Wireless Technologies
Update
Presented by:
Jonathan Sellars,
PCC Network Solutions
CCNA, CCDA, Cisco Wireless Design Specialist, BICSI Certified
Trainer
jsellars@pccinc.com
Why Deploy Wireless?
• Productivity & Business Efficiencies
– Mobilize CRM & ERP applications
– Instant access to information
• Connections on the Go
– Making employees more productive
– Any data, any device, anywhere, any time
• Flexibility to add devices and workgroups
– No waiting for cables
• Cost Savings – Networks without cables
– Wireless uplink replaces cables
– Lower cost than cabling new sites
• Bandwidth, Mobility, Simplicity
– Easy to integrate with wired LAN …
– Without sacrificing performance or security
Wireless LAN Timeline
1940
Spread Spectrum technology first used by US military during WWII for secure voice
communications.
1989
FCC assigns 900MHz, 2.4GHZ, and 5GHz frequencies for commercial use: ISM
(Industrial, Scientific, Medical).
1990
900MHz products begin shipping. IEEE begins work on WLAN industry standard.
1994
2.4GHz products begin shipping.
1997
IEEE 802.11 standard approved. WECA (Wireless Ethernet Compatibility Alliance)
formed by Lucent, 3Com, Aironet (Cisco), Intersil, Nokia, and Symbol.
1999
IEEE 802.11a and 802.11b ratified. WBFH (Wideband Frequency Hoping) released by
FCC. First 802.11 AP and compatible OS ship from Apple Computer.
2000
WECA markets WiFi (short for "wireless fidelity") as the common name for 802.11b.
802.11g Task Group added to 802.11 Work Group. WECA membership grows to over
65 companies with over 50 certified WiFi products.
2002
WECA changes name to Wifi Alliance. IEEE 802.11 Task Groups now range from
802.11a to 802.11i. Dual mode 802.11a/b and 802.11g (802.11b compatible)
products begin shipping.
2003
802.11g standard finalized June, 2003.
IEEE 802.11 WLAN Standards
802.11
Refers to a family of specifications developed by the IEEE for wireless LAN
technology. 802.11 specifies an over-the-air interface between a wireless client and
a base station or between two wireless clients. Applies to wireless LANS and
provides 1 or 2 Mbps transmission in the 2.4 GHz band using either frequency
hopping spread spectrum (FHSS) or direct sequence spread spectrum (DSSS).
802.11a
Standard for 5GHz, 54 Mbps WLAN operation.
802.11b
Standard for 2.4GHz, 11 Mbps WLAN operation.
802.11c
Specifications for 802.11-specific MAC procedures provided to the ISO/IEC.
802.11d
Definitions and requirements published to allow the 802.11 standard to operate in
countries not currently served by the standard. Ongoing.
802.11e
Enhancements to the 802.11 MAC for QoS applications to enable video, audio, voice
traffic, etc. Includes packet bursting to increase throughput. Ongoing.
802.11f
IAPP (Inter Access Point Protocol) to enhance roaming, and to increase compatibility
between AP devices from different vendors. Ongoing.
802.11g
OSI Physical Layer (PHY) extension to the 802.11b standard, while maintaining
backward compatibility with current 802.11b devices. 54 Mbps WLAN operation.
802.11h
Enhances the 802.11 MAC and 802.11a PHY to provide spectrum and transmit
power management in the 5 GHz band. This will allow regulatory acceptance of the
standard in some European countries. Ongoing.
802.11i
Developing standard for security in a WLAN. 802.11i includes 802.1x,
key management, WPA encryption. Ongoing.
IEEE 802.11 WLAN Standard
Activities
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Legend
802.11a: 5 GHz, 54 Mbps
Ratified
802.11b: 2.4 GHz, 11 Mbps
Draft
802.11d: Multiple regulatory domains
18 Months and Beyond
802.11e: Quality of Service (QoS)
802.11f: Inter-Access Point Protocol (IAPP)
802.11g: 2.4 GHz, 54 Mbps
802.11h: Dynamic Frequency Selection (DFS) and Tran Power
802.11i: Security – Ratified | WPAv2 – Draft 9
802.11j: Japan 5 GHz Channels (4.9-5.1 GHz)
802.11k: Measurement
802.11m: Maintenance
802.11n: High Throughput
802.11p: Wireless Access for Vehicular Environment
802.11r: Public WLAN Fast Roaming
802.11s: Mesh Networking
802.11 a/b/g Specifications
802.11a
802.11b
802.11g
Radio Frequency
5GHz U-NII (Unlicensed National
Information Infrastructure)
2.4GHz ISM (Industrial,
Scientific, and Medical)
2.4GHz ISM
Bandwidth (Link
Speed in Mbps)
6, 9, 12, 18, 24, 36, 48, 54
1, 2, 5.5, 11
1, 2, 5.5, 6, 9, 11, 12, 18,
22, 24, 36, 48, 54
26-27 Mbps
5-6 Mbps
20+ Mbps
Carrier
Technique
OFDM (Orthogonal Frequency
Division Multiplexing)
DSSS (Direct Sequence
Spread Spectrum)
DSSS, OFDM
Modulation
Format
BPSK, QPSK, 16 QAM, 64 QAM
CCK, QPSK, DQPSK, DBPSK
PBCC + 802.11a + 802.11b
Channel
Bandwidth
16.6MHz
22MHz
22MHz
Throughput
(Actual max.
payload rate)
IEEE 802.11b Specification
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Ratified as Standard in Sept, 1999
Uses 2.4 GHz RF spectrum
Direct Sequence at 1, 2, 5.5 and 11 Mbps
Can “downshift” to lower data rates for longer
range
• 11 US channels; 13 ETSI channels; 14 Japan
channels
• Power levels: 36 dBm Effective Isotropic
Radiated Power (EIRP)-US; 20 dBm EIRPEurope
• Generally approved for use in many countries
IEEE 802.11b
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Up to (14) 22 MHz-wide channels
3 non-overlapping channels*
(1, 6,11 in US and 1,7,13 in Europe)
Up to 11 Mbps data rate/5.5 Mbps
throughput
• 3 Access Points can occupy the same
space (non-overlapping channels)
– Total of 33 Mbps aggregate throughput, but
not on same radio card
IEEE 802.11b
• 802.11b is usually used in a point-to-multipoint
configuration, wherein an access point communicates
via an omni-directional antenna with one or more
clients that are located in a coverage area around the
access point
• Typical indoor range is 30 m at 11 Mbit/s and 90 m at 1
Mbit/s. With high-gain external antennas, the protocol
can also be used in fixed point-to-point arrangements,
typically at ranges up to 8 kilometers although some
report success at ranges up to 80–120 km where line of
sight can be established. This is usually done in place of
costly leased lines or very cumbersome microwave
communications equipment.
802.11b Channel Optimization
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Since channel bandwidth is 22MHz,
there must be 5 channels between
simultaneously operated Access Points
to eliminate overlap/interference
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Can optimize simultaneous channel
utilization with channels 1, 6, and 11
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However, since the spectral mask only
defines power output restrictions up to
±22 MHz from the center frequency, it
is often assumed that the energy of
the channel extends no further than
these limits. In reality, if the
transmitter is sufficiently powerful, the
signal can be quite strong even
beyond the ±22 MHz point. Therefore,
it is incorrect to say that channels 1,
6, and 11 do not overlap. It is more
correct to say that, given the
separation between channels 1, 6, and
11, the signal on any channel should
be sufficiently attenuated to minimally
interfere with a transmitter on any
other channel
IEEE 802.11a Specification
• The 802.11a amendment to the original standard was ratified
in 1999
• Twelve channels
– Important to avoid the use of adjacent channels in adjacent cells
due to sidebands
• 11 new Channels pending (US)
– Pending FCC testing program
• Not qualified in many countries
• Tx power control and dynamic frequency selection required
(802.11h - Spectrum and Transmit Power Management
Extensions)
• The 802.11a standard uses the same core protocol as the
original standard, operates in 5 GHz band, and uses a 52subcarrier orthogonal frequency-division multiplexing (OFDM)
with a maximum raw data rate of 54 Mbit/s, which yields
realistic net achievable throughput in the mid-20 Mbit/s
IEEE 802.11g Specification
• In June 2003, a third modulation standard was
ratified: 802.11g
• Standard for higher-rate (20+ Mbps)
extensions in the 2.4-GHz band
• Provides data rates up to 54 Mbps at 2.4 GHz
• Same speeds as 802.11a
• Backward compatible with 11 Mbps 802.11b
• Same modulation as 802.11a – orthogonal
frequency-division multiplexing (OFDM)
IEEE 802.11 Tri-Mode Positioning
Both Frequency Bands Will Be Successful!
Support for a, b, and g in a single mobile adaptor
card or access point.
5GHz—802.11a
2.4GHz—802.11b/g
• Maximum Wireless LAN
performance: 54Mbps
• Works only in U.S., Japan,
and other FCC countries
• Works with interim
regulations in Europe
• 5 GHz band has less
interference
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11Mbps - 36Mbps - 54Mbps
3 channels
Worldwide compatibility
Compatibility with installed
base of 802.11b products
• Easy upgrade path to highspeed 802.11g
• Wide selection of client
devices
802.11n Specification
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802.11n is a new standards effort to create a next generation highspeed WLAN protocol at 5 GHz
Objectives: Data Rate >150 Mbps, throughput >100 Mbps
– Backward compatible with 802.11a (like g to b)
IEEE estimates that .11n won’t be completed until 4Q’06/1Q’07
– Initial market: Home entertainment (e.g. HDTV)
There were two competing proposals of the 802.11n standard
– WWiSE Group (World-Wide Spectrum Efficiency)
– TGn SYNC Group
Variety of technologies being considered (61 separate proposals so
far)
– MIMO (multiple input/multiple output) “Double-wide” Channels
– MRC Beam-Forming
– Full Duplex Operation
Pre Standard Implementation will require single vendor APs and NICs
802.11s—Mesh Networks
• 802.11s—Physical/Data link layer specification for meshed
networks that improves coverage with no single point of
failure
• Access points relay information from one to another
– Layer 2 Based
– Looking at Multiple Radios/Channels to overcome single Radio
Mesh limitations - Single Radio meshes reduce bandwidth by half
at every hop
– Will require new hardware
– Standard is 2+ Years away
• Scalability is very important in most networks today
• Large Layer 2 Data networks do not scale and require Network
Layer routers
– Radio networks are no exception
– Wireless networks create a flat network and a single broadcast
domain
IEEE 802.16 WiMAX Specification
• IEEE802.16a is a standard for Wireless
Metropolitan Area Networks operating in the 2–6
GHz range
– See http://www.ieee802.org/16/
– IEEE 802.16a Technical Overview
• WiMAX is an Industry Forum set up to promote
acceptance of the IEEE802.16a standard in the
market place—much like the Wi-Fi Alliance
– See http://www.wimaxforum.org/home
– WiMAX Overview, WiMAX FAQ
• Both address only the Radio subsystem no endto-end architecture
IEEE 802.16d
• 16d is a subset for 2–6 GHz range
– Current version of 802.16 Fixed WiMAX that
supercedes previous standards
– Specific radio and medium access control designs
– Licensed and unlicensed spectrum
– Utilizes the OFDM 256-FFT (Fast Fourier Transform)
– Basically fixed wireless access using outdoor CPEs
IEEE 802.16e
• .16e is a variant of 16d intended for mobile
use
– Licensed and unlicensed spectrum
– Data rates similar to 3G but sustainable and with
much better spectrum efficiency than 3G
– 802.16e will add mobility in the 2 to 6 GHz licensed
bands
– The 802.16e project authorization request specifies
only that it will "support subscriber stations moving
at vehicular speeds“ – WiMAX has achieved speeds
of 120 to 150 kilometers per hour (75 to 93 miles
per hour) in simulations.
#1 Wireless LAN Concern: Security
• Your network is vulnerable if your WLAN
security is not turned on and properly
installed
• Employees will install WLANs on their
own which compromises the security of
your entire network
• Strong security policies must be in
place to maintain WLAN security and
perform intrusion detection activities
Robust Wireless LAN Security Is
Needed
• Each user must be individually
authenticated via a unique identifier
• Data must remain uncorrupted
throughout the sending-and receiving
transmission process
• Security administration should be
scalable, problem-free and not increase
the burden on the IT staff
• Unauthorized users, rogue access
points and network attacks must be
detected and mitigated
Physical Challenges Vs. Range
• Physical challenges affecting range
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Multi-path propagation e.g. reflections
RF signal attenuation e.g. structures
Path loss e.g. signal propagation distance
Radio signal interference e.g. rogue Access
Points or channel overlap
– Access Point placement e.g. installation
location and antenna types (omnidirectional vs. directional antennas)
Distance (Meters/Feet)
802.11 a/b/g Range vs. Bandwidth
120/400
120
 802.11a
 802.11b
 802.11g
100/333
100
80/266
80
60/200
60
40/133
40
20/67
20
0
0
1Mbps
5.5Mbps
6Mbps
11Mbps
12Mbps
24Mbps
Bandwidth (Mbps)
Note: Bandwidth is based on RF rates.
Actual throughput is lower.
36Mbps
54 Mbps
Recent Trends in the Public Sector on
Technology Adoption
• The public sector is leveraging wireless
deployments to address their needs to:
– Improve security, productivity and operational
efficiency
– Enhanced collaboration between multiple agencies:
local/state/federal government, first responders,
public transit
• U.S. Homeland Security funding recently
allocated over $2B to state and local
government for 2004-2005 for buildup of:
– First Responder/Critical Infrastructure
– Security Preparedness
– Communications Interoperability
4.9 Ghz Spectrum—Public Safety
• Access technology designated for First
Responders, City Governments
• If FCC changes its stance on Emissions Mask;
can use COTS 5GHZ products
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Leverage 802.11a/j standards and chips
Licensed 50 Mhz of Spectrum
2 x 20 Mhz Non-Over Lapping channels
EIRP 42 dBm power (33 dBm + 9 dBi Antenna)
Tighter Mask will require additional filters (Hardware)
to use existing radios or new radios
Applications for Public Safety
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Dispatch
Field reporting, premise history lookup
Car-to-car messaging
Auto Vehicle Location/Mapping
Pictures, criminal database/history
E-Ticketing
Vehicle telematics
Situational video transmitting & receiving
Send/receive medical data
Hazard material monitoring