  This paper considers massive Internet of Things systems, especially for LoW
Power Wide Area Networks, that aim at connecting billions of low-cost devices
with multi-year battery life requirements. Current systems for massive Internet
of Things exhibit severe problems when trying to pursue the target of serving a
very large number of users. In this paper, a novel asynchronous spread spectrum
modulation, called Golden Modulation, is introduced. This modulation provides a
vast family of equivalent waveforms with very low cross-interference even in
asynchronous conditions, hence enabling natural multiuser operation without the
need for inter-user synchronization or for interference cancellation receivers.
Thanks to minimal interference between waveforms, coupled with the absence of
coordination requirements, this modulation can accommodate very high system
capacity. The basic modulation principles, relying on spectrum spreading via
direct Zadoff-Chu sequences modulation, are presented and the corresponding
theoretical bit error rate performance in an additive white Gaussian noise
channel is derived and compared by simulation with realistic Golden Modulation
receiver performance. The demodulation of the Golden Modulation is also
described, and its performance in the presence of uncoordinated multiple users
is characterized.
