Wireless communication has become more popular over the last decade. Although
there are many advantages to use wireless over fixed line systems, there is a major
disadvantage, which is a high transmission error rate in a temporal and permanent nois
y
environment. There are techniques to reduce effectiveness off transmission errors in
wireless communications. We have discussed in this paper. Many methods and techniques
have been implementing to deal and resist errors (by increasing transmission power,
switching modulation scheme) as well as evaluation the wireless connection performance
taking into account many factors.
This works aims to study the performance of the mobile system via studying the
effects of adaptive modulation technique on the data rate. Fuzzy logic technique is used as
a tool to analyze the data rate of the downlink connection depending on type
of
modulation, coverage quality and the distant between the receiver and the transmitter. For
parameters were considered as input parameters for the fuzzy logic system mainly are:
power of the station, quality of coverage, the type of modulation technique and the signal
to interface noise ratio. One parameter is used as an output of the fuzzy system which is
spectrum efficiency in bit per second per hertz. Analytical study to select the optimal data
rates for different modulation techniques will be considered. Additionally, studying the
input and output memberships of the data rate parameters using fuzzy logic will be
explained. Keywords: Data rate, downlink, signal to noise ratio, modulation type, Fuzzy
logic, spectrum efficiency.
Speech denoising is a field of engineering that studies techniques used to recover the
original signal from the noisy signal corrupted with different types of noise, such as
broadband noise and narrowband noise, and other types present in environme
nt, but the
spectral subtraction technique consider the most prominent in this area .
In this search we will discuss the parameters impact of the modified spectral
subtraction algorithm and the time window length in the enhancement of speech that
corrupted with broadband noise. We done the study and determine the ideal parameters
values and the ideal window length with different values for the signal -to-noise ratio SNR
for noisy speech and we discuss 18 case for each value. We done
the simulation using MATLAB software and the results were compared based on
improving the value of SNR for each case .
This work aims to analyze the performance of the microwave radio link’s parameters
used to connect different systems and intra systems. Fuzzy logic technique is used to study
the difficulties of the radio link’s parameters based on type of modulati
on, and distance
between the receiver and transmitter. Four parameters are used as an input parameters for
the fuzzy logic system mainly: required power, the length of the microwave radio link,
modulation type and the signal to noise ratio(S/N). The output parameter is determined to
be the microwave link capacity.
Analytical study to select the optimal microwave radio link parameters to examine
the efficiency of the radio link capacity will be shown. Additionally, studying the input and
output memberships of the microwave radio link parameters using fuzzy logic will be
explained.
The aim of this research is to study of detection sensitivity in optical preamplifier, which is used
as a first stage in optical receivers. This subject is important because it is used in laser
rangefinders. The parameters that affect the distance
measurement using time of flight
technique are studied in details. Then, noise analysis and signal to noise ratio calculation are
performed in preamplifiers to detect a signal with pulse width of 30ns using Matlab. The study
results are applied to some preamplifiers to determine the minimum detectable power.