6-ΣΔΥ50 - ΟΣΣ4 - Ασκήσεις
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Transcript of 6-ΣΔΥ50 - ΟΣΣ4 - Ασκήσεις
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: 1 .
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(.. , )
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100 mW, 1m
0.001mW 2.4
2.425 GHz
)10m, )50m,
)100m; :
C HHz S/N Shannon:
4
N
SHC 1log
2
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2
E =2.425 GHz - 2.4 GHz =25
MHz
S/N HHz Shannon:
:
5
N
SHC 1log2
MbpsN
S
BCmWPP
MbpsN
SBCmWPP
MbpsN
SBCmWPP
mm
mm
mm
86001.0
01.0
1log251log01.0100
1
*100d
d
133001.0
04.01log251log04.0
50
1*100
d
d
250001.0
11log251log1
10
1*100
d
d
22
22
01100
22
22
0150
22
22
0110
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Hata
900 MHz. 100 m, 2 m 4 Km
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o Hata
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4 A,
B, C, D . D , C
, p B, C drop
C D error-free.
,
hops,
, :1. hops
2. A C
3. hops
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4 1. 1,2 3 hops
1 hop p
2 hops p(1-p)
3 hops (1-p)2
, hops : p + 2p(1-p) +3(1-p)2=p2-3p+3
2. : (1-p)2.
: 1/(1-p)2
3. 2 hops : (p2-3p+3)/(1-
p)2
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broadcast hosts
slots nhosts
p slot slot;
slot , . ;
slot; 10
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: np(1-p)n-1
: (1-
p)n
, ( slots ) :
Pcol= 1- np(1-p)n-1 - (1-p)n
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6 -ALOHA
ALOHA , . , p= 0.4
1. ;
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6 -ALOHA
2. k( ); k=3. [:
, . . k()
]
3. ( p);
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1. p= 0.4, , p=1-p=0.6
2. H p=0.6,
pp, p pp k pkp
k=3 p3p=0.43 * 0,6=0,0384
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3.
:
666.16.0
1
'
1'
1')
'
'(')
'
1
'
('
)('')1(
222
0 00
p
p
p
p
ppp
pp
pp
ppkpppk k k
kk
k
k
15
6 p0
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7 -TDMA
TDMA. :
1 (frame) 200ms
2Mbps 10ms
1 downlink
, 1 uplink, . (
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7 -TDMA
1. / ;
2. ( ) ,
( )
3. , (request) slot uplink
. , response slot downlink, , .
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7 -TDMA
4. ;
5. TDMA, slottedALOHA, ;
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71. (200-2*10)/10 = 18 /
2. , 200msec
3. uplink frame
200ms . . ,
190msec . 2 , . (180ms +10ms(downlink)=)190msec.
200 msec +190 msec +190 msec =580msec 19
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4. 18 *100kbps = 1800kbps = / = (1800/2000 )=0,9 90%
5. slotted aloha 0.36
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ferry boat 100 10
2 , ;
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Erlang B
100 * 1 / * 3
60 = 5 Erlangs
5 Erlangs, 10 0.02 (2%) blockingprobability Erlang B
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9 )
, )Nreuse=3, ) reuse=7
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( reuse= 7),
n=4
( 120) SINR
;
25
9 )
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9-Nreuse
=3
3
1
2 132 1
32 1 32
32 1 32 1
1 32 1 32
1 32 132
1 32 1 32
1 32 132
1 32 1 32
1 32 1
3
232
3
3
3
2
2
2
2
N=3, =>i=j=1
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9-Nreuse
=7
N=7, =>i=2, j=1
1
2 3
4
56
7
1
2 3
4
56
7
1
2 3
4
56
7
1
2 3
4
56
7
1
2 3
56
7
1
2 3
4
56
7
1
2 3
4
56
7
1 4 56 7
56
4
3 2
23
4 17
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7 )
5 : 2.
CIR : 23 dB. 60o CIR.
5: 6CIR : 19 dB
9
d
N
I
Cn
reuse
5,2325,220
2
5,440
2
*3
d
N
I
Cn
reuse
65,1841,73
6
5,440
6
*3
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10 GSM
GSM TDMA .
50 MHz (25 Hz downlink, 25 Hz uplink). downlink uplink 1 slot frame 8 slots. Downlink uplink 200 KHz. O 4.
.
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