A Flexible Parallel Transmission Scheme Using Frequency Domain Multi-Layered OFDM System

A novel adaptive Orthogonal Frequency-Division Multiplexing (OFDM) system with multi-layered (ML) transmission is proposed for mobile multimedia networks to support transmission of multiple data streams with flexible Quality-of-Service (QoS) adjustment capability and therefore can accommodate users with different QoS requirements or link conditions. The enhanced layers (ELs), formulated by parallel modulated orthogonal pseudo-random sequences, are superimposed onto OFDM data in frequency domain prior to multicarrier modulation and used to transmit different data information without the requirement of additional links. In this paper, the transceiver design particularly the frequency domain correlation detector and ELs induced interference cancellation is presented. A power distribution scheme for ELs is further proposed to optimize the overall system performance. The performance of the proposed ML-OFDM system is evaluated through numerical simulations.