Effect of Jammer on the Performance of OFDM In the Presence of Nonlinearity In Rayleigh Fading Channel with Application to 802.11n WLAN
Chi,David
University of California, San Diego
Das,Pankaj
University of California, San Diego
Orthogonal Frequency Division Multiplexing (OFDM) has been shown to have several technical advantages over its competitors and is currently being considered for the fourth generation (4G) mobile and Wireless Local Area Network (WLAN) communication system. On the contrary to traditional antenna configuration, Single Input Single Output (SISO), Multiple Input Multiple Output (MIMO) antenna implementation has been proven to increase the data rate of the system by employing more than one antenna for simultaneously transmissions and receptions. The IEEE 802.11n incorporates both OFDM and MIMO technologies to achieve better performance. Even though OFDM has advantages over its counter parts, by itself it presents technical challenges to designers such as sensitivity to frequency offsets and peak-to-average ratio (PAPR). The property of orthogonality is essential to OFDM systems, and because of this property the processes of synchronization and data extraction are rather straightforward. However, if the orthogonality is lost during the communication process, the inter-carrier interference (ICI) will occur and lowers the system performance. Another problem that is associated with OFDM is its high peak-to-average power ratio (PAPR) which is due to the nature of FFT/IFFT operations. Practical amplifiers have difficulty reproducing such high PAPR signals and often introduce clipping and spectral regrowth.
In this paper, we analyze the performance of an equalized OFDM system in the presence of nonlinear amplifier and jammer in Rayleigh fading channel. We then extend the analytical model to the system that is in compliance of IEEE 802.11n specifications for simulations. The simulation results obtained from the extended model are compared with the theoretical results.
David W. Chi received the Bachelor of Science (B.S.) degree and Master of Science (M.S.) degree in Electrical and Computer Engineering from University of California, San Diego (UCSD) in 1998 and 2001, respectively. He is currently a Ph.D. student at UCSD. His research interests include Error Correction Code, OFDM, MIMO, Space-Time Codes or Space-Frequency Codes.