Principles of Communications

ProgrammingProject, 2011

  1. Aim of the Project

To study the principles and analyze the performances of various digital modulation techniques (2ASK, 2FSK, 2PSK and 2DPSK).

  1. Contents of the Project:
  1. Generate a random binary sequence consisting of 0 and 1, andmodulate it at a certain carrier frequency using 2ASK, 2FSK, 2PSK and 2DPSK. The modulation parameters are up to your own design. Please plot the signal waveform of the first 8 bits in time domain for each modulation.
  1. Transmit the above four signals over an additive Gaussian white noise channel.Please draw the functional block diagrams of both coherent and non-coherent receivers, and determine the mathematical expression of observation before decision at the receiver for each of them. If a signal cannot be demodulated using non-coherent receiver, please explain.
  1. According to the results in 2), program to implement the decision process at the receiver. By comparing the decision results with the original information bits,find out the bit error ratio (BER, ) at different signal-to-noise ratio (SNR) per bit . Plot the curves of versus.
  2. Plot the theoretical values of BER in the same figure as the simulation results. Please compare and discuss on the simulation results and theoretical values. Please also discuss the performance difference amongthe different modulation techniques.

Note 1: In the simulation program, band-limited Gaussian noise can be used to approximate the white Gaussian noise.Assume that the band-limited Gaussian noise has a bandwidth ofHz and with auto-correlation function given by.If it is sampled at a rate Hz, then all the sample values of the noise are independent with zero-mean and variance of.

Note 2: The relationship between sample frequency and carrier frequency must satisfy .

Note 3: It is recommended that the range of in the simulation is from 0 dB to 10 dB and the interval of adjacent values is 1 dB.

Note 4: Sufficient number of simulation runs are needed in order to obtain reliable estimation of.

  1. Requirement of the Project:
  1. This project requirestwo students working as a team.
  2. You can use any programming language. But MATLAB is recommended. Other programming languages, such as C and C++, are also acceptable. However, you are not allowed to useanyexisting communication module such as those in SIMULINK.
  3. You must submit electronic copy of project report. The project report consists of answer to all the questions, simulation results, analysis and discussion. A template of project report is included in the appendix of this document.
  4. Send the final project report to Mr. Zhengzheng Xiang() on/before December23 (Friday), 5pm, 2011.

Principle of Communications

Project Report

Author / 1．Name： Student ID:
2．Name： Student ID：
Project results & Analysis：
(This template is for reference only.)
  1. Waveform in time domain.
(i)2ASK
(ii)2FSK
(iii)2PSK & 2DPSK
  1. The functional block diagrams of demodulator & expression of observation scalar.
  1. Decision results (the relationship between and (dB)).
  1. Performance comparison.
(i)Comparison between simulation results and theoretical value;
(ii)Comparison between different modulation techniques.
Note: Please indicate meaning of the symbols in all expressions. Please indicate the coordinate and unit in all figures.
Experience
You can write your experience with this project. Any comment and suggestion on this course are also very welcome.
Score

Appendix:

(including source code, reference and so on).