Performance Analysis and Investigation of Digital Symbol Detection Techniques for Single and Multi-carrier Modulations
No Thumbnail Available
Date
2017-10
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
During symbol transmission we may use single carrier or multi-carrier modulation. In case of
single carrier transmission all users share the same transmission medium and this causes the
problem of Inter Symbol Interference (ISI) which leads to error in reception. In case of multicarrier
transmission
there
is
Multiple
Access
Interference
(MAI).
In
several
digital
communication
problems,
the
received
signal
is
given
by
a
linear
combination
of
the
data
symbols
corrupted
by
channel
effects. So the received symbol may be affected by transmission channel noise,
interference, distortion, bit synchronization problems, attenuation, and wireless multipath-fading.
Therefore efficient demodulation and symbol detection strategies are very necessary.
This thesis work on symbol detection is done as per the request of Information Networks Security
Agency (INSA) of Ethiopia. The industry wants to implement advanced digital receiver for local
use. So the industry main aim is to review, investigate, and implement efficient symbol detection
algorithms.
In this paper we have considered a class of single carrier and multi-carrier symbol detection
algorithms and compare their performance in terms of Bit Error Rate (BER) and Signal to Noise
Ratio (SNR) of various modulation type and order. M-ary PSK and M-ary QAM have been
simulated with optimum and sub-optimum detectors like Maximum-Likelihood (ML), Minimum
Mean Square Error (MMSE) and Zero Forcing (ZF) detector.
From our findings, for the single carrier single user case for additive White Gaussian Noise
(AWGN) channel the BER at 15dB is 10
, which is acceptable. Again for the case of Rayleigh
Fading channel at 35dB still we have a BER of 10
-3
. In the case of multicarrier multi user (MCCDMA)
detection over Rayleigh fading channel, we have been shown how the three different
detectors behave in performance and complexity analysis. Finally, it can be seen that the most
complex and the best performing detector, is the Maximum Likelihood detector.
Description
Keywords
Symbol detection, Single user, Single-carrier, Multi-carrier, Multi-user, Mary Modulation, maximum likelihood detection, optimal and sub-optimal detectors, BER, SNR, Complexity analysis, MATLAB