[Bhardwaj, 5(7): July, 2016] ISSN: 2277-9655
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[228]
IJESRT
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH
TECHNOLOGY
PERFORMANCE COMPARISON OF MODIFIED TURBO CODE FOR DIFFERENT CODE
RATE IN COMMUNICATION SYSTEM
Sanskriti Bhardwaj*, Dr. Sumit Sangwan
ECE Department, GITAM, Kablana, INDIA
DOI: 10.5281/zenodo.56951
ABSTRACT
In this paper, based on the simulation result the performance of MTC is compared as code rate decreases, the BER
performance improves but overhead in the form of code bits increases. It is observed that = ͳͲ
−ଷ
at
0
⁄ =
ͳ.ͷ for rate =ͳʹ ⁄ CTC which is Ͳ. and ͳ.ͳ away from
0
⁄ to achieve same BER for rate =
ʹͷ ⁄ ͳ ͵ ⁄ CTC respectively. For rate =ͳʹ ⁄ CTC, = ͳͲ
−
is shown at
0
⁄ = ʹ.ʹ which is
Ͳ.ʹ and Ͳ.͵ away from
0
⁄ to achieve the same BER for rate =ʹͷ ⁄ ͳ ͵ ⁄ . Hence, the reduction
quality of the information signal improves.
KEYWORDS: MTC,CTC,BER, SNR.
INTRODUCTION
To design and simulate Communication system models Simulink provide communication block-set and
communication toolbox. Using these standard tool different blocks can be used to design a model and we can
connect these blocks directly. We can set different Parameters for these blocks according to the system requirement.
We can send and retrieve data from the Simulink to Matlab workspace and from workspace to Simulink model for
further processing of the data.
SIMULATION MODEL
CTC Model
Turbo codes become a popular area of communications research when presented at International Conference held on
Communications in 1993 by C. Berrou, Glavieux, and Thitimajshima. Turbo codes can be achieved by using serial
and parallel concatenation of two or more codes called as constituent codes. Such codes use interleaver between them
so that data sequence for two encoders is different [1-3]. These codes can be either block codes or convolutional
codes. Simulation model for calculation of BER for CTC code have no. of components. Model is designed using
Simulink in Matlab. BER at different
0
⁄ is coumputed using this model. Component and parameters used are
explain as follows:
Bernoulli Binary Generator
The number of elements in the Initial seed and Probability of a zero parameters becomes number of columns in
frame based output or no. of elements in a sample-based vector output[4]. Table 1 below shows parameter used for
Bernoulli binary generator for the simulation of the model of CTC
Table 1 Parameter for Bernoulli Binary Generator
Parameters Values
Probability of Zero. 0.5
Initial Seed 61
Sample time 1
Sample Per Frame 1024*256
O/P Frame Based
O/P Data Type Boolean