Mutual Interference Analysis of FBMC-Based Return Channel for Bidirectional T-DMB System

In this paper, we investigate an effective scheme for implementing the return channel by exploiting the guard band between orthogonal frequency-division multiplexing (OFDM) blocks for uplink transmission, which enables guaranteeing compatibility with legacy systems. In order to resolve the interference problem between the conventional broadcast channel and the return channel, we employ the filter bank-based multicarrier (FBMC) system. Toward this goal, the mutual interference between the return and OFDM channels is derived as a closed form through numerical analysis. Based on the mutual interference analysis and the channel condition, an adaptive modulation scheme is applied to increase data throughput. Through the simulation, it can be seen that more than 350 (500) kb/s/Channel can be achieved for the channel signal-to-noise ratio (SNR) of 20 dB (30 dB) when the quality of service constraint is lower than a bit error rate of <inline-formula><tex-math notation="LaTeX">${\text 10}^-{\text 2}$</tex-math></inline-formula> ( <inline-formula><tex-math notation="LaTeX">$10^-{\text 4}$</tex-math></inline-formula>). Consequently, the additional throughput above can be achieved in a given resource without the adverse effect to the legacy systems.