@article{discovery10067512,
           month = {January},
            note = {This version is the author accepted manuscript. For information on re-use, please refer to the publisher's terms and conditions.},
       publisher = {Institute of Electrical and Electronics Engineers Inc.},
           title = {Waveform and Space Precoding for Next Generation Downlink Narrowband IoT},
            year = {2019},
         journal = {IEEE Internet of Things Journal},
             url = {https://discovery.ucl.ac.uk/id/eprint/10067512/},
            issn = {2327-4662},
          author = {Xu, T and Masouros, C and Darwazeh, I},
        abstract = {Narrowband Internet of things (NB-IoT) was introduced by 3GPP in low power wide area network (LPWAN)
to support low power and wide coverage applications. Since it
follows long term evolution (LTE) standard, its signal quality
is guaranteed and its deployment is straightforward via reusing
existing infrastructures. Current NB-IoT supports low data rate
services via using low order modulation formats for the purpose
of power saving. However, with the increase of data rate driven
applications, next generation NB-IoT would require data rate
enhancement techniques without consuming extra battery power.
In this work, a downlink framework, using a non-orthogonal
signal waveform for next generation enhanced NB-IoT (eNB-IoT),
is proposed and experimentally tested in both single-antenna and
multi-antenna systems. In the single-antenna scenario, waveform
precoding is used to pre-equalize the self-created inter carrier
interference (ICI) distorted signal waveform. For the multiantenna multi-user scenario, both waveform and antenna space
precoding have to be used. Measured results show that in both
single-antenna and multi-antenna systems, the proposed signal
waveform in eNB-IoT can increase data rate by {$\sim$}11\% compared
with NB-IoT occupying the same spectral resource in similar
receiver computational complexity.},
        keywords = {Narrowband 5G, NB-IoT, eNB-IoT, precoding,
multi-antenna, multi-user, MIMO, non-orthogonal, waveform,
software defined radio, prototyping.}
}