Transcript Measurements of Coexistence between 802.11n

July 2008
doc.: IEEE 802.11-08/0893r0
Measurements of Coexistence between
802.11n 40MHz and Bluetooth
Date: 2008-07-14
Authors:
Name
Company
Nick Do
Intel
Address
Phone
[email protected]
om
mohammad.y.ma
[email protected]
dwane.pottratz@i
ntel.com
eldad.perahia@in
tel.com
Mohammad
Intel
Mansour
Dwane Pottratz Intel
Eldad Perahia
Submission
email
Intel
Slide 1
Eldad Perahia (Intel)
July 2008
doc.: IEEE 802.11-08/0893r0
Abstract
Over-the-air measurements of Bluetooth voice
performance in the presence of 802.11n 40 MHz link.
Results show no degradation to quality of the Bluetooth
voice link.
Submission
Slide 2
Eldad Perahia (Intel)
July 2008
doc.: IEEE 802.11-08/0893r0
Test Setup
•
•
•
•
•
•
•
Wired controlled network on Gigabit switch
IxChariot 6.2 traffic is managed on controlled network
WiFi and Bluetooth networks are separate subnets
WiFi link is 2.4GHz/40MHz capable
Bluetooth version 2.0 link is piconet with TCP/IP stack
Windows XP SP2 with Chariot endpoint 6.25 is used for all stations
Clean RF (2.40-2.48GHz) environment verified with spectrum analyzer
Submission
Slide 3
Eldad Perahia (Intel)
doc.: IEEE 802.11-08/0893r0
Deployment Layout
• Test setup is contained
entirely in the one room of a
residential house
• Room is a basic den
– 10 ft x 20 ft
– wood paneling
• WiFi STA located at L0
Submission
July 2008
doc.: IEEE 802.11-08/0893r0
Test Procedure
• Controlled network:
– All nodes are on the same network
– All nodes have static IP addresses
– Chariot management traffic is on the controlled network
• Bluetooth baseline procedure:
–
–
–
–
All WiFi nodes are powered down
Throughput averaged over 2 minute duration with 3 iterations
2 pairs – one per direction (master to slave, slave to master)
Voice RTP throughput: VoIP pair with G.711a (64kbps) codec
• Bluetooth with 802.11 traffic procedure:
– Bluetooth procedures are the same as baseline
– Add WiFi traffic for same duration
– 802.11n (20MHz and 40MHz) traffic: 4 pairs – two per direction (Tx, Rx), high
performance throughput.scr script
– 802.11b traffic: 2 pairs – one per direction (Tx, Rx), throughput.scr script
Submission
Slide 5
Eldad Perahia (Intel)
July 2008
doc.: IEEE 802.11-08/0893r0
Test Methodology
• Bluetooth devices forming Bluetooth link separated by 1 m to
model typical distance between headset and cell phone
• Bluetooth link separated from the 802.11 link by 0.5 m to model
scenario where WLAN connectivity is being using simultaneously
with Bluetooth voice call
• Test measurements conducted for 802.11n 40 MHz, 802.11n 20
MHz, and 802.11b
• Test conducted with a range of 802.11 throughput
– Max throughput for each 802.11 system
– Comparable throughputs for each system to compare impact based on the
same offered load
– Minimum 802.11 throughput tested is 1 Mbps to model typical internet
access
Submission
Slide 6
Eldad Perahia (Intel)
July 2008
doc.: IEEE 802.11-08/0893r0
Results – Bluetooth Measurement Baseline
Bluetooth traffic type
RTP
Bluetooth traffic category
Voice
Throughput
128 kbps
Mean Opinion
Score (MOS)
3.74 (±0.11)
PER
0.08%
• No 802.11 present
Submission
Slide 7
Eldad Perahia (Intel)
July 2008
doc.: IEEE 802.11-08/0893r0
Results – Bluetooth Performance with
802.11 Link Present
WiFi
Channel
6, -1
6
6
WiFi
MOS
Modes
Offered BT-PER VoIP MOS Standard
Load
Error
Max TPT 0.00%
3.91
0.10
70Mbps 0.00%
4.02
0.06
BT+WiFi
22Mbps 0.00%
4.14
0.03
2.4/40 11n
6Mbps 0.04%
4.16
0.03
1Mbps 0.04%
4.20
0.03
BT+WiFi Max TPT 0.00%
4.06
0.08
802.11b
1Mbps 0.00%
4.18
0.06
Max TPT 0.00%
4.09
0.06
BT+WiFi 22Mbps 0.00%
4.16
0.06
2.4/20 11n 6Mbps 0.00%
3.71
0.04
1Mbps 0.00%
3.98
0.01
WiFi TPT
(Mbps)
113.3
68.8
21.3
5.3
1.0
6.1
1.0
76.0
21.7
4.6
0.9
• 802.11 traffic type: TCP
• BT link same as baseline
Submission
Slide 8
Eldad Perahia (Intel)
July 2008
doc.: IEEE 802.11-08/0893r0
Analysis of Results
• All BT MOS measurements in the presence of 802.11n
40MHz are comparable to that of the BT baseline
• No measurable impact due to offered load
• No measurable difference between 802.11n 40 MHz,
802.11n 20 MHz, and 802.11b
Submission
Slide 9
Eldad Perahia (Intel)
July 2008
doc.: IEEE 802.11-08/0893r0
Conclusions
• Over-the-air measurements conducted to determine
coexistence between 802.11n 40 MHz and Bluetooth
voice link
• Measurements demonstrate that neighboring 802.11n
40 MHz link has no impact to quality of nearby
Bluetooth voice link
Submission
Slide 10
Eldad Perahia (Intel)