1. OFDM(2) Matrix Based Simlation
Fire Tom Wada
Professor, Information Engineering, Univ. of the Ryukyus
Chief Scientist at Magna Design Net, Inc
5/9/2019

2. OFDM Modulator P / S M A P S / P IFFT Bit stream generated0~dＮ－１ Copy
to make Guard Interval P / S
M A P S / P
IFFT
OFDM symbol (1/f0) Tg
Bit stream
generated0~dＮ－１
5/9/2019

3. Multi-path channel Tg OFDM symbol (1/f0) Tg OFDM symbol (1/f0)
5/9/2019

4. OFDM Demodulator S / P DFT P / S Noise Equalize Bit Stream D E M A P
Remove Guard Interval
DFT P / S
Noise
OFDM symbol (1/f0) Tg
D E M A P
Equalize
Bit Stream
5/9/2019

5. FFT matrix
5/9/2019

6. IFFT matrix
5/9/2019

7. Multi-path channel in Matrix
GI of n-1
Symbol n-1
GI of n
Symbol n
5/9/2019

8. If Multi-path delay is small than GI length
Channel Matrix is Cyclic Matrix!
5/9/2019

9. Two path Multi path Channel Example
Base Station
Receiver
Channel Impulse Response = [1, 0.5 , 0, 0]

10. Two path Multi path Channel Example
If time domain channel matrix is cyclic, Frequency Domain Channel Matrix is diagonal!

11. Additive Noise
5/9/2019

12. How to recover sending signal from receiver signal. - EQUALIZE -
5/9/2019

13. TASK 2
Modify MATLAB program “MatrixOFDM1.m” to measure Symbol Error Rate vs S/N ratio in M=16 OFDM with QPSK modulation
Make Symbol Error Rate vs SN ratio Graph
Vertical: SER in log scale
Horizontal: SN ratio 0dB, 1dB … to 15dB
5/9/2019