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t
ics a
nd
Co
mm
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I
J
-
I
CT
)
Vo
l.
4
,
No
.
1
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A
p
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201
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p
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.
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~
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SS
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C
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Dete
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tion o
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m
ber of
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ha
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nels in Mul
tiple
A
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Techniqu
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for W
ireless
Co
mm
unic
a
tions
Dr.
M
V
Ra
g
ha
v
endra
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,
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Su
bb
a
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o
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dh
ee
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Un
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Et
h
io
p
ia
*
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Ass
istan
t
P
ro
f
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ss
o
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El
e
c
tri
c
a
l
En
g
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e
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p
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A
d
a
m
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&
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c
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sit
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Et
h
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p
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Art
icle
I
nfo
AB
ST
RAC
T
A
r
ticle
his
to
r
y:
R
ec
eiv
ed
No
v
1
2
,
2
0
1
4
R
ev
i
s
ed
Feb
2
0
,
2
0
1
5
A
cc
ep
ted
Mar
2
6
,
2
0
1
5
In
w
irele
ss
c
o
m
m
u
n
ica
ti
o
n
s
sy
st
e
m
,
it
is
d
e
sira
b
le
to
a
ll
o
w
th
e
su
b
sc
rib
e
r
to
se
n
d
sim
u
lt
a
n
e
o
u
sly
in
f
o
r
m
a
ti
o
n
to
t
h
e
b
a
se
sta
ti
o
n
w
h
il
e
re
c
e
iv
in
g
in
f
o
rm
a
ti
o
n
f
ro
m
b
a
se
sta
ti
o
n
.
M
u
lt
ip
le
a
c
c
e
ss
tec
h
n
iq
u
e
s
a
re
u
se
d
t
o
a
ll
o
w
m
a
n
y
m
o
b
il
e
u
se
rs
to
sh
a
re
sim
u
lt
a
n
e
o
u
sly
a
f
in
it
e
a
m
o
u
n
t
o
f
ra
d
io
sp
e
c
tru
m
.
F
re
q
u
e
n
c
y
d
iv
isio
n
m
u
lt
ip
le
a
c
c
e
s
s
(F
DMA
),
ti
m
e
d
iv
isio
n
m
u
lt
ip
le
a
c
c
e
ss
(
T
DM
A
),
a
n
d
c
o
d
e
d
iv
isio
n
m
u
lt
ip
le
a
c
c
e
ss
(CD
M
A
)
a
re
th
e
th
re
e
m
a
jo
r
a
c
c
e
s
s
t
e
c
h
n
iq
u
e
s
u
se
d
to
s
h
a
re
th
e
a
v
a
il
a
b
le
b
a
n
d
w
id
th
in
a
w
irele
ss
c
o
m
m
u
n
ica
ti
o
n
sy
ste
m
.
In
th
is
p
a
p
e
r
w
e
c
a
lcu
late
d
th
e
n
u
m
b
e
r
o
f
c
h
a
n
n
e
ls
re
q
u
ire
d
f
o
r
F
DMA
&
T
DM
A
te
c
h
n
iq
u
e
s
d
e
p
e
n
d
in
g
o
n
v
a
rio
u
s
f
a
c
to
rs su
c
h
a
s sp
e
c
tru
m
,
c
h
a
n
n
e
l
b
a
n
d
w
id
th
e
tc.
K
ey
w
o
r
d
:
T
DM
A
FDM
A
C
DM
A
C
h
a
n
n
el
Sp
ec
tr
u
m
Co
p
y
rig
h
t
©
2
0
1
5
In
stit
u
te o
f
A
d
v
a
n
c
e
d
E
n
g
i
n
e
e
rin
g
a
n
d
S
c
ien
c
e
.
Al
l
rig
h
ts
re
se
rv
e
d
.
C
o
r
r
e
s
p
o
nd
ing
A
uth
o
r
:
Dr
.
M
V
R
ag
h
a
v
e
n
d
r
a
,
E
lectr
ical
E
n
g
i
n
ee
r
i
n
g
Dep
ar
t
e
m
en
t
,
A
d
a
m
a
Scie
n
ce
&
T
ec
h
n
o
lo
g
y
Un
iv
er
s
it
y
,
E
th
io
p
ia
.
E
m
ail:
m
ir
ia
m
p
a
ll
y
@
g
m
ail.
co
m
1.
I
NT
RO
D
UCT
I
O
N
I
n
n
ar
r
o
w
b
an
d
FDM
A
,
a
u
s
er
is
ass
i
g
n
ed
to
a
p
ar
ticu
lar
ch
a
n
n
el
w
h
ic
h
is
n
o
t
s
h
ar
ed
b
y
o
th
er
u
s
er
s
.
Nar
r
o
w
b
an
d
T
DM
A
allo
w
s
u
s
er
s
to
s
h
ar
e
th
e
s
a
m
e
r
ad
io
ch
an
n
el
b
u
t
allo
ca
te
s
a
u
n
iq
u
e
ti
m
e
s
lo
t
to
ea
ch
u
s
er
in
a
c
y
clica
l
f
as
h
io
n
o
n
th
e
s
a
m
e
ch
a
n
n
el.
I
n
w
id
eb
an
d
m
u
ltip
le
ac
ce
s
s
s
y
s
te
m
s
a
lar
g
e
n
u
m
b
er
o
f
tr
an
s
m
itter
s
ar
e
allo
w
ed
to
tr
an
s
m
it
o
n
t
h
e
s
a
m
e
ch
a
n
n
el.
T
DM
A
al
lo
ca
tes
ti
m
e
s
lo
ts
to
m
an
y
tr
an
s
m
itter
s
o
n
th
e
s
a
m
e
c
h
an
n
el
a
n
d
allo
w
s
o
n
l
y
o
n
e
tr
an
s
m
itter
to
ac
ce
s
s
th
e
c
h
an
n
el
at
a
n
y
in
s
ta
n
t
o
f
ti
m
e.
C
D
M
A
allo
ws
all
o
f
th
e
tr
a
n
s
m
itter
s
to
ac
ce
s
s
th
e
c
h
an
n
el
at
t
h
e
s
a
m
e
ti
m
e.
2.
F
RE
Q
UE
N
CY
DIV
I
S
I
O
N
M
UL
T
I
P
L
E
ACC
E
SS
E
S (
F
DM
A)
FDM
A
a
s
s
i
g
n
s
in
d
i
v
id
u
al
c
h
an
n
el
s
to
in
d
i
v
id
u
a
l
u
s
er
s
;
ea
ch
u
s
er
is
a
llo
ca
ted
a
u
n
iq
u
e
f
r
eq
u
e
n
c
y
b
an
d
o
r
ch
an
n
el.
T
h
ese
ch
a
n
n
els
ar
e
ass
ig
n
ed
o
n
d
e
m
an
d
to
u
s
er
s
w
h
o
r
eq
u
e
s
t
s
er
v
ice.
D
u
r
in
g
t
h
e
p
er
io
d
o
f
ca
ll
n
o
o
th
er
u
s
er
ca
n
s
h
ar
e
th
e
s
a
m
e
ch
a
n
n
el.
O
n
ce
th
e
ca
ll
estab
lis
h
ed
th
e
b
ase
s
tati
o
n
an
d
th
e
m
o
b
ile
s
tatio
n
tr
a
n
s
m
it
d
ata
co
n
ti
n
u
o
u
s
l
y
.
FDM
A
i
s
u
s
u
a
ll
y
i
m
p
le
m
en
ted
in
n
ar
r
o
w
b
an
d
s
y
s
te
m
s
.
T
h
e
s
y
m
b
o
l
ti
m
e
o
f
n
ar
r
o
w
b
an
d
s
ig
n
al
is
lar
g
e
as
co
m
p
ar
ed
to
t
h
e
d
ela
y
s
p
r
ea
d
.
T
h
is
s
h
o
w
s
t
h
e
i
n
ter
s
y
m
b
o
l
in
ter
f
er
en
ce
is
lo
w
.
FDM
A
r
eq
u
ir
es
f
e
w
er
b
its
ar
e
n
ee
d
ed
f
o
r
o
v
er
h
ea
d
p
u
r
p
o
s
es.
I
t
r
eq
u
ir
es
R
F
f
il
ter
in
g
to
m
i
n
i
m
ize
ad
j
ac
en
t c
h
an
n
e
l in
ter
f
er
en
ce
.
Fre
q
u
en
c
y
D
iv
i
s
io
n
M
u
ltip
le
A
cc
e
s
s
o
r
FDMA
is
a
cha
nn
e
l
a
cc
ess
m
et
ho
d
u
s
ed
in
m
u
lti
p
le
-
ac
ce
s
s
p
r
o
to
co
ls
as
a
ch
an
n
eliza
tio
n
p
r
o
to
co
l.
FDMA
g
i
v
e
s
u
s
er
s
an
i
n
d
i
v
id
u
al
al
lo
ca
tio
n
o
f
o
n
e
o
r
s
e
v
er
al
f
r
eq
u
en
c
y
b
a
n
d
s
,
o
r
ch
a
n
n
el
s
.
I
t
is
p
ar
ticu
lar
l
y
co
m
m
o
n
p
la
ce
in
s
a
tellite
co
m
m
u
n
icatio
n
.
FDM
A
,
li
k
e
o
th
er
Mu
ltip
le
A
cc
es
s
s
y
s
te
m
s
,
co
o
r
d
in
ates a
cc
es
s
b
et
w
ee
n
m
u
ltip
le
u
s
er
s
.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
SS
N
:
2
2
5
2
-
8776
IJ
-
I
C
T
Vo
l.
4
,
No
.
1
,
A
p
r
il
20
1
5
:
1
–
6
2
I
n
FDM
A
all
u
s
er
s
s
h
ar
e
th
e
s
atelli
te
s
i
m
u
lta
n
eo
u
s
l
y
b
u
t
ea
ch
u
s
e
r
tr
a
n
s
m
it
s
at
s
i
n
g
le
f
r
eq
u
en
c
y
.
FDM
A
ca
n
b
e
u
s
ed
w
it
h
b
o
th
an
alo
g
an
d
d
ig
ital
s
ig
n
al.
FD
MA
r
eq
u
ir
es
h
i
gh
-
p
er
f
o
r
m
i
n
g
f
ilter
s
in
t
h
e
r
ad
io
h
ar
d
w
ar
e,
i
n
co
n
tr
a
s
t
to
T
DM
A
a
n
d
C
DM
A
.
FDM
A
is
n
o
t
v
u
l
n
er
ab
le
to
th
e
ti
m
i
n
g
p
r
o
b
lem
s
t
h
at
T
DM
A
h
as.
S
in
ce
a
p
r
ed
eter
m
in
ed
f
r
e
q
u
en
c
y
b
an
d
i
s
av
a
ilab
le
f
o
r
th
e
e
n
tire
p
er
io
d
o
f
co
m
m
u
n
ic
atio
n
,
s
tr
ea
m
d
ata
(
a
co
n
tin
u
o
u
s
f
lo
w
o
f
d
ata
th
a
t
m
a
y
n
o
t
b
e
p
ac
k
etize
d
)
ca
n
e
asil
y
b
e
u
s
ed
w
it
h
FDM
A
.
D
u
e
to
t
h
e
f
r
eq
u
en
c
y
f
ilter
i
n
g
,
FDM
A
is
n
o
t
s
e
n
s
it
i
v
e
to
n
ea
r
-
f
ar
p
r
o
b
le
m
w
h
ic
h
is
p
r
o
n
o
u
n
ce
d
f
o
r
C
DM
A
.
E
ac
h
u
s
er
tr
a
n
s
m
it
s
an
d
r
ec
eiv
es a
t d
i
f
f
er
e
n
t f
r
eq
u
en
cies a
s
ea
c
h
u
s
er
g
et
s
a
u
n
iq
u
e
f
r
eq
u
e
n
c
y
s
lo
t
.
FDM
A
is
d
is
ti
n
ct
f
r
o
m
f
r
eq
u
en
c
y
d
i
v
is
io
n
d
u
p
lex
i
n
g
(
FD
D)
.
W
h
ile
FDM
A
allo
w
s
m
u
l
tip
le
u
s
er
s
s
i
m
u
lta
n
eo
u
s
ac
ce
s
s
to
a
tr
an
s
m
i
s
s
io
n
s
y
s
te
m
,
FDD
r
ef
er
s
to
h
o
w
t
h
e
r
ad
io
ch
a
n
n
e
l
is
s
h
ar
ed
b
et
w
ee
n
t
h
e
u
p
lin
k
a
n
d
d
o
w
n
l
in
k
(
f
o
r
in
s
t
an
ce
,
th
e
tr
a
f
f
ic
g
o
i
n
g
b
ac
k
a
n
d
f
o
r
th
b
et
w
ee
n
a
m
o
b
ile
-
p
h
o
n
e
a
n
d
a
m
o
b
ile
p
h
o
n
e
b
ase
s
tatio
n
)
.
Fre
q
u
en
c
y
-
d
i
v
i
s
io
n
m
u
l
tip
lex
i
n
g
(
FDM
)
is
also
d
is
tin
ct
f
r
o
m
F
DM
A
.
FDM
is
a
p
h
y
s
ical
la
y
er
tec
h
n
iq
u
e
th
at
co
m
b
i
n
e
s
a
n
d
tr
an
s
m
its
lo
w
-
b
a
n
d
w
id
th
c
h
a
n
n
el
s
t
h
r
o
u
g
h
a
h
i
g
h
-
b
an
d
w
id
th
ch
a
n
n
el.
FDM
A
,
o
n
th
e
o
t
h
er
h
a
n
d
,
is
an
ac
ce
s
s
m
et
h
o
d
in
th
e
d
ata
li
n
k
la
y
er
.
FDM
A
also
s
u
p
p
o
r
ts
d
e
m
an
d
ass
ig
n
m
en
t
in
ad
d
itio
n
to
f
i
x
ed
ass
i
g
n
m
e
n
t.
Dem
a
n
d
a
s
s
ig
n
men
t
allo
w
s
all
u
s
er
s
ap
p
ar
en
tl
y
c
o
n
tin
u
o
u
s
ac
ce
s
s
o
f
th
e
r
ad
io
s
p
ec
tr
u
m
b
y
a
s
s
i
g
n
in
g
ca
r
r
ier
f
r
eq
u
en
cie
s
o
n
a
te
m
p
o
r
ar
y
b
as
is
u
s
i
n
g
a
s
tatis
t
ica
l a
s
s
i
g
n
m
e
n
t p
r
o
ce
s
s
.
Fig
u
r
e
1
.
Fre
q
u
en
c
y
d
i
v
is
io
n
Mu
ltip
le
x
i
n
g
T
h
e
n
u
m
b
er
o
f
c
h
an
n
el
s
th
at
c
an
s
u
p
p
o
r
t in
a
FDM
A
s
y
s
te
m
is
ca
lcu
lated
as
B
t
=
to
tal
s
p
ec
tr
u
m
allo
ca
tio
n
2
B
g
uard
=
g
u
ar
d
b
an
d
allo
ca
ted
at
th
e
ed
g
e
o
f
th
e
s
p
ec
tr
u
m
b
a
n
d
B
c
=
ch
an
n
el
b
an
d
w
id
t
h
3.
T
I
M
E
DIVI
SI
O
N
M
UL
T
I
P
L
E
AC
CE
SS
(
T
DM
A)
I
n
T
DM
A
s
y
s
t
e
m
s
t
h
e
r
ad
io
s
p
ec
tr
u
m
is
d
iv
id
e
in
to
ti
m
e
s
lo
ts
an
d
ea
ch
s
lo
t
o
n
l
y
o
n
e
u
s
er
is
allo
w
ed
to
eith
er
tr
an
s
m
i
t
o
r
r
ec
eiv
e.
T
h
e
d
ata
tr
an
s
m
i
tted
i
n
T
DM
A
s
y
s
te
m
s
b
y
u
s
i
n
g
b
u
f
f
er
-
an
d
-
b
u
r
s
t
m
et
h
o
d
i
n
t
h
e
f
o
r
m
o
f
f
r
a
m
es.
E
ac
h
f
r
a
m
e
co
n
s
is
ts
o
f
a
p
r
ea
m
b
le,
an
i
n
f
o
r
m
atio
n
m
e
s
s
a
g
e,
an
d
tail
b
its
.
T
h
e
p
r
ea
m
b
le
co
n
tain
s
t
h
e
ad
d
r
ess
an
d
s
y
n
c
h
r
o
n
izatio
n
in
f
o
r
m
a
tio
n
o
f
b
o
th
t
h
e
b
ase
s
tat
io
n
a
n
d
s
u
b
s
cr
ib
er
’
s
i
n
f
o
r
m
atio
n
.
I
t
u
s
e
s
d
if
f
er
en
t ti
m
e
s
lo
ts
f
o
r
tr
a
n
s
m
i
s
s
io
n
a
n
d
r
ec
ep
tio
n
.
I
n
T
DM
A
th
e
s
y
s
te
m
d
i
m
e
n
s
i
o
n
s
ar
e
d
iv
id
ed
alo
n
g
t
h
e
ti
m
e
ax
is
i
n
to
n
o
n
o
v
er
lap
p
in
g
c
h
a
n
n
el
s
,
an
d
ea
ch
u
s
er
i
s
as
s
i
g
n
ed
a
d
if
f
e
r
en
t
c
y
clica
ll
y
-
r
ep
ea
ti
n
g
ti
m
e
s
lo
t.
T
h
ese
T
DM
A
c
h
a
n
n
e
ls
o
cc
u
p
y
t
h
e
e
n
tire
s
y
s
te
m
b
an
d
w
id
t
h
,
w
h
ic
h
is
t
y
p
ica
ll
y
w
id
eb
an
d
,
s
o
s
o
m
e
f
o
r
m
o
f
I
SI
m
it
ig
at
io
n
is
r
eq
u
i
r
ed
.
T
h
e
cy
clica
ll
y
r
ep
ea
tin
g
ti
m
eslo
ts
i
m
p
l
y
t
h
a
t
tr
an
s
m
is
s
io
n
is
n
o
t
co
n
ti
n
u
o
u
s
f
o
r
an
y
u
s
er
.
T
h
er
ef
o
r
e,
d
ig
ital
tr
an
s
m
i
s
s
io
n
tech
n
iq
u
es
w
h
ich
allo
w
f
o
r
b
u
f
f
er
i
n
g
ar
e
r
eq
u
ir
ed
.
T
h
e
f
a
ct
th
at
tr
an
s
m
is
s
io
n
i
s
n
o
t
co
n
ti
n
u
o
u
s
s
i
m
p
li
f
ies
o
v
er
h
ea
d
f
u
n
ctio
n
s
s
u
ch
as
ch
an
n
el
esti
m
at
io
n
,
s
i
n
ce
th
e
s
e
f
u
n
ctio
n
s
ca
n
b
e
d
o
n
e
d
u
r
in
g
t
h
e
ti
m
e
s
lo
ts
o
cc
u
p
ied
b
y
o
th
er
u
s
er
s
.
T
DM
A
al
s
o
h
as
t
h
e
ad
v
a
n
ta
g
e
th
at
it
is
s
i
m
p
le
to
as
s
i
g
n
m
u
ltip
le
ch
an
n
el
s
to
a
s
in
g
le
u
s
er
b
y
s
i
m
p
l
y
as
s
ig
n
i
n
g
h
i
m
m
u
lt
ip
le
ti
m
e
s
lo
ts
.
T
DM
A
i
s
u
s
ed
in
t
h
e
d
ig
ital
2G
c
ellu
lar
s
y
s
te
m
s
s
u
c
h
as
Glo
b
al
S
y
s
te
m
f
o
r
Mo
b
ile
C
o
m
m
u
n
ica
tio
n
s
(
GSM)
,
IS
-
136
,
Per
s
o
n
al
Dig
ital
C
ell
u
lar
(
P
DC
)
an
d
iDE
N
,
an
d
in
th
e
Di
g
ital
E
n
h
a
n
c
ed
C
o
r
d
less
T
elec
o
m
m
u
n
icatio
n
s
(
DE
C
T
)
s
tan
d
ar
d
f
o
r
p
o
r
tab
l
e
p
h
o
n
es
.
I
t
is
also
Evaluation Warning : The document was created with Spire.PDF for Python.
IJ
-
I
C
T
I
SS
N:
2252
-
8776
Dete
r
min
a
n
o
f Nu
mb
er o
f c
h
a
n
n
els in
Mu
ltip
le
a
cc
ess
Tech
n
iq
u
es fo
r
W
i
r
eles
s
....
(
Dr.
M
V
R
a
g
h
a
ve
n
d
r
a
)
3
u
s
ed
ex
te
n
s
i
v
el
y
i
n
s
atel
lite
s
y
s
te
m
s
,
co
m
b
at
-
n
et
r
ad
io
s
y
s
t
e
m
s
,
an
d
P
ON
n
et
w
o
r
k
s
f
o
r
u
p
s
tr
ea
m
tr
af
f
ic
f
r
o
m
p
r
em
i
s
es to
t
h
e
o
p
er
ato
r
.
Fo
r
u
s
ag
e
o
f
D
y
n
a
m
ic
T
DM
A
p
ac
k
et
m
o
d
e
co
m
m
u
n
icatio
n
.
T
DM
A
C
h
ar
ac
ter
i
s
tics
:
a.
Sh
ar
es s
in
g
le
ca
r
r
ier
f
r
eq
u
e
n
c
y
w
it
h
m
u
ltip
le
u
s
er
s
b.
No
n
-
co
n
ti
n
u
o
u
s
tr
an
s
m
is
s
io
n
m
ak
e
s
h
a
n
d
o
f
f
s
i
m
p
ler
c.
Slo
ts
ca
n
b
e
ass
ig
n
ed
o
n
d
e
m
a
n
d
in
d
y
n
a
m
ic
T
DM
A
d.
L
es
s
s
tr
i
n
g
e
n
t p
o
w
er
co
n
tr
o
l th
an
C
DM
A
d
u
e
to
r
ed
u
ce
d
in
t
r
a
ce
ll in
ter
f
er
e
n
ce
e.
Hig
h
er
s
y
n
c
h
r
o
n
izatio
n
o
v
er
h
ea
d
th
an
C
DM
A
f.
A
d
v
an
ce
d
eq
u
aliza
t
io
n
m
a
y
b
e
n
ec
ess
ar
y
f
o
r
h
i
g
h
d
ata
r
ates
if
th
e
c
h
a
n
n
el
i
s
"
f
r
eq
u
en
c
y
s
elec
tiv
e"
an
d
cr
ea
tes
I
n
ter
s
y
m
b
o
l i
n
ter
f
er
e
n
ce
g.
C
ell
b
r
ea
th
i
n
g
(
b
o
r
r
o
w
i
n
g
r
es
o
u
r
ce
s
f
r
o
m
ad
j
ac
en
t c
ells
)
i
s
m
o
r
e
co
m
p
l
icate
d
th
a
n
in
C
D
MA
h.
Fre
q
u
en
c
y
/s
lo
t a
llo
ca
tio
n
co
m
p
lex
it
y
i.
P
u
ls
ati
n
g
p
o
w
er
en
v
elo
p
e:
I
n
t
er
f
er
en
ce
w
it
h
o
th
er
d
ev
ice
s
Fig
u
r
e
2
.
T
im
e
d
iv
i
s
io
n
M
u
lti
p
lex
in
g
T
h
e
n
u
m
b
er
o
f
c
h
an
n
el
s
th
at
c
an
s
u
p
p
o
r
t in
a
T
DM
A
s
y
s
te
m
is
ca
lcu
lated
as
B
t
=
to
tal
s
p
ec
tr
u
m
allo
ca
tio
n
2
B
g
uard
=
g
u
ar
d
b
an
d
allo
ca
ted
at
th
e
ed
g
e
o
f
th
e
s
p
ec
tr
u
m
b
a
n
d
B
c
=
ch
an
n
el
b
an
d
w
id
t
h
4.
CO
M
P
ARIS
O
N
WI
T
H
O
T
H
E
R
M
UL
T
I
P
L
E
-
ACC
E
S
S SCH
E
M
E
S
I
n
r
ad
io
s
y
s
te
m
s
,
T
DM
A
is
u
s
u
all
y
u
s
ed
alo
n
g
s
id
e
Fre
q
u
e
n
c
y
-
d
i
v
i
s
io
n
m
u
ltip
le
ac
ce
s
s
(
F
DM
A
)
a
n
d
Fre
q
u
en
c
y
d
iv
is
io
n
d
u
p
le
x
(
F
DD)
;
th
e
co
m
b
i
n
atio
n
is
r
e
f
er
r
ed
to
as
FDM
A
/T
DM
A
/FD
D
.
T
h
is
is
t
h
e
ca
s
e
i
n
b
o
th
GSM
a
n
d
I
S
-
1
3
6
f
o
r
ex
a
m
p
le.
E
x
ce
p
tio
n
s
to
t
h
is
i
n
cl
u
d
e
th
e
DE
C
T
an
d
P
HS
m
icr
o
-
ce
llu
lar
s
y
s
te
m
s
,
UM
T
S
-
T
DD
UM
T
S
v
ar
ian
t,
an
d
C
h
i
n
a
'
s
TD
-
S
C
DM
A
,
w
h
ich
u
s
e
T
i
m
e
Div
is
io
n
d
u
p
lex
in
g
,
w
h
er
e
d
i
f
f
er
en
t
ti
m
e
s
lo
ts
ar
e
allo
ca
ted
f
o
r
th
e
b
ase
s
tatio
n
an
d
h
an
d
s
e
ts
o
n
t
h
e
s
a
m
e
f
r
eq
u
e
n
c
y
.
A
m
aj
o
r
ad
v
an
tag
e
o
f
T
DM
A
is
th
at
t
h
e
r
ad
io
p
ar
t
o
f
th
e
m
o
b
ile
o
n
l
y
n
ee
d
s
to
lis
te
n
an
d
b
r
o
ad
ca
s
t
f
o
r
its
o
w
n
ti
m
e
s
lo
t.
Fo
r
t
h
e
r
est
o
f
t
h
e
ti
m
e,
t
h
e
m
o
b
il
e
ca
n
ca
r
r
y
o
u
t
m
ea
s
u
r
e
m
en
t
s
o
n
t
h
e
n
et
w
o
r
k
,
d
etec
tin
g
s
u
r
r
o
u
n
d
in
g
tr
an
s
m
itter
s
o
n
d
if
f
er
en
t
f
r
eq
u
en
cie
s
.
T
h
is
allo
w
s
s
a
f
e
i
n
ter
f
r
e
q
u
en
c
y
h
a
n
d
o
v
er
s
,
s
o
m
et
h
i
n
g
w
h
ic
h
is
d
if
f
ic
u
lt
i
n
C
DM
A
s
y
s
te
m
s
,
n
o
t
s
u
p
p
o
r
ted
at
all
in
IS
-
95
an
d
s
u
p
p
o
r
ted
th
r
o
u
g
h
co
m
p
lex
s
y
s
te
m
ad
d
itio
n
s
in
Un
i
v
er
s
a
l
Mo
b
ile
T
elec
o
m
m
u
n
icatio
n
s
S
y
s
te
m
(
UM
T
S).
T
h
is
in
tu
r
n
allo
w
s
f
o
r
co
-
ex
is
te
n
ce
o
f
m
icr
o
ce
ll
la
y
er
s
w
it
h
m
ac
r
o
ce
ll
la
y
er
s
.
C
DM
A
,
b
y
co
m
p
ar
i
s
o
n
,
s
u
p
p
o
r
ts
"
s
o
f
t
h
a
n
d
-
o
f
f
"
w
h
ic
h
allo
w
s
a
m
o
b
ile
p
h
o
n
e
to
b
e
in
co
m
m
u
n
icatio
n
w
i
th
u
p
to
6
b
ase
s
tatio
n
s
s
i
m
u
l
tan
eo
u
s
l
y
,
a
t
y
p
e
o
f
"
s
am
e
-
f
r
eq
u
en
c
y
h
a
n
d
o
v
er
"
.
T
h
e
in
co
m
i
n
g
p
ac
k
ets
ar
e
co
m
p
ar
ed
f
o
r
q
u
ality
,
a
n
d
th
e
b
est
o
n
e
is
s
elec
ted
.
C
DM
A's
"
ce
ll
b
r
ea
th
in
g
"
ch
ar
ac
ter
is
tic,
w
h
er
e
a
ter
m
i
n
al
o
n
t
h
e
b
o
u
n
d
ar
y
o
f
t
w
o
c
o
n
g
es
ted
ce
lls
w
i
ll
b
e
u
n
ab
le
to
r
ec
eiv
e
a
clea
r
s
ig
n
al,
ca
n
o
f
ten
n
e
g
ate
th
is
a
d
v
an
ta
g
e
d
u
r
i
n
g
p
ea
k
p
er
io
d
s
.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
SS
N
:
2
2
5
2
-
8776
IJ
-
I
C
T
Vo
l.
4
,
No
.
1
,
A
p
r
il
20
1
5
:
1
–
6
4
A
d
i
s
ad
v
a
n
tag
e
o
f
T
DM
A
s
y
s
te
m
s
i
s
t
h
at
t
h
e
y
cr
ea
te
i
n
ter
f
er
en
ce
at
a
f
r
eq
u
en
c
y
w
h
ic
h
is
d
ir
ec
tl
y
co
n
n
ec
ted
to
th
e
ti
m
e
s
lo
t
len
g
th
.
T
h
is
is
t
h
e
b
u
zz
w
h
ich
c
an
s
o
m
et
i
m
e
s
b
e
h
ea
r
d
if
a
T
DM
A
p
h
o
n
e
is
le
f
t
n
ex
t
to
a
r
ad
io
o
r
s
p
ea
k
er
s
.
[1]
A
n
o
t
h
er
d
is
ad
v
a
n
tag
e
is
t
h
a
t
th
e
"
d
ea
d
tim
e"
b
et
w
ee
n
ti
m
e
s
lo
ts
li
m
it
s
th
e
p
o
ten
tial
b
an
d
w
id
t
h
o
f
a
T
DM
A
ch
a
n
n
el.
T
h
ese
ar
e
i
m
p
le
m
en
ted
i
n
p
ar
t
b
ec
au
s
e
o
f
t
h
e
d
if
f
ic
u
lt
y
in
e
n
s
u
r
in
g
th
at
d
i
f
f
er
e
n
t
ter
m
i
n
als
tr
a
n
s
m
it
at
e
x
ac
tl
y
t
h
e
ti
m
e
s
r
eq
u
ir
ed
.
Han
d
s
et
s
t
h
at
ar
e
m
o
v
in
g
w
i
ll
n
ee
d
to
co
n
s
ta
n
tl
y
ad
j
u
s
t
t
h
eir
ti
m
i
n
g
s
to
en
s
u
r
e
th
e
ir
tr
an
s
m
i
s
s
io
n
i
s
r
ec
eiv
ed
at
p
r
ec
is
el
y
t
h
e
r
ig
h
t
ti
m
e,
b
ec
au
s
e
as
th
e
y
m
o
v
e
f
u
r
t
h
er
f
r
o
m
t
h
e
b
a
s
e
s
tat
io
n
,
t
h
eir
s
i
g
n
al
w
i
ll
ta
k
e
lo
n
g
er
to
ar
r
i
v
e.
T
h
is
al
s
o
m
ea
n
s
t
h
at
th
e
m
aj
o
r
T
DM
A
s
y
s
te
m
s
h
a
v
e
h
ar
d
li
m
its
o
n
ce
ll
s
izes
in
ter
m
s
o
f
r
a
n
g
e,
t
h
o
u
g
h
i
n
p
r
ac
tice
th
e
p
o
w
er
lev
el
s
r
eq
u
ir
ed
to
r
ec
eiv
e
an
d
tr
an
s
m
it o
v
er
d
is
tan
ce
s
g
r
ea
ter
th
a
n
t
h
e
s
u
p
p
o
r
ted
r
an
g
e
w
o
u
ld
b
e
m
o
s
tl
y
i
m
p
r
ac
tical
an
y
w
a
y
.
Fre
q
u
en
c
y
Di
v
is
io
n
Mu
l
tip
le
A
cc
e
s
s
N
=
(
B
t
-
2
B
g
u
ar
d
)
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g
u
a
r
d
N
C
a
se
-
1
5
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4
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C
a
se
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0
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Z
4
9
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C
a
se
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5
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4
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a
se
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se
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5
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7
4
9
T
im
e
Di
v
is
io
n
Mu
ltip
le
A
cc
es
s
N
=
m
(
B
t
-
2
B
g
u
ar
d
)
⁄
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m
Bt
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g
u
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-
1
6
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4
9
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C
a
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1
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8
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a
se
-
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6
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Z
4
4
9
4
Evaluation Warning : The document was created with Spire.PDF for Python.
IJ
-
I
C
T
I
SS
N:
2252
-
8776
Dete
r
min
a
n
o
f Nu
mb
er o
f c
h
a
n
n
els in
Mu
ltip
le
a
cc
ess
Tech
n
iq
u
es fo
r
W
i
r
eles
s
....
(
Dr.
M
V
R
a
g
h
a
ve
n
d
r
a
)
5
Fig
u
r
e
3
.
Nu
m
b
er
o
f
C
h
a
n
n
ela
in
T
DM
A
&
FDM
A
5.
CO
NCLU
SI
O
N
a.
I
n
f
r
eq
u
e
n
c
y
d
iv
is
io
n
m
u
l
tip
l
e
ac
ce
s
s
b
y
k
ee
p
i
n
g
t
h
e
ch
a
n
n
el
b
an
d
w
id
t
h
as
co
n
s
ta
n
t
,
th
e
n
u
m
b
er
o
f
ch
an
n
el
i
n
th
e
tec
h
n
iq
u
e
ar
e
in
cr
ea
s
ed
.
b.
FDM
A
b
y
k
ee
p
i
n
g
t
h
e
to
tal
s
p
ec
tr
u
m
allo
ca
tio
n
as
co
n
s
ta
n
t
an
d
b
y
v
ar
y
i
n
g
c
h
an
n
el
b
an
d
w
id
th
,
g
u
ar
d
b
an
d
allo
ca
ted
at
th
e
ed
g
es
o
f
th
e
s
p
ec
tr
u
m
b
an
d
t
h
en
th
e
n
u
m
b
er
o
f
c
h
an
n
el
s
in
th
e
m
et
h
o
d
ar
e
d
ec
r
ea
s
in
g
.
c.
I
n
FDM
A
b
y
k
ee
p
i
n
g
t
h
e
g
u
a
r
d
b
an
d
allo
ca
ted
at
th
e
ed
g
e
o
f
th
e
s
p
ec
tr
u
m
b
an
d
is
k
ep
t
co
n
s
ta
n
t
an
d
b
y
v
ar
y
i
n
g
ch
a
n
n
e
l b
an
d
w
id
th
a
n
d
to
tal
s
p
ec
tr
u
m
a
llo
ca
tio
n
t
h
e
n
u
m
b
er
o
f
ch
a
n
n
e
ls
ar
e
in
cr
ea
s
in
g
li
n
ea
r
l
y
.
d.
I
n
ti
m
e
d
iv
i
s
io
n
m
u
lt
ip
le
ac
ce
s
s
tech
n
iq
u
e
b
y
k
ee
p
i
n
g
s
p
e
ec
h
ch
an
n
el
s
an
d
ch
an
n
el
b
an
d
w
it
h
ar
e
k
ep
t
co
n
s
ta
n
t,
an
d
b
y
v
ar
y
i
n
g
g
u
a
r
d
b
an
d
allo
ca
tio
n
,
t
o
tal
s
p
ec
tr
u
m
allo
ca
tio
n
th
e
n
u
m
b
er
o
f
ch
a
n
n
el
s
ar
e
in
cr
ea
s
ed
.
e.
I
n
ti
m
e
d
iv
i
s
io
n
m
u
ltip
le
ac
c
ess
tec
h
n
iq
u
e
b
y
k
ee
p
in
g
s
p
e
ec
h
ch
a
n
n
els
a
n
d
to
tal
s
p
ec
tr
u
m
a
llo
ca
tio
n
as
k
ep
t
co
n
s
ta
n
t,
b
y
v
ar
y
in
g
ch
a
n
n
el
b
an
d
w
id
t
h
,
g
u
ar
d
b
an
d
allo
ca
ted
at
th
e
ed
g
e
o
f
th
e
s
p
ec
tr
u
m
b
an
d
t
h
e
n
u
m
b
er
o
f
ch
a
n
n
els ar
e
d
ec
r
ea
s
ed
.
f.
I
n
T
DM
A
k
ee
p
in
g
s
p
ee
c
h
ch
an
n
el
s
an
d
g
u
ar
d
b
an
d
a
s
co
n
s
ta
n
t,
b
y
v
ar
y
in
g
s
p
ec
tr
u
m
allo
ca
tio
n
an
d
ch
an
n
el
b
an
d
w
it
h
t
h
e
n
u
m
b
er
o
f
ch
an
n
el
s
ar
e
in
cr
ea
s
ed
r
ap
id
ly
.
RE
F
E
R
E
NC
E
S
[1
]
W
irele
ss
Co
m
m
u
n
ica
ti
o
n
s
-
S
T
h
e
o
d
o
re
Ra
p
p
a
p
o
rt
[2
]
W
irele
ss
S
e
n
so
r
n
e
tw
o
rk
s
-
A
n
a
n
th
a
ra
m
a
s
w
a
m
y
,
Qin
g
Zh
a
o
,
Ya
o
-
w
in
h
o
n
g
,
L
a
n
g
to
m
[3
]
W
irele
ss
S
e
n
so
r
n
e
tw
o
rk
s
-
Io
n
F
.
Ak
y
il
d
iz &
M
e
h
m
e
t
c
a
n
v
u
ra
n
[4
]
W
irele
ss
N
e
t
w
o
rk
S
e
c
u
rit
y
–
Y.Xiao
,
X
.
Ch
e
n
B
I
O
G
RAP
H
I
E
S
O
F
AUTH
O
RS
Dr.
M
.
V
.
Ra
g
h
a
v
e
n
d
ra
is
c
u
rre
n
tl
y
w
o
rk
in
g
a
s
A
s
so
c
iate
P
ro
f
e
ss
o
r,
El
e
c
tri
c
a
l
En
g
in
e
e
rin
g
De
p
t,
A
d
a
m
a
S
c
ien
c
e
&
Tec
h
n
o
lo
g
y
Un
iv
e
rsity
,
Et
h
io
p
ia.
He
re
c
e
iv
e
d
h
is
P
h
D
f
ro
m
S
in
g
h
a
n
ia
Un
iv
e
rsit
y
,
Ra
jas
th
a
n
,
In
d
ia
in
th
e
f
ield
o
f
Op
ti
c
a
l
Co
m
m
u
n
ica
ti
o
n
a
n
d
h
e
is
a
Re
se
a
rc
h
sc
h
o
lar,
De
p
a
rtme
n
t
o
f
In
stru
m
e
n
t
Tec
h
n
o
l
o
g
y
,
Co
ll
e
g
e
o
f
En
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