EE_564_F09_HW8_v2

# EE_564_F09_HW8_v2 - −௝2గ௟௙/ௐ ௅−1 ௟=0 3...

This preview shows page 1. Sign up to view the full content.

EE-564 Fall 2009 Homework #8 Due Wednesday, November 25, 2009 1. “Digital Communications”, 5 th Edition, Proakis & Salehi, Problem 11.3 2. Consider the following communication channel ݕሾ݊ሿ = ߙ 0 ݔሾ݊ሿ + ߙ 1 ݔሾ݊ − 1ሿ + ߙ 2 ݔሾ݊ − 2ሿ + ݖ[݊] In which z[n] is a white Gaussian noise, ߙ 0 = 1, ߙ 1 = 0.5 and ߙ 2 = −0.25. Consider OFDM modulation format. a) What is the minimum length of the cyclic prefix required for the above channel? b) Assuming that there are N symbols for OFDM, find the channel coefficients H[k] for ܰ = 3. c) Plot |ܪ[݇]| 2 at points ݇ and for the following cases 1. ܰ = 16, sampling interval = 2ߤݏ. 2. ܰ = 128, sampling interval = 2ߤݏ. d) Using the following description for Fourier transform, plot |ܪ(݂)| 2 and compare it to the results from part c. ܪሺ݂ሻ = ෍ ℎሾ݈ሿ݁
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: −௝2గ௟௙/ௐ ௅−1 ௟=0 3. Consider an OFDM transmission system with 8 tones and cyclic prefix of length 2 over the following communication channel. ݕሾ݊ሿ = ݔሾ݊ሿ + 0.5 ݔሾ݊ − 1ሿ − 0.25 ݔሾ݊ − 2ሿ + ݖ[݊] In which z[n] is a zero mean white Gaussian noise with variance N ଴ . Assume 1ܯܪݖ available bandwidth. Find the average SER for ܴܵܰ ± ܧ ௌ /ܰ ଴ ± 10݀ܤ, 15݀ܤ, 20݀ܤ in each of the following cases and plot SER versus SNR for each signaling format in (a) to (c). a) BPSK signaling on each tone and constant transmit power. b) QPSK signaling on each tone and constant transmit power. c) BPSK signaling and power is transmitted only on half of the tones that have higher SNR. (A form of adaptive modulation.)...
View Full Document

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern