TABLE OF CONTENTS The basic principle of OFDM, explained in Chapter 3, is to split a high-rate data stream into a number of lower rate streams that are transmitted simultaneously over a number of subcarriers. Because the symbol duration increases for the lower rate parallel subcarriers, the relative amount of dispersion in time caused by multipath delay spread is decreased, as introduced in Chapter 2. ISI is eliminated almost completely by introducing a guard interval in each OFDM symbol, where the OFDM signal is cyclically extended to avoid intersubcarrier interference. This whole process of generating an OFDM signal and the reasoning behind it are described in Chapter 3.
In OFDM system development, it is necessary to understand its performance characteristics, which are given qualitatively in [1]. This chapter presents the performance analysis of the OFDM system in great detail. After Section 4.2 shows the radio channel model for the bit error rate (BER) analysis, Section 4.3 first analyzes the BER in an additive white Gaussian noise (AWGN) channel, and then Sections 4.4 and 4.5 extend it for various cases, namely, phase shift keying/coherent detection (CPSK)- and PSK/ differential detection (DPSK)-based OFDM systems in Rayleigh fading channels, respectively. Then, after introducing the robustness against frequency selective fading in Section 4.6, Section 4.7 discusses the robustness against man-made noises. Sections 4.8 and 4.9 analyze the sensitivity to frequency offset and nonlinear amplification, respectively. The sensitivity to analog to digital (A/D) and digital to analog (D/A) resolutions is investigated in Section 4.10. Section 4.11...
