OFDM(2) Matrix Based Simlation Fire Tom Wada Professor, Information Engineering, Univ. of the Ryukyus Chief Scientist at Magna Design Net, Inc wada@ie.u-ryukyu.ac.jp http://www.ie.u-ryukyu.ac.jp/~wada/ 5/9/2019

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

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

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

FFT matrix 5/9/2019

IFFT matrix 5/9/2019

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

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

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

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

Additive Noise 5/9/2019

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

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