A Time Slicing Adaptive OFDM System for Mobile Multimedia Communications

Abstract

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Multi-Symbol Encapsulated-Orthogonal Frequency Division Multiplexing (MSE-OFDM) is an adaptive OFDM system which was proposed earlier to meet the overwhelming needs of spectrum-efficient wireless communication systems. In this technique, one cyclic prefix (CP) is used for multiple OFDM symbols. The motivation for MSE-OFDM is to mitigate two major inherited disadvantages of OFDM system at the same time i.e., the sensitivity to carrier frequency offset (CFO) and high peak to average power ratio (PAPR). In this paper, we propose a new time slicing technique where the cyclic prefix is replaced with the precoded pseudo-random sequence for MSE-OFDM system. Therefore it is possible to multiplex multiple data streams using this technique with dynamic data rates for mobile multimedia communications. It also overcomes disadvantages with other techniques such as high sensitivity to frequency offset inherited with Orthogonal Frequency Division Multiple Access (OFDMA) system and complex equalization problem with conventional Single Carrier-Frequency Division Multiple Access (SC-FDMA). Therefore this technique can be used for both uplink and downlink transmissions of mobile multimedia communications with variable data rates. With those inherent advantages of proposed time slicing technique which is compatible to DVB-H standard, power saving for mobile receivers is enabled and therefore extended battery life can be guaranteed which is very important for the mobile users. </para>