18-04-2012, 04:29 PM
Bit Error Rate Performance Analysis on Modulation Techniques of Wide band Code Division Multiple Access
Bit Error Rate Performance Analysis.pdf (Size: 427.17 KB / Downloads: 160)
INTRODUCTION
Wideband Code Division multiple Access (WCDMA)
is being used by Universal Mobile
Telecommunication System (UMTS) as
platform of the 3rd generation cellular
communication system. W-CDMA uses noise-like
broadband frequency spectrum where it has high
resistance to multipath fading where as this was
not present in conventional narrowband signal of
2nd generation (2G) communication system.
High data rate signal transmission can be
transmitted over the air by using W-CDMA
system, thus enabling of multimedia rich
applications such as video streams and high
resolution pictures to end users. Thus, we need
suitable modulation technique and error correction
mechanism to be used in W-CDMA system. In 2G
networks, Gaussian Minimum Shift Keying
(GMSK) modulation scheme is widely used in GSM
(Global System for Mobile) Communication.
SYSTEM MODEL
This research has been initiated the reviewing of
the high speed data rate on the modulation
schemes, DSSS W-CDMA and fading effects on the
channels. Then, we have developed a generic
model of DSSS W-CDMA as it is shown in fig.1 and
is being simulated by MATLAB modulation
schemes 16-QAM and QPSK. Both modulation
techniques are chosen in this thesis because there
are the most important candidates to deliver higher
data rate for High Speed Downlink Packet Access
(HSDPA), an extension of 3G networks [1]-[3]. The
simulation is done under AWGN noise and
multipath fading channel using MATLAB 7.6.
RESULT AND DISCUSSION
Based on data generated by computer simulation of
W-CDMA models, relationship for model using
QPSK and QAM modulation techniques between
BER as a function of the following parameters are
obtained.
CONCLUSION
In telecommunication field the major challenges is
to convey the information as efficiently as possible
through limited bandwidth, though the some of
information bits are lost in most of the cases and
signal which is sent originally will face fading. To
reduce the bit error rate the loss of information and
signal fading should be minimized. In our thesis
we analyze two modulation techniques, QPSK and
16-QAM to reduce the error performance of the
signal and compare which technique is better
through Rayleigh Fading Channel in the presence
of AWGN. The performance of W-CDMA system
in AWGN channel shows that QPSK modulation
technique has a better performance compared to
that of 16-QAM.