Ofdm Simulation Using Matlab-goldsmith

OFDM Simulation Using Matlab Smart Antenna Research Laboratory Faculty Advisor: Dr. Mary Ann Ingram Guillermo Acosta August, 2000 OFDM Simulation Using Matlab iiCONTENTS Abstract. 1 1 Introduction . 1 2 OFDM Transmission . 2 2.1 DVB-T Example. 2 2.2 FFT Implementation. 4 3 OFDM Reception . 9 4 Conclusion. 11 5 Appendix. 11 5.1 OFDM Transmission. 11 5.2 OFDM Reception. 13 5.3 Eq. (2.1.4) vs. IFFT . 16 6 References. 17 iii FIGURES AND TABLES Figure 1.1: DVB-T transmitter 1.2 Figure 2.1: OFDM symbol generation simulation. .5 Figure 2.2: Time response of signal carriers at (B).5 Figure 2.3: Frequency response of signal carriers at (B).5 Figure 2.4: Pulse shape g(t). .6 Figure 2.5: D/A filter response. .6 Figure 2.6: Time response of signal U at (C).6 Figure 2.7: Frequency response of signal U at (C) .6 Figure 2.8: Time response of signal UOFT at (D).7 Figure 2.9: Frequency response of signal UOFT at (D).7 Figure 2.10: ()cos(2 )Icuoft t f t frequency response.7 Figure 2.11: ()sin(2 )Qcuoft t f t frequency response.7 Figure 2.12: Time response of signal s(t) at (E).8 Figure 2.13: Frequency response of signal s(t) at (E).8 Figure 2.14: Time response of direct simulation of (2.1.4) and IFFT. .8 Figure 2.15: Frequency response of direct simulation of (2.1.4) and IFFT. .8 Figure 3.1: OFDM reception simulation. .9 Figure 3.2: Time response of signal r_tilde at (F). .9 Figure 3.3: Frequency response of signal r_tilde at (F). .9 Figure 3.4: Time response of signal r_info at (G). .10 Figure 3.5: Frequency response of signal r_info at (G).10 Figure 3.6: Time response of signal r_data at (H). .10 Figure 3.7: Frequency response of signal r_data at (H).10 Figure 3.8: info_h constellation.10 Figure 3.9: a_hat constellation.10 Table 1: Numerical values for the OFDM parameters for the 2k mode.4 Abstract Orthogonal frequency division multiplexing (OFDM) is becoming the chosen modulation technique for wireless communications. OFDM can provide large data rates with sufficient robustness to radio channel impairments. Many research cen-ters in the world have specialized teams working in the optimization of OFDM for countless applications. Here, at the Georgia Institute of Technology, one of such teams is in Dr. M. A. Ingram's Smart Antenna Research Laboratory (SARL), a part of the Georgia Center for Advanced Telecommunications Technology (GCATT). The purpose of this report is to provide Matlabcode to simulate the basic proc-essing involved in the generation and reception of an OFDM signal in a physical channel and to provide a description of each of the steps involved. For this pur-pose, we shall use, as an example, one of the proposed OFDM signals of the Digi-tal Video Broadcasting (DVB) standard for the European terrestrial digital television (DTV) service. 1 Introdu