submission doc.: ieee 11-10/1511r0 company confidential november 2011 chittabrata ghosh, nokiaslide...
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Submission
doc.: IEEE 11-10/1511r0
Company Confidential
November 2011
Chittabrata Ghosh, NokiaSlide 1
Fairness of DCF in 802.11ah
Date: 2011-11-07
Name Affiliations Address Phone email ZhongYi Jin Nokia 2054 University
Ave, Suite 600 Berkeley, CA 94703
+16502846138
Taejoon Kim Nokia +15102198304
HongKun Li Nokia [email protected]
Klaus Doppler Nokia +15104232458
Chittabrata Ghosh
Nokia +16502007566 [email protected]
Authors:
Submission
doc.: IEEE 11-10/1511r0
Company Confidential
Abstract
Study the fairness of DCF for 802.11ah depending on the traffic load with different DCF parameters
Slide 2 Chittabrata Ghosh, Nokia
November 2011
Submission
doc.: IEEE 11-10/1511r0
Company Confidential
Simulation Scenarios
Num of AP: 1
Num of Stations: 1000
Topology:
Slide 3 Chittabrata Ghosh, Nokia
November 2011
Submission
doc.: IEEE 11-10/1511r0
Company Confidential
Simulation Parameters
Slide 4 Chittabrata Ghosh, Nokia
November 2011
Channel Bandwidth 2MHz and 1000 nodes
Data Rate 100bps[1] /500bps/1kbps
TX Power 20dBm
Antenna Gains 3dB
Max Communication Range 1012 Meters (-88dBm)
Max Interference Range 1293 Meters (-92dBm)
Packet Size 250Bytes
DIFS 256µs
SIFS 160µs
Slot Time 48µs
CWmin 15/63/127/255/511
CWmax 1023/1023/1023/2047/4095
Simulation time 160s
MCS BPSK ½
Submission
doc.: IEEE 11-10/1511r0
Company Confidential
Simulation Parameters 2
• Pathloss model• Outdoor Macro [2]: PL(d) =8+37.6log10(d)
• Station to Station model [3]: PL(d)=16.90 + 42.4*log10(d)
• Traffic Model • Simulation Time = 160 Seconds
• TX time for each packet is randomly selected in the 160 seconds
Slide 5 Zhong-Yi Jin, Nokia
November 2011
160 seconds
Submission
doc.: IEEE 11-10/1511r0
Company Confidential
Chittabrata Ghosh, Nokia
Fairness: throughput CDF (CWmin 15)
Slide 6
November 2011
RTS/CTS Without RTS/CTS
0 0.5 1 1.50
0.2
0.4
0.6
0.8
1
User throughput (kbps)
Out
age
(CD
F)
0.1kbps0.2kbps0.5kbps1kbps1.6kbps
0 0.5 1 1.50
0.2
0.4
0.6
0.8
1
User throughput (Kbps)
Out
age
(CD
F)
0.1kbps0.2kbps0.5kbps1kbps1.6kbps
Submission
doc.: IEEE 11-10/1511r0
Company Confidential
Fairness: STA with throughput zero (CWmin 15)
Slide 7 Chittabrata Ghosh, Nokia
November 2011
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 20
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
Data rate (kbps)
Per
cent
age
of Z
ero
Thr
ough
put
ST
As
with RTS/CTSwithout RTS/CTS
Submission
doc.: IEEE 11-10/1511r0
Company Confidential
Effect of increasing load on througput with link adaptation (CWmin 15)
Slide 8 Chittabrata Ghosh, Nokia
November 2011
0 0.5 1 1.5 260
70
80
90
100
110
120
130
140
Data rate (kbps)
Tot
al t
hrou
ghpu
t (k
bps)
RTS/CTS onlyno RTS/CTS and LARTS/CTS with LAno RTS/CTS with LA
Submission
doc.: IEEE 11-10/1511r0
Company Confidential
STA with zero throughput for varying CW
Slide 9 Chittabrata Ghosh, Nokia
November 2011
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 20
0.05
0.1
0.15
0.2
0.25
0.3
0.35
Data rate (kbps)
Per
cent
age
of z
ero-
thro
ughp
ut S
TA
s
(15,1023)(255,2047)(127,1023)(127,2047)(511,4095)
Without RTS/CTSWith RTS/CTS
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 20
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
Data rate (kbps)
Per
cent
age
of Z
ero
Thr
ough
put S
TA
s
(15,1023)(127,1023)(127,2047)(255,2047)(511,4095)
Submission
doc.: IEEE 11-10/1511r0
Company Confidential
Conclusions
• DCF is unfair and inefficient in terms of energy and throughput under heavy/bursty traffics
• Varying CW sizes does not solve the problem
Slide 10 Chittabrata Ghosh, Nokia
November 2011
Submission
doc.: IEEE 11-10/1511r0
Company Confidential
References
[1] 11-11-1229-r0 TGah 11ah M2M channel access performance
[2] TGah channel model – proposed text, IEEE802.11-11/0968r1
[3] STA-STA Pathloss Model, IEEE802.11-11/1263r4
Slide 11 Chittabrata Ghosh, Nokia
November 2011