Superposition Coded-Orthogonal Frequency Division Multiplexing

Orthogonal frequency division multiplexing (OFDM) technique is the most used approach in various wireless communication technologies due to its implementation advantages. However, OFDM has also some significant drawbacks, such as the sensitivity against real-time impairments and the poor peak to-average power ratio (PAPR) performance. These drawbacks decrease the usage potential of OFDM in future networks. Recent OFDM alternatives, which have been proposed in 5G waveform research activities, can provide limited improvements and these mostly include modified filtering operations when compared to the OFDM. In this paper, as a novel and flexible approach, superposition coding is adopted to OFDM, and superposition coded-OFDM (SC-OFDM) is proposed. By exploiting superposition coding as a new transmission dimension, an adaptive waveform solution that solves the PAPR problem without creating any inefficiency is provided. At the same time, throughput or error performance, and sensitivity against real-time impairments can also be improved. Features for each problem are proposed within the SC-OFDM approach. Performances of each SC-OFDM features are measured with extensive computer simulations and real-time experiments. Real-time experiments are realized by using software defined radio nodes and these are compared with the computer simulation results. To the best of authors' knowledge, such a comprehensive waveform design is proposed for the first time in the literature. As observed with the results, SC-OFDM can meet the requirements of future communication technologies.