Doc.: IEEE 802.11-10/0505r2 Submission June 2010 Bruce Kraemer, MarvellSlide 1 Smart Grid Technology Information - May 2010 Date: 2010-5-05 Abstract: Information

June 2010

Bruce Kraemer, Marvell

Slide 1

doc.: IEEE 802.11-10/0505r2

Submission

Smart Grid Technology Information - May 2010

Date: 2010-5-05Abstract: Information on 802.11 technology for inclusion in the June 2010 NIST PAP#2 Report

Name Company Address Phone emailBruce Kraemer Marvell 5488 Marvell Lane,

Santa Clara, CA, 95054

+1-321-751-3988 [email protected]

Kaberi Banerjee

June 2010


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Submission

Agenda

Status Report on Connectivity Week - Santa Clara May 24-28

Any other items from members

June 2010


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Submission

Status report

Connectivity Week - Santa Clara May 24-28

• Included meetings for SGIP & P2030

• Most of the SGIP DEWGs & PAPs held working meetings

• P2030 held 4 days of meetings

June 2010


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Submission

P2030 Overview

• Standard Title

• IEEE P2030 Draft Guide for Smart Grid Interoperability of Energy Technology and Information Technology Operation with the Electric Power System (EPS), and End-Use Applications and Loads

• Scope This document provides guidelines for smart grid interoperability. This guide provides a knowledge base addressing terminology, characteristics, functional performance and evaluation criteria, and the application of engineering principles for smart grid interoperability of the electric power system with end-use applications and loads. The guide discusses alternate approaches to good practices for the smart grid.

June 2010


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Submission

P2030 Highlights

P2030 held 4 days of meetings

• Primary activity was review and proposed edits of Draft 2.1

• https://mentor.ieee.org/2030/dcn/10/2030-10-0242-00-0015-p2030-draft-2-1-with-line-numbers-added.pdf

• Most time spent in each group refining the diagrams

• Comments collected will be incorporated during June

• Draft 3.0 due out for comment in July

http://grouper.ieee.org/groups/scc21/2030/2030_index.html

June 2010


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Submission

SGIP Events

– SGIP Plenary Meetings and Webinars (attendance required for participating members)

• Meeting Name Type Date/Times of upcoming meetings Registration

• Spring Meeting Face-to-Face May 24 to May 27 Agenda for week.

• Plenary Update Webinar July 23rd, 1pm to 3pm Eastern To register and receive web/phone access

• Plenary Update Webinar Sept. 17th, 1pm to 3pm Eastern To register and receive web/phone access

• Plenary Update Webinar Oct. 29th, 1pm to 3pm Eastern To register and receive web/phone access

• Fall Meeting Face-to-Face Nov. 30 to Dec. 3 Current details. Further details to post in early October.

June 2010


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Submission

Near Term Action Items

Completion for review of PAP#2 report Section 4 (Wireless)Current version of overall report can be found at:http://collaborate.nist.gov/twiki-sggrid/pub/SmartGrid/PAP02Wireless/NIST_Priotity_Action_Plan_2_r04.pdf

Next Call Wednesday June 9 (877) 627-6785 00692

Status report on all activities for IEEE 802 July Plenary

June 2010


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Submission

Previous Discussion Material

June 2010


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Submission

Introduction to the NIST PAP2 Report

• Report Preface• This guide is the output of the Priority Action Plan number 2 (PAP#2),

wireless communications for the smart grid, which is part of the Smart Grid Interoperability Panel (SGIP). PAP#2’s work area investigates the strengths, weaknesses, capabilities, and constraints of existing and emerging standards-based physical media for wireless communications. The approach is to work with the appropriate standard development organizations (SDOs) to determine the characteristics of each technology for Smart Grid application areas and types. Results are used to assess the appropriateness of wireless communications technologies for meeting Smart Grid applications’ requirements.

• This guide contains the smart grid reference architecture, the user applications’ requirements, candidate wireless technologies and their capabilities, a methodology to assess the appropriateness of wireless communications technologies along with an example model, and some results.

June 2010


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Submission

Report Outline• Table of Contents• Revision History ............................................................................................................................................. iii• Preface ...................................................................................................................................................... - 1 -• Authors ...................................................................................................................................................... - 2 -• 1 Overview of the process .................................................................................................................... - 3 -• 2 Acronyms and Definitions.................................................................................................................. - 4 -• 2.1 Acronyms ........................................................................................................................................ - 4 -• 2.2 Definitions ....................................................................................................................................... - 7 -• 3 Smart grid....................................................................................................................................... - 11 -• 3.1 Reference Architecture................................................................................................................... - 11 -• 3.2 List of actors.................................................................................................................................. - 13 -• 3.3 Use Cases..................................................................................................................................... - 14 -• 3.4 Application requirements................................................................................................................ - 16 -• 3.4.1 Smart grid user applications’ quantitative requirements......................................................... - 16 -• 3.4.2 Aggregation of requirements per actor to actor...................................................................... - 16 -• 4 Wireless Technology ....................................................................................................................... - 20 -• 5 Evaluation approach / Modeling approach ...................................................................................... - 21 -• 5.1 Channel Models ............................................................................................................................. - 23 -• 5.1.1 Indoor-indoor environments ................................................................................................... - 24 -• 5.1.2 Outdoor-outdoor environments .............................................................................................. - 25 -• 5.1.3 Outdoor-indoor environments ................................................................................................ - 25 -• 5.2 Physical Layer............................................................................................................................... - 26 -• 5.3 MAC sublayer................................................................................................................................ - 26 -• 5.4 Example Modeling Tool.................................................................................................................. - 26 -• 5.5 Other Tools ................................................................................................................................... - 27 -• 6 Findings / Results........................................................................................................................... - 28 -• 7 Conclusions.................................................................................................................................... - 31 -• 8 References ..................................................................................................................................... - 32 -• 9 Bibliography.................................................................................................................................... - 32 -

June 2010


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Section 4 – Wireless Technology -Contents Outline• Introduction• The data collection form

– Group categories– Row descriptions

• Clarification of the row entry• Technology information (Columns)

– Technology names – Technology sources– Explanation of Entries & Validation source

• Per Technology descriptions– Completed– Under development

• Reference Sources

June 2010


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Submission

Wireless Characteristics• 1. Link Availability• 2. Data/Media Type Supported• 3. Coverage Area• 4. Mobility• 5. Data Rates• 6. RF Utilization• 7. Data Frames & Packets• 8. Link Quality Optimization• 9. Radio Performance Measurment & Management• 10. Power Management• 11. Connection Topologies• 12. Connection Management• 13. QoS & Traffic Prioritization• 14. Location Characterization• 15. Security & Security Management• 16. Radio Environment• 17. Intra-technology Coexistence• 18. Inter-technology Coexistence• 19. Unique Device Identification• 20. Technology Specification Source• 21. Deployment Domain Characterization• 22. Exclusions

June 2010


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Submission

Wireless Technologies• Cdma2000 1x and cdma2000 HRPD• Cdma2000 xHRDP• GMR-1 3G• IPOS/DVB-S2• RSM-A• IEEE 802.16 e,m• IEEE 802.11• IEEE 802.15• Inmarsat BGAN• LTE• HSPA+• UMTS• EDGE

June 2010


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Submission

Technology Description and Behavior

in support of

Throughput calculations

Range Calculations

Security

June 2010


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Submission

Technology Description Clarifications

June 2010


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Submission

Group 2: Data/Media Type Supported, b: Data;• 2.1 Group 2: Data/Media Type Supported, b: Data;• Over the air PHY rate• What is the meaning of Data? It is in measurement units of Maximum user data rate per

user in Mb/s.• Since 802.15.4 gives 0.25 Mb/s one might assume that it is the physical medium rate.

However with that assumption, it does not apply to the value for 802.11 of 0.70 Mb/s.• Therefore one must assume another meaning. For example data rate minus protocol

(and/or framing) overhead results in 0.70 Mb/s (i.e., maximum user data rate (i.e., MAC Service Data Unit)), if so then the 802.15.4 value must be changed to comply with that assumption.

• Agreement on a consistent meaning of Data is needed.• Is it the maximum user data rate seen at the interface to/from the MAC sublayer?• Is it an instantaneous data rate?• Since it states Maximum user data rate per user, perhaps the number of users that was

assumed for the calculation needs to be stated as well, especially when the medium is shared as in 802.11 and 802.15.4.

June 2010


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Submission

2.3 Group 5: Data Rates items c and d (Peak goodput over the air UL/DL data rate)

• How is the goodput calculated?

• Is goodput strictly calculated on a single MAC sublayer frame’s payload divided by the resulting physical layer packet?

• Is the goodput calculated including any CSMA overhead and the entire message exchange (e.g., data frame and acknowledgement frame)?

• Both 802.11 and 802.15.4 can act as either peer to peer (p2p) or AP to/from STA for 802.11 or coordinator to/from device for 802.15.4. So for the peer case UL and DL would be the same. However for the non-P2P case UL and DL might be different. Both 802.11 and 802.15 use the same channel in this case, but the protocol overhead might be different (e.g., polling a PAN coordinator to retreive data vs device sending to PAN coordinator for 802.15.4). Clarification (i.e., note) on the type of mode that is being used to achieve the values for the data rates is needed.

June 2010


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Submission

2.3.2 Sample peak goodput for 802.11 baseline

• Was not able to obtain 0.7 Mb/s, assuming only data transmission overhead for one data frame transmission and its associated acknoledgement. What other additional overhead assumptions were assumed? Beacon transmission? RTS/CTS? Association and authentication procedures?

• 2.3.2.1 (A)• Assuming one message exchange of one 50us DIFS + zero backoff + long

preamble (144) + PLCP (48) + 28 bytes MAC overhead + 2312 bytes user data (maximum) + 10 us SIFS + ACKnowledgement packet under DCF; a peak throughput of 0.959 Mb/s.

• 2.3.2.2 (B)• Assuming one message exchange of one 50us DIFS + 15.5 backoff slots

(average first attempt successful)+ long preamble (144) + PLCP (48) + 28 bytes MAC overhead + 2312 bytes user data (maximum) + 10 us SIFS + ACKnowledgement packet under DCF and DS; a peak throughput of 0.944 Mb/s.

June 2010


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Submission

Group 7, Data frames and packets, item a frame duration and item b Maximum packet size

What is meant by frame?What is meant by packet?Are they the same or different?

June 2010


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Submission

2.4 Group 7, Data frames and packets, item a frame duration and item b Maximum packet size

What is meant by frame?There are three primary Frame group types identified in 802.11Management, Control & Data. Payload data is transported inside a data frame. The Data Frame is composed of a number of sub fields: control field, duration field, address fields, sequence field, data, frame check sequence. This collection of fields is referred to as a MAC Protocol Data Unit (MPDU). The source payload data may fit into one frame or if larger than 2312 bytes requires fragmentation and transmission using multiple data frames.

When the MPDU is prepared to send out over the air there are additional fields added for preamble, start of frame delimiter and header. These fields then comprise the Physical Layer Packet Data Unit (PPDU).

What is meant by packet?“Packet” is a general term that refers to the combination of control, address, and data fields described above that includes the payload data of interest .

Are they the same or different?When the terms Packet and Frame are used without further qualifiers they can be considered to be equivalent.

June 2010


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Submission

Technology Description

Protocol Details

June 2010


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Submission

Frame Control

(2 bytes)

Frame Control

(2 bytes)

Duration /ID

(2 bytes)

Duration /ID

(2 bytes)

Address1(6 bytes)Address1(6 bytes)



Sequence. Control

(2 bytes)

Sequence. Control

(2 bytes)

QoS Control

(2 bytes)

QoS Control

(2 bytes)

HT Control

(2 bytes)

HT Control

(2 bytes)

802.11 MAC and Physical Layer Data Frame Encapsulation(Ref: Draft P802.11-REVmb/D3.0, March 2010)

MSDUMSDU

Frame CheckSum(4 bytes)


MAC

MSDUMSDUCCMP Header (8 bytes)CCMP Header (8 bytes)MAC HeaderMAC Header

LLC

MIC(8 bytes)

MIC(8 bytes)

PHY

MPDU

PHY Layer Specific PPDU ( Example : OFDM Phy , Clause 17)

PLCP HeaderPLCP HeaderPLCP PreamblePLCP Preamble PSDUPSDU TailTail Pad BytesPad Bytes

June 2010


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Submission

802.11 MAC and Physical Layer Control Frame Encapsulation(Ref: Draft P802.11-REVmb/D3.0, March 2010)

Frame Control

(2 bytes)

Frame Control

(2 bytes)

Duration /ID

(2 bytes)

Duration /ID

(2 bytes)


OptionalAddress2(6 bytes)

OptionalAddress2(6 bytes)



MAC

MAC HeaderMAC Header

LLC

PHY

MPDU



Optional Control InfoOptional Control Info

Optional Control InfoOptional Control Info

Optional Control Info(BlockAck and BlockAckReq)

Optional Control Info(BlockAck and BlockAckReq)

Carried Frame Control

Carried Frame Control

HT Control

HT Control

Carried Frame Carried Frame

June 2010


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Submission

802.11 MAC and Physical Layer Management Frame Encapsulation(Ref: Draft P802.11-REVmb/D3.0, March 2010)

LLC LLC Management Frame Body

Management Frame Body

Frame Control

(2 bytes)

Frame Control

(2 bytes)

Duration /ID

(2 bytes)

Duration /ID

(2 bytes)




Sequence. Control

(2 bytes)

Sequence. Control

(2 bytes)

HT Control

(2 bytes)

HT Control

(2 bytes)



MAC


Management Frame BodyMAC HeaderMAC Header

LLC

PHY

MMPDU



June 2010


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Submission

802.11 MAC and Physical Layer Management Frame Encapsulation(Ref: Draft P802.11-REVmb/D3.0, March 2010)

LLC LLC Management Frame Body


Frame Control

(2 bytes)

Frame Control

(2 bytes)

Duration /ID

(2 bytes)

Duration /ID

(2 bytes)




Sequence. Control

(2 bytes)

Sequence. Control

(2 bytes)

HT Control

(2 bytes)

HT Control

(2 bytes)



MAC


Management Frame BodyMAC HeaderMAC Header

LLC

PHY

MMPDU


PPDUPPDU

June 2010


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Submission

Framing

http://forskningsnett.uninett.no/wlan/throughput.html

June 2010


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Submission

Resulting Data Message sizes (for this selection)

• On-demand meter read 100 bytes• TLS 25 bytes• Transport TCP 20 bytes• IP-SEC (Tunnel mode) 80 bytes• IPv6 40 bytes• IEEE 802.11 CCMP 16 bytes• IEEE 802.11 28 bytes• DSSS 24 bytes

– ----------------------------------------------------------------------• TOTALS 333 bytes• Similarly for Application Error on-demand meter read

– TOTALS 283 bytes• Similarly for Multiple interval meter read

– TOTALS 1833 bytes - 2833 bytes*• *Exceeds MTU of 802.11 must segment into two frames

http://collaborate.nist.gov/twiki-sggrid/pub/SmartGrid/PAP02Wireless/March31NISTPresentation.ppt

June 2010


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Submission

Technology Description

PHY Details

June 2010


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Submission

802.11a ThroughputPARAMETER

Channel BW (MHz) Modulation BPSK BPSK QPSK QPSK 16-QAM 16-QAM 64-QAM 64-QAM

Payload (PSDU/MPDU)Data Rate(Mbps) 6 9 12 18 24 36 48 54

MPDU/PSDU Length (min) (in octets) 1 1 1 1 1 1 1 1

MPDU/PSDU Length (max) (in octets) 4095 4095 4095 4095 4095 4095 4095 4095

MPDU framing basic overhead(Frame Control + 3 Address fields + DuID +Sequence Control + FCS) 28 28 28 28 28 28 28 28

MPDU framing : With CCMP overhead(+16) 44 44 44 44 44 44 44 44

MPDU framing : With CCMP and QoS overhead(+2) 46 46 46 46 46 46 46 46MSDU Length min(in octets) 1 1 1 1 1 1 1 1MSDU Length max(in octets) 2304 2304 2304 2304 2304 2304 2304 2304

MPDU Length max(in octets) 2350 2350 2350 2350 2350 2350 2350 2350

NDBPS 24 36 48 72 96 114 192 216NSYM 785 523 393 262 197 166 99 88

TSYM(us) 4 4 4 4 4 4 4 4 (Preamble+ SIGNAL) overhead(us) 20 20 20 20 20 20 20 20

PPDU Duration max(us) 3160 2112 1592 1068 808 684 416 372 Throughput(Mb/s) 5.83 8.73 11.58 17.26 22.81 26.95 44.31 49.55

Note1 :Indicates Mandatory Data Rates

Ref1 : Draft P802.11-REVmb/D3.0, March 2010, Clause 17

OFDM PHY20

June 2010


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Submission

Behavior

June 2010


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Submission

Example throughput calculations - #1

microsec/bit1

bitsEXAMPLE 1

difs 50 50 50 50 50 50backoff 0 0 0 0 0 0

header/adress etc transmit 192 192 192 192 192 192 192 192 192 192 192 192payload 400 400 1000 1000 1500 1500 12000 12000 15000 15000 18496 18496

sifs 10 10 10 10 10 10ack 192 192 192 192 192 192

MAC 112 112 112 112 112 112difs 50 50 50 50 50 50

backoff 0 0 0 0 0 0header/adress etc transmit 192 192 192 192 192 192 192 192 192 192 192 192

payload 400 400 1000 1000 1500 1500 12000 12000 15000 15000 18496 18496sifs 10 10 10 10 10 10

ack PHY 192 192 192 192 192 192ack MAC 112 112 112 112 112 112

microsec total 1912 3000 4000 25000 31000 37992payload bits 800 2000 3000 24000 30000 36992

payload Mbits/sec 0.418 0.667 0.750 0.960 0.9677 0.9737

1Mbps PHY rate, DCF, single sender to receiver pair, no backoff

June 2010


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Submission

Example throughput calculations - #21Mbps PHY rate, DCF, single sender to receiver pair, minimal backoff

EXAMPLE 2difs 50 50 50 50 50 50


payload 400 400 1000 1000 1500 1500 12000 12000 15000 15000 18496 18496sifs 10 10 10 10 10 10ack 192 192 192 192 192 192

MAC 112 112 112 112 112 112difs 50 50 50 50 50 50


payload 400 400 1000 1000 1500 1500 12000 12000 15000 15000 18496 18496sifs 10 10 10 10 10 10

ack PHY 192 192 192 192 192 192ack MAC 112 112 112 112 112 112

microsec total 1943 3031 4031 25031 31031 38023payload bits 800 2000 3000 24000 30000 36992

payload Mbits/sec 0.412 0.660 0.744 0.959 0.9668 0.9729

June 2010


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Submission

MPDU Structure

• A question of how much detail to provide?

• How to account for variables such as security options?

MAC Header Variable length frame body containing payload data Frame Check Sequence

Preamble Header MPDU

PPDU Structure

June 2010


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Submission

Throughput Question

• 2.3.2.1 (A)

• Assuming one message exchange of one 50us DIFS + zero backoff + long preamble (144) + PLCP (48) + 28 bytes MAC overhead + 2312 bytes user data (maximum) + 10 us SIFS + ACKnowledgement packet under DCF; a peak throughput of 0.959 Mb/s

• Again, how much detail to provide?

• What is precise enough?

• How to account for theory vs practice?

June 2010


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Submission

Example 1: 11b 2Mbps Measured Throughput

page 45 Open WEP 40 WEP 128 TKIP/PEAP CCMP/PEAPrates 1570.3 1559.3 1555.6 1524.2 1551.2

% 78.5% 78.0% 77.8% 76.2% 77.6%

Security Protocol

Analyzing Wireless LAN Security OverheadHarold Lars McCarterThesis submitted to the Faculty of the Virginia Polytechnic Institute and State Universityin partial fulfillment of the requirements for the degree of Master of Science in Electrical Engineering17-Apr-06Falls Church, Virginiahttp://scholar.lib.vt.edu/theses/available/etd-04202006-080941/unrestricted/mccarter_thesis.pdf

June 2010


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Example 2: Various 802.11 Reported Throughputs

802.11g and 802.11a Modulation and Coding Options 802.11g and 802.11a Modulation and Coding Optionsover payload over payloadthe Code theair rate air

(Mbps) (Mbps) (%) (Mbps) (Mbps) (%)BPSK 1 0.81 81% BPSK 1/2 6 4.64 77%QPSK 2 1.58 79% BPSK 3/4 9 6.55 73%CCK 5.5 4.07 74% QPSK 1/2 12 8.31 69%CCK 11 7.18 65% QPSK 3/4 18 11.5 64%

16-QAM 1/2 24 14.18 59%avg 74.8% 16-QAM 3/4 36 18.31 51%

64-QAM 1/2 48 23.25 48%64-QAM 3/4 54 26.12 48%

avg 61%

Huawei Quidway WA1006E Wireless Access Point http://www.sersat.com/descarga/quidway_wa1006e.pdf

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Behavior

June 2010


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Submission

Relationship betweenThroughput and Payload

Payload Length

Throughput

Lower SNR

High SNR

Low SNR

June 2010


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Effect of payload length on throughput for various retransmission limits (6 Mbps, SNR of 2 dB)

June 2010


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Throughput versus payload (18 Mbps, SNR 8dB)

10.66 Mbps59.2%

June 2010


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Capacity with 5 data users in thenetwork (SNR is 8 dB , 6 Mbps)

June 2010


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Submission

June 2010


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Individual 802.11 station

June 2010


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Submission

June 2010


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Submission

Group of 802.11 stations

June 2010


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802.11 Inter-frame Spacing

June 2010


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Submission

Frame Spacing Relationships

• aSIFSTime and aSlotTime are fixed per PHY.• aSIFSTime is: aRxRFDelay + aRxPLCPDelay + aMACProcessingDelay +

aRxTxTurnaroundTime.• aSlotTime is: aCCATime + aRxTxTurnaroundTime + aAirPropagationTime• + aMACProcessingDelay.• The PIFS and DIFS are derived by the following equations, as illustrated in Figure 9-12.• PIFS = aSIFSTime + aSlotTime• DIFS = aSIFSTime + 2 × aSlotTime• The EIFS is derived from the SIFS and the DIFS and the length of time it takes to

transmit an ACK Control• frame at the lowest PHY mandatory rate by the following equation:• EIFS = aSIFSTime + DIFS + ACKTxTime• where• ACKTxTime is the time expressed in microseconds required to transmit an ACK frame,

including• preamble, PLCP header and any additional PHY dependent information, at the lowest

PHY• mandatory rate.

June 2010


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Submission

PHY Header Details

• The value of the TXTIME parameter returned by the PLME_TXTIME.confirm primitive shall be calculated

• according to Equation (19-9):• TXTIME = PreambleLengthDSSS + PLCPHeaderTimeDSSS• + PreambleLengthOFDM + PLCPSignalOFDM• + 4 × Ceiling((PLCPServiceBits + 8 × (NumberOfOctets) + PadBits) /

NDBPS) + SignalExtension(19-9)• where• PreambleLengthDSSS is 144 μs if the PREAMBLE_TYPE value from the

TXVECTOR parameter• indicates “LONGPREAMBLE,” or 72 μs if the PREAMBLE_TYPE value• from the TXVECTOR parameter indicates “SHORTPREAMBLE”• =144+48 or 24+8+

June 2010


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Submission

802.11 PreamblePreamble

The preamble is used to communicate to the receiver that data is on its way. Technically speaking, it is the first portion of the Physical Layer Convergence Protocol/Procedure (PLCP) Protocol Data Unit (PDU). The preamble allows the receiver to acquire the wireless signal and synchronize itself with the transmitter. A header is the remaining portion and contains additional information identifying the modulation scheme, transmission rate and length of time to transmit an entire data frame.

Long Preamble: • Compatible with legacy IEEE 802.11 systems operating at 1 and 2 Mbps (Megabits per second) • PLCP with long preamble is transmitted at 1 Mbps regardless of transmit rate of data frames • Total Long Preamble transfer time is a constant at 192 usec (microseconds)Short Preamble: • Not compatible with legacy IEEE 802.11 systems operating at 1 and 2 Mbps • PLCP with short preamble: Preamble is transmitted at 1 Mbps and header at 2 Mbps • Total Long Preamble transfer time is a constant at 96 usec (microseconds)

June 2010


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Submission

802.11 MCS options for “a” & “g”

Data Rate (Mbps)

Modulation Coding Rate Coded bits per subcarrier

Coded bits per OFDM symbol

Data bits per OFDM symbol

6 BPSK 1/2 1 48 24

9 BPSK 3/4 1 48 36

12 QPSK 1/2 2 96 48

18 QPSK 3/4 2 96 72

24 16-QAM 1/2 4 192 96

36 16-QAM 3/4 4 192 144

48 16-QAM 2/3 6 288 192

54 64-QAM 3/4 6 288 216

June 2010


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Long preamble

Mbit/s Net Mbit/s Efficiency

1 0.75 74.9%

2 1.41 70.7%

5.5 3.38 61.5%

11 5.32 48.4%


June 2010


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Submission

Short Preamble

Mbit/s Net Mbit/s Efficiency

1 0.77 76.9%

2 1.49 74.3%

5.5 3.83 69.6%

11 6.52 59.3%


June 2010


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Submission

Short list of citations on Throughput

• Churong Chen; Choi Look Law; , "Throughput performance analysis and experimental evaluation of IEEE 802.11b radio link," Information, Communications & Signal Processing, 2007 6th International Conference on , vol., no., pp.1-5, 10-13 Dec. 2007doi: 10.1109/ICICS.2007.4449813URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4449813&isnumber=4449533

Na, C.; Chen, J.K.; Rappaport, T.S.; , "Measured Traffic Statistics and Throughput of IEEE 802.11b Public WLAN Hotspots with Three Different Applications," Wireless Communications, IEEE Transactions on , vol.5, no.11, pp.3296-3305, November 2006doi: 10.1109/TWC.2006.05043URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4027799&isnumber=4027759

Garg, S.; Kappes, M.; , "An experimental study of throughput for UDP and VoIP traffic in IEEE 802.11b networks," Wireless Communications and Networking, 2003. WCNC 2003. 2003 IEEE , vol.3, no., pp.1748-1753 vol.3, 20-20 March 2003doi: 10.1109/WCNC.2003.1200651URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=1200651&isnumber=27030

Bruno, R.; Conti, M.; Gregori, E.; , "Throughput Analysis of UDP and TCP Flows in IEEE 802.11b WLANs: A Simple Model and Its Validation," Techniques, Methodologies and Tools for Performance Evaluation of Complex Systems, 2005. (FIRB-Perf 2005). 2005 Workshop on , vol., no., pp. 54- 63, 19-19 Sept. 2005doi: 10.1109/FIRB-PERF.2005.20URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=1587695&isnumber=33459

Mahasukhon, P.; Hempel, M.; Song Ci; Sharif, H.; , "Comparison of Throughput Performance for the IEEE 802.11a and 802.11g Networks," Advanced Information Networking and Applications, 2007. AINA '07. 21st International Conference on , vol., no., pp.792-799, 21-23 May 2007doi: 10.1109/AINA.2007.46URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4220972&isnumber=4220857

Bruno, R.; Conti, M.; Gregori, E.; , "IEEE 802.11 optimal performances: RTS/CTS mechanism vs. basic access," Personal, Indoor and Mobile Radio Communications, 2002. The 13th IEEE International Symposium on , vol.4, no., pp. 1747- 1751 vol.4, 15-18 Sept. 2002URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=1045479&isnumber=22399

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• Other Backup material

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TCP data TCP ACK

DIFS 28 µs 28 µs

802.11 Data20 µs + 57 * 4 µs/symbol +6 µs= 20 µs + 228 µs= 254µs

20 µs + 3 * 4 µs/symbol + 6 µs= 20 + 12 µs= 38 µs

SIFS 10 µs 10 µs

802.11 ACK20 µs + 1 * 4 µs/symbol + 6 µs= 20 µs + 4 µs + 6 µs= 30µs = 30 µs

Frame exchange total 322 µs 106 µs

Transaction Total 428 µs

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Example throughput calculation

Assuming that there are two stations exchanging data using 802.11 DCF using basic access what is MAC layer throughput?

Answer:• Total data in 1 frame = 1452 byte• MAC Header length = 28 bytes• Total frame size = 1452+28 = 1480 byte• Time required for transmission at 54 Mbps = 1480*8 /(54 Mbps)= 219.25 μs• Total time required for transmission of 1 Frame =• DIFS (34μs ) + Data Time (219.25 μs ) + propagation time(1μs ) + Physical overhead (20 μs ) +

SIFS(16 μs ) + ACK time(2.07 μs ) + propagation time for Ack (1 μs )+ Physical overhead for Ack (20 μs ) = 313.2 μs

• Hence we are using 313.2 μs to transmit 1452 bytes• Hence MAC layer throughput = 37 Mbps• 37/54 = 68.5%

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Documents

Doc.: IEEE 802.11-10/0505r2 Submission June 2010 Bruce Kraemer, MarvellSlide 1 Smart Grid Technology Information - May 2010 Date: 2010-5-05 Abstract: Information