OFDM Inspired Waveforms for 5G

As the standardization activities are being formed to lay the foundation of 5G wireless networks, there is a common consensus on the need to replace the celebrated orthogonal frequency division multiplexing (OFDM) by a more effective air interface that better serves the challenging needs of 5G. To this end, in the recent past, a number of new waveforms have been introduced in the literature. Interestingly, and at the same time not surprising, these methods share a common fundamental principle with OFDM: each data packet is made up of a number of complex-valued sinusoidals (pure tones) that are modulated by the information symbols. In this tutorial article, we build a common framework based on the said OFDM principle and derive these new waveforms from this point of view. This derivation provides a new perspective that facilitates straightforward understanding of channel equalization and the application of these new waveforms to multiple-input multiple-output channels. It also facilitates derivation of new structures for more efficient synthesis/analysis of these waveforms than those that have been reported in the literature.