New Development and Performance Evaluation of Transform Domain OFDM Baseband System

Abstract

Wireless Communication has gained much popularity in the field of Communication because of its ability to transfer the data at high rate with much more increased high quality, low cost and better performance. Also it offers variety of services for the wide range of applications.
Orthogonal frequency division multiplexing (OFDM) is becoming widely applied in wireless communications system due to its high rate transmissions capability with high bandwidth efficiency and its robustness with regard to multipath and delay. It has been used in digital audio broadcasting systems (DAB), digital video broadcasting (DVB) systems, digital subscriber line (DSL) standards, and wireless LAN standards such as the American IEEE std. 802.11(WiFi) and WiMAX (stands for Worldwide Interoperability for Microwave Access), are one of the standards of IEEE which utilizes the idea of OFDM, and is aimed to provide high-throughput broadband connections over long distances.
Conventially we use discrete Fourier transform (DFT) in OFDM system. This thesis presents the simulation of 4 Qudrature Amplitude Modulation (QAM) orthogonal frequency divison multiplexing (OFDM) baseband system and channel estimation which uses inverse discrete Hartley transform (IDHT) and discrete Hartley transform (DHT). As the calculation of DHT and IDHT involves real operations hence the computational complexities are less as comapred to DFT and IDFT. Moreover as IDHT is same as DHT hence we can use same hardware for both, while the DFT and IDFT require separate hardware to implement. As compared to DFT based OFDM system, the simulated DHT based OFDM system achieves approximately the same transmission performance with less computational complexity and hardware requirements.