  Internet-of-things (IoT) architectures connecting a massive number of
heterogeneous devices need energy efficient, low hardware complexity, low cost,
simple and secure mechanisms to realize communication among devices. One of the
emerging schemes is to realize simultaneous wireless information and power
transfer (SWIPT) in an energy harvesting network. Radio frequency (RF)
solutions require special hardware and modulation methods for RF to direct
current (DC) conversion and optimized operation to achieve SWIPT which are
currently in an immature phase. On the other hand, magneto-inductive (MI)
communication transceivers are intrinsically energy harvesting with potential
for SWIPT in an efficient manner. In this article, novel modulation and
demodulation mechanisms are presented in a combined framework with
multiple-access channel (MAC) communication and wireless power transmission.
The network topology of power transmitting active coils in a transceiver
composed of a grid of coils is changed as a novel method to transmit
information. Practical demodulation schemes are formulated and numerically
simulated for two-user MAC topology of small size coils. The transceivers are
suitable to attach to everyday objects to realize reliable local area network
(LAN) communication performances with tens of meters communication ranges. The
designed scheme is promising for future IoT applications requiring SWIPT with
energy efficient, low cost, low power and low hardware complexity solutions.
