<s>
Wireless	B-General_Concept
grids	I-General_Concept
are	O
wireless	O
computer	O
networks	O
consisting	O
of	O
different	O
types	O
of	O
electronic	O
devices	O
with	O
the	O
ability	O
to	O
share	O
their	O
resources	O
with	O
any	O
other	O
device	O
in	O
the	O
network	O
in	O
an	O
ad	O
hoc	O
manner	O
.	O
</s>
<s>
The	O
technologies	O
that	O
make	O
up	O
the	O
wireless	B-General_Concept
grid	I-General_Concept
can	O
be	O
divided	O
into	O
two	O
main	O
categories	O
;	O
ad	B-Protocol
hoc	I-Protocol
networking	I-Protocol
and	O
grid	B-Architecture
computing	I-Architecture
.	O
</s>
<s>
In	O
traditional	O
networks	O
,	O
both	O
wired	O
and	O
wireless	O
,	O
the	O
connected	O
devices	O
,	O
or	O
nodes	O
,	O
depend	O
on	O
dedicated	O
devices	O
(	O
edge	B-Device
devices	I-Device
)	O
such	O
as	O
routers	O
and/or	O
servers	O
for	O
facilitating	O
the	O
throughput	O
of	O
information	O
from	O
one	O
node	O
to	O
the	O
other	O
.	O
</s>
<s>
They	O
give	O
out	O
names	O
and	O
addresses	O
(	O
IP	B-Protocol
addresses	I-Protocol
)	O
to	O
each	O
connected	O
node	O
and	O
regulate	O
the	O
traffic	O
between	O
them	O
.	O
</s>
<s>
In	O
wireless	B-General_Concept
grids	I-General_Concept
,	O
such	O
dedicated	O
routing	O
devices	O
are	O
not	O
(	O
always	O
)	O
available	O
and	O
the	O
bandwidth	O
that	O
is	O
permanently	O
available	O
to	O
traditional	O
networks	O
has	O
to	O
be	O
either	O
'	O
borrowed	O
 '	O
from	O
an	O
already	O
existing	O
network	O
or	O
publicly	O
accessible	O
bandwidth	O
(	O
open	B-Algorithm
spectrum	I-Algorithm
)	O
has	O
to	O
be	O
used	O
.	O
</s>
<s>
A	O
group	O
addressing	O
this	O
problem	O
is	O
MANET	B-General_Concept
(	O
Mobile	B-General_Concept
Ad	I-General_Concept
Hoc	I-General_Concept
Network	I-General_Concept
)	O
.	O
</s>
<s>
One	O
of	O
the	O
intended	O
aspects	O
of	O
wireless	B-General_Concept
grids	I-General_Concept
is	O
that	O
it	O
will	O
facilitate	O
the	O
sharing	O
of	O
a	O
wide	O
variety	O
of	O
resources	O
.	O
</s>
<s>
Ad	O
hoc	O
resource	O
sharing	O
between	O
mobile	O
devices	O
in	O
the	O
wireless	B-General_Concept
grid	I-General_Concept
require	O
for	O
the	O
devices	O
to	O
agree	O
on	O
sharing/communication	O
protocols	O
without	O
the	O
existence	O
of	O
dedicated	O
servers	O
.	O
</s>
<s>
Examples	O
of	O
such	O
mechanisms	O
are	O
:	O
SMB	B-Operating_System
or	O
NFS	B-Protocol
for	O
sharing	O
disk	O
space	O
and	O
the	O
distributed.net	O
client	O
for	O
sharing	O
processor	O
cycles	O
.	O
</s>
<s>
There	O
are	O
systems	O
currently	O
in	O
operation	O
that	O
can	O
provide	O
a	O
certain	O
amount	O
of	O
trust	O
like	O
the	O
public	B-Architecture
key	I-Architecture
infrastructure	I-Architecture
that	O
makes	O
use	O
of	O
certificates	O
;	O
now	O
often	O
used	O
in	O
web	O
based	O
email	O
systems	O
,	O
and	O
Kerberos	B-Protocol
.	O
</s>
<s>
When	O
a	O
client	O
enters	O
the	O
grid	O
,	O
such	O
as	O
a	O
PDA	B-Application
,	O
it	O
has	O
to	O
be	O
able	O
to	O
communicate	O
to	O
the	O
other	O
users	O
that	O
it	O
is	O
a	O
PDA	B-Application
and	O
it	O
has	O
a	O
camera	O
,	O
GPS	O
capabilities	O
,	O
a	O
telephone	O
function	O
and	O
various	O
office	O
applications	O
such	O
as	O
a	O
text	B-Application
editor	I-Application
.	O
</s>
<s>
Protocols	O
like	O
UPnP	B-Application
and	O
zeroconf	B-Application
can	O
detect	O
a	O
new	O
node	O
in	O
the	O
network	O
when	O
it	O
enters	O
.	O
</s>
<s>
Commercial	O
service	O
providers	O
can	O
'	O
advertise	O
 '	O
the	O
resources	O
they	O
have	O
to	O
offer	O
through	O
IP	B-Protocol
multicasts	I-Protocol
.	O
</s>
<s>
Standards	O
as	O
IETF	O
's	O
zeroconf	B-Application
,	O
Microsoft	O
's	O
UPnP	B-Application
,	O
the	O
Grid	O
Resource	O
Description	O
Language	O
(	O
GRDL	O
)	O
,	O
the	O
Web	O
Services	O
Description	O
Language	O
(	O
WSDL	O
)	O
for	O
describing	O
various	O
specific	O
web	O
services	O
and	O
parts	O
of	O
QoS	O
that	O
describe	O
bandwidths	O
all	O
offer	O
devices	O
a	O
way	O
to	O
describe	O
and	O
publish	O
their	O
specific	O
resources	O
and	O
needs	O
.	O
</s>
<s>
The	O
OpenGrid	O
Services	O
Architecture	O
(	O
OGSA	B-Operating_System
)	O
uses	O
a	O
Web	O
service-style	O
IndexService	O
.	O
</s>
<s>
The	O
Web	O
services	O
community	O
has	O
defined	O
UDDI	O
which	O
can	O
makes	O
a	O
database	O
of	O
services	O
that	O
are	O
available	O
on	O
the	O
network	O
,	O
and	O
JXTA	B-Language
uses	O
zeroconf	B-Application
to	O
identify	O
resources	O
in	O
a	O
network	O
.	O
</s>
<s>
However	O
,	O
the	O
problem	O
with	O
using	O
these	O
in	O
wireless	B-General_Concept
grids	I-General_Concept
is	O
that	O
no	O
stable	O
publisher	O
of	O
these	O
descriptions	O
may	O
exist	O
.	O
</s>
<s>
Grid	B-Architecture
computing	I-Architecture
came	O
into	O
existence	O
as	O
a	O
manner	O
of	O
sharing	O
heavy	O
computational	O
loads	O
among	O
multiple	O
computers	O
to	O
be	O
able	O
to	O
compute	O
highly	O
complex	O
mathematical	O
problems	O
(	O
a	O
good	O
real-world	O
example	O
being	O
the	O
SETI	B-Application
@Home	I-Application
project	O
)	O
.	O
</s>
<s>
Wired	O
grids	O
are	O
now	O
used	O
to	O
share	O
not	O
only	O
computing	O
power	O
,	O
but	O
also	O
hard	B-Device
disk	I-Device
space	O
,	O
data	O
,	O
and	O
applications	O
.	O
</s>
<s>
The	O
goal	O
of	O
grid	B-Architecture
computing	I-Architecture
is	O
described	O
as	O
"	O
to	O
provide	O
flexible	O
,	O
secure	O
and	O
coordinated	O
resource	O
sharing	O
among	O
dynamic	O
collections	O
of	O
individuals	O
,	O
institutions	O
and	O
resources	O
"	O
(	O
McKnight	O
,	O
Howison	O
,	O
2004	O
)	O
.	O
</s>
<s>
there	O
is	O
the	O
need	O
for	O
a	O
hub	O
or	O
a	O
switch	B-Protocol
to	O
plug	O
into	O
)	O
.	O
</s>
<s>
Argawal	O
,	O
Norman	O
&	O
Gupta	O
(	O
2004	O
)	O
identify	O
three	O
forces	O
that	O
drive	O
the	O
development	O
of	O
the	O
wireless	B-General_Concept
grid	I-General_Concept
:	O
</s>
<s>
Applications	O
that	O
exist	O
on	O
current	O
wired	O
grids	O
need	O
to	O
be	O
adapted	O
to	O
fit	O
the	O
devices	O
used	O
in	O
wireless	B-General_Concept
grids	I-General_Concept
.	O
</s>
<s>
These	O
devices	O
are	O
usually	O
hand	O
held	O
and	O
therefore	O
the	O
user	O
interface	O
devices	O
(	O
screens	O
,	O
keyboards	O
(	O
if	O
any	O
)	O
)	O
are	O
significantly	O
smaller	O
and	O
availability	O
of	O
additional	O
input	O
devices	O
like	O
a	O
mouse	B-Device
are	O
limited	O
.	O
</s>
<s>
The	O
infrastructure	O
of	O
the	O
wireless	B-General_Concept
grid	I-General_Concept
consists	O
of	O
three	O
basic	O
levels	O
:	O
</s>
<s>
The	O
physical	B-Application
layer	I-Application
technologies	O
and	O
policies	O
.	O
</s>
<s>
The	O
physical	B-Application
layer	I-Application
contains	O
the	O
spectrum	O
on	O
which	O
the	O
wireless	O
devices	O
can	O
operate	O
and	O
communicate	O
.	O
</s>
