<s>
Smartphone	B-Application
ad	I-Application
hoc	I-Application
networks	I-Application
(	O
SPANs	O
;	O
also	O
smart	B-Application
phone	I-Application
ad	I-Application
hoc	I-Application
networks	I-Application
)	O
are	O
wireless	B-General_Concept
ad	I-General_Concept
hoc	I-General_Concept
networks	I-General_Concept
that	O
use	O
smartphones	B-Application
.	O
</s>
<s>
Once	O
embedded	O
with	O
ad	O
hoc	O
networking	O
technology	O
,	O
a	O
group	O
of	O
smartphones	B-Application
in	O
close	O
proximity	O
can	O
together	O
create	O
an	O
ad	O
hoc	O
network	O
.	O
</s>
<s>
Smart	B-Application
phone	I-Application
ad	I-Application
hoc	I-Application
networks	I-Application
use	O
the	O
existing	O
hardware	O
(	O
primarily	O
Bluetooth	B-Protocol
and	O
Wi-Fi	O
)	O
in	O
commercially	O
available	O
smartphones	B-Application
to	O
create	O
peer-to-peer	O
networks	O
without	O
relying	O
on	O
cellular	O
carrier	O
networks	O
,	O
wireless	O
access	O
points	O
,	O
or	O
traditional	O
network	O
infrastructure	O
.	O
</s>
<s>
SPANs	O
differ	O
from	O
traditional	O
hub	O
and	O
spoke	O
networks	O
,	O
such	O
as	O
Wi-Fi	O
Direct	O
,	O
in	O
that	O
they	O
support	O
multi-hop	B-General_Concept
routing	I-General_Concept
(	O
ad	O
hoc	O
routing	O
)	O
and	O
relays	O
and	O
there	O
is	O
no	O
notion	O
of	O
a	O
group	O
leader	O
,	O
so	O
peers	O
can	O
join	O
and	O
leave	O
at	O
will	O
without	O
destroying	O
the	O
network	O
.	O
</s>
<s>
Primarily	O
use	O
Bluetooth	B-Protocol
Mesh	O
or	O
Wi-Fi	O
,	O
since	O
the	O
cellular	O
spectrum	O
is	O
licensed	O
and	O
controlled	O
by	O
cellular	O
providers	O
and	O
FCC	O
regulations	O
.	O
</s>
<s>
The	O
ad	O
hoc	O
networking	O
technology	O
operating	O
on	O
Wi-Fi	O
ad	B-General_Concept
hoc	I-General_Concept
mode	I-General_Concept
,	O
at	O
the	O
unlicensed	O
ISM	B-Algorithm
band	I-Algorithm
of	O
2.4GHz	B-Algorithm
may	O
result	O
in	O
profit	O
loss	O
by	O
cellular	O
carriers	O
since	O
ISM	B-Algorithm
band	I-Algorithm
is	O
free	O
and	O
unlicensed	O
while	O
cellular	O
carriers	O
operate	O
on	O
licensed	O
band	O
at	O
900MHz	O
,	O
1200MHz	O
,	O
1800MHz	O
,	O
etc	O
.	O
</s>
<s>
Smart	B-Application
phone	I-Application
mobile	B-General_Concept
ad	I-General_Concept
hoc	I-General_Concept
networks	I-General_Concept
can	O
operate	O
independently	O
and	O
allow	O
communications	O
among	O
smart	B-Application
phones	I-Application
users	O
without	O
the	O
need	O
for	O
any	O
3G	B-Architecture
or	O
4G	B-Architecture
LTE	O
signals	O
to	O
be	O
present	O
.	O
</s>
<s>
Wi-Fi	O
ad	B-General_Concept
hoc	I-General_Concept
mode	I-General_Concept
was	O
first	O
implemented	O
on	O
Lucent	O
WaveLAN	O
802.11a/b	O
on	O
laptop	O
computers	O
.	O
</s>
<s>
Since	O
Wi-Fi	O
is	O
present	O
and	O
embedded	O
in	O
all	O
smart	B-Application
phones	I-Application
today	O
,	O
this	O
earlier	O
technology	O
was	O
adapted	O
for	O
smartphones	B-Application
.	O
</s>
<s>
Smartphone	B-Application
ad	I-Application
hoc	I-Application
networks	I-Application
may	O
be	O
useful	O
in	O
situations	O
that	O
include	O
:	O
</s>
<s>
2015	O
–	O
By	O
2015	O
,	O
millions	O
of	O
teenagers	O
and	O
school	O
children	O
in	O
the	O
United	O
States	O
had	O
started	O
using	O
smart	B-Application
phone	I-Application
ad	I-Application
hoc	I-Application
networks	I-Application
to	O
chat	O
and	O
communicate	O
,	O
without	O
the	O
need	O
for	O
Wi-Fi	O
or	O
cellular	O
signals	O
.	O
</s>
<s>
2019	O
–	O
During	O
the	O
2019	O
–	O
20	O
Hong	O
Kong	O
protests	O
that	O
started	O
in	O
opposition	O
to	O
a	O
proposed	O
modification	O
of	O
an	O
extradition	O
law	O
,	O
Bridgefy	B-Application
,	O
a	O
smartphone	B-Application
ad	I-Application
hoc	I-Application
network	I-Application
app	O
apparently	O
running	O
on	O
Bluetooth	B-Protocol
Mesh	O
,	O
was	O
used	O
to	O
communicate	O
during	O
protests	O
in	O
a	O
way	O
that	O
minimised	O
tracking	O
and	O
interference	O
by	O
authorities	O
.	O
</s>
<s>
In	O
Apple	O
Inc	O
.	O
iPhones	B-Device
released	O
with	O
iOS	O
version	O
7.0	O
and	O
higher	O
,	O
multipeer	O
connectivity	O
APIs	O
(	O
application	O
programmable	O
interfaces	O
)	O
are	O
enabled	O
and	O
provided	O
to	O
allow	O
Apple	O
iPhones	B-Device
to	O
operate	O
in	O
peer-to-peer	O
ad	O
hoc	O
mesh	O
networking	O
mode	O
.	O
</s>
<s>
This	O
means	O
iPhones	B-Device
can	O
now	O
talk	O
to	O
each	O
other	O
without	O
using	O
a	O
cellular	O
signal	O
or	O
connection	O
.	O
</s>
<s>
With	O
700+	O
millions	O
of	O
iPhones	B-Device
being	O
used	O
globally	O
,	O
ad	O
hoc	O
peer-to-peer	O
networks	O
will	O
gain	O
pervasive	O
presence	O
almost	O
instantly	O
.	O
</s>
<s>
Software	O
packages	O
that	O
implement	O
smartphone	B-Application
ad	I-Application
hoc	I-Application
networks	I-Application
include	O
GPL-licensed	O
Serval	B-Application
Project	I-Application
over	O
Bluetooth	B-Protocol
or	O
WiFi	O
;	O
GPL-licensed	O
Commotion	O
Wireless	O
;	O
proprietary	B-Application
FireChat	B-Protocol
over	O
Bluetooth	B-Protocol
,	O
Bridgefy	B-Application
over	O
Bluetooth	B-Protocol
,	O
and	O
GPL-licensed	O
Briar	B-Protocol
over	O
Bluetooth	B-Protocol
or	O
WiFi	O
.	O
</s>
