<s>
The	O
Packet	O
Radio	O
Network	O
(	O
PRNET	B-Protocol
)	O
was	O
a	O
set	O
of	O
early	O
,	O
experimental	O
mobile	B-Protocol
ad	I-Protocol
hoc	I-Protocol
networks	I-Protocol
whose	O
technologies	O
evolved	O
over	O
time	O
.	O
</s>
<s>
ARPA	O
initiated	O
the	O
PRNET	B-Protocol
project	O
in	O
1973	O
,	O
funding	O
both	O
theoretical	O
and	O
experimental	O
research	O
.	O
</s>
<s>
The	O
earlier	O
ALOHAnet	O
served	O
as	O
an	O
inspiration	O
,	O
but	O
PRNET	B-Protocol
tackled	O
a	O
significantly	O
harder	O
set	O
of	O
problems	O
,	O
namely	O
,	O
multi-hop	O
communications	O
between	O
mobile	O
vehicles	O
without	O
a	O
central	O
station	O
.	O
</s>
<s>
The	O
first	O
PRNET	B-Protocol
was	O
established	O
under	O
the	O
auspices	O
of	O
SRI	O
in	O
the	O
San	O
Francisco	O
Bay	O
Area	O
,	O
with	O
BBN	O
contributing	O
network	O
technology	O
and	O
Collins	O
creating	O
the	O
Experimental	O
Packet	O
Radios	O
(	O
EPRs	O
)	O
,	O
which	O
implemented	O
L-band	O
spread-spectrum	O
waveforms	O
and	O
supported	O
half-duplex	O
communications	O
at	O
100	O
or	O
400	O
kilobits/second	O
.	O
</s>
<s>
PRNET	B-Protocol
was	O
sufficiently	O
advanced	O
by	O
1977	O
to	O
participate	O
in	O
the	O
initial	O
three-way	O
internetworking	B-Architecture
demonstration	O
,	O
which	O
linked	O
a	O
mobile	O
vehicle	O
in	O
PRNET	B-Protocol
with	O
nodes	O
in	O
the	O
ARPANET	O
,	O
and	O
via	O
SATNET	O
,	O
to	O
nodes	O
in	O
London	O
run	O
by	O
Peter	O
Kirstein	O
's	O
research	O
group	O
at	O
University	O
College	O
London	O
.	O
</s>
<s>
By	O
September	O
1979	O
,	O
"	O
Ron	O
 [ Kunzelman ] 	O
reported	O
that	O
SRI	O
is	O
now	O
operating	O
two	O
PRNETs	B-Protocol
in	O
the	O
San	O
Francisco	O
bay	O
area	O
,	O
and	O
one	O
PRNET	B-Protocol
at	O
Ft	O
.	O
Bragg	O
,	O
North	O
Carolina	O
.	O
</s>
<s>
The	O
Experimental	O
Packet	O
Radios	O
were	O
later	O
replaced	O
by	O
Upgraded	O
Packet	O
Radios	O
(	O
UPR	O
)	O
,	O
circa	O
1978	O
,	O
and	O
in	O
1986	O
by	O
Low-Cost	O
Packet	O
Radio	O
(	O
LPR	O
)	O
as	O
part	O
of	O
DARPA	O
's	O
follow-on	O
SURAN	B-Protocol
project	O
.	O
</s>
