<s>
High-speed	B-Application
multimedia	I-Application
radio	I-Application
(	O
HSMM	O
)	O
is	O
the	O
implementation	O
of	O
high-speed	O
wireless	O
TCP/IP	O
data	O
networks	O
over	O
amateur	B-Algorithm
radio	I-Algorithm
frequency	I-Algorithm
allocations	I-Algorithm
using	O
commercial	O
off-the-shelf	O
(	O
COTS	O
)	O
hardware	O
such	O
as	O
802.11	O
Wi-Fi	B-Device
access	I-Device
points	I-Device
.	O
</s>
<s>
This	O
is	O
possible	O
because	O
the	O
802.11	O
unlicensed	O
frequency	O
bands	O
partially	O
overlap	O
with	O
amateur	B-Algorithm
radio	I-Algorithm
bands	I-Algorithm
and	O
ISM	B-Algorithm
bands	I-Algorithm
in	O
many	O
countries	O
.	O
</s>
<s>
Since	O
the	O
unlicensed	O
802.11	O
or	O
Wi-Fi	O
frequency	O
bands	O
overlap	O
with	O
amateur	O
frequencies	O
,	O
only	O
custom	O
firmware	B-Application
is	O
needed	O
to	O
access	O
these	O
licensed	O
frequencies	O
.	O
</s>
<s>
HSMM	O
can	O
support	O
most	O
of	O
the	O
traffic	O
that	O
the	O
Internet	O
currently	O
does	O
,	O
including	O
video	O
chat	O
,	O
voice	B-Application
,	O
instant	B-Application
messaging	I-Application
,	O
email	O
,	O
the	O
Web	O
(	O
HTTP	B-Protocol
)	O
,	O
file	O
transfer	O
(	O
FTP	B-Protocol
)	O
,	O
and	O
forums	B-Application
.	O
</s>
<s>
For	O
long-range	O
links	O
extending	O
outside	O
of	O
metropolitan	O
areas	O
802.11b	O
DSSS	B-Device
modulations	O
or	O
802.11ah	O
(	O
900MHz	B-Algorithm
)	O
equipment	O
can	O
be	O
used	O
,	O
further	O
increasing	O
range	O
at	O
the	O
cost	O
of	O
speed	O
.	O
</s>
<s>
The	O
following	O
is	O
a	O
list	O
of	O
the	O
802.11	O
channels	O
that	O
overlap	O
into	O
an	O
amateur	B-Algorithm
radio	I-Algorithm
band	I-Algorithm
under	O
the	O
FCC	O
in	O
the	O
United	O
States	O
.	O
</s>
<s>
Note	O
that	O
the	O
5	B-Algorithm
cm	I-Algorithm
amateur	B-Algorithm
band	I-Algorithm
extends	O
from	O
5.65	O
to	O
5.925GHz	O
,	O
so	O
that	O
there	O
are	O
many	O
frequencies	O
outside	O
the	O
Part	O
15	O
ISM/UNII	O
block	O
used	O
for	O
802.11a	O
.	O
</s>
<s>
Many	O
commercial	O
grade	O
802.11a	O
access	B-Device
points	I-Device
can	O
also	O
operate	O
in	O
between	O
the	O
normal	O
channels	O
by	O
using	O
5MHz	O
channel	O
spacing	O
instead	O
of	O
the	O
standard	O
20MHz	O
channel	O
spacing	O
.	O
</s>
<s>
The	O
802.11a	O
amateur	B-Algorithm
radio	I-Algorithm
band	I-Algorithm
consists	O
of	O
30	O
overlapping	O
channels	O
in	O
the	O
5.650	O
–	O
5.925GHz	O
(	O
5cm	O
)	O
band	O
.	O
</s>
<s>
The	O
802.11a	O
standard	O
uses	O
OFDM	B-Protocol
or	O
"	O
Orthogonal	B-Protocol
Frequency	I-Protocol
Division	I-Protocol
Multiplexing	I-Protocol
"	O
to	O
transmit	O
data	O
and	O
therefore	O
is	O
not	O
classified	O
as	O
spread-spectrum	B-Architecture
.	O
</s>
<s>
The	O
802.11b	O
amateur	B-Algorithm
radio	I-Algorithm
band	I-Algorithm
consists	O
of	O
8	O
overlapping	O
channels	O
in	O
the	O
2.390	O
–	O
2.450GHz	O
(	O
13cm	O
)	O
band	O
.	O
</s>
<s>
The	O
802.11b	O
specification	O
uses	O
Direct	B-Device
Sequence	I-Device
Spread	I-Device
Spectrum	I-Device
(	O
DSSS	B-Device
)	O
to	O
transmit	O
data	O
and	O
is	O
subject	O
to	O
the	O
rules	O
of	O
FCC	O
.	O
</s>
<s>
The	O
802.11g	O
amateur	B-Algorithm
radio	I-Algorithm
band	I-Algorithm
consists	O
of	O
8	O
overlapping	O
channels	O
in	O
the	O
2.4GHz	B-Algorithm
(	O
13cm	O
)	O
band	O
.	O
</s>
<s>
The	O
802.11g	O
standard	O
uses	O
OFDM	B-Protocol
or	O
"	O
Orthogonal	B-Protocol
Frequency	I-Protocol
Division	I-Protocol
Multiplexing	I-Protocol
"	O
to	O
transmit	O
data	O
and	O
therefore	O
is	O
not	O
classified	O
as	O
spread-spectrum	B-Architecture
.	O
</s>
<s>
The	O
802.11n	O
amateur	B-Algorithm
radio	I-Algorithm
band	I-Algorithm
consists	O
of	O
8	O
overlapping	O
channels	O
in	O
the	O
2.4GHz	B-Algorithm
(	O
13cm	O
)	O
band	O
.	O
</s>
<s>
The	O
802.11n	O
standard	O
uses	O
OFDM	B-Protocol
or	O
"	O
Orthogonal	B-Protocol
Frequency	I-Protocol
Division	I-Protocol
Multiplexing	I-Protocol
"	O
to	O
transmit	O
data	O
and	O
therefore	O
is	O
not	O
classified	O
as	O
spread-spectrum	B-Architecture
.	O
</s>
<s>
The	O
802.11y	O
amateur	B-Algorithm
radio	I-Algorithm
band	I-Algorithm
consists	O
of	O
24	O
overlapping	O
channels	O
in	O
the	O
3.4GHz	O
(	O
9cm	O
)	O
band	O
.	O
</s>
<s>
The	O
802.11y	O
standard	O
uses	O
OFDM	B-Protocol
or	O
"	O
Orthogonal	B-Protocol
Frequency	I-Protocol
Division	I-Protocol
Multiplexing	I-Protocol
"	O
to	O
transmit	O
data	O
and	O
therefore	O
is	O
not	O
classified	O
as	O
spread-spectrum	B-Architecture
.	O
</s>
<s>
The	O
5cm	O
band	B-Algorithm
is	I-Algorithm
shared	I-Algorithm
with	O
the	O
fixed-satellite	O
service	O
in	O
ITU	O
Region	O
1	O
,	O
and	O
the	O
radiolocation	B-Algorithm
service	O
.	O
</s>
<s>
In	O
ITU	O
Region	O
2	O
(	O
US	O
)	O
the	O
primary	O
user	O
is	O
military	O
radiolocation	B-Algorithm
,	O
specifically	O
naval	O
radar	B-Application
.	O
</s>
<s>
Amateur	O
radio	O
operators	O
have	O
secondary	O
privileges	O
to	O
the	O
Federal	O
radiolocation	B-Algorithm
service	O
in	O
the	O
entire	O
band	O
and	O
may	O
not	O
cause	O
interference	O
to	O
these	O
users	O
.	O
</s>
<s>
Amateur	O
operators	O
are	O
allocated	O
this	O
band	O
are	O
in	O
a	O
co-secondary	O
basis	O
with	O
ISM	B-Algorithm
devices	O
and	O
space	O
research	O
.	O
</s>
<s>
Amateur	O
,	O
space	O
research	O
,	O
and	O
ISM	B-Algorithm
operators	O
each	O
have	O
the	O
"	O
right	O
to	O
operate	O
"	O
.	O
</s>
<s>
Due	O
to	O
the	O
lack	O
of	O
a	O
high	O
number	O
of	O
Part	O
15	O
users	O
(	O
compared	O
to	O
2.4GHz	B-Algorithm
)	O
,	O
the	O
noise	O
level	O
tends	O
to	O
be	O
lower	O
in	O
many	O
parts	O
of	O
the	O
US	O
but	O
can	O
be	O
quite	O
congested	O
in	O
urban	O
centers	O
and	O
on	O
mountaintops	O
.	O
</s>
<s>
The	O
frequencies	O
from	O
5.6-5.65	O
GHz	O
(	O
channel	O
132	O
)	O
should	O
generally	O
be	O
avoided	O
to	O
prevent	O
interfering	O
with	O
TDWR	B-Algorithm
weather	O
radar	B-Application
stations	I-Application
.	O
</s>
<s>
The	O
13cm	O
band	B-Algorithm
is	I-Algorithm
shared	I-Algorithm
with	O
Part	O
15	O
users	O
as	O
well	O
as	O
the	O
Federal	O
radiolocation	B-Algorithm
service	O
,	O
and	O
ISM	B-Algorithm
(	O
industrial	O
,	O
scientific	O
,	O
medical	O
)	O
devices	O
.	O
</s>
<s>
Amateur	O
radio	O
operators	O
have	O
secondary	O
privileges	O
to	O
the	O
Federal	O
radiolocation	B-Algorithm
service	O
in	O
the	O
entire	O
band	O
and	O
may	O
not	O
cause	O
interference	O
to	O
these	O
users	O
.	O
</s>
<s>
Amateur	O
radio	O
operators	O
have	O
primary	O
privileges	O
to	O
ISM	B-Algorithm
devices	O
from	O
2.390	O
–	O
2.417GHz	O
and	O
secondary	O
privileges	O
from	O
2.417	O
–	O
2.450GHz	O
.	O
</s>
<s>
The	O
9cm	O
band	B-Algorithm
is	I-Algorithm
shared	I-Algorithm
with	O
fixed	O
services	O
and	O
space-to-Earth	O
communications	O
.	O
</s>
<s>
Amateur	O
radio	O
operators	O
using	O
this	O
band	O
may	O
not	O
cause	O
interference	O
to	O
other	O
licensed	O
users	O
,	O
including	O
government	O
radar	B-Application
stations	I-Application
.	O
</s>
<s>
One	O
acceptable	O
method	O
for	O
doing	O
so	O
is	O
to	O
transmit	O
one	O
's	O
call	O
sign	O
inside	O
an	O
ICMP	B-Protocol
echo	I-Protocol
request	I-Protocol
(	O
commonly	O
known	O
as	O
a	O
ping	B-Protocol
)	O
.	O
</s>
<s>
If	O
the	O
access	B-Device
point	I-Device
is	O
set	O
to	O
"	O
master	O
"	O
then	O
the	O
user	O
's	O
call	O
sign	O
may	O
be	O
set	O
as	O
the	O
"	O
SSID	B-General_Concept
"	O
and	O
therefore	O
will	O
be	O
transmitted	O
at	O
regular	O
intervals	O
.	O
</s>
<s>
It	O
is	O
also	O
possible	O
to	O
use	O
a	O
DDNS	B-Protocol
"	O
push	O
"	O
request	O
to	O
automatically	O
send	O
an	O
amateur	O
call	O
sign	O
in	O
plain	O
text	O
(	O
ASCII	B-Protocol
)	O
every	O
10	O
minutes	O
.	O
</s>
<s>
This	O
requires	O
that	O
a	O
computer	O
's	O
hostname	B-Protocol
be	O
set	O
to	O
the	O
call	O
sign	O
of	O
the	O
amateur	O
operator	O
and	O
that	O
the	O
DHCP	B-Protocol
servers	I-Protocol
lease	O
time	O
be	O
set	O
to	O
less	O
than	O
or	O
equal	O
to	O
10	O
minutes	O
.	O
</s>
<s>
With	O
this	O
method	O
implemented	O
the	O
computer	O
will	O
send	O
a	O
DNS	O
"	O
push	O
"	O
request	O
that	O
includes	O
the	O
local	O
computers	O
hostname	B-Protocol
every	O
time	O
the	O
DHCP	B-Protocol
lease	O
is	O
renewed	O
.	O
</s>
<s>
This	O
method	O
is	O
supported	O
by	O
all	O
modern	O
operating	O
systems	O
including	O
but	O
not	O
limited	O
to	O
Windows	B-Application
,	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
,	O
BSD	B-Operating_System
,	O
and	O
Linux	B-Application
.	O
</s>
<s>
Current	O
schemes	O
include	O
using	O
MAC	O
address	O
filtering	O
,	O
WEP	B-Protocol
and	O
WPA/WPA2	O
.	O
</s>
<s>
MAC	O
address	O
filtering	O
and	O
WEP	B-Protocol
are	O
all	O
hackable	O
by	O
using	O
freely	O
available	O
software	O
from	O
the	O
Internet	O
,	O
making	O
them	O
the	O
less	O
secure	O
options	O
.	O
</s>
<s>
Per	O
FCC	O
rules	O
the	O
encryption	O
keys	O
themselves	O
must	O
be	O
published	O
in	O
a	O
publicly	O
accessible	O
place	O
if	O
using	O
WEP	B-Protocol
,	O
WPA/WPA2	O
or	O
any	O
other	O
encryption	O
,	O
thereby	O
undermining	O
the	O
security	O
of	O
their	O
implementation	O
.	O
</s>
<s>
Using	O
professional	O
or	O
modified	O
hardware	O
it	O
is	O
possible	O
to	O
operate	O
on	O
802.11a	O
channels	O
that	O
are	O
outside	O
the	O
FCC	O
authorized	O
Part	O
15	O
bands	O
but	O
still	O
inside	O
the	O
5.8GHz	O
(	O
5cm	O
)	O
or	O
2.4GHz	B-Algorithm
(	O
13cm	O
)	O
amateur	B-Algorithm
radio	I-Algorithm
bands	I-Algorithm
.	O
</s>
<s>
Transverters	O
or	O
"	O
frequency	O
converters	O
"	O
can	O
also	O
be	O
used	O
to	O
move	O
HSMM	O
802.11b/g/n	O
operations	O
from	O
the	O
2.4GHz	B-Algorithm
(	O
13cm	O
)	O
band	O
to	O
the	O
3.4GHz	O
(	O
9cm	O
)	O
amateur	B-Algorithm
radio	I-Algorithm
band	I-Algorithm
.	O
</s>
<s>
In	O
the	O
past	O
it	O
used	O
to	O
be	O
easy	O
to	O
use	O
modified	O
consumer	O
grade	O
hardware	O
to	O
operate	O
802.11	O
on	O
channels	O
that	O
are	O
outside	O
of	O
the	O
normal	O
FCC	O
allocated	O
frequencies	O
for	O
unlicensed	O
users	O
but	O
still	O
inside	O
an	O
amateur	B-Algorithm
radio	I-Algorithm
band	I-Algorithm
.	O
</s>
<s>
The	O
newer	O
Linux	B-Application
drivers	O
implement	O
that	O
prevents	O
a	O
casual	O
user	O
from	O
operating	O
outside	O
of	O
the	O
country-specific	O
operating	O
bands	O
.	O
</s>
<s>
Frequency	O
conversion	O
involves	O
the	O
use	O
of	O
transverters	O
that	O
convert	O
the	O
operating	O
frequency	O
of	O
the	O
802.11b/g	O
device	O
from	O
2.4GHz	B-Algorithm
to	O
another	O
band	O
entirely	O
.	O
</s>
<s>
Commercially	O
available	O
converters	O
can	O
convert	O
a	O
2.4GHz	B-Algorithm
802.11b/g	O
signal	O
to	O
the	O
3.4GHz	O
(	O
9cm	O
)	O
band	O
which	O
is	O
not	O
authorized	O
for	O
unlicensed	O
Part	O
15	O
users	O
.	O
</s>
<s>
The	O
3.5GHz	O
band	O
is	O
currently	O
used	O
for	O
DoD	O
or	O
Navy	O
(	O
shipborne	O
and	O
ground-based	O
)	O
radar	B-Application
operations	O
and	O
covers	O
60	O
percent	O
of	O
the	O
U.S.	O
population	O
.	O
</s>
<s>
These	O
frequencies	O
are	O
outside	O
of	O
the	O
FCC-allocated	O
Part	O
15	O
unlicensed	O
band	O
,	O
but	O
still	O
inside	O
of	O
the	O
5.8GHz	O
(	O
5cm	O
)	O
amateur	B-Algorithm
radio	I-Algorithm
band	I-Algorithm
.	O
</s>
<s>
Modifying	O
consumer	O
hardware	O
to	O
operate	O
on	O
these	O
expanded	O
channels	O
often	O
involves	O
installing	O
after-market	O
firmware	B-Application
and/or	O
changing	O
the	O
"	O
country	O
code	O
"	O
setting	O
of	O
the	O
wireless	O
card	O
.	O
</s>
<s>
One	O
popular	O
way	O
to	O
access	O
amateur-only	O
frequencies	O
is	O
to	O
modify	O
an	O
off-the-shelf	O
access	B-Device
point	I-Device
with	O
custom	O
firmware	B-Application
.	O
</s>
<s>
This	O
custom	O
firmware	B-Application
is	O
freely	O
available	O
on	O
the	O
Internet	O
from	O
projects	O
such	O
as	O
DD-WRT	B-Protocol
and	O
OpenWrt	B-Application
.	O
</s>
<s>
The	O
AREDN	O
Project	O
supports	O
off-the-shelf	O
firmware	B-Application
that	O
supports	O
Part-97-only	O
frequencies	O
on	O
Ubiquiti	O
and	O
TP-Link	O
hardware	O
.	O
</s>
<s>
A	O
popular	O
piece	O
of	O
hardware	O
that	O
is	O
modified	O
is	O
the	O
Linksys	O
WRT54GL	B-Application
because	O
of	O
the	O
widespread	O
availability	O
of	O
both	O
the	O
hardware	O
and	O
third-party	O
firmware	B-Application
,	O
however	O
,	O
the	O
Linksys	O
hardware	O
is	O
not	O
frequency	O
agile	O
due	O
to	O
the	O
closed	O
nature	O
of	O
the	O
Linksys	O
drivers	O
.	O
</s>
