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© UNIVERSITY of NEW HAMPSHIRE INTEROPERABILITY LABORATORY Wireless Networking Overview January 2006.

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Presentation on theme: "© UNIVERSITY of NEW HAMPSHIRE INTEROPERABILITY LABORATORY Wireless Networking Overview January 2006."— Presentation transcript:

1 © UNIVERSITY of NEW HAMPSHIRE INTEROPERABILITY LABORATORY Wireless Networking Overview January 2006

2 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 2 Presentation Goals: What is 802.11 Wireless Networking WLAN Past and Present –802.11b, 802.11a, 802.11g, WEP Future of WLAN –Enhanced Security (802.11i) –QoS (802.11e) –Mesh Networking (802.11s) –WAVE (802.11p) –High Speed (802.11n) Other types of wireless networking (WANs, MANs, PANs) What is 802.11 Wireless Networking WLAN Past and Present –802.11b, 802.11a, 802.11g, WEP Future of WLAN –Enhanced Security (802.11i) –QoS (802.11e) –Mesh Networking (802.11s) –WAVE (802.11p) –High Speed (802.11n) Other types of wireless networking (WANs, MANs, PANs)

3 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 3 The 802 Wireless Space Data Rate (Mbps) Range ZigBee 802.15.4 802.15.3 802.15.3a 802.15.3c WPAN WLAN WMAN WWAN WiFi 802.11 0.010.11101001000 Bluetooth 802.15.1 IEEE 802.22 WiMax IEEE 802.16 IEEE 802.20 Courtesy of Zigbee Alliance

4 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 4 What is Wireless networking? A Wireless Local Area Network (WLAN) is a type of local- area network that uses high-frequency radio waves rather than wires to communicate between nodes. WLAN is a flexible data communication system used as an alternative to, or an extension of a wired LAN.

5 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 5 What are 802.11 WLANs? 802.11 is the part of the IEEE LMSC that defines wireless LAN networking First 802.11 wireless networks started showing up in the 90s Designed to connect in different way depending on environment –Stations can connect directly to one another (Ad-Hoc) –Stations can connect to Access Points (APs) to gain access to other networks 802.11 is the part of the IEEE LMSC that defines wireless LAN networking First 802.11 wireless networks started showing up in the 90s Designed to connect in different way depending on environment –Stations can connect directly to one another (Ad-Hoc) –Stations can connect to Access Points (APs) to gain access to other networks

6 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 6 What is unique about wireless? Difficult media –interference and noise –quality varies over space and time –shared with unwanted wireless devices –shared with non-802 devices (unlicensed spectrum, microwave ovens) Full connectivity cannot be assumed –hidden node problem Multiple international regulatory requirements Difficult media –interference and noise –quality varies over space and time –shared with unwanted wireless devices –shared with non-802 devices (unlicensed spectrum, microwave ovens) Full connectivity cannot be assumed –hidden node problem Multiple international regulatory requirements Category 5,6,7 cable –NEXT –Medium characteristics are very stable –Most links are switched point-to-point Network Capacity –Easier to run more cable or fiber to expand capacity than to find unused spectrum.

7 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 7 Regulatory Bodies Political and Legal issues FCC Federal Communications Commission, Part 15 Industry Canada, GL36 ETSI European Telecommunications Standard Institute, ETS300-328, 300-339 MPHPT Ministry of Public Management, Home Affairs, Post and Telecommunications (Japan) FCC Federal Communications Commission, Part 15 Industry Canada, GL36 ETSI European Telecommunications Standard Institute, ETS300-328, 300-339 MPHPT Ministry of Public Management, Home Affairs, Post and Telecommunications (Japan)

8 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 8 Regulatory Approaches All unlicensed bands impose power limits ISM bands require spread spectrum depending on tx power, but is changing UPCS: Isochronous and asynchronous band, each with Spectrum Etiquette (rules regulating access and usage, e.g. Listen Before Talk (LBT)) UNII bands & Mmwave bands: Minimal regulations e.g. power spectral density limits and emission limits

9 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 9 Licensed vs Unlicensed Spectrum Licensed –Cell phones, police & fire radio, taxi dispatch, etc. Unlicensed –Industrial, Scientific, Medical (ISM) bands e.g. (900MHz, 2.4GHz, 5.8GHz) –Unlicensed Personal Communication System e.g. 1.910-1.920 GHz and 2.390-2.400 GHz –Unlicensed National Information Infrastructure (UNII) bands e.g. (5.2GHz) Licensed –Cell phones, police & fire radio, taxi dispatch, etc. Unlicensed –Industrial, Scientific, Medical (ISM) bands e.g. (900MHz, 2.4GHz, 5.8GHz) –Unlicensed Personal Communication System e.g. 1.910-1.920 GHz and 2.390-2.400 GHz –Unlicensed National Information Infrastructure (UNII) bands e.g. (5.2GHz)

10 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 10 bandf (Hz)λ (m)T (K)comments -----10+0010+08 10-111 Hz radio 10+01 10+0710-10 AC power, submarine communication waves 10+0310+05 10-081 kHz 10+0510+03 10-06LW radio, 1 km 10+0610+02 10-05AM radio, 1 MHz 10+0710+01 10-04SW radio 10+0810+00 10-03VHF TV & FM radio, UHF TV, 1 m 10+0910-01 10-02microwave ovens, 1 GHz, radar Micro-10+10 10-0210-01radar, 1 cm waves10+1110-03 10+00 cosmic background, 1 mm 10+1210-04 10+011 THz infrared 10+1310-05 10+02human bodies 10+1410-06 10+031 µm, 1 eV 10+1510-07 10+04solar peak wavelength, 1 PHz visible 10+1810-10 10+07atomic diameter light bandf (Hz)λ (m)T (K)comments -----10+0010+08 10-111 Hz radio 10+01 10+0710-10 AC power, submarine communication waves 10+0310+05 10-081 kHz 10+0510+03 10-06LW radio, 1 km 10+0610+02 10-05AM radio, 1 MHz 10+0710+01 10-04SW radio 10+0810+00 10-03VHF TV & FM radio, UHF TV, 1 m 10+0910-01 10-02microwave ovens, 1 GHz, radar Micro-10+10 10-0210-01radar, 1 cm waves10+1110-03 10+00 cosmic background, 1 mm 10+1210-04 10+011 THz infrared 10+1310-05 10+02human bodies 10+1410-06 10+031 µm, 1 eV 10+1510-07 10+04solar peak wavelength, 1 PHz visible 10+1810-10 10+07atomic diameter light

11 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 11 Common Applications

12 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 12 2.4 GHz Interference Micro-wave oven Bluetooth voice link Bluetooth PDA 802.11b/g WLAN HomeRF PC FHSS Cordless phone DSSS Cordless phone Analog video link Micro-wave oven Bluetooth voice link Bluetooth PDA 802.11b/g WLAN HomeRF PC FHSS Cordless phone DSSS Cordless phone Analog video link

13 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 13 Contrast to Wired LANs Allowed packet error rates (PER) –Ethernet BER = 10 -9 (copper), 10 -12 (fiber), –802.11a FER 10% with 1000 byte Packets (equivalent BER = 1.25x10 -5 ) Data rates –Ethernet 10, 100, 1000, 10000 Mbits/sec –802.111-54 Mbits/sec –Auto-negotiation vs. Basic & Extended rate sets Point-to-point vs. Broadcast medium CSMA/CD vs CSMA/CA Security issues Power drain Allowed packet error rates (PER) –Ethernet BER = 10 -9 (copper), 10 -12 (fiber), –802.11a FER 10% with 1000 byte Packets (equivalent BER = 1.25x10 -5 ) Data rates –Ethernet 10, 100, 1000, 10000 Mbits/sec –802.111-54 Mbits/sec –Auto-negotiation vs. Basic & Extended rate sets Point-to-point vs. Broadcast medium CSMA/CD vs CSMA/CA Security issues Power drain

14 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 14 Wired vs. Wireless Data Rates Ethernet has auto-negotiation –Link setup as 10, 100, 1000, or 10,000 Mb & half or full duplex 802.11 has basic and extended rate sets –Beacons contain rate sets for basic & extended –11g may transmit at any of 12 defined rates –11b (HRDS) uses extended 11& 5.5 Mb rates, but also uses 1&2 Mb base rates to communicate with legacy devices Ethernet has auto-negotiation –Link setup as 10, 100, 1000, or 10,000 Mb & half or full duplex 802.11 has basic and extended rate sets –Beacons contain rate sets for basic & extended –11g may transmit at any of 12 defined rates –11b (HRDS) uses extended 11& 5.5 Mb rates, but also uses 1&2 Mb base rates to communicate with legacy devices

15 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 15 WWANs, WMANs, WLANs, WPANS Wide Area Network & Cellular –Ardis, CDPD, 3G, Metropolitan Area Network –802.16, 802.11? Local Area Network –802.11, Hiperlan2, HomeRF, RangeLAN2 Personal Area Network –802.15.1 ~ Bluetooth, –802.15.3 ~ WiMedia, W-USB –802.15.4 ~ Zigbee – RFID Wide Area Network & Cellular –Ardis, CDPD, 3G, Metropolitan Area Network –802.16, 802.11? Local Area Network –802.11, Hiperlan2, HomeRF, RangeLAN2 Personal Area Network –802.15.1 ~ Bluetooth, –802.15.3 ~ WiMedia, W-USB –802.15.4 ~ Zigbee – RFID

16 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 16 Approximate Data Rate vs. Range for existing devices WPANs WLANs WMANs WWANs

17 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 17 IEEE 802.11 (WLANs) Modulation: BPSK, QPSK, 16QAM, 64QAM –Direct Sequence Spread Spectrum (DSSS) –Frequency Hopping Spread Spectrum (FHSS) –Orthogonal Frequency Division Multiplexing (OFDM) –Multi-Input, Multi-Output (MIMO) systems being discussed in 802.11 Task Group N. Data rates up to 56 Mbps, proprietary speeds of 108 Mbps Range up to 300 meters 2.4 GHz & 5 GHz operating bands Marketing group: Wi-Fi Alliance http://www.wi-fi.org Modulation: BPSK, QPSK, 16QAM, 64QAM –Direct Sequence Spread Spectrum (DSSS) –Frequency Hopping Spread Spectrum (FHSS) –Orthogonal Frequency Division Multiplexing (OFDM) –Multi-Input, Multi-Output (MIMO) systems being discussed in 802.11 Task Group N. Data rates up to 56 Mbps, proprietary speeds of 108 Mbps Range up to 300 meters 2.4 GHz & 5 GHz operating bands Marketing group: Wi-Fi Alliance http://www.wi-fi.org

18 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 18 Medium Variations Copyright 1996 IEEE Desk Doorway

19 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 19 Open System Interconnect (OSI) Model A framework for Networking

20 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 20 Encapsulation of Layers

21 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 21 802.11 Wireless LAN PHY 802.11 – 2.4GHz, 1-2Mbps, DSSS/FHSS/IR 802.11a – 5GHz, 6-54Mbps, OFDM 802.11b – 2.4GHz, 1-11Mbps, CCK (extension of DSSS) or PBCC (optional) 802.11g – 2.4GHz, 1-54Mbps, OFDM or PBCC (optional) 802.11n – task group looking at MIMO systems 802.11 – 2.4GHz, 1-2Mbps, DSSS/FHSS/IR 802.11a – 5GHz, 6-54Mbps, OFDM 802.11b – 2.4GHz, 1-11Mbps, CCK (extension of DSSS) or PBCC (optional) 802.11g – 2.4GHz, 1-54Mbps, OFDM or PBCC (optional) 802.11n – task group looking at MIMO systems

22 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 22 1990 1997 1999 2003 2004 2005 2007 2008 802.11 begun 802.11 base standard 2.4GHz 2mbit FH, DS & IR 802.11b standard 2.4GHz 11Mb HRDS 802.11a standard 5GHz 54 Mb OFDM 11g (2.4GHz >20Mb HRDS & OFDM), 11f(IAPP), 11h(TPC) TGi (security) ? TGn (MIMO) TGe (QoS) TGs (Mesh) 802.11 at a Glance

23 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 23 802.11 at 2.4GHz Why still an interest in the 2.4GHz band? –Available spectrum worldwide Why still an interest in the 2.4GHz band? –Available spectrum worldwide

24 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 24 802.11 at 5.8GHz vs. 2.4GHz Currently 12 non-overlapping channels Fewer non-802.11 interferers Shorter distances –less interference with co-located networks –More APs required for same coverage area Higher frequency means higher power consumption OFDM phy layer nearly identical to Hiperlan2 phy Currently 12 non-overlapping channels Fewer non-802.11 interferers Shorter distances –less interference with co-located networks –More APs required for same coverage area Higher frequency means higher power consumption OFDM phy layer nearly identical to Hiperlan2 phy

25 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 25 2.4 GHz Channel Allocation Regulatory Domains CHNL_IDFrequency (MHz) X10 FCC X20 IC X30 ETSI X31 Spain X32 France X40 Japan X41 Japan 12412XXX---X 22417XXX---X 32422XXX---X 42427XXX---X 52432XXX---X 62437XXX---X 72442XXX---X 82447XXX---X 92452XXX---X 102457XXXXX-X 112462XXXXX-X 122467--X-X-X 132472--X-X-X 142484----X-

26 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 26 5 GHz Channel Allocation (USA)

27 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 27 802.11a 5-GHz band Uses orthogonal frequency division multiplexing (OFDM) –Not spread spectrum Multiple carrier signals at different frequencies Some bits on each subcarrier –Similar to FDM but all subcarriers dedicated to single source Data rates 6, 9, 12, 18, 24, 36, 48, and 54 Mbps 52 subcarriers modulated using BPSK, QPSK, 16-QAM, or 64-QAM –Depending on rate –Subcarrier frequency spacing 0.3125 MHz –Convolutional code at rate of 1/2, 2/3, or 3/4 provides forward error correction

28 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 28 1 Mbps & 2 Mbps 802.11 Barker sequence – 11 chips in length –1 Mbit = 1 bit sent as Barker sequence –2 Mbit = 2 bits sent using Barker sequence Barker sequence – 11 chips in length –1 Mbit = 1 bit sent as Barker sequence –2 Mbit = 2 bits sent using Barker sequence Signal symbol is spread with a sequence Wider Bandwidth Less Power Density DSSS Transmitter

29 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 29 802.11b Extension of 802.11 DSSS scheme 5.5 and 11 Mbps Chipping rate 11 MHz –Same as original DS-SS scheme –Same occupied bandwidth –Complementary code keying (CCK) modulation to achieve higher data rate in same bandwidth at same chipping rate –CCK modulation complex Overview on next slide –Input data treated in blocks of 8 bits at 1.375 MHz 8 bits/symbol 1.375 MHz = 11 Mbps Six of these bits mapped into one of 64 code sequences Output of mapping, plus two additional bits, forms input to QPSK modulator

30 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 30 802.11 FH Slow hopper – hop lasts up to 0.4 seconds per channel 1 & 2 Mbps data rates 79 channels, 1 MHz spacing Not much current interest Slow hopper – hop lasts up to 0.4 seconds per channel 1 & 2 Mbps data rates 79 channels, 1 MHz spacing Not much current interest

31 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 31 Frequency Time

32 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 32 ComponentsComponents BSS - Basic Service Set (Infrastructure) IBSS - Independent BSS (Ad-hoc or peer-to-peer) ESS - Extended Service Set STA – Station – e.g. Client card AP – Access Point DS – Distribution System BSS - Basic Service Set (Infrastructure) IBSS - Independent BSS (Ad-hoc or peer-to-peer) ESS - Extended Service Set STA – Station – e.g. Client card AP – Access Point DS – Distribution System

33 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 33 802.11 Architecture BSS BSS 2 STA 1 STA 2 STA 3 STA 4 AP DS ESS 802.11 Components

34 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 34 Whats In A Wireless MAC? CSMA/CA Carrier Sense Multiple Access / Collision Avoidance Virtual carrier sense – the NAV RTS/CTS – hidden node problem Access by Interframe spacing Fragmentation Retries Powersave state Synchronization Privacy – WEP (wired equivalent privacy) Multiple data rates CSMA/CA Carrier Sense Multiple Access / Collision Avoidance Virtual carrier sense – the NAV RTS/CTS – hidden node problem Access by Interframe spacing Fragmentation Retries Powersave state Synchronization Privacy – WEP (wired equivalent privacy) Multiple data rates

35 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 35 IEEE 802.11 MAC Frame Format Stallings Chapter 17 Wireless LANs

36 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 36 MAC Frame Fields (1) Frame Control: –Type of frame –Control, management, or data –Provides control information Includes whether frame is to or from DS, fragmentation information, and privacy information Duration/Connection ID: –If used as duration field, indicates time (in s) channel will be allocated for successful transmission of MAC frame –In some control frames, contains association or connection identifier Addresses: –Number and meaning of address fields depend on context –Types include source, destination, transmitting station, and receiving station

37 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 37 MAC Frame Fields (2) Sequence Control: –4-bit fragment number subfield For fragmentation and reassembly –12-bit sequence number –Number frames between given transmitter and receiver Frame Body: –MSDU (or a fragment of) LLC PDU or MAC control information Frame Check Sequence: –32-bit cyclic redundancy check Stallings Chapter 17 Wireless LANs

38 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 38 MAC Frames Management –Beacon & Probe Response –Authentication, Deauthentication –Association, Re-association, Disassociation –Action frames Control –ACK, RTS, CTS, PS-POLL Data –Data, Null-Data, QoS Management –Beacon & Probe Response –Authentication, Deauthentication –Association, Re-association, Disassociation –Action frames Control –ACK, RTS, CTS, PS-POLL Data –Data, Null-Data, QoS

39 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 39 CSMA-CA Explained Reduce collision probability where mostly needed. –Stations are waiting for medium to become free. –Select Random Backoff after a Defer, resolving contention to avoid collisions. Reduce collision probability where mostly needed. –Stations are waiting for medium to become free. –Select Random Backoff after a Defer, resolving contention to avoid collisions. Copyright 1996 IEEE, doc Efficient Backoff algorithm stable at high loads. Exponential Backoff window increases for retransmissions. Backoff timer elapses only when medium is idle.

40 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 40 This flowchart illustrates the operation of the CSMA/CA contention-based 802.11 DCF medium access protocol.

41 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 41 Hidden Node Problem

42 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 42 RTS & FRAG example

43 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 43 NAV Example CTS RTS Frag 1 ACK Frag 2 ACK Station 3 Station 4

44 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 44 MAC Overhead Fragmentation and RTS settings in MAC Legacy equipment Hidden nodes Retries DCF back-off algorithm Fragmentation and RTS settings in MAC Legacy equipment Hidden nodes Retries DCF back-off algorithm

45 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 45 MAC Layer Overhead 22112 1

46 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 46 Locating a Network Passive Scanning –Stations listen for a beacon frame –Based on the information contained, station may or may not attempt association Active Scanning –Station sends a probe request / listens for response –Attempt to associate based on information in response Passive Scanning –Stations listen for a beacon frame –Based on the information contained, station may or may not attempt association Active Scanning –Station sends a probe request / listens for response –Attempt to associate based on information in response

47 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 47 Starting an Infrastructure Network Station Probes for APs with desired SSID –(Service Set Identifier) Authentication Association Data transfer Deauthentication and/ or Dissassociation Station Probes for APs with desired SSID –(Service Set Identifier) Authentication Association Data transfer Deauthentication and/ or Dissassociation staAP bc Probe Req Probe Resp Ack Auth req Ack Auth resp Assoc. req

48 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 48 Infrastructure vs. Ad Hoc Infrastructure All traffic goes through AP Possible use of a Point Coordinator for polled access Requires Association Usually connects to a separate wired network Infrastructure All traffic goes through AP Possible use of a Point Coordinator for polled access Requires Association Usually connects to a separate wired network Ad Hoc All communication is direct Distributed nature of BSS functions No association Typically no network services found on a wired network available (DHCP, domain servers, etc.)

49 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 49 802.11e (TGe) - QoS 4 Queues for different priorities –Higher priority traffic gets sent first (i.e. VoIP, Video,…) Direct communication between wireless stations in an infrastructure network –Reduces medium utilization –Normally stations must go through the AP Block Acknowledgements –Reduce number of management frames EDCA & HCCA modes –More efficient methods for coordinating who, what, and when stations get access to medium 4 Queues for different priorities –Higher priority traffic gets sent first (i.e. VoIP, Video,…) Direct communication between wireless stations in an infrastructure network –Reduces medium utilization –Normally stations must go through the AP Block Acknowledgements –Reduce number of management frames EDCA & HCCA modes –More efficient methods for coordinating who, what, and when stations get access to medium

50 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 50 802.11h – TPC & DFS Transmitter Power Control –Needed for use of U-NII bands in EU Dynamic Frequency Selection Transmitter Power Control –Needed for use of U-NII bands in EU Dynamic Frequency Selection

51 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 51 802.11i (TGi) - security WEP – Wired EQUIVALENT Privacy –Only covers data payload and is point to point Management(beacons) and MAC data header sent in the clear –Many papers published on WEPs weaknesses WPA – WiFi Protected Access Mode –TKIP protocol uses RC4 engine from WEP –Includes a 4-way handshake Other security features in TGi –Port based authentication: 802.1x, RADIUS –Stronger cryptography: AES – Advanced Encryption Standard End to End Solutions can always be used –SSH – secure shell, Stunnel – secure tunnel, VPN – virtual private network WEP – Wired EQUIVALENT Privacy –Only covers data payload and is point to point Management(beacons) and MAC data header sent in the clear –Many papers published on WEPs weaknesses WPA – WiFi Protected Access Mode –TKIP protocol uses RC4 engine from WEP –Includes a 4-way handshake Other security features in TGi –Port based authentication: 802.1x, RADIUS –Stronger cryptography: AES – Advanced Encryption Standard End to End Solutions can always be used –SSH – secure shell, Stunnel – secure tunnel, VPN – virtual private network

52 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 52 802.11n – High speed High Throughput Group –Looking to achieve speeds of >100Mbs Improve MAC efficiency –Using lots of the improvements for QoS, this would reduce the management overhead needed Higher data rates –Using MIMO and OFDM to get more data though –Use higher constellation sizes (256 QAM) –Higher bandwidth channels 40MHz instead of 20MHz –Takes advantage of multipath There are still multiple proposals about how to actually do this High Throughput Group –Looking to achieve speeds of >100Mbs Improve MAC efficiency –Using lots of the improvements for QoS, this would reduce the management overhead needed Higher data rates –Using MIMO and OFDM to get more data though –Use higher constellation sizes (256 QAM) –Higher bandwidth channels 40MHz instead of 20MHz –Takes advantage of multipath There are still multiple proposals about how to actually do this

53 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 53 802.11p – Vehicular Wireless Enable Wireless connections in vehicle-to-vehicle as well as vehicle-to-roadside locations –Would enable download of information about what is around you and what is going on –Could allow for more advanced services for cars EZPass type applications Accident prevention/preparation could occur Traffic and road condition report downloads More intelligent car navigation services Hard to do because vehicles are moving fairly quickly –Various nodes move in and out of range within seconds Range of ~1000 ft. 6Mbs in the 5.9GHz band Enable Wireless connections in vehicle-to-vehicle as well as vehicle-to-roadside locations –Would enable download of information about what is around you and what is going on –Could allow for more advanced services for cars EZPass type applications Accident prevention/preparation could occur Traffic and road condition report downloads More intelligent car navigation services Hard to do because vehicles are moving fairly quickly –Various nodes move in and out of range within seconds Range of ~1000 ft. 6Mbs in the 5.9GHz band

54 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 54 802.11s – Mesh Networking Mesh Networks are getting more and more popular –Many large cities are deploying large metropolitan mesh networks Philadelphia is one of the most notable –Allows for large networks to be built without the need for lots of cabled infrastructure. Takes a lot from Internet Protocol (IP) routing systems to allow for hopping through a network –routing needs to occur at the MAC layer and at the IP layer in order to deliver traffic to the clients or APs which are located across the network Many proprietary methods already exist –Tropos –Strix Mesh Networks are getting more and more popular –Many large cities are deploying large metropolitan mesh networks Philadelphia is one of the most notable –Allows for large networks to be built without the need for lots of cabled infrastructure. Takes a lot from Internet Protocol (IP) routing systems to allow for hopping through a network –routing needs to occur at the MAC layer and at the IP layer in order to deliver traffic to the clients or APs which are located across the network Many proprietary methods already exist –Tropos –Strix

55 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 55 IEEE 802.15 (WPANs) 802.15.1 adoption of Bluetooth 1.0/1.1 standard into IEEE 802.15.2 coexistence of WPANs and WLANs in the 2.4GHz band 802.15.3 high rate WPAN –802.15.3a UWB PHY task group 802.15.4 low rate WPAN –Zigbee 802.15.1 adoption of Bluetooth 1.0/1.1 standard into IEEE 802.15.2 coexistence of WPANs and WLANs in the 2.4GHz band 802.15.3 high rate WPAN –802.15.3a UWB PHY task group 802.15.4 low rate WPAN –Zigbee

56 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 56 Bluetooth & 802.15 Frequency band: 2.4 GHz Range: 10 meters Power: 0 or 10 dBm (1mW or 10 mW) Data rate: 3 Mbps signaling rate replace the wire FH physical layer - 1600 hops/sec Frequency band: 2.4 GHz Range: 10 meters Power: 0 or 10 dBm (1mW or 10 mW) Data rate: 3 Mbps signaling rate replace the wire FH physical layer - 1600 hops/sec

57 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 57 802.15.3 Standard Frequency Range 2.4-2.4835 GHz Symbol rate 11 Msymbols/s (22-66Mbps) Base Modulation OQPSK –Optional 16,32, & 64QAM up to 66Mbps RF Bandwidth < 22 MHz Number of channels at least 4 Transmit power 0 to 8 dBm Range 10 m Frequency Range 2.4-2.4835 GHz Symbol rate 11 Msymbols/s (22-66Mbps) Base Modulation OQPSK –Optional 16,32, & 64QAM up to 66Mbps RF Bandwidth < 22 MHz Number of channels at least 4 Transmit power 0 to 8 dBm Range 10 m

58 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 58 IEEE 802.16 (WiMAX) Developed from DOCSIS 1.1 (Data Over Cable Service Interface Specification)

59 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 59 Additional Resources Higher layer Protocols –http://www.ietf.org/html.charters/manet-charter.htmlhttp://www.ietf.org/html.charters/manet-charter.html –http://www.ietf.org/html.charters/mip4-charter.htmlhttp://www.ietf.org/html.charters/mip4-charter.html –http://www.ietf.org/hmtl.charter/mip6-charter.htmlhttp://www.ietf.org/hmtl.charter/mip6-charter.html Service Discovery –http://www.upnp.org/http://www.upnp.org/ –http://www.artima.com/jini/index.htmlhttp://www.artima.com/jini/index.html Geier, Jim. Wireless LANs. Pearson Education, 2001. Security –Schneier, Bruce. Applied Cryptography, Second Edition. John Wiley & Sons, Inc. 1996. (http://www.counterpane.com/applied.html)http://www.counterpane.com/applied.html Standards Committees –http://grouper.ieee.org/groups/802/dots.htmlhttp://grouper.ieee.org/groups/802/dots.html Higher layer Protocols –http://www.ietf.org/html.charters/manet-charter.htmlhttp://www.ietf.org/html.charters/manet-charter.html –http://www.ietf.org/html.charters/mip4-charter.htmlhttp://www.ietf.org/html.charters/mip4-charter.html –http://www.ietf.org/hmtl.charter/mip6-charter.htmlhttp://www.ietf.org/hmtl.charter/mip6-charter.html Service Discovery –http://www.upnp.org/http://www.upnp.org/ –http://www.artima.com/jini/index.htmlhttp://www.artima.com/jini/index.html Geier, Jim. Wireless LANs. Pearson Education, 2001. Security –Schneier, Bruce. Applied Cryptography, Second Edition. John Wiley & Sons, Inc. 1996. (http://www.counterpane.com/applied.html)http://www.counterpane.com/applied.html Standards Committees –http://grouper.ieee.org/groups/802/dots.htmlhttp://grouper.ieee.org/groups/802/dots.html

60 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 60 Additional Resources (2) Zigbee Alliance –http://www.zigbee.orghttp://www.zigbee.org WiMAX Forum –http://www.wimaxforum.orghttp://www.wimaxforum.org Bluetooth –http://www.bluetooth.comhttp://www.bluetooth.com Wireless News –http://www.wi-fiplanet.comhttp://www.wi-fiplanet.com –http://www.unstrung.comhttp://www.unstrung.com UWB Forum –http://www.uwbforum.orghttp://www.uwbforum.org Zigbee Alliance –http://www.zigbee.orghttp://www.zigbee.org WiMAX Forum –http://www.wimaxforum.orghttp://www.wimaxforum.org Bluetooth –http://www.bluetooth.comhttp://www.bluetooth.com Wireless News –http://www.wi-fiplanet.comhttp://www.wi-fiplanet.com –http://www.unstrung.comhttp://www.unstrung.com UWB Forum –http://www.uwbforum.orghttp://www.uwbforum.org

61 U NIVERSITY of N EW H AMPSHIRE I NTER O PERABILITY L ABORATORY Wireless Overview 61 ReferencesReferences http://hypertextbook.com/physics/electricity/em- spectrum/http://hypertextbook.com/physics/electricity/em- spectrum/ Stallings, William. Data and Computer Communications. Prentice Hall: New Jersey, 2000. http://hypertextbook.com/physics/electricity/em- spectrum/http://hypertextbook.com/physics/electricity/em- spectrum/ Stallings, William. Data and Computer Communications. Prentice Hall: New Jersey, 2000.


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