doc.: IEEE 802.19-yy/xxxxr0 Submission Mukul Goyal, U Wisconsin Mi Slide 1 Impact of IEEE 802.11n Operation On IEEE 802.15.4 Performance Notice: This document has been prepared to assist IEEE 802.19. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Date: 2008-11-02 N am e C om pany A ddress Phone em ail M ukulG oyal U W isconsin M ilwaukee 3200 N Cram erSt, M ilwaukee W I 53201 1-414-229- 5001 m ukul@ uwm .edu Y usufBashir Johnson ControlsInc. 507 E M ichigan St, M ilwaukee W I 53202 1-414-526- 8380 Yusuf.Bashir@ jci.com Authors: November 2008
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doc.: IEEE 802.19-yy/xxxxr0
Submission Mukul Goyal, U Wisconsin MilwaukeeSlide 1
Impact of IEEE 802.11n Operation On IEEE 802.15.4 Performance
Notice: This document has been prepared to assist IEEE 802.19. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.
Date: 2008-11-02
Name Company Address Phone email Mukul Goyal U Wisconsin
Milwaukee 3200 N Cramer St, Milwaukee WI 53201
1-414-229-5001
Yusuf Bashir Johnson Controls Inc.
507 E Michigan St, Milwaukee WI 53202
1-414-526-8380
Authors:
November 2008
doc.: IEEE 802.19-yy/xxxxr0
Submission Mukul Goyal, U Wisconsin MilwaukeeSlide 2
Abstract
In this presentation, we evaluate the impact of IEEE 802.11n operation on IEEE 802.15.4 performance via test bed experiments. The IEEE 802.15.4 performance is measured in terms of packet loss rate and the latency for successfully delivered packets.
November 2008
doc.: IEEE 802.19-yy/xxxxr0
Submission
IEEE 802.15.4: Overview
• A MAC/PHY layer protocol for low power, low data rate (< 250 kbps) wireless sensor applications
• Based on CSMA/CA
November 2008
Slide 3 Mukul Goyal, U Wisconsin Milwaukee
doc.: IEEE 802.19-yy/xxxxr0
Submission
The CSMA/CA algorithm in (unslotted) 802.15.4
• The source node backoffs for a random number of slots between 0 and (2^BE) – 1– BE is Backoff Exponent
• After the backoff, the source node does the clear channel assessment (CCA)
• If the channel is not idle (CCA Failure), the source node increments BE and repeat the process up to 4 times– The initial BE value is 3 and max BE value is 5
November 2008
Slide 4 Mukul Goyal, U Wisconsin Milwaukee
doc.: IEEE 802.19-yy/xxxxr0
Submission
The CSMA/CA algorithm in (unslotted) 802.15.4
• If the CCA fails even after 4th retry, the source node declares channel access failure (CAF) and abandons the packet transmission
• If the CCA succeeds, the source node transmits the packet.
• On receiving the packet, the destination optionally sends an acknowledgement back
November 2008
Slide 5 Mukul Goyal, U Wisconsin Milwaukee
doc.: IEEE 802.19-yy/xxxxr0
Submission
Collisions and Retransmissions
• If the packet or the ack suffers a collision, the source node waits for a certain time duration and then repeat the (backoff + transmission) process up to 3 more times.
• If the ack is not received even after the 3rd retry, the source node declares a collision failure and abandons the packet.
November 2008
Slide 6 Mukul Goyal, U Wisconsin Milwaukee
doc.: IEEE 802.19-yy/xxxxr0
Submission
Packet Loss in IEEE 802.15.4
• Channel access failure– channel access failure occurs after 5 back-to-back CCA
failures during a try.
• Collision failure – occurs after failure to receive the ack even after 4 tries.
• Note that a channel access failure causes abandonment of packet transmission attempt even if 4 tries have not been made.
November 2008
Slide 7 Mukul Goyal, U Wisconsin Milwaukee
doc.: IEEE 802.19-yy/xxxxr0
Submission
Impact of IEEE 802.11n operation on IEEE 802.15.4 Performance
• IEEE 802.15.4 performance is measured in terms of the packet loss rate and latency for successfully delivered packets.
• In the following graphs, we plot the increase in average loss rate/latency values for IEEE 802.15.4 nodes due to the presence of an IEEE 802.11n network.
November 2008
Slide 8 Mukul Goyal, U Wisconsin Milwaukee
doc.: IEEE 802.19-yy/xxxxr0
Submission
Traffic in IEEE 802.15.4 Network
• 15 nodes sending packets to the coordinator.
• The packet size is 112 bytes.
• Each node sends on average one packet per second (poisson distributed) for 15 minutes
• IEEE 802.15.4 network uses a 3 MHz wide channel centered at 2425 MHz (Channel 15)
• Power level: 10dBm
November 2008
Slide 9 Mukul Goyal, U Wisconsin Milwaukee
doc.: IEEE 802.19-yy/xxxxr0
Submission
Traffic in IEEE 802.11n Network
• An iperf client sends a UDP stream to an iperf server over an IEEE 802.11n network
• Power level 17dBm
• Packet size: 1470 bytes
• Client generates traffic at rates 1, 2, 5, 10, 15, 20 Mbps.
November 2008
Slide 10 Mukul Goyal, U Wisconsin Milwaukee
doc.: IEEE 802.19-yy/xxxxr0
Submission
IEEE 802.11n Channels Used
• Scenario 1: Channel 1, 20 MHz wide, no overlap with IEEE 802.15.4 channel
• Scenario 2: Channel 6, 40 MHz wide (extends towards channel 11), no overlap with IEEE 802.15.4 channel
• Scenario 3: Channel 1, 40 MHz wide, extends into the channel used by IEEE 802.15.4 network
• Scenario 4: Channel 4, 20 MHz wide, overlaps the channel used by IEEE 802.15.4 network
November 2008
Slide 11 Mukul Goyal, U Wisconsin Milwaukee
doc.: IEEE 802.19-yy/xxxxr0
Submission
Scenario 1: IEEE 802.11n on Channel 1, 20 MHz wide
3MHz
2425 MHz2412 MHz
22MHz
IEEE 802.11n
IEEE 802.15.4
November 2008
Slide 12 Mukul Goyal, U Wisconsin Milwaukee
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Submission
Scenario 1: Impact of IEEE 802.11n Operation on IEEE 802.15.4 Loss Rate
November 2008
Slide 13 Mukul Goyal, U Wisconsin Milwaukee
doc.: IEEE 802.19-yy/xxxxr0
Submission
Scenario 1: Impact of IEEE 802.11n Operation on IEEE 802.15.4 Latency
November 2008
Slide 14 Mukul Goyal, U Wisconsin Milwaukee
doc.: IEEE 802.19-yy/xxxxr0
Submission
Scenario 2: IEEE 802.11n on Channel 6, 40 MHz wide
3MHz
2425 MHz 2437 MHz
44MHz
IEEE 802.11n
IEEE 802.15.4
November 2008
Slide 15 Mukul Goyal, U Wisconsin Milwaukee
doc.: IEEE 802.19-yy/xxxxr0
Submission
Scenario 2: Impact of IEEE 802.11n Operation on IEEE 802.15.4 Loss Rate
November 2008
Slide 16 Mukul Goyal, U Wisconsin Milwaukee
doc.: IEEE 802.19-yy/xxxxr0
Submission
Scenario 2: Impact of IEEE 802.11n Operation on IEEE 802.15.4 Latency
November 2008
Slide 17 Mukul Goyal, U Wisconsin Milwaukee
doc.: IEEE 802.19-yy/xxxxr0
Submission
Scenario 3: IEEE 802.11n on Channel 1, 40 MHz wide
3MHz2425 MHz2412 MHz
44MHz
IEEE 802.11n
IEEE 802.15.4
November 2008
Slide 18 Mukul Goyal, U Wisconsin Milwaukee
doc.: IEEE 802.19-yy/xxxxr0
Submission
Scenario 3: Impact of IEEE 802.11n Operation on IEEE 802.15.4 Loss Rate
November 2008
Slide 19 Mukul Goyal, U Wisconsin Milwaukee
doc.: IEEE 802.19-yy/xxxxr0
Submission
Scenario 3: Impact of IEEE 802.11n Operation on IEEE 802.15.4 Latency
November 2008
Slide 20 Mukul Goyal, U Wisconsin Milwaukee
doc.: IEEE 802.19-yy/xxxxr0
Submission
Scenario 4: IEEE 802.11n on Channel 4, 20 MHz wide
3MHz
2425 MHz 2427 MHz
22MHz
IEEE 802.11n
IEEE 802.15.4
November 2008
Slide 21 Mukul Goyal, U Wisconsin Milwaukee
doc.: IEEE 802.19-yy/xxxxr0
Submission
Scenario 4: Impact of IEEE 802.11n Operation on IEEE 802.15.4 Loss Rate
November 2008
Slide 22 Mukul Goyal, U Wisconsin Milwaukee
doc.: IEEE 802.19-yy/xxxxr0
Submission
Scenario 4: Impact of IEEE 802.11n Operation on IEEE 802.15.4 Latency
November 2008
Slide 23 Mukul Goyal, U Wisconsin Milwaukee
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