Internati
o
nal
Journal of Ele
c
trical
and Computer
Engineering
(IJE
CE)
V
o
l.
6, N
o
. 3
,
Ju
n
e
201
6, p
p
. 1
072
~ 10
76
I
S
SN
: 208
8-8
7
0
8
,
D
O
I
:
10.115
91
/ij
ece.v6
i
3.9
843
1
072
Jo
urn
a
l
h
o
me
pa
ge
: h
ttp
://iaesjo
u
r
na
l.com/
o
n
lin
e/ind
e
x.ph
p
/
IJECE
Special Features of Radio
Interception of APCO P25
Messages in Russia
D
m
it
ry
S
e
rg
ee
v
i
c
h
S
ilno
v
Departm
e
nt o
f
I
n
form
ation S
y
s
t
em
s
and T
echno
logies
,
Nation
a
l
Res
earch
Nucl
ea
r Univers
i
t
y
M
E
P
h
I
(Moscow Engin
eering
Ph
y
s
i
c
s I
n
stitute)
,
Mosco
w
, Russia
Article Info
A
B
STRAC
T
Article histo
r
y:
Received Oct 12, 2015
Rev
i
sed
D
ec 30
, 20
15
Accepte
d
Ja
n 10, 2016
Ma
ny
spec
ia
l forc
e
s
in Russia use
AP
CO P25 encoding while r
a
dio talks.
Using google sp
eech or
y
a
ndex speechk
it while d
ecoding rad
i
o tal
k
s can give
huge advantage. Search engines
can i
ndex deco
ded text or knowledge base
can b
e
cre
a
ted
.
Keyword:
A
p
co
p2
5
Google Speech
Rad
i
o
In
terceptio
n
Yande
x
Speec
hkit
Copyright ©
201
6 Institut
e
o
f
Ad
vanced
Engin
eer
ing and S
c
i
e
nce.
All rights re
se
rve
d
.
Co
rresp
ond
i
ng
Autho
r
:
Dm
itry
Sergee
vich
Silno
v
,
Depa
rt
m
e
nt
of
In
fo
rm
at
i
on Sy
st
em
s and
Tec
h
n
o
l
o
gi
es,
Natio
n
a
l Research Nu
clear
Un
iv
ersity MEPh
I (Moscow
En
g
i
n
eeri
n
g Ph
ysics In
stitu
te),
Kashi
r
skoe
sh.
31, Moscow, Russian Fe
derati
on.
Em
a
il: d
s
@siln
ov
.pro
1.
INTRODUCTION
Am
ateur radio as a hobby appeare
d
a ve
ry long tim
e
ago,
lon
g
be
fo
re w
e
saw the first
com
puters
.
Until recently,
airwa
v
es interc
eption
was
a c
o
m
p
licated tas
k
re
qui
ring profe
ssional skills in radi
o electronic
s
along with high
c
o
sts of
the
equi
pm
ent capable
of receivi
ng wa
ves
in wi
de fre
que
ncy
ranges. Mainly, thi
s
co
stly p
a
stim
e
n
o
rm
all
y
b
o
iled
d
o
wn
to listen
i
ng
to th
e tal
k
s b
e
t
w
een p
ilo
t
s
and
traffic con
t
ro
llers.
2.
TASK RES
C
RIPTIO
N
Wh
en
th
e C
h
in
ese USB TV
tu
n
e
rs bu
ilt o
n
th
e RTL28
3
2
ch
ip
ap
p
e
ared
, ev
eryth
i
n
g
b
e
ca
m
e
m
u
ch
easi
e
r. It
beca
m
e
possi
bl
e t
o
b
u
i
l
d
an i
n
e
xpe
nsi
v
e radi
o
waves sca
nne
r wi
t
h
o
u
t
pay
i
ng a l
o
t
.
A
n
d
radi
o
in
tercep
tion
is n
o
long
er li
mited
b
y
liste
n
i
ng
to
th
e
air talk
s. Tod
a
y, p
o
rtab
le
transceive
rs are
used
every
w
he
re
by
every
m
uni
ci
pal
ser
v
i
ce,
fr
om
bui
l
d
ers a
n
d t
a
xi
dri
v
ers t
o
al
l
ki
n
d
s
of
ope
rat
i
o
nal
ag
enci
es
,
suc
h
as t
h
e M
i
ni
st
ry
o
f
Em
ergency
Si
t
u
at
i
o
ns, t
h
e p
o
l
i
ce,
and
ot
he
r
go
ve
rnm
e
nt
al
orga
n
i
zat
i
ons. T
h
e c
u
r
r
ent
situ
atio
n
in
R
u
ssia is th
at
m
o
st rad
i
o
talk
s are no
t en
cr
yp
ted
at all. En
cry
p
tio
n
is
o
b
lig
at
o
r
y on
ly for the rad
i
o
contacts
of Fe
deral
Security Service and
ot
her special
fo
rces th
at the
n
a
tio
n
a
l security d
e
p
e
nd
s
on
,
but th
o
s
e
talk
s on
ly m
a
k
e
a sm
all p
a
rt of th
e to
tal vo
lume o
f
t
h
e rad
i
o con
t
acts in
t
h
e cou
n
t
ry.
Let’s see how
we can
u
s
e a
USB TV tun
e
r to
m
a
k
e
an
inex
p
e
n
s
i
v
e an
d h
i
gh-qu
ality rad
i
o wav
e
s
in
tercep
t
o
r.
A
USB t
u
n
e
r
with
an
RTL28
32 ch
ip is t
h
e
h
a
r
d
w
a
r
e
th
a
t
r
e
ce
iv
e
s
th
e s
i
gn
al.
T
h
e s
i
gn
a
l
ca
n
b
e
bot
h anal
og
ue
or
di
gi
t
a
l
.
I
n
c
a
se of a
di
gi
t
a
l
si
gnal
,
t
h
e dec
odi
ng i
s
d
one
by
t
h
e C
P
U
o
f
t
h
e com
put
er t
h
at
t
h
e
USB
receive
r i
s
connected wi
th. P25/DMR/
Mototrbo/
NXDN/ProVoice signal form
at
s
can be dec
ode
d
t
h
ere
[1]
.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
J
ECE
I
S
SN
:
208
8-8
7
0
8
Speci
al
Fe
at
ur
es of
R
a
di
o
I
n
t
e
rcept
i
o
n
of
A
P
C
O
P
2
5 Mes
sag
e
s i
n
R
u
si
a
(
Dmi
t
r
y Se
rgee
vi
ch Si
l
n
ov)
1
073
Ori
g
inally, the
receive
r s
p
eci
fications
show unde
rsta
ted values. B
u
t actually, the recei
ver is a
b
le to
get
not
only T
V
si
gnals; t
h
e
receiva
ble fre
q
uency
ra
nge
is
ve
ry wi
de a
n
d
provides
sol
u
tions for nearly
all
ki
n
d
s o
f
t
a
sks
fo
r ra
di
o am
ateurs
. The
onl
y
possi
bl
e l
i
m
itat
i
on o
f
t
h
e re
cei
vabl
e f
r
eq
u
e
nci
e
s i
s
t
h
e ant
e
n
n
a
bundled
with the tuner. Th
e a
n
tenna supplied by the m
a
nufacturer is
only intende
d for
hi
gh-quality
recepti
on
o
f
th
e TV
r
a
nge f
r
e
qu
en
cies, so
sign
als o
f
an
y o
t
h
e
r
r
a
ng
es can
no
t b
e
receiv
ed
with
the
sam
e
efficiency. But
t
h
i
s
can be eas
i
l
y
resol
v
ed by
repl
aci
n
g
t
h
e ant
e
n
n
a wi
t
h
a
not
her
one d
e
s
i
gne
d f
o
r rece
pt
i
on
of t
h
e re
qui
red
fre
que
ncy
ran
g
e
.
B
e
fo
re,
one
ha
d t
o
use
p
o
rt
a
b
l
e
t
r
an
scei
ve
r
s
t
o
per
f
o
r
m
the re
q
u
i
r
e
d
t
a
s
k
s a
n
d
set
t
h
e
fre
que
nci
e
s
manually to receive signals, and th
e
output
signal was analogue
, whi
c
h
resulted in low ove
r
all quality.
Besid
e
s, th
ey u
s
ed
sp
ecial rad
i
o
eq
u
i
p
m
en
t
th
at allo
ws listen
i
ng
to
bo
th
an
alog
u
e
and
d
i
g
ital sig
n
a
ls, bu
t th
e
cost
of t
h
i
s
t
y
pe
of
eq
ui
pm
ent
i
s
very
hi
g
h
,
s
o
no
o
r
di
nar
y
radi
o am
at
eur c
oul
d e
v
er
af
fo
rd
i
t
.
B
u
t
n
o
w
t
h
e
si
t
u
at
i
on
has
c
h
an
ge
d:
usi
n
g
a chea
p
USB
TV t
une
r,
we
can a
u
t
o
m
a
t
i
c
al
l
y
set
t
h
e de
si
red
f
r
eq
ue
nci
e
s ve
ry
q
u
i
ck
ly and
receiv
e
orig
i
n
al
d
i
g
ital sign
als
with
n
o
qu
ality lo
sses.
3.
SOLUTION
On
e
of th
e featu
r
es
of a USB tu
n
e
r is th
e ab
ility
to
bu
ild
a syste
m
fo
r in
tercep
tio
n
of tru
n
k
n
e
t
w
orks
wh
ere th
e in
tercep
tion
qu
ality b
eco
m
e
s a f
e
w ti
m
e
s b
e
tte
r. As tru
n
k
n
e
twork
s
are in
ten
d
e
d
fo
r talk
i
n
g
at
di
ffe
re
nt
fre
qu
enci
es an
d o
n
e
cann
o
t
k
n
o
w
whi
c
h fre
q
u
en
cy
i
s
chosen
b
y
t
h
e base st
at
ion
,
y
ou ca
nn
ot
go t
h
e
classical way to
in
tercep
t su
ch
talk
s b
y
sim
p
ly settin
g
on
e certain
freq
u
e
n
c
y.
To l
i
s
t
e
n i
n
t
o
t
a
l
k
s o
v
e
r
t
r
u
n
k
net
w
o
r
k
s
,
we
have t
o
us
e t
w
o
USB
t
u
ners
. E
v
ery
t
u
ner
sh
o
u
l
d
be
co
nn
ected with a sp
litter to a
co
mm
o
n
an
tenn
a,
o
r
two
an
ten
n
a
s sh
ou
ld b
e
u
s
ed
,
with
every tun
e
r con
n
ected
to its own a
n
t
e
nna
. The
Unitrunke
r app is use
d
to inte
rce
p
t trunk
networks
. It allows
setting each tuner t
o
perform
specific tasks. One of the USB
tune
rs is adjuste
d
to work as the signal recei
ver, and the a
pp
us
es it to
get a list of c
u
rrently active c
h
annels.
Using the ot
her t
une
r, the a
pp
direct
ly recei
ves the
sound signal from
a
certain
chann
e
l. Th
is allows au
to
m
a
tin
g
th
e in
tercep
tion
of all th
e ch
ann
e
ls
o
f
a
sp
ecific tru
n
k
n
e
two
r
k
au
to
m
a
tic, with
n
o
n
e
ed
t
o
set th
e ch
ann
e
ls
man
u
a
lly.
To m
a
ke t
h
e i
n
t
e
rcept
i
o
n,
rec
o
r
d
i
n
g a
n
d
dec
odi
ng
p
r
o
c
ess
au
to
m
a
tic in
case of d
i
g
ital tal
k
s,
we
h
a
v
e
t
o
b
u
i
l
d
a
sy
st
em
of
vari
ous
soft
ware t
ool
s
t
h
at
d
o
not
re
qui
re any
pe
r
m
anent
ad
j
u
st
m
e
nt
s or
co
nt
r
o
l
.
T
h
e
soft
ware t
o
ol
s
i
n
cl
ude:
a
pps
t
o
co
nfi
g
u
r
e t
h
e U
S
B
t
une
r
and
get
t
h
e si
gnal
f
r
o
m
it
, an ap
p t
o
deco
de t
h
e
d
i
g
ital sign
al,
an
d a sp
ecial
dr
iv
er ap
p to
r
e
d
i
r
ect th
e
o
u
t
pu
t aud
i
o
sign
al
f
r
o
m
th
e sound
car
d
ter
m
in
al
to
t
h
e
audi
o st
ream
d
ecode
r. T
h
e
Wi
nd
ows
OS i
s
not
s
u
i
t
a
bl
e
for b
u
ild
ing
su
ch
a syste
m
,
beca
use there a
r
e a lot of
im
portant tool
s designe
d
as
applica
tions with visual i
n
terface and
requi
r
ing that a
human operator
shoul
d
d
i
rectly con
f
i
g
u
r
e th
em
. Bu
t
wh
en
t
h
e
PC reb
o
o
t
s, it w
ill b
e
requ
ired
t
o
restart
a
ll th
e ap
p
s
an
d recon
f
ig
ure
them
from
the very
be
gin
n
in
g
.
It is m
o
re
pre
f
er
a
b
le to
build suc
h
a
system
base
d
on Free
BSD.
FreeB
S
D
al
l
o
ws usi
ng
read
y
-
t
o
-
u
se so
ft
w
a
re t
ool
s re
q
u
i
r
ed f
o
r i
n
t
e
rce
p
t
i
on
of ra
di
o
waves a
n
d
savi
n
g
t
h
e
resu
l
t
s
. The sy
st
em
i
s
l
a
unche
d
wi
t
h
a si
ngl
e c
o
m
m
a
nd and
re
qui
res n
o
hum
an i
n
vol
vem
e
nt
i
n
t
h
e
ope
rat
i
o
n. T
h
i
s
sy
st
em
al
l
o
ws com
p
l
e
t
e
aut
o
m
a
t
i
on of t
h
e r
a
di
o
wave
s i
n
t
e
rcept
i
o
n
pr
oc
ess an
d al
so sa
vi
n
g
th
e in
tercep
ted resu
lts. Th
ere h
a
v
e
b
een some si
m
i
lar
so
l
u
tio
ns
b
e
fo
re,
b
u
t
t
h
ey cou
l
d on
ly retran
smit th
e
so
und
to v
a
riou
s
web
s
ites
wi
th
ou
t th
e
po
ssi
b
ility to
listen
to
th
e talk
s h
i
sto
r
y. Th
e system
p
r
o
d
u
ces
read
-t
o
-
u
s
e au
d
i
o
files
wh
ich
allow ed
itin
g
and
im
p
r
ov
ing
t
h
e so
un
d qu
ality, savin
g
t
h
e
d
a
ta, an
d rep
l
ayin
g the aud
i
o
fi
l
e
s at
any
m
o
m
e
nt
. Let
’
s
des
c
ri
be eac
h a
p
p
i
n
t
h
e
pac
k
a
g
e
separat
e
l
y
.
Rtl_
fm
. Th
is
u
tility
is d
e
sign
ed
for op
eratin
g
d
i
r
ectly with
a USB tun
e
r. It is u
s
ed to
set th
e
o
p
e
rating
frequ
en
cy, th
e sh
ift, th
e p
a
ram
e
te
rs o
f
th
e reco
rd
ed
so
und
, and
to
ad
ju
st some o
t
h
e
r settin
g
s
. Th
e
o
u
t
p
u
t
is a so
un
d file in its orig
in
al cond
ition
.
SOX. Th
is is
a
m
u
ltitask
u
tility fo
r soun
d file p
r
o
cessi
ng
.
We inpu
t a sou
n
d
file in
its o
r
ig
i
n
al
co
nd
itio
n, as t
a
k
e
n
fro
m
th
e USB tun
e
r, in
t
o
th
e
u
tility. T
h
e soun
d
is con
v
e
rted
d
e
p
e
nd
ing
on
th
e selected
p
a
r
a
m
e
ter
s
. H
e
r
e
w
e
h
a
v
e
W
A
V
as th
e so
un
d
f
ile f
o
r
m
at.
Th
en
it is u
s
ed
f
o
r
f
u
r
t
h
e
r
p
r
ocessin
g
o
f
th
e
sound
file; it h
a
s filters for
h
i
gh
an
d
lo
w
frequ
en
ci
es
and
allows rem
o
v
i
n
g
n
o
i
ses o
r
p
a
u
s
es.
DSD. This
utility is used if receivi
ng
an
encode
d
si
gna
l. The e
n
c
o
de
d signal is l
o
a
d
ed into the
u
tility, an
d
it
produ
ces a
d
e
cod
e
d aud
i
o signal th
at can b
e
listen
e
d to
on
line and
sav
e
d
.
The c
o
mm
and that launc
h
es
the system
when re
a
d
y-t
o
-listen
WAV
files are
create
d
. Each fil
e
co
n
t
ains ind
i
v
i
d
u
a
l talk
s t
h
at can
b
e
sep
a
rated
with
t
h
e SOX
u
tility wh
ich
fi
n
d
s
t
h
e fra
m
e
s o
f
ev
ery
talk
according t
o
the pa
uses:
rtl_fm
-M
fm
-f $
1
-d
0
-
p
2
2
-s
4
8
k
-F
9
-
E
deem
p | \
sox
-
v
5.
0 -r
4
8
k
-e
sig
n
e
d
-i
nteger
-c 1 -
b
16
-t
ra
w -
-t wa
v -
|
\
d
s
d -u
1
-v99
-i /d
ev
/std
i
n
-o /d
ev
/st
d
ou
t | \
sox
-v 5
.
0 -e s
i
gne
d-i
n
t
e
ge
r -
r
80
0
0
-c 1 -
b
16 -t
ra
w - $cur
di
r/
$
1
_
$
D
T/
$1
.wa
v
si
l
e
nce
1 0.
30 1
%
10.3 1%
Evaluation Warning : The document was created with Spire.PDF for Python.
I
S
SN
:
2
088
-87
08
IJEC
E
V
o
l
.
6,
No
. 3,
J
u
ne 2
0
1
6
:
10
7
2
– 10
76
1
074
If t
h
e system
man
a
g
e
s t
o
p
r
o
d
u
ce aud
i
o files with th
e
d
e
sired
qu
ality, th
e n
e
x
t
feat
u
r
e is reco
gn
iti
on
o
f
t
h
e sp
eech
in
th
e aud
i
o
files an
d g
e
tting
th
e
scri
p
t
of th
e co
nv
ersatio
n
s
. To
do
so, we
u
s
e t
h
ird-p
a
rty
services
, s
u
ch
as Ya
ndex Spe
ech
Kit
or Google Sp
eech (Figure
1).
Fi
gu
re
1.
Dec
o
di
n
g
ci
rc
ui
t
v
o
i
ce cal
l
s
Wh
en
testing
th
e system
, we
man
a
g
e
d
t
o
in
t
e
rcep
t talk
s at
v
a
ri
o
u
s
frequ
en
cies. Th
e soft
ware too
l
s
receiving the data from
the USB tuner allow visual dem
ons
tration of the c
u
rrently
active freque
n
cies of the
rad
i
o
tran
sm
iss
i
o
n
,
with th
e
peak
s
o
n
th
e
grap
h showing
th
e talk
s wh
ich are in
p
r
o
g
ress at th
e m
o
m
e
n
t
. When
a fre
que
ncy with talks curre
n
tly in progres
s
is select
ed, the signal is be
ing recei
ved a
nd t
h
e talks can be
listen
e
d
to in th
e
real tim
e
mo
d
e
. Th
e
gr
aphs show
t
h
at th
e sign
als
h
a
v
e
per
f
ect
po
w
e
r
lev
e
ls an
d allow d
a
t
a
reception with no
losses
(Figure
2).
Fi
gu
re
2.
Pea
k
s o
f
e
n
co
de
d si
gnal
s
The talks at the freque
n
cies arou
nd
452 MHz are of grea
test intere
st to detache
d
radi
o am
ateurs
(Fi
g
ure
3)
. Thi
s
i
s
t
h
e fre
que
ncy
use
d
by
va
ri
o
u
s di
vi
si
on
s
of t
h
e
pol
i
ce,
roa
d
t
r
af
fi
c co
nt
r
o
l
depa
rt
m
e
nt
an
d
non-de
partm
e
ntal security services.
And
des
p
ite the fact
t
h
at th
e talk
s are transm
i
tted
in
en
cryp
ted
dig
ital
form
at (P2
5
Stan
d
a
rd
[2
]-[4
]
), th
e
USB tun
e
r allows receiv
in
g
t
h
e sign
al with
h
i
g
h
q
u
a
lity with
out an
y
lo
sses,
wh
ich giv
e
s an
yon
e the po
ssib
ility to
easily r
ead
,
d
e
co
d
e
and
listen to
th
e talk
s
righ
t away.
Fi
gu
re 3.
St
re
n
g
t
h
o
f
45
2.
4
0
0
si
gnal
Evaluation Warning : The document was created with Spire.PDF for Python.
I
J
ECE
I
S
SN
:
208
8-8
7
0
8
Speci
al
Fe
at
ur
es of
R
a
di
o
I
n
t
e
rcept
i
o
n
of
A
P
C
O
P
2
5 Mes
sag
e
s i
n
R
u
si
a
(
Dmi
t
r
y Se
rgee
vi
ch Si
l
n
ov)
1
075
Th
e on
ly p
r
o
b
l
e
m
th
at
may
i
m
p
e
d
e
th
e reco
gn
itio
n
o
f
th
e talk
s is
th
e q
u
ality
o
f
th
e resu
ltin
g
aud
i
o
file. For in
stance, th
is m
a
y
o
ccu
r as a
resu
lt o
f
ind
i
s
tinct pronunciation, prese
n
ce
o
f
ex
tern
al no
ise in
the
wave
s o
r
l
o
w
vol
um
e. In t
h
i
s
case, t
h
e
voi
c
e
m
a
y
not
be
recognized
or recognized
im
p
r
op
erly [5
]. The
SOX
u
tility al
lo
ws re
m
o
v
i
ng
th
e
fau
lts o
f
th
e
resultin
g
aud
i
o
file b
y
m
ean
s o
f
usin
g
t
h
e bu
ilt-in
filters and
editing
th
e vo
lu
m
e
level.
We also
h
a
v
e
th
e
p
o
ssi
b
ility
to
run th
e serv
ice
on
a rem
o
te serv
er co
m
p
u
t
er,
with a
USB t
u
n
e
r
connected to it. Radi
o
wa
ves
can
be i
n
terce
p
ted the
n
on
a
client PC
with internet
acces
s from
any c
o
rner
of
th
e g
l
o
b
e
[6
]. In
th
is case,
we
u
s
e the rtl_
tcp
u
tility:
it sh
ou
ld
b
e
laun
ch
ed
o
n
th
e serv
er co
m
p
u
t
er as a serv
ice,
the client gets
connected and
receives t
h
e si
gnal
from
the USB tuner in i
t
s pure form
. If necessa
ry, the
signal
can
be
deco
de
d a
n
d
l
i
s
t
e
ned
t
o
on
t
h
e cl
i
e
nt
si
de.
Exam
ple of t
h
e
service laun
c
h
on a
server com
puter:
r
tl_
tcp
-
a
8
8
.1
51
.1
17
.13
6
-d
1
-
p
123
45
.
Talks e
x
am
ples:
–
One
t
e
n,
w
h
a
t
’s u
p
?
– Te
nt
h
an
d
ni
nt
h,
t
h
ree
bi
kes
an
d a
pa
rki
n
g
.
–
Zero zero
,
stir
u
p
th
e
p
a
rk
ing
an
d loo
k
at t
h
e tin
ting
.
– T
w
o se
ven
t
h
ree, M
y
t
i
s
hc
hi
,
t
w
o
se
ven
t
h
re
e.
– T
w
o se
ven
t
h
ree,
here
.
– S
u
bway
b
r
i
d
ge,
n
o
di
rect
i
o
n, a
bl
ac
k B
e
nt
l
e
y
,
a h
u
n
d
r
ed
and
t
h
ree
di
gi
t
a
l
,
hea
d
-
o
n cr
a
s
h.
–
Go
t
it.
–
Kal
u
ga
Kal
u
ga,
si
x ze
ro
t
w
o,
o
n
e t
o
t
h
e
h
ous
e, y
o
u
cal
l
e
d a
sq
ua
d
?
– Yeah
, we di
d
.
– Proceed to
Dons
kaya, I
got
the house, there’s a
unit working i
n
the
stree
t
, chec
k it
out.
–
Go
t
it.
4.
CO
NCL
USI
O
N
B
u
y
i
ng a chea
p USB
t
u
ner a
nd c
o
n
n
ect
i
n
g i
t
t
o
an ordi
na
ry
pers
onal
co
m
put
er, any
radi
o am
at
eur
obtains a powe
rful instrum
e
nt for
radi
o wa
ves interception. By usi
ng it, anyone can
gain access to classifie
d
inform
ation transm
itted over
the radi
o. Of course, th
e
ordinary tuner pac
k
age
only allows receivi
ng t
h
e T
V
sig
n
a
l,
b
u
t
no
sp
ecial k
nowled
g
e
o
r
sk
ills in
rad
i
o
en
g
i
n
eerin
g
is req
u
i
red to
retu
n
e
t
h
e u
n
it. All you
need
i
s
to
in
stall th
e
n
e
cessary so
ft
ware,
wh
ich
an
y ad
v
a
n
c
ed
PC
u
s
er is ab
le to
do
.
The P
25
di
gi
t
a
l
st
andar
d
wa
s sup
p
o
se
d t
o
be
com
e
t
h
e barri
er p
r
eve
n
t
i
n
g f
r
om
i
n
t
e
rcept
i
ng t
h
e ra
di
o
cont
act
s
of
t
h
e
p
o
l
i
ce, r
o
ad
t
r
affi
c c
ont
rol
d
e
part
m
e
nt
and
ot
he
r g
o
v
er
nm
ent
a
l
an
d
pri
v
a
t
e di
vi
si
o
n
s.
It
d
o
es
n
o
t
allow to
li
sten
in
to
t
h
e talk
s in
th
ei
r pu
re
fo
rm
, but
usi
n
g a
USB
t
une
r a
nd s
p
eci
al
soft
wa
re, y
o
u can
im
m
e
di
at
el
y
get
t
hose
t
a
l
k
s
deco
de
d.
The
C
P
U
of
an
o
r
di
na
ry
PC
i
s
f
u
l
l
y
capabl
e
o
f
t
h
at
ki
n
d
of
si
gnal
decoding.
Fu
rt
h
e
r
u
p
g
r
adin
g
of th
e syste
m
b
r
in
g
s
th
e
p
o
s
sib
ility to
r
eco
gn
ize th
e talk
s an
d
sav
e
the
m
as
tex
t
s,
wh
ich
allo
ws accu
m
u
latin
g
th
e d
a
ta in
as con
v
e
n
i
en
t a fo
r
m
as possi
bl
e.
As t
h
e dat
a
r
e
prese
n
t
e
d i
n
t
h
at
way
can
b
e
easily in
d
e
x
e
d
,
it cou
l
d
resu
lt in
a
h
u
g
e
kno
wled
g
e
b
a
se. Th
is
will p
r
ov
id
e th
e
possib
ility to
easi
l
y fin
d
an
d stru
cture t
h
e
d
a
ta ob
tain
ed
fro
m
th
e rad
i
o
talk
s.
REFERE
NC
ES
[1]
Kile
y P.
and Be
nedet
t
T
., “
P
ubli
c
safe
t
y
int
e
rope
rabili
t
y
with
an
SCA m
ilitar
y
ra
dio using th
e P25 waveform
,”
i
n
Military Communications
Conf
er
ence, 2007
. MIL
COM IEEE
,
pp.1-8, 2007
.
[2]
Clark S
.,
et al.
,
“Why
(Special
Agent) Johnn
y
(
S
till) Can
'
t Encr
y
p
t
:
A Securit
y
Anal
y
s
is of th
e
APCO
Project 2
5
Two-Way
R
a
dio
S
y
stem,”
in
USENIX Security Symposium,
2011.
[3]
Gla
ss S.
,
et al.
, “A
software-defined radio r
e
ceive
r for APCO
Project 25 signals,” in
Proceedings of the 2009
International Co
nference on
Wir
e
less Communications
and Mob
i
le Computing
:
C
onnecting th
e W
o
rld Wirelessly,
pp. 67-72
, 2009
.
[4]
Cigirkan G.,
et al.
, “
E
ffi
ci
ent a
nd Reliab
l
e Mul
tic
ast of Data in
APCO P25
Sy
s
t
em
s,” in
Veh
i
cular Technology
Conference (
V
TC Spring)
, IEEE 81
st
,
pp. 1-5, 20
15.
[5]
J. Joost, “Explo
r
ing Possible V
u
lnerab
ilities of
868MHz
Communication S
y
s
t
ems: A
Step-B
y
-
Step Framework,”
2015.
[6]
B. Ben
j
amin
an
d L. Shamir, “
A
ssessing the efficacy
of
benchmarks for auto
matic sp
eech
accent recognition
,”
Proceed
ings of
the 8th In
ternat
ional Conf
erenc
e
on
Mobil
e
M
u
ltimedia
Communications. IC
ST (
I
n
s
titute
fo
r
Computer Scien
ces, So
cia
l
-Infor
m
atic
s and Telecommunications
Engineering)
, 20
15.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
S
SN
:
2
088
-87
08
IJEC
E
V
o
l
.
6,
No
. 3,
J
u
ne 2
0
1
6
:
10
7
2
– 10
76
1
076
BI
O
G
R
A
P
HY
OF
A
U
T
HO
R
Assosia
t
e
d
Profe
ssor a
t
De
pa
rtme
nt of In
for
m
ation S
y
stems and
Techno
lo
gies, National
Research Nuc
l
e
a
r
Universit
y
ME
PhI (Moscow E
ngineer
ing Ph
y
s
i
c
s Institute
). Doi
ng research
es
in th
e fi
eld
of
inf
o
rm
ation secu
tir
y.
Evaluation Warning : The document was created with Spire.PDF for Python.