Title page for ETD etd-12212000-222112

Type of Document Master's Thesis
Author Qu, Xin
URN etd-12212000-222112
Title Automated Testbench Generation for Communication Systems
Degree Master of Engineering
Department Computer Engineering
Advisory Committee
Advisor Name Title
Gray, Festus Gail Committee Chair
Armstrong, James R. Committee Member
Midkiff, Scott F. Committee Member
  • VHDL
  • GSM
  • Viterbi
  • Testbench
Date of Defense 2000-11-28
Availability unrestricted
This thesis develops semi-automated methods to generate testbenches for VHDL models

of communication systems. To illustrate the methods, a VHDL model was constructed for

the speech-coding channel of the Global System for Mobile Communication (GSM).

GSM is the Pan-European digital mobile telephony standard specified by the European

Telecommunication Standards Institute (ETSI). This thesis emphasizes the error detection

and error correction procedures that form an important part of the standard.

First, a test bench template was generated using “Testbench Pro”, a waveform generation

tool developed by SynaptiCAD. The template includes a random sequence of speech

data. A C program was then developed as a user interface to control the simulation

procedure. Using the C program, the user can select a test bench template and specify the

input test vectors. The C program adds the user’s test vectors to the test bench template to

create a final VHDL test bench that is ready for simulation. The testing data is then

encoded by the GSM encoder models, passed through the noisy channel model that

introduces errors into the data stream and, finally, passed through the GSM decoder models which attempt to correct the channel errors. Sophisticated error detection and

error correction algorithms are used in the encoder/decoder models to increase the

reliability of data transmission over the noisy channel. Finally, the original speech data is

compared to the decoder output to detect any remaining bit errors and to evaluate the

system performance.

The simulation system is semi-automated. The user selects a set of parameters using the

C program interface. A testbench is then automatically created and simulated. Two final

report files are automatically generated. No user interaction is needed after the initial

parameter selection.

Several experiments were performed to illustrate the various features of the automated

testbench generation system.

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