  A range of efficient wireless processes and enabling techniques are put under
a magnifier glass in the quest for exploring different manifestations of
correlated processes, where sub-Nyquist sampling may be invoked as an explicit
benefit of having a sparse transform-domain representation. For example,
wide-band next-generation systems require a high Nyquist-sampling rate, but the
channel impulse response (CIR) will be very sparse at the high Nyquist
frequency, given the low number of reflected propagation paths. This motivates
the employment of compressive sensing based processing techniques for frugally
exploiting both the limited radio resources and the network infrastructure as
efficiently as possible. A diverse range of sophisticated compressed sampling
techniques is surveyed and we conclude with a variety of promising research
ideas related to large-scale antenna arrays, non-orthogonal multiple access
(NOMA), and ultra-dense network (UDN) solutions, just to name a few.
