Modulation

Cognitive radio has the ability to sense the environment and adapt its behavior to optimize communication features, such as quality of service in the presence of interference and noise. In physical layer to achieve this goal, different phases of sensing, channel estimation, and configuration selection are necessary. The sensing part measures the interference level, recognize the spectrum holes, and send this information to channel estimator. In the next step, channel state information (CSI) is used for data detection and also sent to the transmitter through a limited feedback. CSI feedback consists of achievable rate, SNR value, modulation or coding schemes (MCS). Feedback link improves the system performance in the cost of complexity and delay. In this paper, we present and compare different feedback schemes for cognitive radio and study the channel capacity when an imperfect feedback link is corrupted by noise and delay.

In MPEG coding, there are three types of encoded pictures. Since these picture coding types have different importance of data content, the cell loss of each picture coding type affects the video quality differently in MPEG video transmission through ATM networks. This paper analyzed the per-session cell loss properties of MPEG video traffic in an ATM switching node in both the steady-state case and the transient case considering each picture type. In the analysis, a 3-state Markov modulated Bernoulli process (MMBP) is proposed as a traffic model for MPEG video which is tractable analytically. Numerical results revealed the influence of the picture transmission pattern on the cell loss properties of each picture coding type

Advanced modulation formats can enable >40 Gb/s data rates in waveguide-based optical interconnects without the need for high-specification optoelectronic components. Record 56Gb/s PAM-4 data transmission is demonstrated over a 1 m-long multimode polymer waveguide.

Abstract: Xenopus oocytes expressing high voltage-gated calcium channels (Cav) were exposed to formalin (0.5%, v/v, 5 min.) and the oocyte death and Cav currents were studied for up to 10 days. Cav channels were expressed with α1β1b and α2δ sub-units and the currents (IBa) were studied by voltage clamp. None of the oocytes was dead during the exposure to formalin. Oocyte death was significant between day 1 and day 5 after the exposure to formalin and was uniform among the oocytes expressing various Cav channels. Peak IBa of all Cav and A1, the inactivating current component was decreased whereas the non-inactivated R current was not affected by 5 min. exposure to formalin. On day 1 after the exposure to formalin, Cav1.2c currents were increased, 2.1 and 2.2 currents were decreased and 2.3 currents were unaltered. On day 5, both peak IBa and A1 currents were increased. Cav1.2c, 2.2 and 2.3 currents were increased and Cav2.1 was unaltered on day 10 after the exposure to formalin. Protein kinase C (PKC) may be involved in formalin-induced increase in Cav currents due to the (i) requirement for Cavβ1b sub-units; (ii) decreased phorbol-12-myristate,13-acetate potentiation of Cav2.3 currents; (iii) absence of potentiation of Cav2.3 currents following down-regulation of PKC; and (iv) absence of potentiation of Cav2.2 or 2.3 currents with Ser→Ala mutation of Cavα12.2 or 2.3 sub-units. Increased Cav currents and PKC activation may coincide with changes observed in in vivo pain investigations, and oocytes incubated with formalin may serve as an in vitro model for some cellular mechanisms of pain.

The working principles and design equations of four different isolated, bi-directional DC to DC converter topologies (a dual active bridge converter, a series resonant converter and two multiple stage topologies) for a 2 kW bi-directional battery charger that can be operated in a wide input and output voltage range are presented in this paper. The results of a detailed mathematical

Abstract: The size, complexity and performances of modern wireless communication circuits are getting more and more challenging whereas marketing time and cost must be reduced as much as possible. In order to fill the current lack in CAD tools, this work is dedicated to the mixed simulation of complete communication systems driven by digital and digitally modulated RF signals. This paper describes a methodology for top-down design, modeling, and simulation of complete RF system using hardware description language VHDL-AMS (Very high speed integrated circuit Hardware Description Langage – Analog Mixed Signal). As application, we consider a complex M-QAM system (transmitter, channel, and receiver) and we show some details of

We have applied the diffractive optics and digital holography technologies to the design and fabrication of fiber Bragg gratings (FBG). We studied the phase mask near field diffraction using the numerical simulation. Our new understanding on the phase mask has critical importance for fabrication of complex FBGs, such as the sampled grating DBR laser, multi-channel dispersion compensator, and phase-shift band-pass filters. In the design of the FBGs we introduced the phase-only sampling multi-channel FBGs using the Dammann ...

The current research aims to investigate mood and modality in Sorani Kurdish within the Systemic Functional approach (Halliday and Matthiessen 2014). Specifically, the present study is an attempt to explore the nature of mood markers and the formalization of modality in Sorani Kurdish. The primary data has been collected using the Plank Questionnaire, administered to 442 participants. To explore mood-marking, the mood constituent in Kurdish clauses will be delineated, with the subject, finite, and mood adjuncts identified as the three main components of the mood constituent. Then, system of modality in Kurdish, modalization, and modulation will be discussed. Data analysis suggests that finite in Kurdish does not stand on its own and needs to be conflated with the predicate. The main grammatical categories used in Kurdish to represent modalization and modulation are modal verbs and pseudo-grammaticalized modal clauses. Statistical data also shows that mood adjuncts are only sporadically used in Kurdish to describe modality. Moreover, the morphological subjunctive mood will be analyzed as operative over verbal categories and hence not part of the mood constituent.

Phase noise (PN) impact in communication systems is considered as great, especially in wireless communication systems using higher m-QAM modulation schemes. The objective of this evaluation study is to investigate the exact impact of Phase noise in relation to AWGN, within a wide range of QAM schemes, since an implementation, of higher QAM usage, is anticipated to be widely used in modern wireless communication industry.

Capítulo publicado no livro Sociedade de Controle: manipulação e modulação nas redes digitais, organizado por Joyce Souza, Rodolfo Avelino e Sérgio Amadeu da Silveira.

Disponível em: https://www.amazon.com.br/sociedade-controle-Manipula%C3%A7%C3%A3o-modula%C3%A7%C3%A3o-digitais/dp/8577155285