Mobile and Satellite Communication Systems
Assessment - Signal coding and modulation
Purpose of the assessment (with ULO Mapping) At the completion of this unit students should be capable of the following:
a. Using numerical analysis methods, critically review and analyse mobile and satellite communication systems.
b. Explain the underlying principles and concepts of telecommunication modulation techniques.
c. Identify engineering techniques, tools and resources, and exercise critical thinking and judgement, to identify and solve problems related to antenna and GSM laboratories.
d. Demonstrate ethical behaviour for, and personal and collaboration responsibility and accountability to, the professional practice in the telecommunication industry.
Description of Assessment Task:
The purpose of this assignment is to understand data coding and modulation concepts and to apply this knowledge in practice. In this assignment you will create a report about different modulation schemes. Than you will develop and test a Matlab program for encoding a data sequence using QAM modulation. Also the assessment develops skills in writing technical reports and working as a team.
Part 1
This assignment is done in a group. Each group member is required to select one type of digital modulation scheme and write a 1 page report describing the main concepts with appropriate diagrams for illustration and references to the materials used in the report. The modulations schemes are: AFK, FSK, BPSK, QPSK, 8-PSK. Contribution of each member must be included in the report.
Part 2
Encode the phrase "MIT BE" according to ASCII coding and apply 16 QAM modulation. Each group member is required to select one letter of the phrase anddo the following:
I. Report howeach letter convertsto ASCII code system using binary, decimal, octal and hexadecimal representation.
II. Using ASCII binary code for the letter as a data streamwrite a Matlab code to apply 16-QAM modulation to the data.
Follow the following steps to complete the task:
a. Create a variable that contains data according to the binary representation of the letter in ASCII.
b. Group data bits appropriately according to the required number of bits per constellation point.Use the bits assignment logic to each modulation state (constellation point) from the diagram in Fig. 1. Determine which constellation points are required to represent your data.
Fig. 1. 16-QAM modulation diagram.
c. Determine the amplitudes and types of In-phase ( cos (x)) and Quadrature ( sin(x)) carrier wave components for each requiredconstellation point. Assume possible amplitudes of the In-phase (I) and Quadrature (Q) components are 1 and 2.
Prepare a table showing how to add In-phase and Quadrature components for each state.
d. Demonstrate In-phase and Quadrature components addition for each required state.
Write a Matlab codeto plot the carrier wave after addition of In-phase and Quadrature components corresponding toeach required modulation state.Include titles and labels on each plot.
Choose frequency and time interval to fit 5 periods of the sinusoid for clear visibility on the graph. Comment on the initial phase of the resultant wave after addition.
Write code and export each figure into a .jpg file. (Alternatively use save button in Matlab).
III. Demonstrate the final result for a carrier wave modulated with the data(MIT BE) by joining all resultant waves corresponding to each required constellation point.
Write a Matlabcodeto plot the modulated carrier wave corresponding to your data sequence. Make sure your time axis is long enough to fully display all the states on the plot.
Export image into a .jpg file.
General guidelines
The Assignment 2 report format should include the title page with assignment title, name and student numbers and sections entitled Introduction, Method, Results, and Discussion. Subsections may be included as required. References should be in IEEE format. Attach your Matlab codes to your report as appendix.
Example of carrier modulated with digital message signal for BPSK:
