System-on-a-Chip Radio Transceivers for 60-GHzWireless Body-Centric Communications - Ultra-Wideband and 60 GHz Communications for Biomedical Applications - page 175

Therefore, considering that the feasibility of wireless body-centric communica-
tions is dependent on the feasibility of SoC transceivers, currently not addressed by
the research community, our objective in this chapter is to introduce and then acceler-
ate the research and development of this interesting frontier of the emerging wireless
applications. In particular, on the basis of the latest advances of the microelectronic
CMOS technology [ 17 - 19 ]—today superior to all the other commercial technolo-
gies and capable of providing transistors with maximum cut-off in excess of 300
GHz and low noise figure (NF) (e.g., lower than 2 dB at 60 GHz)—we report here-
inafter a preliminary feasibility of SoC transceivers in nano-scale CMOS technology
in support of the needs of 60-GHz wireless body-centric communications.

Wireless Body-Centric Communications

The continuing miniaturization of electronic devices, together with the development
of wearable computing technologies, leads toward the realization of a series of de-
vices that can be carried on the human body [ 8 ]. Before stepping into the details of
the specific design challenges for the SoC implementations of radio transceivers in
nano-scale CMOS technology, it is worth summarizing in short the typical scenarios
of the body-centric wireless communications.
In particular, the concept of wireless body area networks (WBANs) consists in
a network of several sensors placed around the human body that can communicate
information via wireless link. These sensors can monitor several vital parameters
(ECG, EEG, glucose level, etc.) and transmit the information through a wireless link
to a central node. In some cases, the sensor itself may use RF contactless sensing
technologies [ 16 ], which remove the need of contact, reduce the encumbrance, and
improve the wearability [ 20 - 23 ]. As mentioned earlier, the main advantages of ex-
ploiting the 60 GHz wireless link are the very high data rates of multi-Gb/s for short
range applications, covertness, high frequency reuse, reduced interference, narrow
antenna beam width, and small antenna size [ 10 , 24 ]. We can distinguish three levels
of communication [ 8 ] (see Fig. 2 ):
•

In-body wireless transceivers are implanted in the body and most of channel is
inside the body (for example a sensor placed on a broken bone to monitor its
recovering). In Fig. 2 a, the in-body sensor is represented with an orange spots,
the central node with blue spots, and the wireless link between them with orange
arrows.

• On-body wireless transceivers are placed on the surface of the body or on a

wearable garment. This can be the case of external sensors as respiratory and
heart-rate monitors [ 25 , 26 ], EEG, motion detectors, etc. In this case most of the
channel is on the surface of the body. In 2 and 2 b, the sensors are represented by
the green spots, while the central nodes by the blue spots. The on-body wireless
link is represented by the green arrows.

• Off-body wireless transceivers are placed on the surface of the body, but they

communicate outside the body, to a central node worn by other persons (e.g., as