  With the huge advancement of nanotechnology over the past years, the devices
are shrinking into micro-scale, even nano-scale. Additionally, the Internet of
nano-things (IoNTs) are generally regarded as the ultimate formation of the
current sensor networks and the development of nanonetworks would be of great
help to its fulfilment, which would be ubiquitous with numerous applications in
all domains of life. However, the communication between the devices in such
nanonetworks is still an open problem. Body-centric nanonetworks are believed
to play an essential role in the practical application of IoNTs. BCNNs are also
considered as domain specific like wireless sensor networks and always deployed
on purpose to support a particular application. In these networks,
electromagnetic and molecular communications are widely considered as two main
promising paradigms and both follow their own development process. In this
survey, the recent developments of these two paradigms are first illustrated in
the aspects of applications, network structures, modulation techniques, coding
techniques and security to then investigate the potential of hybrid
communication paradigms. Meanwhile, the enabling technologies have been
presented to apprehend the state-of-art with the discussion on the possibility
of the hybrid technologies. Additionally, the inter-connectivity of
electromagnetic and molecular body-centric nanonetworks is discussed.
Afterwards, the related security issues of the proposed networks are discussed.
Finally, the challenges and open research directions are presented.
