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MTS, Field Applications Engineering National Semiconductor, Irvine,CA

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1 MTS, Field Applications Engineering National Semiconductor, Irvine,CA
IEEE Orange County Computer Society Joint Meeting with IEEE OC ComSig Chapter Wireless LAN Instrumentation, Scientific, Medical Band Dwight Borses MTS, Field Applications Engineering National Semiconductor, Irvine,CA Feb 25, 2002

2 Local volunteers needed!
The IEEE ("eye-triple-E") The Institute of Electrical and Electronics Engineers, Inc., helps advance global prosperity by promoting the engineering process of creating, developing, integrating, sharing, and applying knowledge about electrical and information technologies and sciences for the benefit of humanity and the profession. Local volunteers needed!

3 Points to Ponder Standards - so many to choose from
Cellular/PCS - both a competitor and a complement to WLAN DECT – up-banded applications for proprietary applications UWB – yet another contender FSO – Light based wireless

4 Wireless Technologies: Short Distance

5 802.11 Infrared A real standard that sort of died

6 Wireless Technologies: Long Distance

7 Data Migration Path to 3G WWAN
3/28/2017 Data Migration Path to 3G WWAN 3G Fixed access at 2Mbps 2 M 384 K 144 K 64 K 14.4 K 9.6 K 3G Phase II IS-2000 Rel A (3XRTT) Packet Data / Voice / Video 3G Phase I IS-2000 Rel 0 (1XRTT) Packet Data Subscriber Data Rate 2.5G IS-95B Packet Data 2G IS-95-A Circuit Switched + QNC 1G Analogue Cellular




11 2.4GHz ISM Band

12 ISM Band Inhabitants (Besides 802.11) Frequency & Modulation Spec’s
3/28/2017 ISM Band Inhabitants (Besides ) Frequency & Modulation Spec’s The data transmitted has a symbol rate of 1 Ms/s. A Gaussian-shaped, binary FSK modulation( is applied with a BT product of 0.5). A binary one is represented by a positive frequency deviation, a binary zero by a negative frequency deviation. The maxmium frequency deviation shall be between 140 khz and 175 kHz. The transmitted initial center frequency accuracy must be +75 kHz from Fc. Note that the frequency drift is not included in 75 kHz. For bluetooth, each slot is 625 us and for multislot packets, Packets transmitted may extend over up to 5 times slots. Drift must be less than 40 kHz. Notes costs and tight specification.

13 Comparing Different WLAN Technologies

14 5 GHz Unlicensed National Information Infrastructure

15 IEEE 802 Framework

16 802.11 Standards Overview IEEE 802.11 802.11a 802.11b 802.11d 802.11e
802.11f 802.11g 802.11h 802.11i

17 802.11 Standards Original 802.11, circa 1999
FHSS, DSSS, IR 1 & 2 Mbps Wired Equivalent Privacy (WEP) SNMP v2 for remote management 802.11b (shortly after ) DSSS 1, 2, 5.5 & 11 Mbps, Complementary Code Keying (CCK)

18 802.11 Standards 802.11a (Approved same time as .11b)
6, 9, 12, 18, 24, 36, 48, 54 Mbps Only 6, 12, 24 Mbps support is mandatory 5 GHz UNII band (not universally free)

19 802.11 Standards 802.11c (completed, subsumed into d)
Bridge operation 802.11d (ongoing) Specs for other regulatory domains 802.11e (ongoing) QoS (Security moved to i (May 2001)) 802.11f (ongoing) Inter Access Point interoperability

20 802.11 Standards 802.11g (ongoing) 802.11h (ongoing) 802.11i (ongoing)
High-speed extension to b, > 20Mbps Just approved! 802.11h (ongoing) improvement to a, w.r.t. power and spectrum management 802.11i (ongoing) Security enhancements

21 Wireless Data Standards Technology Comparison
3/28/2017 Wireless Data Standards Technology Comparison

22 PANs, LANs, and Bluetooth

23 Full Range of Wireless LANs
EHF (milli-wave) SHF (micro-wave) VHF UHF Wired LAN Middle Speed 2.4GHz Range LAN High Speed 5GHz Range LAN Very High Speed 60 GHz Range LAN 4Mbps/16Mbps Token Ring IEEE 802.5 10Mbps Ethernet IEEE 802.3 25/52/100Mbps ATM-LAN (ATM Forum) 100Mbps Fast Ethernet IEEE 802.3u 156/622 Mbps ATM-LAN (ATM Forum) 1000Mbps Gigabit Ethernet IEEE 802.3z, 802.3ab Bandwidth Frequency IEEE Mbps/2Mbps IEEE802.11b 5.5Mbps/11Mbps (1)IEEE a 6/12/24Mbps (2)HIPERLAN (ETSI BRAN) Type ½: 23.5/25Mbps (3)WATM (ATM Forum) 25Mbps 19GHz range LAN 10Mbps (ARIB) 156Mbps MMAC(Japan) 156Mbps MEDIAN (German) 300GHz 30GHz 3GHz 300MHz 1GHz

24 Data Rates and Range by Technology

25 802.11 – Infrastructure Architecture

26 Layers and Functions

27 Binary Phase Shift Keying Quadrature Phase Shift Keying

28 Quadrature Modulation

29 Quadrature Amplitude Modulatoion

30 IEEE 802.11 Direct Sequence Spread Spectrum DSSS

31 Frequency Hopping Spread Spectrum (FHSS)
Transmitted signal is “spread” over a wide range of frequencies (ISM GHz) Transmission hops 8 to 30 times per second Freq. f1 f2 f3 f4 f5 f6 f7 Time t1 t2 t3 t4 t5 t6 AU 1 AU 2 AU 4 AU 3

32 Complementary Code Keying
This sequence 1 has 4 pairs of like elements with a separation of 1 and 3 pairs of unlike elements with a separation of 1

33 Complementary Code Keying
This sequence has 4 pairs of unlike elements with separation of 1 and 3 pairs of like elements.

34 Modulation Set

35 Binary Phase Shift Keying



38 CSMA/CD CSMA/CD For wire communication No control BEFORE transmission
Carrier Sense, Multiple Access/Collision Detection For wire communication No control BEFORE transmission Generates collisions Collision Detection How?

39 CSMA/CA CSMA/CA For wireless communication
Carrier Sense, Multiple Access/Collision Avoidance For wireless communication Collision avoidance BEFORE transmission Pre-avoidance of collision Why avoidance on wireless?

40 Collision Detection On Wireless?
Difference on energy/power for transmit and receive At maximum, transmission power is a million times larger than receiving Very hard to detect because of this difference Energy often matter on wireless environment Portable devices/terminals with batteries

41 Backoff Decrease the possibility of contention/collision
Backoff window Time to wait ot avoid collision Random backoff Use random length of time to wait

42 IFS – Inter Frame Spacing
Defined length of time for control To assure the control of multiple access DIFS – Distributed Inter Frame Spacing PIFS – Point Inter Frame Spacing SIFS – Short Inter Frame Spacing DIFS (MAX) > PIFS > SIFS (MIN)

43 Basic Access Method: CSMA/CA
Backoff Time = Random() x aSlotTime

44 802.11 - Competing Stations - Simple Version

45 RTS/CTS RTS : Request To Sent. CTS : Clear To Sent
Duration/ID fields that define the period of time that the medium is to be reserved to transmit the actual data frame and the returning ACK frame

46 Network Allocation Vector NAV
The NAV maintains a prediction of future traffic on the medium based on duration information that is announced in RTS/CTS frames prior to the actual exchange of data The duration information is also available in the MAC header of all frames sent during the CP other than PS-Poll Control frames

47 RTS/CTS/Data/ACK and NAV

48 Security

49 Basic Security Concerns
Impractical to stop RF signals from propagating beyond your premises “Parking lot” attack, war-driving Poorly configured networks can be woefully exposed Hackers can be highly stealthy, guerilla warfare style That’s the reason for WEP

50 Baseline Security Features
Wired Equivalent Privacy Shared 40/128 bit key Static, i.e. not designed to change often RC4 stream cipher Any AP/client can be configured to handle up to 4 keys

51 Baseline Security Features
Mutual authentication Open, i.e. null Shared key (if WEP is enabled), MS-CHAP style challenge and response Access control list at AP based on MAC addresses of WLAN cards Access Control List can be easily bypassed MAC addresses can be sniffed from the air client’s MAC address can be easily spoofed Service set ID (SSID) “secret” word that identifies a WLAN segment SSID is not a security feature transmitted in the clear in beacon frames clients can set as null string

52 Basic Security Concerns
Sniffing tools are easily available Freeware Ethereal + Prism II card Now can capture raw encrypted packets Commercial tools WildPacket Airopeek (~$2.5K) NAI Sniffer Wireless (~ $20K) Others are available FREE on the web

53 Basic Security Concerns
Besides WEP key, no other credentials required to access WLAN network Difficult to manage shared WEP key in large deployments Keys are seldom changed, manual process If a WLAN card is stolen, have to reconfigure all other WLAN cards configured with that same WEP key

54 The End of WEP? Undeniable fact: WEP in its current form is not secure
Security issues are now better understood No false sense of security => a good thing Vendors have always advocated higher level security is needed anyway e.g. VPN, IPSec

55 IPSec

56 IPSec Sessions

57 802.11g Newest standard provides for up to 54 Mbps data transfers within the 2.4 GHz band. 802.11g devices will be backwards compatible with b. Potentially enables GHz-based b networks to easily upgrade to future g networks Consumers confusion with a and g standards entering the market simultaneously Cellular phone service providers are considering augmenting their "3G" third generation digital cellular networks with support of the unlicensed WLAN devices, particularly in peak usage areas in downtown cities and at airports

58 Something for Everyone

59 HomeRF Roadmap

60 Bluetooth: Lose the Cable!

61 Overview of Bluetooth Bluetooth is: Short-range radio technology
3/28/2017 Overview of Bluetooth Bluetooth is: Short-range radio technology Class 1 (100 m) +20dBm max to 0 dBm w/ power control Class 2 ( 30 m) + 4 dBm to -6 dBm Class 3 ( 10 m) dBm max Connections without cables Laptops, Cell phones, PDA’s, Printers, etc Royalty-free IEEE Standard through (PAN) Bluetooth is a low-cost, low-power, short-range radio technology. It was originally developed as a cable replacement to connect devices such as cell phone handsets and portable computers. It has been extended to include standardized wireless communications between any electrical device over a short range (maximum range of 100 meters using the high-power Class 1 mode). Bluetooth now represents the concept of a Personal Area Network (PAN), and it is intended to revolutionize the way people interact with the information infrastructure around them. It remains to be seen if Bluetooth can live up to this larger role. The technology was named after a Viking and King of Denmark who lived in the late 900’s (AD), whose real name was Harald Blaatand. He was the son of Gorm the Old and Thyra Danebod. Harald united and then ruled over both Denmark and Norway. The founding members of the Bluetooth Special Interest Group (SIG) are: Ericsson, Intel, IBM, Toshiba and Nokia.

62 Overview of Bluetooth Bluetooth Applications:
3/28/2017 Overview of Bluetooth Bluetooth Applications: Internet and bridge Ad Hoc network via access point Home networking Hidden computing Wireless wallet Laptop and PDA to cell phone modem Headset Digital camera Ad Hoc network means a network dynamically created when you walk into a room with a Bluetooth device, and perform an inquiry to find out if any other Bluetooth devices are in the room and willing to talk to your Bluetooth device.

63 Source: Jim Kardach, Intel
Who Was Bluetooth? Harald Blaatand “Bluetooth” II King of Denmark Son of Gorm the Old (King of Denmark) and Thyra Danebod (daughter of King Ethelred of England) This is one of two Runic stones erected in his capitol city of Jelling (central Jutland) This is the front of the stone depicting the chivalry of Harald. The stone’s inscription (“runes”) say: Harald Christianized the Danes Harald controlled Denmark and Norway Harald thinks notebooks and cellular phones should seamlessly communicate Source: Jim Kardach, Intel








71 Typically used for voice.
Guaranteed bandwidth No re-transmission. Typically used for data. Point to multi-point. Reliable data (error correction / re-transmission) No guaranteed bandwidth (best effort).

72 3/28/2017

73 Mutual Interference Problems
IEEE and Bluetooth both operate in same 2.4 GHz ISM Band Bluetooth enabled devices likely to be portable and need to operate in IEEE WLAN environment There will be some level of mutual interference Source: [John Barr] Company [Motorola] IEEE Report at BT DevCon

74 Coexistence Mechanisms
Collaborative Mechanisms Communication between the WLAN and WPAN Provide fair sharing of medium through link Non-Collaborative Mechanisms No communication between WLAN and WPAN Techniques minimize effects of mutual interference Source: [John Barr] Company [Motorola] IEEE Report at BT DevCon

75 Impact of Bluetooth on 802.11b:


77 National Semiconductor Wireless Solutions for 802.11 and Bluetooth
First to market with BT 1.O compliance 802.11a/b/g solution Expect to meet all mandatory parts of g Complete solutions Development boards for Radio and Baseband Reference boards for MiniPCI and PCMCIA Drivers and utilities Bluetooth PC Card, Compact Flash, and Printer Adapters solutions shipping now

78 Thank you! Dwight Borses
3/28/2017 Thank you! Dwight Borses 78

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