<title>Generalized OFDM method for multimedia transmission over wireless fading channels</title>

Abstract

A method to reliably transmit multimedia data over wireless fading channels by using a generalized OFDM technique is presented in this research. Multimedia delivery over wireless links is sensitive to fading effects. It is furthermore characterized by a number of different properties, including unequal error protection needs, time-varying bandwidth requirements, etc. Layered multimedia representation, such as MPEG-4 FGS, has been widely studied to meet these requirements. However, only this component is not sufficient to provide the desired quality of service (QoS). To further improve the overall system performance, we focus on the design of an adaptive modulation scheme, which maintains the ability to adapt to time-varying channel conditions as well as the layered multimedia representation. In particular, we study and analyze the performance of a technique known as Wavelet Packet Modulation (WPM) from the viewpoint of Orthogonal Frequency Division Multiplexing (OFDM), and demonstrate its application to wireless multimedia communication. In our framework, WPM is viewed as a general case of OFDM, which allows flexibility in terms of channel allocation and adaptability with respect to channel conditions. The algorithm demonstrates the flexibility of the new proposed method in transmitting multimedia data over interference-laden channels.

Scheduling algorithms for OFDM broadband wireless systems

“…Time varying introduces slow or fast fading. [34], [35], [36]. This technique has been successfully applied in the ADSL applications, Digital Audio Broadcasting (DAB), Terrestrial Digital Video Broadcasting (DVB-T) system, HIPERLAN/2, and satellite communications.…”