Electrical Connection Summer 2016

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spectral efficiency. Instead of dodging
interference, pCell exploits it by
combining radio signals to synthesise
small, personal cells, or pCells, that
follow each device around. This means
that instead of users taking turns –
sharing the capacity of one large cell
– each user has access to full wireless
capacity at all times. Instead of cell
towers, the technology uses pWave
radios: small transmitters about
the size of a lunchbox (connected to
data centres) that create signals that
interfere with each other and are
calibrated to synthesise pCells
about 1cm in size around every device
in range.
“When we compare the different
wireless technologies, we see that 3G
HSPA+ achieves 1.2bps/Hz per sector
average down-link spectral efficiency
as opposed to a 4G LTE 1.7bps/Hz – so
we can see there’s only a marginal
gain. But with pCell technology we
have achieved spectral efficiency of up
to 59.3bps/Hz with 16 4G LTE devices
clustered in 1m 2 (see Figure 1). So we’re
achieving these results in a worse than
a worst case scenario,” says Antonio.
To explain how pCell achieves such a
high spectral efficiency gain, Antonio
compares a conventional cellular
layout against a pCell architecture.
“A conventional cellular system has
base stations (indicated by the blue dots
in Figure 2) that are placed based on a
very specific cell plan. They can transmit
a higher or lower power depending on
whether it is a macro cell or a small cell
(often small cells will overlap a macro
cell umbrella).
“Performance varies dramatically
for users (indicated by the red dots)
depending on their location. So as a user
moves from the cell centre towards the
cell edge, the signal quality degrades
because of path loss and shadowing
as well as inter-cell interference,
particularly in a frequency use one
system such as LTE networks.
“On the other hand we have pCell (the
blue dots indicate the position of the
access point). In its simplest form it is
single antenna transceiver that can be
placed anywhere. They can transmit
at higher power and they can also be
placed in much higher density than a
cellular layout because the interference
from all these access points is what we
exploit in order to create a high signal
quality around the user’s location.”
The technology has started to pique
the curiosity of some big players in the
US. Late last year, Nokia Networks and
Rearden LLC (Artemis’ parent company)
signed a memorandum of understanding
(MoU) to jointly test pCell in 2016 with
wireless operators.
The test will initially take place in
large indoor venues and other high
density areas, and will be offered as
pCell Proof-of-Concept deployments to
selected Nokia Networks customers.
The collaboration may also be extended
to consider further advanced features
that could be enabled by pCells, such as
precise 3D location positioning.
Another company that is helping
to test pCell technology is Webpass,
a provider of high speed internet to
residential and business customers in
several US cities. Webpass has installed
Artemis antennas in buildings it provides
internet to.
What makes this partnership
particularly interesting is that Webpass
has recently been acquired by Google
Fibre, giving the tech giant a first-hand
look at pCell in action.
> Artemis
Base Station
User Equipment Power Distribution
Cellular
Coverage
pCell
Coverage
Cellular vs. pCell Coverage
Figure 2: Conventional vs pCell coverage.
We’re running out of spectrum and current
technologies that are using densification through
small cells in 4G LTE networks are not enough...