in this paper, for the purpose of investigating horizontal sound propagation, based on the results obtained from practical measurements in the strait of hormoz and available data on sound speed variations at different depths, a comprehensive model for shallow water multipath underwater acoustic channel is presented. mathematical modeling of multipath effect is based on ray theory and the image ...

This study evaluates the impact of underwater ambient noise using seven real noise samples; Dolphin, Rain, Ferry, Sonar, Bubbles, Lightning, and Outboard Motor in three frequency ranges in extremely low frequency (ELF) band. The ELF band is the most significant bandwidth for underwater long-range communication. ELF band which is extended from 3 to 3000 Hz clearly, faces bandwidth limitation. Me...

We demonstrate 3-Gb/s wireless link using a 60-GHz receiver front-end fabricated in 0.25-μm SiGe:C bipolar complementary metal oxide semiconductor (BiCMOS) and a mixed-mode quadrature phase-shift keying (QPSK) demodulator fabricated in 60-nm CMOS. The 60-GHz receiver consists of a low-noise amplifier and a downconversion mixer. It has the peak conversion gain of 16 dB at 62 GHz and the 3-dB int...

Various digital modulation techniques have been extensively studied and have found numerous applications in wireless communication systems. One example of this success is the QPSK modulation used in the third generation Universal Mobile Telecommunication System (UMTS). This paper presents a new modulation method that produces less adjacent channel interference (ACI) and lower bit error rate (BE...

The peak-to-average ratio (PAR) of a signal is commonly used for estimating the backoff required for an radio-frequency/microwave power amplifier to exhibit acceptable intermodulation distortion. In this paper, it is shown that the PAR is an inaccurate metric for predicting the backoff and can lead to improper choices for modulation with respect to the linearity–efficiency tradeoff. A specific ...

We propose a transceiver architecture for automatic beamforming and instantaneous setup of a multigigabit-per-second wireless link between two millimeter wave radios. The retro-directive architecture eliminates necessity of slow and complex digital algorithms required for searching and tracking the directions of opposite end radios. Simulations predict <5 micro-seconds setup time for a 2Gbps bi...

this paper presents a new control structure to reduce torque ripple in switched reluctance motor. although srm possesses many advantages in motor structure, it suers from large torque ripple that causes some problems such as vibration and acoustic noise. in this paper another control loop is added and torque ripple is de ned as an objective function. by using fuzzy sliding mode strategy, the dc...

This report presents the process of designing a 1 Gbps wireless data link system with an isotropic antenna. The data link specification requires a Bit Error Rate (BER) of less than 1× 10−6 without any error correction coding. A high frequency is required to provide a large bandwidth for this high data rate. Since the Federal Communications Commission (FCC) allocates 57–64 GHz for unlicensed ope...

A 10.5 Tbit/s optical transmission (15 x 100 Gbit/s QPSK channels per core) over 2,520 km of multicore fiber is achieved using an integrated multicore transmission link consisting of directly spliced multicore components such as fan-in/fanout fiber couplers, a 60 km trench-assisted 7-core hexagonal fiber and cladding-pumped erbium-ytterbium-doped fiber amplifiers.

Modulation techniques have concerned increasing attention in optical wireless communications. Downlink transmission (base station to mobile terminal) using high data rate Mary Quadrature Amplitude Modulation (QAM), Quadrature Phase Shift Keying (QPSK) and Binary Phase Shift Keying (BPSK) modulation schemes are considered in a Wideband-Code Division Multiple Access (W-CDMA) system. QPSK or Quadr...