Wireless Communication Technologies 1 Summary OFDM is a bandwidth efficient modulation technique that is tolerant to channel disturbance such as delay spread multipath and impulse noise. The principle of OFDM is to split high-rate data-streams into number of lower rate streams that are transmitted simultaneously over a number of sub-carriers. To demodulate the OFDM subcarriers, it has to perform at least two synchronization tasks: symbol timing and frequency synchronization. Frequency offset destroys the orthogonality between tones. It is important to obtain an accurate estimate of carrier frequency in order to minimize degradation. OFDM has a higher PAPR than concentional single carrier systems. These attributes require that special attention be paid to the linearity of power amplifiers, or be taken to decrease the PAPR

Wireless Communication Technologies 2 References [1] R. v. Nee, R. Prasad, OFDM for Wireless Multimedia Communications, Artech House Publishers, [2] L-H Li, F-L Lin, and H-R Chuang, “Complete RF-System Analysis of Direct Conversion Receiver (DCR) for a WLAN OFDM System,” IEEE Transactions on Vehicular Technology, Vol. 56, No 4, pp , July [3] T. Pollet, M. van Bladel and M. Moeneclaey, “BER Sensitivity of OFDM Systems to Carrier Frequency Offset and Wiener Phase Noise,” IEEE Trans. On Comm., Vol. 43, No. 2/3/4, pp , Feb.-Apr [4] Anuj Batra, “Multi-band OFDM Physical Layer Proposal (ppt: 03267r1P _TG3a-Multi-band-OFDM-CFP-Presentation),” IEEE P Working Group for Wireless Personal Area Networks, Available: http: //grouper.ieee.org/groups/802/15/pub/2003/Jul03/.http: //grouper.ieee.org/groups/802/15/pub/2003/Jul03/ [5] I. Arsic, V. Stankovic, D. Drajic and Z. Nikolic, “Performance of the OFDM System,” IEEE TELSIKS 2001, Niš, Yugoslavia, pp , September ,

Wireless Communication Technologies 3 References [6] U. Tureli, H. Liu, M. D. Zoltowski, “OFDM blind carrier offset estimation: ESPRIT,” IEEE Trans. Commun, vol. 48, no. 9, pp , Sep [7] A. Ren, Q. Yin, Y. Meng, “Carrier Frequency Offset Estimation for OFDM systems”, Circuits and Systems, ISCAS IEEE International Symposium on May 2005 Page(s):3019 – 3022, Vol. 4. [8] F.-L. Lin, S.-F. Chen, and H.-R. Chuang, “Computer Simulation of Nonlinear Effects of RF Power Amplifiers based on EVM and ACPR for Digital Wireless Communications”, Electronics Letter, vol. 36, no. 1, pp , Jan [9] R. E. Ziemer, R. L. Peterson, Introduction to Digital Communication, Prentice Hall, Inc.,