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A technology that has taken many years to develop is the foundation of Meteor-burst Communications (MBC). Many MBC systems have been installed and tested successfully. MBC systems comprise dynamic vehicular networks, fixed station networks, and point-to-point links. Currently available systems include medium data rate message handling, low data rate telemetry, and high-speed conversational voice advancements. In addition to describing the systems and technology currently being developed, this paper summarises earlier work in the field.

The effect of stimulated Raman scattering in a Raman gain medium produces an optical amplifier based on Raman gain, known as a Raman amplifier. Although it can also be a bulk crystal, a waveguide in a photonic integrated circuit, or a cell with a gas or liquid medium, that medium is typically an optical fiber (perhaps a highly nonlinear fiber). When an input signal co-or counterpropagates with a pump beam, whose wavelength is usually a few tens of nanometers shorter, it can be amplified. In conclusion, this paper underscores the importance of understanding and harnessing the principles of Raman amplification in various dynamic optical landscapes. Also, the paper concisely presents US patents related to Raman amplifier.

The Adaptive Differential Pulse Code Modulation (ADPCM) has been standardized by the International Telecommunication Union (ITU) due to its significance and extensive applications within telecommunication networks. This paper provides a concise overview of the recent US patents related to ADPCM, covering the years 2024 to 2025. Additionally, the general architecture of ADPCM is discussed. The findings presented herein aim to inspire researchers and motivate further explorations in this domain.

This review paper studies the performance of massive MIMO uplink system over Rician fading channel. The performance is measured in terms of spectral efficiency versus number of base station antennas using three schemes of linear detection, maximum- ratio- combining (MRC), zero forcing receiver (ZF), and minimum mean- square error receiver (MMSE). The simulation results show that the spectral efficiency increases significantly with increasing the number of base station antennas. Also, the spectral efficiency with MMSE is better than that with ZF, and the latter is better than that with MRC. In addition, the spectral efficiency decreases with increasing the fading parameter.

Аннотация. В этой работе представлены два детектора, которые используются для управления межсимвольными помехами, которые вносят каналы связи. Эти два детектора работают, объединяя детектор Витерби и нелинейный эквалайзер. Второй детектор, который вносит вклад в это исследование, называется комбинированным детектором-2 (CDR2). Первый детектор, который был ранее сконструирован, известен как комбинированный детектор-1 (CDR1). С другой последовательностью данных CDR2 сопоставим c CDR1. Передача данных со скоростью 9,6 кбит/с по телефонному каналу используется для тестирования этих детекторов с нелинейным эквалайзером. Согласно данным моделирования, CDR2 работает лучше, чем CDR1, тогда как нелинейный эквалайзер работает лучше, чем CDR1.

Three phase induction motor is the most popular type AC motor, it is very commonly used for industrial drives. It is cheap, robust, efficient and reliable. It has good speed regulation and high starting torque. It requires little maintenance. It has a reasonable over load capacity. This paper deals with the simulation of three phase induction machine using MATLAB Simulink. The results are obtained for generating mode and motoring mode.

Cell phones are widely used in the world. While people have to be connected to one another, there are situations or places where there usage is to be prohibited either due to security reasons or it may cause health hazards. Cell phone detection has been on investigation for a long time. There are techniques which have been formulated or proposed on how cell phones can be detected. Most of them use the features such as audio system, radio frequency (RF) system and common materials of the phones and try to look into how they can be used as basis to detect mobile phones. This paper utilizes the RF system of the cell phone as the feature to be used to detect its presence. A circuit that detects signals of the range 0.9GHz to 3GHz is used to detect a cell phone when in use. When the signal is detected, a light emitting diode (LED) blinks to indicate the usage of a cell phone within a radius of 1.5metres.

Digital communication has proven to be the most efficient method of data transmission especially where long distances are involved. This led to the invention of more sophisticated methods of communication ranging from mobile handset communication to more advanced satellite communication. The speeds of passing information have been improving over the years and real time video communication has been made possible with digital devices. various methods of digital data transmission are employed based on the information to be transmitted. This paper focuses on carrier recovery in digital communication systems, especially those based on Quadrature Phase shift Keying (QPsK) modulation and demodulation scheme. The design being implemented is that of coherent demodulation for QPSK scheme using SIMULINK design tool. Performance of QPsK is also investigated to make a comparison and the suitability of the scheme to use in digital data transmission applications.

Frequency hopping spread spectrum (FHSS) communication systems offer significant performance advantages in view of their low probability of intercept, improved performance in multipath fading environments and their ability to avoid interference by hopping into low interference frequency channels. For the transmitted sequence to be correctly received and demodulated, the frequency hop sequence used at the receiver should be similar to that employed in the transmitter. Code acquisition in frequency hopping attempts to address this problem by providing a frequency hop pattern at the receiver that is nearly identical to that used at the transmitter. Code acquisition brings the alignment between the transmitter and the receiver hop pattern to at least one hop period. In this paper, the serial search code acquisition, which is the first step of synchronization, is studied for frequency hopping spread spectrum (HFSS) system over Rayleigh fading channel. Simulation results show the effect of fading channel on the code acquisition.

This article deals with developing new modified algorithms of 40kb/s ADPCM. Beside the standard algorithm, three algorithms are developed to reduce the ADPCM distortion. The performances of all algorithms are evaluated with QAM signal at speed of 9.6kb/s. The outcomes demonstrate that the first proposed algorithm outperforms the other algorithms.