Generalized index and mode modulated OFDM with improved spectral and energy efficiency

Recently developed trends in wireless communication encounter extremely high surge in data traffic, which makes it inevitable to employ energy efficient techniques to reduce detrimental consequence of carbon emission over society. This concern has motivated us to upgrade our previous work on index and mode modulated orthogonal frequency division multiplexing (IMM-OFDM) for achieving dual benefits in terms of spectral and energy efficiency. In this paper, we have proposed a generalized index and mode modulated OFDM scheme with variable number of subcarrier activation. Novelty of this generalized scheme is its capability to act as a unified model for classic OFDM and three other benchmark index modulated OFDM schemes along with our previously proposed IMM-OFDM scheme. This new scheme outperforms those five descendent schemes in terms of energy efficiency and error performance as indicated by simulation results. Spectral efficiency improvement in this scheme is achieved through optimum sets of active subcarrier number, which are determined to gain most optimized trade-off between spectral and energy efficiency with least detector complexity. This generalized parent scheme can replace individual models of its five descendent schemes and consequently can be considered to be one of the most promising candidates for next generation mobile communication system.