Mickposter Nuim
1
IEEE 802.11 WLAN Capacity and Optimization for Multiplayer Network Games Hanghang Qi Hamilton Institute, National University of Ireland, Maynooth, Ireland. [email protected] David Malone Hamilton Institute, National University of Ireland, Maynooth, Ireland. [email protected] Dmitri Botvich TSSG, Waterford Institute of Technology, Ireland. [email protected] 1 Problem define:network game within an WLAN . . . AP C C C S λ c λ c λ c n n(λ c + λ s ) nλ s Figure 1: How many players can play a good game within a 802.11 WLAN? 2 Network games traffic We did many experiments in our 4 PCs wireless game network testbed and got the game traffic in packet transmission level. The key characteristics are shown in Fig. 2 0 0.02 0.04 0.06 0.08 0.1 0.12 0 2000 4000 6000 8000 10000 12000 14000 AtoS interarrival time (s) (a) Client to Server 0 0.02 0.04 0.06 0.08 0.1 0.12 0 50 100 150 200 250 300 350 400 450 500 StoA interarrival time (s) (b) Server to Client 0 50 100 150 200 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 AtoS packet size (bytes) (c) Client to Server 0 50 100 150 200 0 100 200 300 400 500 600 700 StoA packet size (bytes) (d) Server to Client Figure 2: Quake 4 game traffic characteristics 3 802.11 network model and performance IEEE 802.11 MAC DCF uses a CSMA/CA with exponential backoff scheme which can be modelled with a 2-D Markov Chain. ... ... ... ... ... ... ... ... 0,0e 0,w0-1e 1-q 1-q 1-q 0,1e 0,2e ... 0,0 0,w0-1 i-1,0 i,wi-1 0,1 0,2 ... 1 1 1 1 1 1 1 1 1 m,wm-1 i,0 i,1 i,2 ... m,0 m,1 m,2 ... ... 1-p 1-p 1-p 1-p q q q q Figure 3: Markov chain model of 802.11 MAC The Bianchi’s 2-D Markov chain model together with the traffic arrival model are used to calculate the throughput, delay and jitter. Then Frank’s em- pirical mapping model is used to get Mean Opinion Score (MOS) from delay and jitter. 0 5 10 15 20 25 30 35 0 0.2 0.4 0.6 0.8 1 Number of stations Throughput efficiency stations game server AP (a) Throughput efficiency 0 5 10 15 20 25 30 35 0 0.002 0.004 0.006 0.008 0.01 0.012 0.014 Number of stations Delay (s) stations AP game server (b) Delay 0 5 10 15 20 25 30 35 0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 Number of stations Jitter (s) stations AP game server (c) Jitter 0 5 10 15 20 25 30 35 1.5 2 2.5 3 3.5 4 4.5 Number of stations MOS DCF (d) Mean Opinion Score Figure 4: Performance of a basic 802.11 DCF network 4 AP and Server with larger TXOP n Larger TXOP, one of the 802.11e parameters, are given to AP and Server as n increases (n is the number of clients; normal client’s TXOP is 1) to give AP and Server larger transmission opportunity, the network performance can be improved for the games. 0 5 10 15 20 25 30 35 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Number of stations Throughput efficiency game server stations AP (a) Throughput efficiency 0 5 10 15 20 25 30 35 0 0.005 0.01 0.015 0.02 Number of stations Delay (s) game server stations AP (b) Delay 0 5 10 15 20 25 30 35 0 0.01 0.02 0.03 0.04 0.05 Number of stations Jitter (s) game server stations AP (c) Jitter 0 5 10 15 20 25 30 35 1.5 2 2.5 3 3.5 4 4.5 Number of stations MOS TXOP (d) MOS Figure 5: AP and Server priority with TXOP 5 Conclusions Our analytical model suggests that a basic DCF 802.11b WLAN can support maximum 10 players of Quake 4. By using 11e parameter TXOP to give AP and Game Server higher priority to access the channel, the network perfor- mance can be improved to 15 players. References [Bianchi, 2000] Bianchi, G. (2000). Performance analysis of the ieee 802.11 distributed coordination function. Selected Areas in Communications, IEEE Journal on, 18(3):535–547. [Cricenti and Branch, 2007] Cricenti, A. and Branch, P. (2007). Arma(1,1) modeling of quake4 server to client game traffic. In NetGames ’07, NY, USA. ACM. [Wattimena et al., 2006]Wattimena, A. F., Kooij, R. E., van Vugt, J. M., and Ahmed, O. K. (2006). Predicting the perceived quality of a first person shooter: the quake iv g-model. In NetGames ’06, NY, USA. ACM.
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Transcript of Mickposter Nuim
IEEE 802.11 WLAN Capacity and Optimization forMultiplayer Network Games
Hanghang QiHamilton Institute, National University of
Ireland, Maynooth, [email protected]
David MaloneHamilton Institute, National University of
Ireland, Maynooth, [email protected]
Dmitri BotvichTSSG, Waterford Institute of Technology,
1 Problem define:network game within an WLAN
. . .
AP
CC C
S
λc λc λc
n
n(λc + λs)
nλs
Figure 1: How many players can play a good game within a 802.11WLAN?
2 Network games trafficWe did many experiments in our 4 PCs wireless game network testbed and gotthe game traffic in packet transmission level. The key characteristics are shownin Fig. 2
0 0.02 0.04 0.06 0.08 0.1 0.120
2000
4000
6000
8000
10000
12000
14000AtoS
interarrival time (s)
(a) Client to Server
0 0.02 0.04 0.06 0.08 0.1 0.120
50
100
150
200
250
300
350
400
450
500StoA
interarrival time (s)
(b) Server to Client
0 50 100 150 2000
500
1000
1500
2000
2500
3000
3500
4000
4500
5000AtoS
packet size (bytes)
(c) Client to Server
0 50 100 150 2000
100
200
300
400
500
600
700StoA
packet size (bytes)
(d) Server to Client
Figure 2: Quake 4 game traffic characteristics
3 802.11 network model and performanceIEEE 802.11 MAC DCF uses a CSMA/CA with exponential backoff schemewhich can be modelled with a 2-D Markov Chain.
... ... ... ...
... ... ... ...
0,0e 0,w0−1e1−q 1−q 1−q
0,1e 0,2e ...
0,0 0,w0−1
i−1,0
i,wi−1
0,1 0,2 ...1 1 1
1 1 1
1 1 1m,wm−1
i,0 i,1 i,2 ...
m,0 m,1 m,2 ...
...
1−p
1−p
1−p
1−p
q q q q
Figure 3: Markov chain model of 802.11 MAC
The Bianchi’s 2-D Markov chain model together with the traffic arrivalmodel are used to calculate the throughput, delay and jitter. Then Frank’s em-pirical mapping model is used to get Mean Opinion Score (MOS)from delayand jitter.
0 5 10 15 20 25 30 350
0.2
0.4
0.6
0.8
1
Number of stations
Thr
ough
put e
ffici
ency
stationsgame serverAP
(a) Throughput efficiency
0 5 10 15 20 25 30 350
0.002
0.004
0.006
0.008
0.01
0.012
0.014
Number of stations
Del
ay (
s)
stationsAPgame server
(b) Delay
0 5 10 15 20 25 30 350
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
Number of stationsJi
tter
(s)
stations
AP
game server
(c) Jitter
0 5 10 15 20 25 30 351.5
2
2.5
3
3.5
4
4.5
Number of stations
MO
S
DCF
(d) Mean Opinion Score
Figure 4: Performance of a basic 802.11 DCF network
4 AP and Server with larger TXOP nLarger TXOP, one of the 802.11e parameters, are given to AP and Server as nincreases (n is the number of clients; normal client’s TXOP is 1) to give APand Server larger transmission opportunity, the network performance can beimproved for the games.
0 5 10 15 20 25 30 350.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Number of stations
Thr
ough
put e
ffici
ency
game serverstationsAP
(a) Throughput efficiency
0 5 10 15 20 25 30 350
0.005
0.01
0.015
0.02
Number of stations
Del
ay (
s)game serverstationsAP
(b) Delay
0 5 10 15 20 25 30 350
0.01
0.02
0.03
0.04
0.05
Number of stations
Jitte
r (s
)
game serverstationsAP
(c) Jitter
0 5 10 15 20 25 30 351.5
2
2.5
3
3.5
4
4.5
Number of stations
MO
S
TXOP
(d) MOS
Figure 5: AP and Server priority with TXOP
5 ConclusionsOur analytical model suggests that a basic DCF 802.11b WLAN can supportmaximum 10 players of Quake 4. By using 11e parameter TXOP to give APand Game Server higher priority to access the channel, the network perfor-mance can be improved to 15 players.
References[Bianchi, 2000] Bianchi, G. (2000). Performance analysis of the ieee 802.11
distributed coordination function.Selected Areas in Communications, IEEEJournal on, 18(3):535–547.
[Cricenti and Branch, 2007] Cricenti, A. and Branch, P. (2007). Arma(1,1)modeling of quake4 server to client game traffic. InNetGames ’07, NY,USA. ACM.
[Wattimena et al., 2006] Wattimena, A. F., Kooij, R. E., van Vugt, J. M., andAhmed, O. K. (2006). Predicting the perceived quality of a first personshooter: the quake iv g-model. InNetGames ’06, NY, USA. ACM.
