrum occupied by the DSRC carriers in the 5.8 GHz frequency band of at least 25 dB, with a minimal insertion loss at 5. 9 GHz of 1.6 dB; secondly, when inserted in the ITS receiver chain, it exhibits high linearity that prevents the generation of intermodulation products falling into the filter pass band. The prototype features more than 21 dBm of third-order input intercept points, and a tuning range of 26 MHz while maintaining a minimal loaded Q factor of 93. The prototype is discussed regarding the detailed equivalent circuit parameter extraction and their dependency upon the control voltage.

A Single Chain 800M/1.8G/2.4GHz Multistandard Transceiver With Multibranch Transformer for Low-Cost IoT Applications

An 800M/1.8G/2.4GHz multi-band multi-standard single chain transceiver is presented to support terminals under NB-IoT, BLE and ZigBee protocols. The multi-branch co-wound transformer structure co-designed with RF front-end blocks (i.e., LNA & Power Mixer) is proposed and adopted for compact and efficient in-out matching with moderate Q value. Such co-designed topology enables the single transceiver chain to cover wide-spreading frequency ranging over three times of its minimum band frequency, without compromising performance. The measurement shows that, in receiver chain, the sensitivity is better than −102 dBm, consuming less than 20mW, in transmitter chain, the EVM is 4.63% and 5.2% for NB-IoT multi-tone 12-tone transmission with 0dBm output power in LB and MB. The transceiver has been implemented in 65nm CMOS process, with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.5mm^{2}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.6mm^{2}$ </tex-math></inline-formula> for receiver and transmitter, respectively. The design is consistent with the requirement of low-cost multi-standard Internet-of-Things (IoT) applications.

Manhaj Penulisan Hadith Dalam Fiqh Al-Sunnah Oleh Sayyid Sabiq

The fame achieved by Sayyid Sabiq as a renowned Muslim scholar is undisputed. However, he is not spared from criticism. In his work entitled Fiqh al-Sunnah, he is said to have no method in applying hadith to substantiate rules that it entails several contradictions against the aspects affecting the disciplines of hadith. This study therefore intends to investigate the method of hadith writing by Sayyid Sabiq in Fiqh al-Sunnah. To achieve the purpose, qualitative research is conducted through the content analysis method in examining textual contents in Fiqh al-Sunnah. The study finds that Sayyid Sabiq does have his own method in the writing of hadith. Among the approaches he employs is shortening the chain of transmitters, clarifying the status of some hadith and providing comments on the hadith transmitters. Further, this study discovers that the hadiths of which status he does not clarify come under criticism by the scholars who evaluate the same as weak hadith. The criticism however does not impair his credibility as a figure who contributes in elevating hadith as a primary reference in the discourse of fiqh.

Correctly Modeling TX and RX Chain in (Distributed) Massive MIMO—New Fundamental Insights on Coherency

This letter shows that the TX and RX models commonly used in literature for downlink (distributed) massive MIMO are inaccurate, leading also to inaccurate conclusions. In particular, the Local Oscillator (LO) effect should be modeled as <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$+\varphi $ </tex-math></inline-formula> in the transmitter chain and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-\varphi $ </tex-math></inline-formula> in the receiver chain, i.e., different signs. A common misconception in literature is to use the same sign for both chains. By correctly modeling TX and RX chain, one realizes that the LO phases are included in the reciprocity calibration and whenever the LO phases drift apart, a new reciprocity calibration becomes necessary (the same applies to time drifts). Thus, free-running LOs and the commonly made assumption of perfect reciprocity calibration (to enable blind DL channel estimation) are both not that useful, as they would require too much calibration overhead. Instead, the LOs at the base stations should be locked and relative reciprocity calibration in combination with downlink demodulation reference symbols should be employed.

Design and Performance Investigation of a Temperature Compensated Transmitter With GaN HEMTs for Phased-Array Applications

This article presents a temperature compensated transmitter for phased-array applications. The high-temperature effects on each individual transmitter building block are studied and compensated to mitigate the performance variations. Furthermore, a new active, tunable, and variable gain phase shifter VGPS) architecture is proposed, which features low-performance variation with temperature and high gain without compromising the phase shift range. A temperature sensor is designed to adaptively adjust the critical dc bias voltages to minimize the variation of the active devices. A class- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{F}^{-1}$ </tex-math></inline-formula> power amplifier PA) is designed, as the last stage in the transmitter chain, and its performance variation is compensated through the VGPS stage by adaptively tuning its characteristics. Gallium-nitride (GaN)-on-silicon-carbide (SiC) high-electron-mobility transistors (HEMTs) are adopted as the active devices and a voltage-controlled capacitor (varactor) used in the VGPS stage. The transmitter is prototyped on a piece of Rogers 4003C substrate, and the system performance is measured. The transmitter has the minimum and the maximum small-signal gain of 5.2 and 31.5 dB, respectively, with the maximum variation of < 2.3 dB across the temperature range and the frequency range of 2–2.1 GHz. The insertion phase variation also remains below 6.5° across the phase shift, temperature, and frequency range. The maximum output power and power added efficiency (PAE) are measured to be 33 dBm and 58%, respectively, at the maximum ambient temperature of 220 °C. The measurement results also show that the transmitter is able to transmit 64-QAM signals with the data rate of 120 Mb/s at the maximum ambient temperature of 220 °C.

Air-Induced PIM Cancellation in FDD MIMO Transceivers

In this letter, air-induced passive intermodulation (PIM) modeling and cancellation schemes are presented in a multiple-input multiple-output (MIMO) frequency-division duplexing (FDD) transceiver context. PIM is distortion generated by nonlinear passive devices either within the transmitter chain or outside the transceiver system, as is the case in air-induced PIM. In FDD systems, the PIM products may lie on the receiver band, thus possibly desensitizing the receiver chain. Unlike previous PIM cancellation works, we consider a challenging rank-2 dual-carrier MIMO transceiver scenario, with two spatially multiplexed signals per component carrier (CC). Stemming from the PIM modeling, we first present a cancellation method based on a complete set of identified basis functions (BFs). Additionally, to relax the processing complexity, we propose an alternative canceller solution with a reduced number of BFs, inspired by the problem modeling. RF measurements conducted with real-life equipment indicate favorable PIM suppression levels of up to 20 dB using both introduced techniques.

Hadis Prediktif Pembunuhan 'Usman bin 'Affan (Analisis Sosio-Historis)

Predictive Hadith on the Murder of 'Uṡmān Bin 'Affān (Socio-Historical Analysis) This paper analyzes the predictive hadith of the murder of ‘Uṡmān ibn ‘Affān by using a socio-historical approach. Hadith as a source of Islamic teachings can’t be separated from the language that used by the Prophet. Among the forms of language that used in the hadith is prediction. Prophet often predict an event that will occur after his death, among of that was the murder of ‘Uṡmān. From the several books of hadith, only al-Mustadrak ‘alā al-Ṣaḥīḥain by al-Ḥākim (321-405 AH./933-1012 M.) explicitly narrated that hadith. The important question that will be answered in this paper is how the authenticity of the isnād (chain of transmitters) and the understanding of the predictive hadith about the murder of ‘Uṡmān? The authenticity of the predictive hadith can’t be said to be valid (ṣaḥīḥ), because there is a narrator who are considered less credible (gairu ṡiqah). The classical method of hadith criticism must be assisted by new scientific disiplines, so the hadith can be understandood comprehensively. By using the socio-historical approach and the theory of hadith criticism, this paper proves that the predictive hadith about the murder of ‘Uṡmān is considered valid (ṣaḥīḥ), because it is supported by historical data. Therefore, the predictive hadith of the murder of ‘Uṡmān can be justified for its authenticity accoding to socio-historical analysis

On Historicity of the Najran Treatise on Jizya: Dating and Alternative Versions

This publication is the fourth in a series of articles devoted to the dominant thesis in traditional Islamic political and legal theology about Jizya as a tribute from Non-Muslims, established by the Prophet Muhammad. The focus of these four articles is the main paradigmatic precedent – the deputation of Najran Christians to Medina and the agreement concluded with the Prophet on the payment of jizya. The formal Hadith analysis (i. e. in the aspect of the reliability of the isnad — the chain of transmitters) of the relevant traditions, given in the first article, is followed by their substantive analysis. The historicity of the aforementioned embassy, discussed in the previous two parts in terms of the composition of the deputation and the text of the treaty, is disputed here in the light of chronological inconsistencies and the presence of other versions that do not include the condition of paying tribute. The study is conducted in line with the reformist-modernist discourse, orientated on the disclosure of the tolerant-pluralistic intention of prophetic Islam.

A Weighted Linearization Method for Highly RF-PA Nonlinear Behavior Based on the Compression Region Identification

In this paper, we present an adaptive modeling and linearization algorithm using the weighted memory polynomial model (W-MPM) implemented in a chain involving the indirect learning approach (ILA) as a linearization technique. The main aim of this paper is to offer an alternative to correcting the undesirable effect of spectral regrowth based on modeling and linearization stages, where the 1-dB compression point (P1dB) of a nonlinear device caused by memory effects within a short time is considered. The obtained accuracy is tested for a highly nonlinear behavior power amplifier (PA) properly measured using a field-programmable gate array (FPGA) system. The adaptive modeling stage shows, for the two PAs under test, performances with accuracies of −32.72 dB normalized mean square error (NMSE) using the memory polynomial model (MPM) compared with −38.03 dB NMSE using the W-MPM for the (i) 10 W gallium nitride (GaN) high-electron-mobility transistor (HEMT) radio frequency power amplifier (RF-PA) and of −44.34 dB NMSE based on the MPM and −44.90 dB NMSE using the W-MPM for (ii) a ZHL-42W+ at 2000 MHz. The modeling stage and algorithm are suitably implemented in an FPGA testbed. Furthermore, the methodology for measuring the RF-PA under test is discussed. The whole algorithm is able to adapt both stages due to the flexibility of the W-MPM model. The results prove that the W-MPM requires less coefficients compared with a static model. The error vector magnitude (EVM) is estimated for both the static and adaptive schemes, obtaining a considerable reduction in the transmitter chain. The development of an adaptive stage such as the W-MPM is ideal for digital predistortion (DPD) systems where the devices under test vary their electrical characteristics due to use or aging degradation.

A Ḥadīth Collection over the Generations: The Transmission of Ṣaḥīḥ Ibn Ḥibbān

The study of ḥadīth scholarship, even if concentrating ḥadīth corpus, or even extracting the transmission of ḥadīth collections, has faced growing criticism. Many scholars of ḥadīth have no lack of confidence about the preservation of ḥadīth collections, while others have thoughtfully been sceptical. The discussion of the “authenticity” of authorship of ḥadīth collections, Arabic literature furnishes with a chain of transmitters for texts made about the past. Alongside both famous Ṣaḥīḥayn of al-Bukhārī and Muslim, Ibn Ḥibbān al-Bustī (d. 354/965) - a scholar from Lashkar Gah, Afghanistan - compiled at least one gigantic ḥadīth collection usually regarded as the last collection of this ‘Ṣaḥīḥ movement’. Among the eighty-plus works that Ibn Ḥibbān’s biographers say he wrote is his famous ḥadīth collection named “al-Musnad al-Ṣaḥīḥ ʿalā al-Taqāsim wa al-Anwāʿ min ghayr wujūd qaṭʿ fī sanadihā walā thubūt jarḥ fī nāqilīhā.” The Ṣaḥīḥ, like the many existing ḥadīth compilations, was handed down to succeeding generations by chains of authority. What follows is an explanatory study of the transmission of Ṣaḥīḥ Ibn Ḥibbān in post-hadith compilation literatures to which his fame is principally due. A library-based research which focuses on descriptive analytical method is used in this study. This study also aims to examine some conceptual grounds for the exploration by looking into the literary dimension of hadith literatures. Explaining the transmission of Ibn Ḥibbān’s Ṣaḥīḥ is demanding despite his noble status which is required in recognizing that the early and canonical ḥadīth collection was very limited in dissemination. Conclusion of this study notes that the availability of transmission is central for the assessment of the well-preserved book and the role of isnād and certain ḥadīth literatures are vital in transmitting and preserving the Ṣaḥīḥ.

I/Q Imbalance Compensation in Wideband Millimeter-Wave Transmitters Using a Single Undersampling ADC

In this paper, a new method to identify and compensate for the I/Q imbalance in wideband millimeter-wave transmitters using a single undersampling analog-to-digital converter (ADC) is proposed. The proposed method alleviates the need for an I/Q demodulator; hence, simplifying the structure and calibration procedure of the required transmitter-observation receiver (TOR). In addition, an algorithm for estimating the delay and phase offsets between the transmitter and the single-ADC TOR is devised. The presented algorithm improves upon the exhaustive search methods employed in the literature. Measurement results using an off-the-shelf I/Q modulator, driven by an 800 MHz test signal, show about a 5% reduction in the root normalized mean-square error (RNMSE) of its output signal when the proposed method is utilized. Further measurements were conducted to assess the performance of this method, in conjunction with digital predistortion (DPD), when a power amplifier (PA) is added to the transmitter chain. When compared with the application of DPD only, the I/Q imbalance correction allowed additional reductions of about 4% in the RNMSE and 1.5 dB in the adjacent-channel power ratio of the PA output signal. These improvements were obtained with ADC sampling rates as low as 20 times below the Nyquist rate.

Intelligent User Association for Symbiotic Radio Networks Using Deep Reinforcement Learning

In this paper, we are interested in symbiotic radio networks (SRNs), in which an Internet-of-Things (IoT) network parasitizes in a primary cellular network to achieve spectrum-, energy-, and infrastructure-efficient communications. Each IoT device transmits its own information by backscattering the signals from the primary network without using active radio-frequency (RF) transmitter chain. We consider the symbiosis between the cellular network and the IoT network and focus on the user association problem in SRN. Specifically, the base station (BS) in the primary network serves multiple cellular users using time division multiple access (TDMA) and each IoT device is associated with one cellular user for information transmission. The objective of user association is to link each IoT device to an appropriate cellular user by maximizing the sum rate of all IoT devices. However, the difficulty in obtaining the full real-time channel information makes it difficult to design an optimal policy for this problem. To overcome this issue, we propose two deep reinforcement learning (DRL) algorithms, both use historical information to infer the current information in order to make appropriate decisions. One algorithm, referred to as centralized DRL, makes decisions for all IoT devices at one time with globally available information. The other algorithm, referred to as distributed DRL, makes a decision only for one IoT device at one time using locally available information. Finally, simulation results show that the two proposed DRL algorithms achieve performance comparable to the optimal user association policy which requires perfect real-time information, and the distributed DRL algorithm has the advantage of scalability.

Aṭrāfs as a Method of Classification (Taṣnīf) and Inclusion (Takhrīj)

Ḥadīths have been preserved and recorded in various ways since the Companions. These activities continued dur-ing the Tābiīn (the successors of the Companions) Period. So much so that these methods have formed the infra-structure of other methods that will emerge later. In this context, before the 70's (A.H.), works named al-Aṭrāf appeared. However, these first works consisted of the notes that they wrote some of the ḥadīths before coming to the science assemblies to help students remember in ḥadīth learning. Ḥadīth scholars have adopted and applied this method in a very short time. Thus, this method also provided the opportunity for the formation of the first written ḥadīth documents. In addition, with the writing of ḥadīth works, it has turned into a system of al-Taṣnīf and al-Takhrīj in order to make maximum use of these books and to reach the source of a narration that is tried to be found. As a result, al-Aṭrāf literature, which can be evaluated as index, has emerged. As a matter of fact, the first examples of this literature, arranged alphabetically according to the names of the Companions or ḥadīth texts, started to be given since the 4th (A.H.) century. In this way, the way to quickly benefit from the accumulation of the ḥadīth area has been opened. This article focuses on the historical adventure of al-Aṭrāf and their contributions to the ḥadīth field, as well as literature knowledge of the works of al-Aṭrāf which are of great importance for both al-Kitābah, al-Taṣnīf and al-Takhrīj.