NC-OFDM-SPM: a two-dimensional non-coherent modulation scheme for achieving the coherent performance of OFDM along with sending an additional data-stream

Abstract

A promising candidate solution for reducing complexity in future wireless systems is the use of non-coherent designs; however, it is very well known in the literature that non-coherent schemes perform worse than their coherent counterparts. To address this longstanding challenging trade-off, we demonstrate and prove in this work the ability of the proposed two-dimensional modulation scheme termed as non-coherent orthogonal frequency division multiplexing with subcarrier power modulation and differential phase shift keying in achieving the performance of a coherent design, while reducing complexity. Although the proposed design is non-coherent (i.e., it uses differential phase shift keying and power difference to convey information), it achieves the same bit error rate (BER) performance as conventional OFDM with coherent BPSK. Furthermore, since the proposed scheme employs two-dimensional modulations simultaneously (i.e., DPSK and subcarrier power levels), an additional data stream can be transmitted through the power subcarriers’ levels. Thus, the proposed design not only solves the trade-off between coherent and non-coherent modulations in terms of reliability by achieving the same BER, but also provides higher data rates by exploring the power domain as an additional dimension for conveying extra data bits, while maintaining low complexity transceiver design, thus making it very appealing for IoT applications.