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CT
)
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Dec
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201
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.
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N:
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K
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:
BS
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@
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1.
I
NT
RO
D
UCT
I
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N
W
ir
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tech
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ted
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p
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y
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m
.
All
th
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eq
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m
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t
s
h
a
s
b
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n
f
u
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f
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b
y
MI
MO
tec
h
n
o
lo
g
y
w
h
ich
is
i
n
u
s
e
lat
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it
h
elp
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h
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o
f
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m
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u
n
icatio
n
s
y
s
te
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alo
n
g
w
it
h
b
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o
b
u
s
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eliab
le.
A
ls
o
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t
h
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s
e
o
f
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le
a
n
ten
n
a
s
h
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er
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t
h
e
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f
o
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ex
p
a
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b
a
n
d
w
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d
th
as
w
e
ll a
s
th
e
tr
a
n
s
m
it
ter
p
o
w
er
[
1
]
.
B
u
t th
i
s
tec
h
n
o
lo
g
y
w
a
s
f
ir
s
t d
ev
e
lo
p
ed
f
o
r
s
i
n
g
le
u
s
er
s
y
s
te
m
s
i.e
.
tr
an
s
m
itter
h
a
v
i
n
g
m
u
lt
ip
le
an
te
n
n
a
s
alo
n
g
w
it
h
m
u
ltip
le
a
n
te
n
n
a
s
at
th
e
r
ec
eiv
er
.
B
u
t
d
u
e
to
ex
p
o
n
en
tial
i
n
cr
ea
s
e
in
t
h
e
n
u
m
b
er
o
f
u
s
er
s
in
th
e
w
ir
eless
f
ield
,
th
is
te
ch
n
o
lo
g
y
h
as
b
ee
n
ex
ten
d
ed
to
t
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e
m
u
lti
u
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y
s
te
m
s
.
Mu
l
tiu
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MI
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s
co
n
s
id
er
ed
th
e
ad
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a
n
ce
m
e
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t
o
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SDM
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en
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s
o
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g
le
c
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an
n
el
[
2
]
.
M
u
lti
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s
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MI
MO
p
r
o
v
id
es
lar
g
e
n
u
m
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f
b
en
e
f
it
s
o
v
er
s
in
g
le
u
s
er
MI
MO
lik
e
m
u
lti
u
s
er
d
i
v
er
s
it
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e
n
h
an
ce
s
c
h
a
n
n
el
co
n
d
itio
n
as
u
s
er
s
h
a
v
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g
b
est
c
h
an
n
el
q
u
alit
y
ar
e
all
o
w
ed
to
o
cc
u
p
y
th
e
c
h
an
n
el
[
3
]
.
Mu
lt
iu
s
er
MI
MO
i
s
r
ig
id
to
t
h
e
p
r
o
p
ag
atio
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li
m
ita
tio
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s
lik
e
r
an
k
lo
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an
ten
n
a
co
r
r
elatio
n
p
er
tain
i
n
g
i
n
s
i
n
g
le
u
s
er
MI
MO
[
4
]
.
I
n
m
u
lti
u
s
er
MI
MO
s
y
s
te
m
s
,
th
e
b
ase
s
tatio
n
h
a
s
m
u
ltip
l
e
n
u
m
b
er
s
o
f
an
te
n
n
a
s
alo
n
g
w
it
h
th
e
m
u
ltip
le
n
u
m
b
er
s
o
f
u
s
er
s
.
T
h
e
u
s
e
r
s
ca
n
h
a
v
e
m
u
ltip
le
a
n
ten
n
a
s
o
r
s
in
g
le
an
te
n
n
as.
B
u
t
th
ese
v
ar
iatio
n
s
i
n
th
e
u
s
er
eq
u
ip
m
en
t
ca
n
b
e
o
f
m
u
c
h
i
m
p
o
r
tan
ce
.
Firstl
y
,
th
er
e
n
ee
d
s
to
b
e
les
s
h
ar
d
w
ar
e
f
o
r
t
h
e
u
s
er
eq
u
ip
m
e
n
t
i
n
o
r
d
er
to
s
av
e
p
o
w
er
a
n
d
m
a
k
e
th
e
s
y
s
te
m
p
o
r
tab
le
an
d
ea
s
y
to
h
a
n
d
le.
Seco
n
d
l
y
,
t
h
e
co
s
t
at
t
h
e
u
s
er
e
n
d
n
ee
d
s
to
b
e
m
i
n
i
m
a
l
in
o
r
d
er
to
m
a
k
e
t
h
e
s
y
s
te
m
m
o
r
e
v
iab
le
to
t
h
e
u
s
er
s
[
5
]
.
So
,
it
is
o
f
m
o
r
e
i
m
p
o
r
tan
ce
t
h
at
u
s
er
s
h
o
u
ld
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av
e
les
s
n
u
m
b
er
o
f
a
n
ten
n
a
s
an
d
if
p
o
s
s
ib
le
o
n
l
y
o
n
e
a
n
ten
n
a
s
h
o
u
ld
b
e
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.
5
,
No
.
3
,
Dec
em
b
er
2
0
1
6
:
8
9
–
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90
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m
p
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s
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m
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A
lo
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h
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et
w
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b
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is
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atis
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W
h
ile
h
ab
it
u
ati
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g
lar
g
e
n
u
m
b
er
o
f
u
s
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s
in
t
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n
et
w
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k
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it
is
s
u
r
e
t
h
at
th
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s
y
s
te
m
p
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f
o
r
m
an
ce
w
i
ll
b
e
d
eter
io
r
ated
s
u
r
ely
.
So
,
it
h
as
b
ee
n
a
p
r
o
b
le
m
w
h
ile
o
p
ti
m
iz
in
g
th
e
s
y
s
te
m
.
So
,
o
n
e
o
f
th
e
w
a
y
is
to
m
a
k
e
th
e
g
r
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p
s
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f
u
s
er
s
w
h
ich
w
il
l
u
s
e
t
h
e
n
et
w
o
r
k
alter
n
atel
y
[
6
]
.
Mo
r
e
th
e
n
u
m
b
er
o
f
g
r
o
u
p
s
th
e
les
s
w
ill
b
e
th
e
in
ter
f
er
en
ce
a
n
d
m
o
r
e
w
ill
b
e
th
e
s
i
g
n
al
s
tr
en
g
th
.
B
u
t
also
,
i
t
h
as
an
e
f
f
ec
t o
n
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e
n
u
m
b
er
o
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s
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ein
g
s
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.
So
,
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m
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p
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g
r
o
u
p
in
g
s
h
o
u
ld
b
e
d
o
n
e
s
u
ch
th
at
th
e
m
a
x
i
m
u
m
n
u
m
b
er
o
f
u
s
er
s
is
ac
co
m
m
o
d
ated
alo
n
g
w
it
h
p
r
o
v
id
in
g
t
h
e
g
o
o
d
s
ig
n
al
s
tr
en
g
th
to
t
h
e
u
s
er
s
in
s
y
s
te
m
.
2.
SYST
E
M
M
O
DE
L
I
n
th
i
s
,
co
n
s
id
er
th
e
s
y
s
te
m
f
o
r
th
e
d
o
w
n
li
n
k
s
ce
n
ar
io
,
in
wh
ich
th
er
e
ar
e
tr
an
s
m
it
a
n
ten
n
as
at
t
h
e
b
ase
s
tatio
n
an
d
r
ec
eiv
e
ter
m
in
als
i.e
.
u
s
er
s
.
A
l
l
u
s
er
ter
m
i
n
als
ar
e
h
av
in
g
o
n
l
y
o
n
e
an
te
n
n
a
b
ec
au
s
e
o
f
th
e
h
ar
d
w
ar
e
a
n
d
co
s
t
co
n
s
tr
ai
n
ts
o
f
th
e
u
s
er
eq
u
ip
m
en
t.
A
ll
t
h
e
tr
an
s
m
it
an
te
n
n
as
f
o
r
m
th
e
u
n
i
f
o
r
m
li
n
ea
r
ar
r
a
y
as th
e
y
ar
e
p
lace
d
alo
n
g
a
lin
e
at
eq
u
id
is
tan
t p
o
in
ts
.
Fig
u
r
e
1
.
Mu
lti
u
s
er
MI
MO
S
y
s
te
m
Mo
d
el
T
h
e
s
ig
n
al
r
ec
ei
v
ed
b
y
th
e
u
s
e
r
s
is
g
i
v
e
n
b
y
[
2
]
(
1
)
H,
is
th
e
ch
an
n
el
m
atr
i
x
b
etw
ee
n
th
e
tr
an
s
m
i
t
an
ten
n
a
s
an
d
th
e
u
s
er
s
an
d
h
a
v
e
d
i
m
en
s
io
n
an
d
d
en
o
tes th
e
Her
m
itia
n
o
f
th
e
m
a
tr
ix
;
(
2
)
No
w
i
n
th
i
s
,
d
en
o
tes
th
e
d
i
m
en
s
io
n
al
ch
a
n
n
e
l
m
atr
i
x
f
o
r
th
e
u
s
er
f
r
o
m
all
b
ase
s
tatio
n
an
ten
n
a
s
.
Her
e,
is
t
h
e
tr
an
s
m
itted
s
ig
n
al
v
ec
to
r
.
A
ls
o
,
b
ein
g
ad
d
iti
v
e
co
m
p
le
x
Ga
u
s
s
ian
n
o
is
e
w
i
th
ze
r
o
m
ea
n
a
n
d
u
n
it
v
ar
ian
ce
.
T
h
e
b
ase
s
tatio
n
h
as c
o
m
p
lete
k
n
o
wled
g
e
o
f
ch
a
n
n
els
f
o
r
all
u
s
er
s
.
2
.
1
.
User
G
ro
up
ing
B
a
s
ed
o
n
K
-
M
ea
n
Clus
t
er
ing
I
n
r
ea
l
li
f
e
s
ce
n
ar
io
s
,
th
er
e
ar
e
lar
g
e
n
u
m
b
er
s
o
f
u
s
er
s
s
u
c
h
th
at
a
ll
ca
n
n
o
t
b
e
ac
co
m
m
o
d
ated
in
t
h
e
s
y
s
te
m
at
t
h
e
s
a
m
e
ti
m
e.
T
o
av
o
id
s
u
c
h
ca
s
e
s
,
s
o
m
e
u
s
er
s
ar
e
s
elec
ted
f
r
o
m
to
tal
n
u
m
b
e
r
o
f
u
s
er
s
to
m
a
k
e
g
r
o
u
p
s
.
B
u
t,
t
h
is
g
r
o
u
p
i
n
g
o
f
u
s
er
s
i
s
a
b
it
p
r
o
b
le
m
.
Fo
r
ex
a
m
p
le,
i
f
s
e
lectio
n
o
f
u
s
er
s
f
r
o
m
a
ll
t
h
e
n
u
m
b
er
o
f
u
s
er
s
is
to
b
e
d
o
n
e,
th
en
th
er
e
w
ill
b
e
co
m
b
i
n
ati
o
n
s
.
T
h
is
w
ill
b
e
r
ea
lly
a
co
m
p
licated
p
r
o
ce
s
s
.
So
,
ad
ap
tin
g
u
s
er
g
r
o
u
p
in
g
b
a
s
ed
o
n
s
o
m
e
p
ar
a
m
eter
r
ed
u
ce
s
th
e
co
m
p
u
tatio
n
al
co
m
p
lex
it
y
o
f
t
h
e
s
y
s
te
m
[
7
]
.
So
,
th
e
u
s
er
g
r
o
u
p
in
g
u
s
ed
is
t
h
e
K
-
m
ea
n
cl
u
s
ter
in
g
w
h
ic
h
h
elp
s
to
g
r
o
u
p
t
h
e
u
s
er
s
b
y
m
ea
n
s
o
f
t
h
eir
d
is
ta
n
ce
f
r
o
m
th
e
b
ase
s
ta
tio
n
an
ten
n
a
s
.
Fo
r
ex
a
m
p
le,
a
r
an
d
o
m
s
e
t
o
f
d
ata
(
u
s
er
s
)
is
g
iv
e
n
,
an
d
w
e
w
an
t
to
d
iv
id
e
th
e
m
i
n
to
g
r
o
u
p
s
u
s
in
g
t
h
i
s
al
g
o
r
ith
m
.
Fir
s
tl
y
,
th
e
n
u
m
b
er
o
f
g
r
o
u
p
s
n
ee
d
s
to
b
e
d
e
ter
m
i
n
ed
i.e
.
in
h
o
w
m
a
n
y
g
r
o
u
p
s
t
h
e
u
s
er
s
n
ee
d
to
b
e
d
iv
id
ed
.
A
cc
o
r
d
in
g
l
y
,
t
h
e
v
al
u
e
o
f
K
is
d
eter
m
i
n
ed
as
it
d
e
n
o
tes
th
e
n
u
m
b
er
o
f
g
r
o
u
p
s
f
o
r
m
ed
.
I
f
t
w
o
g
r
o
u
p
s
ar
e
f
o
r
m
ed
th
e
n
th
e
v
al
u
e
o
f
K
is
t
w
o
.
Evaluation Warning : The document was created with Spire.PDF for Python.
IJ
-
I
C
T
I
SS
N:
2252
-
8776
P
erfo
r
ma
n
ce
I
mp
r
o
ve
men
t o
f
MU
-
MIMO
S
ystem
b
y
Op
timi
z
in
g
th
e
K
-
F
a
cto
r
fo
r
th
e
…
(
A
n
ku
s
h
K
a
n
s
a
l
)
91
T
h
e
s
tep
s
to
f
o
r
m
th
e
cl
u
s
ter
s
u
s
i
n
g
K
-
m
ea
n
alg
o
r
it
h
m
s
[
7
]
:
a.
C
h
o
o
s
e
o
n
e
d
ata
p
o
in
t
a
s
t
h
e
ce
n
tr
e
f
r
o
m
th
e
to
tal
s
et
o
f
d
ata
p
o
in
ts
a
n
d
m
a
k
e
t
h
e
s
u
b
s
et
f
r
o
m
b
y
ch
o
o
s
in
g
w
h
ich
ar
e
clo
s
e
e
n
o
u
g
h
to
t
h
e
ce
n
tr
o
id
an
d
ar
e
s
i
m
i
lar
in
r
eq
u
ir
ed
p
r
o
p
e
r
ties
.
b.
T
h
e
m
ea
n
s
o
f
th
e
d
ata
p
o
in
ts
i
n
ea
c
h
cl
u
s
ter
ar
e
co
m
p
u
ted
,
a
n
d
th
is
m
ea
n
v
ec
to
r
b
ec
o
m
e
s
t
h
e
n
e
w
ce
n
tr
e
f
o
r
th
at
cl
u
s
ter
.
Fig
u
r
e
2
.
E
x
a
m
p
le
o
f
K
-
Me
a
n
C
lu
s
ter
in
g
A
ll
t
h
e
u
s
er
s
in
t
h
e
p
r
ac
tical
s
ce
n
ar
io
ar
e
d
is
p
lace
d
to
d
if
f
e
r
en
t
lo
ca
tio
n
s
.
So
m
e
o
f
th
e
m
ar
e
at
r
est
an
d
s
o
m
e
ar
e
m
o
v
in
g
.
So
,
t
h
is
lead
s
to
v
ar
y
in
g
s
tr
en
g
th
o
f
s
i
g
n
al
w
h
ich
r
ea
c
h
es o
u
t to
t
h
e
u
s
er
s
f
r
o
m
th
e
b
ase
s
tatio
n
a
n
te
n
n
a
s
.
So
,
it
b
ec
o
m
es
m
o
r
e
n
ec
es
s
ar
y
to
g
r
o
u
p
th
e
u
s
er
s
ac
co
r
d
in
g
to
t
h
ei
r
co
n
d
itio
n
s
at
t
h
at
p
ar
ticu
lar
ti
m
e.
T
h
i
s
alg
o
r
it
h
m
w
h
en
u
s
ed
in
m
u
lti
u
s
er
M
I
MO
s
y
s
te
m
s
,
co
n
s
id
er
s
v
ar
i
o
u
s
p
ar
a
m
eter
s
lik
e
s
ig
n
al
to
n
o
i
s
e
r
atio
(
SNR
)
,
p
o
s
itio
n
,
v
elo
cit
y
o
f
t
h
e
u
s
er
s
a
n
d
ch
a
n
n
el
t
h
r
o
u
g
h
w
h
ic
h
t
h
e
s
ig
n
al
p
ass
e
s
w
h
ile
tr
av
elli
n
g
f
r
o
m
b
a
s
e
s
tatio
n
to
u
s
er
s
[
8
]
.
A
ll
t
h
ese
co
n
d
itio
n
s
h
elp
to
f
o
r
m
t
h
e
g
r
o
u
p
in
g
wh
ich
m
a
x
i
m
ize
s
th
e
ca
p
ac
it
y
o
f
t
h
e
s
y
s
te
m
.
T
h
e
m
ain
s
tep
s
to
f
o
r
m
th
e
g
r
o
u
p
i
n
g
ar
e
as sh
o
w
n
i
n
f
lo
w
ch
ar
t b
el
o
w
.
Fig
u
r
e
3
.
Flo
w
C
h
ar
t
f
o
r
User
Gr
o
u
p
in
g
U
s
i
n
g
K
-
Me
a
n
C
l
u
s
ter
in
g
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.
5
,
No
.
3
,
Dec
em
b
er
2
0
1
6
:
8
9
–
93
92
As
it
is
k
n
o
w
n
,
w
h
e
n
u
s
er
g
r
o
u
p
s
ar
e
m
ad
e
it
h
elp
s
to
i
n
cr
ea
s
e
th
e
s
y
s
te
m
ca
p
ac
it
y
b
y
m
iti
g
ati
n
g
t
h
e
in
ter
f
er
e
n
ce
f
r
o
m
t
h
e
o
t
h
er
g
r
o
u
p
s
a
n
d
w
it
h
i
n
t
h
e
s
a
m
e
u
s
e
r
g
r
o
u
p
b
y
p
er
f
o
r
m
in
g
th
e
p
r
ec
o
d
in
g
.
A
lo
n
g
w
it
h
th
at,
it
h
elp
s
to
m
a
k
e
th
e
u
s
er
g
r
o
u
p
s
b
ased
o
n
s
o
m
e
co
m
m
o
n
p
r
o
p
e
r
ties
w
h
ich
f
u
r
t
h
er
h
elp
s
to
m
ai
n
tai
n
th
e
q
u
alit
y
o
f
t
h
e
s
ig
n
al.
W
h
i
le
m
ak
in
g
g
r
o
u
p
s
,
t
h
e
i
n
ter
f
e
r
e
n
ce
is
s
u
r
el
y
r
ed
u
ce
d
b
u
t
t
h
e
n
u
m
b
er
o
f
u
s
er
s
b
ei
n
g
s
er
v
ed
at
a
ti
m
e
also
r
ed
u
ce
s
.
So
,
it
is
n
ec
ess
ar
y
to
m
ak
e
o
u
t
th
e
b
ala
n
ce
s
u
c
h
t
h
at
th
e
p
er
f
o
r
m
an
ce
o
f
th
e
s
y
s
te
m
i
s
m
ain
tain
ed
w
h
ile
ac
co
m
m
o
d
ati
n
g
m
a
x
i
m
u
m
n
u
m
b
er
o
f
u
s
er
s
.
So
,
o
p
ti
m
u
m
n
u
m
b
er
o
f
u
s
er
g
r
o
u
p
s
n
ee
d
s
to
b
e
f
o
r
m
ed
.
3
.
RE
SUL
T
S AN
D
DIS
CUS
SI
O
N
T
h
e
s
i
m
u
latio
n
r
es
u
lts
d
e
m
o
n
s
tr
ati
n
g
t
h
e
o
p
ti
m
izat
io
n
o
f
g
r
o
u
p
in
g
ar
e
p
r
ese
n
ted
h
er
e.
I
n
th
i
s
s
y
s
te
m
,
to
tal
o
f
1
0
0
an
ten
n
a
s
at
th
e
b
ase
s
ta
tio
n
a
n
d
1
0
0
u
s
er
s
w
it
h
s
i
n
g
le
an
te
n
n
a
ar
e
co
n
s
id
er
ed
f
o
r
co
m
m
u
n
icatio
n
.
T
h
e
en
v
ir
o
n
m
en
t
tak
e
n
is
th
e
R
a
y
leig
h
f
a
d
in
g
.
Fo
r
all
th
e
s
i
m
u
latio
n
s
,
tr
an
s
m
it
p
o
w
er
u
s
ed
is
1
0
d
B
an
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Evaluation Warning : The document was created with Spire.PDF for Python.
IJ
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CO
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ter
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o
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h
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to
tal
n
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m
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ed
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s
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m
b
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to
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m
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ca
p
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th
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ized
w
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t
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f
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s
t
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v
a
lu
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o
f
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f
u
r
t
h
er
i
n
cr
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s
ed
to
f
i
v
e
th
e
s
u
m
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ate
d
ec
r
ea
s
e
s
.
So
th
e
o
p
ti
m
ized
g
r
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u
p
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n
g
is
d
o
n
e
f
o
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th
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v
al
u
e
o
f
f
o
u
r
.
RE
F
E
R
E
NC
E
S
[1
]
D T
se
;
P
V
isw
a
n
a
th
,
F
u
n
d
a
m
e
n
tals o
f
W
ir
e
les
s Co
m
m
u
n
ica
ti
o
n
,
C
a
m
b
rid
g
e
Un
iv
e
rsit
y
P
re
ss
,
2
0
0
5
.
[2
]
Ka
i
-
Kit
W
o
n
g
;
Ro
ss
D
M
u
rc
h
;
Kh
a
led
Be
n
L
e
taie
f
,
P
e
rf
o
r
m
a
n
c
e
En
h
a
n
c
e
m
e
n
t
o
f
M
u
lt
iu
se
r
M
IM
O
W
irele
ss
Co
m
m
u
n
ica
ti
o
n
S
y
ste
m
s
,
IEE
E
T
ra
n
sa
c
ti
o
n
s
o
n
C
o
mm
u
n
ica
ti
o
n
s
,
v
o
l.
50
,
p
p
.
1
9
6
0
-
1
9
7
0
,
2
0
0
2
.
[3
]
S
e
rb
e
tl
i
S
;
Ye
n
e
r
A
,
T
ra
n
sc
e
iv
e
r
Op
ti
m
iza
ti
o
n
f
o
r
M
u
lt
i
u
se
r
M
IM
O
S
y
ste
m
s,
IEE
E
T
ra
n
sa
c
ti
o
n
s
o
n
S
i
g
n
a
l
Pro
c
e
ss
in
g
,
v
o
l
.
5
2
,
p
p
.
2
1
4
-
2
2
6
,
2
0
0
4
.
[4
]
A
n
d
re
a
G
o
ld
sm
it
h
,
W
irele
ss
Co
m
m
u
n
ica
ti
o
n
,
Ca
m
b
rid
g
e
Un
iv
e
rsity
P
re
ss
,
2
0
0
5
.
[5
]
S
e
rb
e
tl
i
S
;
Ye
n
e
r
A
,
T
ra
n
sc
e
iv
e
r
Op
ti
m
iza
ti
o
n
f
o
r
M
u
lt
i
u
se
r
M
IM
O
S
y
ste
m
s
,
IEE
E
T
r
a
n
sa
c
ti
o
n
s
o
n
S
i
g
n
a
l
Pro
c
e
ss
in
g
,
v
o
l
.
5
2
,
p
p
.
2
1
4
-
2
2
6
,
2
0
0
4
.
[6
]
Yi
X
u
;
G
u
o
se
n
Yu
e
;
Na
ra
y
a
n
P
ra
sa
d
;
S
a
m
p
a
th
Ra
n
g
a
ra
jan
;
S
h
iw
e
n
M
a
o
,
Us
e
r
Gr
o
u
p
in
g
a
n
d
S
c
h
e
d
u
li
n
g
f
o
r
L
a
rg
e
S
c
a
le
M
IM
O
S
y
ste
m
s
wi
th
T
wo
-
S
ta
g
e
Pre
c
o
d
in
g
,
IEE
E
In
tern
a
ti
o
n
a
l
Co
n
f
e
re
n
c
e
o
n
Co
m
m
u
n
ica
ti
o
n
s
,
pp.
5
1
9
7
-
5
2
0
2
,
2
0
1
4
.
[7
]
Ka
n
u
n
g
o
T;
M
o
u
n
t
D
M
;
Ne
tan
y
a
h
u
N
S
.
A
n
e
ff
ici
e
n
t
K
-
m
e
a
n
s
c
lu
ste
rin
g
a
lg
o
rit
h
m
:
A
n
a
l
y
sis
a
n
d
im
p
le
m
e
n
tatio
n
P
a
tt
e
r
n
A
n
a
l
y
sis a
n
d
M
a
c
h
in
e
I
n
t
e
ll
ig
e
n
c
e
,
IEE
E
T
ra
n
sa
c
ti
o
n
s
o
n
C
o
mm
u
n
ica
ti
o
n
s
, v
o
l
.
24
,
p
p
.
8
8
1
-
892
,
2
0
0
2
.
[8
]
M
in
c
h
a
e
Ju
n
g
;
Yo
u
n
su
n
Kim
;
Ju
h
o
L
e
e
;
S
o
o
y
o
n
g
Ch
o
i
,
Op
ti
m
a
l
Nu
m
b
e
r
o
f
Us
e
rs
in
Zero
-
F
o
rc
in
g
Ba
se
d
M
u
lt
i
u
se
r
M
IM
O
S
y
ste
m
s
w
it
h
L
a
r
g
e
Nu
m
b
e
r
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f
A
n
ten
n
a
s,
J
o
u
rn
a
l
Of
Co
mm
u
n
ica
ti
o
n
s
A
n
d
Ne
two
rk
s
,
v
o
l.
15
,
pp.
3
6
2
-
3
6
9
,
2
0
1
3
.
[9
]
L
in
X
.
Ca
i;
Ha
n
g
g
u
a
n
S
h
a
n
;
We
ih
u
a
Z
h
u
a
n
g
;
Xu
e
m
in
S
h
e
n
;
J
o
n
W
M
a
rk
;
Zo
n
g
x
in
W
a
n
g
,
A
Distrib
u
ted
M
u
lt
i
-
Us
e
r
M
IM
O
M
AC
Pro
to
c
o
l
fo
r
W
ire
les
s
L
o
c
a
l
Are
a
Ne
two
rk
,
IE
EE
G
lo
b
a
l
T
e
lec
o
m
m
u
n
ica
ti
o
n
Co
n
f
e
re
n
c
e
,
p
p
.
1
-
5,
2
0
0
8
.
0
5
10
15
20
25
30
0
5
10
15
20
25
30
S
N
R
(
d
B
)
S
u
m
r
a
t
e
(
(
b
p
s
/
H
z
)
K
-
m
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(
G
r
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u
p
s
=
2
)
K
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(
G
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p
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=
3
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K
-
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(
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p
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=
4
)
K
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m
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n
(
G
r
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u
p
s
=
5
)
Evaluation Warning : The document was created with Spire.PDF for Python.