Several new technologies had been presented in LTE system
standards in order to achieve higher performance and more
reliability than Previous cellular communications systems. The
added new standards describe advanced technologies that integrated
into the system environment so that we can meet subscribers
Growing requirements. in this study we'll discuss in details the
different patterns of modulation schemes, which are adopted in (3
GPP) standards for (LTE) system downlink.
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.
