Quadrupling the data rate for narrowband internet of things without modulation upgrade

This work proposes a novel signalling method for Narrowband Internet of Things (NB-IoT) mobile system where a quadrupled data rate can be achieved by combining two orthogonal techniques; the frequency orthogonal Fast-Orthogonal Frequency Division Multiplexing (Fast-OFDM) scheme coupled with the time orthogonal Hilbert transform (HT) pair. In this paper, the orthogonality features of one dimension in Fast-OFDM and of the HT pair are explored. The newly designed system structure is presented where the HT pulse pair is generated by square root raised cosine (SRRC) filter with a matched configuration at the receiver. System performance is investigated in terms of bit error rate (BER), effective data rate and spectral efficiency. Simulation results show that the HT-Fast-OFDM system provides 4 times the data rate relative to an OFDM system employing the same modulation scheme and occupying the same bandwidth. Furthermore, the proposed system has compelling advantages over 16-QAM OFDM for it achieves a better BER performance at the same spectral efficienc

On Spectral Coexistence of CP-OFDM and FB-MC Waveforms in 5G Networks

Future 5G networks will serve a variety of applications that will coexist on the same spectral band and geographical area, in an uncoordinated and asynchronous manner. It is widely accepted that using CP-OFDM, the waveform used by most current communication systems, will make it difficult to achieve this paradigm. Especially, CP-OFDM is not adapted for spectral coexistence because of its poor spectral localization. Therefore, it has been widely suggested to use filter bank based multi carrier (FB-MC) waveforms with enhanced spectral localization to replace CP-OFDM. Especially, FB-MC waveforms are expected to facilitate coexistence with legacy CP-OFDM based systems. However, this idea is based on the observation of the PSD of FB-MC waveforms only. In this paper, we demonstrate that this approach is flawed and show what metric should be used to rate interference between FB-MC and CP-OFDM systems. Finally, our results show that using FB-MC waveforms does not facilitate coexistence with CP-OFDM based systems to a high extent.Comment: Manuscript submitted for review to IEEE Transactions on Wireless Communication