Mobile and Satellite Communication Systems
Description of Assessment Task:
In this assignment you will develop and test a Matlab program for encoding a data sequence using QPSK modulation. The result will be a graph of phase modulated carrier corresponding to the data steam.
The data sequence to encode is d = [0 1 1 0 0 0 1 1].
Follow the steps to complete the task and write a report.
Step 1: Describe your QPSK constellation diagram.
Use the following QPSK constellation diagram:
Calculate how many bits per each state (point) on the constellation diagram can you assign. Assign each state a bit group of your choice and show the bit groups on the diagram.
Step 2: Determine In-phase and Quadrature carrier wave components for each point on the constellation diagram.
For each point on the constellation diagram, determine amplitudes of In-phase and Quadrature components for carrier waves in sin or cos form.
Prepare a table showing how to add In-phase and Quadrature components for each state.
Step 3: Demonstrate In-phase and Quadrature components addition for each state.
In Matlab write a code to display 3 subplots: one showing In-phase carrier wave (sin), one for Quadrature wave (cos) and one subplot for resultant carrier wave representing one state on the constellation diagram, which was obtained by addition of In-phase and Quadrature components. Include titles for each subplot. Assume absolute amplitudes of input waves are equal to 1, choose frequency and time interval to fit a few periods of the sinusoid for clear visibility on the graph. Comment on the initial phase of the resultant wave after addition and its relation to the constellation diagram. (Alternatively create the plot by drawing or other method).
Repeat for all 4 states.
Write code and export each figure into a .jpg file. (Alternatively use save button in Matlab).
Step 4: Encode data.
Break up the data sequence into groups of correct number of bits, each representing a state from the constellation diagram.
Step 5: Plot modulated carrier wave corresponding to the given data sequence.
In Matlab write a code to display a plot of modulated carrier wave corresponding to the given data sequence by joining resultant waves constructed in step 3 in correct sequence. Use 5 carrier cycles per modulation state. (Alternatively create the plot by drawing or other method).
Export image into a .jpg file.
General guidelines
The Assignment 2 report format should include the title page with assignment title, your name and student number and sections entitled Introduction, Method, Results, and Discussion. Subsections may be included as required. References should be in IEEE format. Attach your Matlab code to your report as appendix.
Sample modulated carrier for BPSK for reference:
