OHP CDMA ALOHA 1999 2 Copyrighted Hiraku Okada 1999 all rights reserved.
CDMA ALOHA
1. 2. CDMA ALOHA 3. 4. 5.
5000 4000 3000 2000 1000 PHS 1997 2005 2010 1,115 4,136 4,459 287 1,929 2,755 0 87 88 89 90 91 92 93 94 95 96 97 98 5 6.4% 41.8% 54.9% PHS,
,, (IMT-2000)
(CDMA),, ( )
,
ALOHA packet hub station user 1 user 2 user k collision collision collision success time t
CDMA ALOHA CDMA ALOHA CDMA ALOHA,,
CDMA ALOHA
CDMA ALOHA
(H6-10) (H7-3), (H8-12) (H9-3), (H10.7) CLSP CDMA ALOHA (H7-5), (H8-9) ORC (H7-5), (H8-9) CDMA ALOHA CDMA Slotted ALOHA (H9-12), (H10-6), (H10-7) CDMA Unslotted ALOHA (H10-10), (H10-10) MCLSP (H8-11), (H8.12) OACP (H7-12), (H8-7), (H9-3) CLSP CDMA ALOHA
1. 2. CDMA ALOHA 3. 4. 5.
CDMA ALOHA CDMA unslotted ALOHA CDMA slotted ALOHA Number of packets t Time Number of packets Time t
CDMA Slotted ALOHA CDMA Unslotted ALOHA [packet/ Tp ] 6 5 N=60 L=L=500 [bits] Eb/No=10 [db] Throughput S 4 3 2 CDMA Unslotted ALOHA CDMA Slotted ALOHA 1 0 0 5 10 15 20 25 30 Offered load G [packet/ Tp]
1. 2. CDMA ALOHA 3. 4. 5.
, packet Tw= 1 λr packet t packet packet t
λo: λr:
d(r) (H7-5), (H8-9) d(r) r = d(r) > 0 d(r) < 0 d(r) = 0 ( r ) ( r )
d(r) 4 3 2 1 0-1 -2-3 Go=6.13 Gr=35 Gr=25 Gr=5 Gr=15 λ o Go=K Tp Gr=K Tp λ r K: Tp: -4 0 0.2 0.4 0.6 0.8 1 r (= )
Optimal Retransmission Control (ORC) (H7-5), (H8-9)
: λr(r) λr(r) : λr(r) Tp 1 Tw= (r) λ r t t
λ r (r) r λ r (r) = Gmax (1 r) Go Tp K r Gmax : Go=K λ o Tp K : Tp : 5 Throughput S 4 3 2 1 CDMA ALOHA System 0 0 5Gmax 10 15 20 Offered Load G
d(r) 4 3 2 1 0-1 Go=6.13 Gr=35 Gr=5 Gr=25 no access control -2 Gr=15-3 ORC -4 0 0.2 0.4 0.6 0.8 1 r (= )
[packet/ Tp ] 7 6 5 ORC Throughput S 4 3 2 1 N=60 L=500 [bits] Eb/No=10 [db] no access control 0 0 5 10 15 20 Offered load Go [packet/ Tp] (all users are in originating mode)
ORC Optimal Access Control Protocol (OACP) (H9-3), (H7-12), (H8-7),.
Channel Load Sensing Protocol (CLSP) A. H. Abdelmonem et. al channel load 4 3 2 1 0 sensing threshold packet transmission t
OACP λo () Yes No λr(r) ()
[packet/ Tp ] 7 6 5 OACP CLSP only ORC only Throughput S 4 3 2 1 N=60 L=500 [bits] Eb/No=10 [db] no access control 0 0 5 10 15 20 Offered load Go [packet/ Tp] (all users are in originating mode)
CDMA, Throughput S 7 6 5 4 3 2 1 00 5 10 15 20 Offered load Go (all users are in originating mode)
[packet/ Tp ] 7 6 5 upper bound OACP CLSP only ORC only Throughput S 4 3 2 1 N=60 L=500 [bits] Eb/No=10 [db] no access control 0 0 5 10 15 20 Offered load Go [packet/ Tp] (all users are in originating mode)
[s/ Tp ] Delay D 200 150 100 N=60 L=500 [bits] Eb/No=10 [db] K=1000 no access control ORC CLSP 50 OACP 0 0 5 10 15 20 Offered load Go [packet/ Tp] (all users are in originating mode)
(1,000km):0.013 [s] (36,000km):0.5[s]
CLSP ( ) 4 channel3 load 2 1 X 0 sensing controlled by old information threshold packet to be transmitted packet transmission access timing delay T D t
CLSP [packet/ Tp ] 7 6 5 N=60 L=500 [bits] Eb/No=10 [db] α=9 τd=0 (no access timing delay) τd =0.1 Throughput S 4 3 2 1 without CLSP τd =9.2 (GEO) τd =0.26 (LEO) τd=1 0 0 5 10 15 20 Offered load G [packet/ ] Tp
ORC r r : r system state r constant controlled by system state r packet to be transmitted packet transmission access timing delay T D t
OACP [packet/ Tp ] 7 6 Throughput S 5 4 3 2 1 N=60 L=500 [bits] Eb/No=10 [db] OACP τd=0 =0.1 =0.26 =1 =9.2 No access control 0 0 5 10 15 20 Offered load Go [packet/ Tp] (all users are in originating mode)
ORC OACP ORC,. OACP,,. OACP,., OACP.
1. 2. CDMA ALOHA 3. 4. 5.
CDMA ALOHA
,,
CDMA ALOHA (H10-10), (H10-10) λ K λ λ B
p p=g max/k G max : K : 1/p t
? λ N No? Yes Yes No p
[packet/ Tp ] Throughput S 6 5 4 3 2 1 p=0.10 (=Gmax/K) p=0.15 p=0.20 p=0.05 N=60 Eb/No=10dB K=100 L=500 [bits] B=3 0 0 5 10 15 20 Offered load of new packet GN [packet/ Tp]
[packet/ Tp ] 6 5 Throughput S 4 3 2 1 B=1 2 3 4 5 N=60 Eb/No=10dB K=100 L=500 p=0.1 0 0 5 10 15 20 Offered load of new packet GN [packet/ Tp]
1 Rejection probability Q R 10-1 10-2 10-3 B=1 2 3 4 5 N=60 Eb/No=10dB K=100 L=500 p=0.1 10-4 0 5 10 15 20 Offered load of new packet GN [packet/ Tp]
CLSPCDMA ALOHA? λ N Yes? Yes No No p CLSP Yes
CLSPCDMA ALOHA [packet/ Tp ] Throughput S 7 6 5 4 3 2 N=60 Eb/No=10dB K=100 L=500 B=5 with CLSP τd=0 =0.1 =0.26 =1 =9.2 w/o CLSP 1 0 0 5 10 15 20 Offered load of new packet GN [packet/ Tp]
CLSPCDMA ALOHA [packet/ Tp ] Throughput S 7 6 5 4 3 2 N=60 Eb/No=10dB K=100 L=500 B=5 with CLSP τd=0 =0.1 =0.26 =1 =9.2 w/o CLSP 1 OACP 0 0 5 10 15 20 Offered load of new packet GN [packet/ Tp]
CDMA ALOHA,,. CLSP CDMA ALOHA OACPCDMA ALOHA
1. 2. CDMA ALOHA 3. 4. 5.
CDMA ALOHA CDMA ALOHA,, OACP, CDMA ALOHA CDMA ALOHA,
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