CCNAW 80211 Antenna Protocol S3 C5-6 v2

CCNA Wireless 802.11 Antennas and ProtocolsBill Wolfe Senior Enterprise Architect

CCNAW_80211_A_P_S3_v2

2010 Cisco and/or its affiliates. All rights reserved.

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A radio needs a proper antennaAs the frequency goes up the radiating element gets smaller

Cisco antennas are identified by color Blue indicates 5 GHz Black indicates 2.4 GHz

Omni-Directional antennas like the one on the left, radiate much like a raw light bulb would everywhere in all directions

Directional antennas like this Patch antenna radiate forward like placing tin foil behind the light bulb or tilting the lamp shade Note: Same RF energy is used but results in greater range as its focused at the cost of other coverage areas

Antennas are custom made and have frequency ranges and specificationsCCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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Wi-Fi Radio SpectrumThe 2.4 GHz spectrum has only (three non-overlapping channels 1,6 and 11 (US) There are plenty of channels in the 5 GHz spectrum and they do not overlap 2.4 GHz and 5 GHz are different portions of the radio band and usually require separate antennas Most if not all 5 GHz devices also have support for 2.4 GHzEven today many portable devices in use are limited to 2.4 GHz only including newer devices but this is changing 802.11b/g is 2.4 GHz 802.11a is 5 GHz 802.11n (can be either band) 2.4 or 5 GHz

Note: There are still many 2.4 GHz only devices today primarily because those chipsets are less costly to produce



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Basic 802.11 RF terminology and Radio Hardware Identification

CCNAW_80211_A_P_S3_v2 Presentation_ID


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Common RF termsAttenuation a loss in force or intensity As radio waves travel through objects or in media such as coaxial cable attenuation occurs. BER Bit Error Rate - the fraction of bits transmitted that are received incorrectly. Channel Bonding act of combining more than one channel for additional bandwidth dBd abbreviation for the gain of an antenna system relative to a dipole dBi abbreviation for the gain of an antenna system relative to an isotropic antenna dBm decibels milliwatt -- abbreviation for the power ratio in decibels (dB) of the measured power referenced to one milliwatt of transmitted RF power. Isotropic antenna theoretical ideal antenna used as a reference for expressing power in logarithmic form.CCNAW_80211_A_P_S3_v2

MRC Maximal Ratio Combining a method that combines signals 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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Identifying RF connectors

RP-TNC Connector

Used on most Cisco Access Points

RP-SMA ConnectorUsed on some Linksys Products

N Connector

Used on the 1520 Mesh and 1400 Bridge

SMA Connector

Pig tail type cable assemblies



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Identifying different cable types

LMR- 400 Foil & shield

LMR 1200


inch solid copper cable Leaky Coax shield cut away on one sometimes called hardline or heliax trade names (side side 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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Antenna Cables LMR SeriesThis is a chart depicting different types of Times Microwave LMR Series coaxial cable. Cisco uses Times Microwave cable and has standardized on two types: Cisco Low Loss (LMR-400) and Cisco Ultra Low Loss (LMR-600). LMR-600 is recommended when longer cable distances are required Larger cables can be used but connectors are difficult to find and install



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Antenna CablesLMR-400 is 3/8 inch Cisco Low Loss LMR-600 is inch Cisco Ultra Low Loss


Trivia: LMR Stands for Land Mobile Radio 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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Antenna Cables - PlenumPlenum is the air-handling space that is found above drop ceiling tiles or below floors. Because of fire regulations this type of cable must burn with low smoke The 3 Ft white cable attached to most Cisco antennas is plenum rated. Our outdoor cable (black) is not Plenum

If the cable is ORANGE in color it is usually Plenum Rated.CCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

Plenum cable is more expensive

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802.11 Antenna basics



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Antenna basicsAntenna - a device which radiates and/or receives radio signals Antennas are usually designed to operate at a specific frequency Wide-Band antennas can support additional frequencies but its a trade-off and usually not with the same type of performance. Antenna Gain is characterized using dBd or dBiAntenna gain can be measured in decibels against a reference antenna called a dipole and the unit of measure is dBd (d for dipole) Antenna gain can be measured in decibels against a computer modeled antenna called an isotropic dipole and the unit of measure is dBi (i for isotropic dipole) (computer modeled ideal antenna)

WiFi antennas are typically rated in dBi.dBi is a HIGHER value (marketing folks like higher numbers) Conventional radio (Public safety) tend to use a dBd rating. To convert dBd to dBi simply add 2.14 so a 3 dBd = 5.14 dBi Again dBd is decibel dipole, dBi is decibel isotropic.



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Effective Isotropic Radiated Power

Transmit power is rated in dBm or mW. Power coming off an antenna is Effective Isotropic Radiated Power (EIRP). FCC and ETSI use EIRP for power limits in regulations for 2.4-GHz and 5-GHz WLANs. EIRP [dBm] = Power [dBm] cable_loss [db] + antenna_gain [dBi] 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public


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How does a Omni-directional dipole radiate?The radio signal leaves the center wire using the ground wire (shield) as a counterpoise to radiate in a 360 degree pattern



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How does a directional antenna radiate?Although you dont get additional RF power with a directional antenna it does concentrate the available energy into a given direction resulting in greater range - much like bringing a flashlight into focus. Also a receive benefit - by listening in a given direction, this can limit the reception of unwanted signals (interference) from other directions for better performance

A dipole called the driven element is placed in front of other elements. This motivates the signal to go forward into a given direction for gain.CCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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Patch Antenna a look insidePatch antennas can have multiple radiating elements that combine for gain. Sometimes a metal plate is used behind the antenna as a reflector for more gain

9.5 dBi Patch, AIR-ANT5195-RCCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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Antennas identified by colorBlue indicates 5 GHz Black indicates 2.4 GHz



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Most common 2.4 GHz antennas for Access Points (single and diversity)Antenna Description

AIR-ANT49412.2 dBi Swivel-mount Dipole; most popular mounts directly to radio, low gain, indoor

AIR-ANT59592 dBi Diversity Ceiling-mount Omni

AIR-ANT17296 dBi Wall-mount Patch

AIR-ANT17285.2 dBi Ceiling-mount Omni

AIR-ANT35499 dBi Wall-mount PatchCCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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Most common 5 GHz antennas for Access Points (single and diversity)Antenna Description AIR-ANT5135D-R 3.5 dBi Omni-directional Antenna; mounts directly to radio, low gain, indoor AIR-ANT5145V-R 4.5 dBi Omni-directional Diversity Antenna; unobtrusive, ceiling mount, low gain, indoor AIR-ANT5160V-R 6 dBi Omni-directional Antenna; ceiling or mast mount, indoor/outdoor AIR-ANT5170P-R 7 dBi Patch Diversity Antenna; directional, small profile, wall mount, indoor/outdoor AIR-ANT5195-R 9.5 dBi Patch Antenna; directional, small profile, wall mount, indoor/outdoorCCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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Understanding and interpreting antenna patterns



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Understanding antenna patternsDipole (Omni-directional)

Low gain dipoles radiateCCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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Dipole Antenna Radiation PatternSide View (E)

The radiation patterns will be shown as a horizontal, looking down (H-plane) radiation pattern, an Elevation, looking across (E-plane), or Vertical radiation pattern, or both.

Top View (H)CCNAW_80211_A_P_S3_v2

Side View (E) 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

Side View (E)22

2.2 dBi Dipole rubber duck antenna(s) (AIR-ANT4941)

Indoor diversity dipole antennas with a base are designed to extend the range of Aironet LMC client adapters and has two MMCX (2) connectors instead of the RP-TNC connector.



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Cisco 2.2 dBi ceiling mount diversity patch antenna

Side View (E Plane) Vertical Radiation



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Cisco 5.2 dBi ceiling mount omnidirectional antenna

Side View (E Plane) Vertical RadiationCCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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5.2 dBi Mast Mount Vertical Omnidirectional indoor/outdoor antenna


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12 dBi Omnidirectional antenna (outdoor only)


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5 GHz outdoor wireless bridge 9-dBi omnidirectional antennaUsed with 1400 Bridge


Top View (H)28

5.14 dBi Pillar Mount Diversity OmniDesigned to be mounted to the side of a pillar


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Integrated Antennas - 1200



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Understanding antenna patternsMonopole (Omni-Directional) MIMO



When three monopoles are next to each other the radiating elements interact slightly with each other The higher gain 4 dBi also changesCisco Public

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Understanding antenna patternsPatch (Directional)

5 GHz Patch Antenna



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Directional Antennas

Directional antennas do not offer any added power to the signal, and instead simply redirects the energy it received from the transmitter. By redirecting this energy, it has the effect of providing more energy in one direction, and less energy in all other directions. As the gain of a directional antenna increases, the angle of radiation usually decreases, providing a greater coverage distance, but with a reduced coverage angle. Directional antennas include Yagis, patch antennas, and parabolic dishes. Parabolic dishes have a very narrow RF energy path and the installer must be accurate in aiming these at each other.CCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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Cisco 6 dBi patch antenna




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6 dBi diversity patch antennaIndoor/outdoor antenna with two RPTNC connectors. It is similar to the above patch, but providing diversity antennas in the same package for areas where multipath problems existSide View (E Plane) Vertical RadiationCCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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Cisco 8.5 dBi antenna




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13.4 dBi Yagi (outdoor/indoor)

Linear array of parallel dipoles

The Yagi is constructed of at least three elements, which are metal bars that supplement the wave energy transmitted. In a Yagi antenna, there is at least one driven element, one reflector element, and usually one or more director elements. The Yagi antenna is also known as a linear end-fire antenna or a Yagi-Uda array, has a linear array of parallel dipoles. Yagi antennas are directional and designed for long distance communication.CCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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13.4 dBi Yagi (outdoor/indoor)

Top View (H Plane) Horizontal Radiation

The Cisco Yagi provides 13.5 dBi of gain and features a range of up to 10 km (6.5 miles) at 2 Mbps, and 3.2 km (2 miles) at 11 Mbps. Most Yagi antennas are mounted with U-bolts, to a sturdy mast.CCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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21 dBi Parabolic Dish

Side View (E Plane) Vertical RadiationDistances of up to 40 km (25 miles) may be possible. It is important to evaluate how well the dish will withstand icy conditions and high winds. Equally important is the sturdiness of the mast and tower the antenna will be mounted on. The Cisco high gain parabolic dish is designed to be used as a bridge antenna between two networks or for point-to-point communications



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5 GHz 28-dBi dish antenna antenna

Side View (E Plane) Vertical RadiationOperates in the UNII-3 band (5725 to 5825 MHz) Can be extended up to 12.9 miles (20.7 kilometers) at 54 Mbps.




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9.5-dBi sector antenna



Used with the Cisco Aironet 1400 Series Outdoor Wireless Bridge The antenna is not compatible with other Cisco Aironet radio products operating in the 5-GHz frequency band.



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Understanding antenna patternsPatch (Higher Gain Directional)

Four element Patch Array

Single Patch AntennaCCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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Understanding antenna patternsSector (Higher Gain Directional)

Elevation plane has nulls due to high gain 14 dBiCCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

AIR-ANT2414S-R 14 dBi Sector 2.4 GHz43

Understanding antenna patternsSector (Higher Gain Directional)


Elevation plane has nulls due to high gain 14 dBi but antenna was designed with Null-Fill meaning we scaled back the overall antenna gain so as to have less nulls or low signal 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

AIR-ANT2414S-R 14 dBi Sector 2.4 GHz44

Understanding multipath and diversity and the technical elements of 802.11a/b/g/n



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Understanding MultipathAs radio signals bounce off metal objects they often combine at the receiver

Multipath can change signal strength

This often results in either an improvement constructive or a destructive Note: Bluetooth type radios that hop across the entire band can reduce multipath type of by constantly changing the angles of multipath as the radio wave interference increases and decreases in size interference these methods (as the frequency constantly changes) however throughput using are very limited but multipath is less of a problemCCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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Understanding Multipath

Multipath reflections can cause distortion

As the radio waves bounce they can arrive at slightly different times and angles causing signal distortion and potential signal strength fading Different modulation schemes fair better 802.11a/g/n uses a type of modulation based on 2010 Cisco and/or its affiliates. All rights reserved.

802.11n with more receivers can use destructive interference (multipath) as a benefit. Tip: It is still best to reduce multipath conditions whenever possible Keep antennas away from metal objects


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Antenna placement considerations

AP antennas need placements that are away from reflective surfaces for best performance Avoid metal support beams, lighting and other obstructions. When possible or practical to do so, always mount the Access Point (or remote antennas) as close to the actual users as you reasonably can 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

Never mount antennas near metal objects as it causes increased multipath and directionality48


Understanding Diversity (SISO)802.11a/b/g diversity has just one radioNon-802.11n diversity Access Points use two antennas sampling each antenna choosing the one with the least multi-path distortion

Cisco 802.11a/b/g Access Points start off favoring the right (primary antenna port) then if multi-path or packet retries occur it will sample the left port and switch to that antenna port if the signal is better.Note: Diversity Antennas should always cover the same cell areaCCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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Understanding Diversity (MIMO)

MRC Maximal Ratio Combining (three radios)

Receiver benefit as each antenna has a radio section MRC is done at Baseband using DSP techniques Multiple antennas and multiple RF sections are used in parallel The multiple copies of the received signal are corrected and combined at Baseband for maximum SNR (Signal to Noise) benefit This is a significant benefit over traditional 802.11a/b/g diversity where only one radio is usedCCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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Access Point Models and Features



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Introduction of new Access Points11abg 11n1240 1250 1260

11n + CleanAir3500e

Ruggedized

Ne w1130 1140

Ne w

3500i

Carpeted

Ne w



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Aironet Indoor Access Point ComparisonAP 1130AP 1140

AP 3500i AP 1240

AP 1250

1260

3500e

Integrated CleanAir Data Uplink (Mbps) Power Requirement Installation Temp Range Antennas Wi-Fi standards DRAM Flash

No 10/100 802.3af Carpeted 0 to +40C Internal a/b/g 32 MB 16 MB

No 10/100/1000 802.3af Carpeted 0 to +40C Internal a/b/g/n 128 MB 32 MB

Yes 10/100/1000 802.3af Carpeted 0 to +40C Internal a/b/g/n 128 MB 32 MB

No 10/100 802.3af Rugged -20 to +55C External a/b/g 32 MB 16 MB

No 10/100/1000 E-PoE 802.3af* Rugged -20 to +55C External a/b/g/n 64 MB 32 MB

No 10/100/1000 802.3af Rugged -20 to +55C External a/b/g/n 128 MB 32 MB

Yes 10/100/1000 802.3af Rugged -20 to +55C External a/b/g/n 128 MB 32 MB


802.3af fully powers single radio AP1250 or provides 1x3 performance on a dual radio 1250 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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Integrated antenna? External antenna? Carpeted areas Rugged areas

Integrated antenna versions are designed for mounting on a ceiling (carpeted areas) where aesthetics is aCCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved.

Use for industrial applications where external or directional antennas are desired and or applications requiring higherCisco Public

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When to use integrated antennasWhen there is no requirement for directional antennas and the unit will be ceiling mounted Areas such as enterprise carpeted office environments where aesthetics are important When the temperature range will not exceed 0 to +40C



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When to use external antennasReasons to consider deploying a rugged AP When directional focused coverage is desired or greater range is needed The environment requires a more industrial strength AP with a higher temperature rating of -20 to +55 C (carpeted is 0 to +40 C) The device is going to be placed in a NEMA enclosure and the antennas need to be extended You have a desire to extend coverage in two different areas with each radio servicing an independent area - for example 2.4 GHz in the parking lot and 5 GHz indoors Requirement for outdoor or greater range Bridging application (aIOS version) Requirement for WGB or mobility application where the device is in the vehicle but antennas need to be mounted externalCCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved.

Rugged AP in ceiling enclosure

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When to use AP-1240 and AP-1250Reasons to consider the AP-1240 or AP-1250 The AP-1240 and AP-1250 support higher gain antennas - a benefit only if a high gain antenna already exists or is required Higher gain (up to 10 dBi) can improve WGB and outdoor Bridging distances Recommend the AP-1240 if the infrastructure is older 10/100 ports and there is no interest in upgrading to 11n AP-1240 will work with older Cisco PoE switches (Cisco proprietary power) AP-1240 draws less power so better for solar applications AP-1240 supports Cisco Fiber injectors Tip: Higher than 10 dBi antenna gains are supported with the 1300 Series Bridge/AP



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802.11a/b/g/n Design and Deployment



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Phases of 802.11n deployment

Design Considerations Which AP to choose 1:1 Replacement Strategy for Capacity 5 GHz Strategy 11n ClientsCCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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Which 802.11n Access Point is right?

AP-3500i and AP-3500e have the very latest Cisco features such as Clean Air Ciscos spectrum intelligence AP-1140 and AP-1260 are of similar design less Cisco Clean Air features and can also run autonomous code (aIOS) for stand alone or Workgroup Bridge applications. Note: 3500 Series does not support the older aIOS autonomous mode All the Access Points were designed to have similar coverage for ease of deployment



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Coverage Comparison 5GHzAP1140 AP1250

AP3500i

AP3500e



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1130 Access PointPlacement

1130 Access Point Placement

1 per 5,000 sq feet for data only 1 per 3,000 sq feet for voice, locationRadio Resource Management

Adaptive channel / power coverage Operational simplicityWeb Email

Several Supported Apps



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1140, 3500i Access PointPlacement

1 for 1 replacement

AP1140, 3500i reuses existing AP1130 T-Rail ClipImproved coverage at higher data ratesERP Backup Video Voice Web Email

ABG ABG

ABG ABG


More Applications Supported at Any Given Location


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Antenna Patterns

Azimuth and Elevation Patterns for 2.4 GHz & 5 GHz

2.4 GHz Azimuth

5 GHz Azimuth

2.4 GHz Elevation

5 GHz Elevation



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AP Placement Wall Mounting

AP-1140 and AP-3500i

AP-1260 and AP-3500e

Wall mounting is acceptable for small deployments such as hotspots, kiosks, etc but radiation is better on ceilingCCNAW_80211_A_P_S3_v2


Best for enterprise deployments as coverage is more uniform especially for advanced features such as voice andCisco Public

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What about mounting options?Different mounting options for ceiling APs

Cisco has options to mount to most ceiling rails and directly into the tile for a more elegant lookCCNAW_80211_A_P_S3_v2


Locking enclosures and different color plastic skins available from third party sources such as www.oberonwireless.comCisco Public

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AP PlacementEvaluate Problem Areas

Object in Signal Path

Signal Attenuation


Plasterboard wall Glass wall with metal frame Cinder block wall Office window Metal door Metal door in brick wall Phone and Head 2010 Cisco and/or its affiliates. All rights reserved.

3 dB 6 dB 4 dB 3 dB 6 dB 12 dB 6 dB67

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Effective Frequency Use5GHz and 2.4GHzCreate a 5GHz Strategy

5GHz Recommended for 802.11n

More available spectrumgreater number of channels Reduced interference (no Bluetooth, Microwave Ovens, etc.) Maximum throughput in a 40MHz channel Many 11n devices only support 40MHz in 5GHz

2.4GHz still benefits from MIMO and packet aggregation2.4GHz 20MHz Channels 5GHz 40MHz Channels

1 6CCNAW_80211_A_P_S3_v2

2 11 1 3

4 5

6 7

8 9

10 1168


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Third Party Survey ToolsAirmagnet EDX Ekahau Helium Networks Wireless Valley and many others

There are many and I believe they are all good

Tip: Survey and use Cisco antennas If you contract this out, some companies use their own antennas and then lock you into them saying thats what we surveyed with if in doubt use Cisco Advanced Services 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public


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Site Survey

Site Survey Recommendations

Use Active Survey tools

Example - AirMagnet 6.0 uses Iperf to send traffic when surveying to measure actual data link speeds

Survey for lowest common client

Once for 11a/g clients Once for 11n clients (optional)

Survey at intended AP power levels



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Improved 802.11g Coverage1130 vs. 114011G Active Survey

1130 11G Survey 48 Mbps Coverage 86 Feet

1140 11G Survey 48 Mbps Coverage 102 Feet

Note the more uniform coverage of high (green) data rates 18% Increase in 802.11g CoverageCCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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5GHz - Maximum RangeAP1130 5GHz Click to edit Master text stylesSecond level

AP1140 5GHz Click to edit Master text stylesSecond level

Third level

Fourth level Fifth level

Third level

Fourth level Fifth level

10-15% Increase in 802.11a RangeCCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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802.11n Deployment

Designing Around 5GHz 40MHz Channels

One AP Data Rate vs. RSSI

Full Deployment Contiguous 5GHz Coverage



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5 GHz Dynamic Frequency SelectionWhen Radar Is PresentAPs Shift Channels Results in Lower Available Channels and Loss of UNI 2 and UNI 2e BandsNo DFS Support DFS Support

Radar

Available 40MHz Channels

4

11

5 GHz Frequency 2 UNI UNI 1CCNAW_80211_A_P_S3_v2

UNI 2 Ext.

UNI 3


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Mixed ModePerformance

WLAN Controller

Mixed mode experiences slight performance impact due to ABG clients 11n clients still transmit at full performance PHY and MAC for 11n provides co-existence and protection for ABG clients Move 11n clients to 5GHz, keep legacy clients at 2.4GHz

11n

54 Mb11g

300 Mb11n



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Improving Mixed Mode PerformanceDisabling Unnecessary Data Rates Benefit: Beacons and Broadcast traffic utilize less airtime For 802.11b/g deployments Disable: 1, 2, 5.5, 6 and 9Mbps For 802.11g-only deployments Disable: 1, 2, 5.5, 6, 9 and 11Mbps For 802.11a deployments Disable: 6 and 9 Mbps Higher rates can also be disabled (ex. 12, 18Mbps) dependant on 2010 Cisco and/or its affiliates. All rights reserved.

Tuned 802.11b/g Data Rates


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Installations Above Ceiling (Plenum) When they must be invisible



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AP Placement in Plenum AreasWhen placing the Access Point above the ceiling tiles (Plenum area) Cisco recommends using rugged Access Points with antennas mounted below the Plenum area whenever possible Cisco antenna have cables that are plenum rated so the antenna can be placed below the Plenum with cable extending into the plenum If there is a hard requirement to mount carpeted or rugged Access Points using dipoles above the ceiling This can be done however uniform RF coverage becomes more challenging especially if there are metal obstructions in the ceiling Tip: Try to use rugged Access Points and locate the antennas below the ceiling whenever possibleCCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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Installation above the ceiling tilesMount AP close to the tiles and away from objects

Installing Access Points above the ceiling tiles should be done only when mounting below the ceiling is not an option. Such mounting methods can be problematic for advanced RF features such as voice and location as they depend on uniform coverage

Try to find open ceiling areas away from metal obstructions (use common sense)CCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

Tip: Mount antennas either below ceiling tile or the AP as close to the inside of the tile as possible79

Plenum installs that went wrongYes it happens and when it does its badWhen a dipole is mounted against a metal object you lose all Omni-directional properties. It is now essentially a directional patch suffering from acute multipath distortion problems. Add to that the metal pipes and it is a wonder it works at all.

Dipole antennas up against a metal box create a patch like antenna - that plus metal pipes create unwanted Multipath Destructive Interference



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Tip: Try to get Access Points close to the actual users This antenna is radiating forward high in the ceiling where there are 80

Plenum installs that went wrongHuh?? You mean it gets worse?


Antennas cannot radiate well with all this mess someone went to a lot of trouble to mount this -- just to encounter even more connectivity trouble. 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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Installations that went wrong

eiling mount AP up against pipe not good blocking antenna causin Metal duct ntennas are obstructed Multipath interferenceCCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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Installations that went wrong

Patch antenna - Shooting across a metal fence Put it on a cross arm away from fence or find a better locationCCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

Mount the box lid down with the antennas pointing downward Tip: Antennas do not work well against metal

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Installations that went wrongSure glad this particular model runs a bit on the warm side --- Chirp Chirp



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I guess most dry wall guys are not radio engineers Exactly how did this happen?

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Minimize the Impact of MultipathTemptation is to mount on beams or ceiling rails This reflects transmitted as well as received packets Dramatic reduction in SNR due to high-strength, multipath signals

Minimize Reflections When Choosing LocationsCCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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Outdoor weatherproofingCoax-Seal can be used with or without electrical tape. Taping first with a quality electrical tape like Scotch 33+ vinyl allows the connection to be taken apart easier. Many people tape then use Coax-Seal then tape again this allows easy removal with a razor blade.

www.coaxseal.comCCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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Introduction to 802.11 Protocols



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802.11b



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802.11b StandardStandard was ratified in September 1999 Operates in the 2.4-GHz band Specifies direct sequence spread spectrum (DSSS) Specifies four data rates up to 11 Mbps

DSSS, Barker 11 Coding, DBPSK, 1 bit/symbol DSSS, Barker 11 Coding, DQPSK, 2 bits/symbol

5.5 11

HR/DSSS, Barker 8 Coding, DQPSK, 4 bits/symbol + CCK HR/DSSS, Barker 8 Coding, DQPSK, 8 bits/symbol + CCK

Provides specifications for vendor interoperability (over the air) Defines basic security, encryption, and authentication for the wireless link Is the most commonly deployed WLAN standard



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2.4-GHz ChannelsRegulatory Domain Channel Identifier 1 2 3 4 5 6 7 8 9 10 11 12 13 14CCNAW_80211_A_P_S3_v2

Channel Center Channel Frequency Frequency Range [MHz] 2412 MHz 2417 MHz 2422 MHz 2427 MHz 2432 MHz 2437 MHz 2442 MHz 2447 MHz 2452 MHz 2457 MHz 2462 MHz 2467 MHz 2472 MHz 2484 MHz 2401 2423 2406 2428 2411 2433 2416 2438 2421 2443 2426 2448 2431 2453 2436 2458 2441 2463 2446 2468 2451 2473 2466 2478 2471 2483 2473 2495

Americas X X X X X X X X X X X

Europe, Middle East, and Asia X X X X X X X X X X X X X

Japan X X X X X X X X X X X X X X


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2.4-GHz Channel Use

Each channel is 22 MHz wide. North America: 11 channels. Europe: 13 channels. There are three nonoverlapping channels: 1, 6, 11. Using any other channels will cause interference. Three access points can occupy the same area.CCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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802.11b/g (2.4 GHz) Channel Reuse



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802.11b Access Point Coverage



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802.11g



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802.11g StandardStandard was ratified June 2003 Operates in the 2.4-GHz band as 802.11bSame three nonoverlapping channels: 1, 6, 11

DSSS (CCK) and OFDM (CC) transmission 12 data rates of up to 54 Mbps 1, 2, 5.5, 11 Mbps (DSSS / 802.11b) 6, 9 12, 18 24, 36 48, 54 OFDM, DBPSK OFDM, DQPSK OFDM, 16-QAM OFDM, 64-QAM

Full backward compatiblity to 802.11b standardCCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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802.11g Protection MechanismProblem: 802.11b stations cannot decode 802.11g radio signals. 802.11b/g access point communicates with 802.11b clients with max. 11 Mbps. 802.11b/g access point communicates with 802.11g clients with max. 54 Mbps. 802.11b/g access point activates RTS/CTS to avoid collisions when 802.11b clients are present. 802.11b client learns from CTS frame the duration of the 802.11g transmission. Reduced throughput is caused by additional overhead.



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802.11g Protection MechanismProblem: 802.11b stations cannot decode 802.11g radio signals. 802.11b/g AP communicates with 802.11b clients with max. 11 Mbps. 802.11b/g AP communicates with 802.11g clients with max. 54 Mbps. 802.11b/g AP activates RTS/CTS to avoid collisions when 802.11b clients are present. Additonal overhead reduces throughput.



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802.11a



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802.11a StandardStandard was ratified September 1999 Operates in the 5-GHz band Uses orthogonal frequency-division multiplexing (OFDM) Uses eight data rates of up to 54 Mbps6, 9 12, 18 24, 36 48, 54 OFDM, DBPSK OFDM, DQPSK OFDM, 16-QAM OFDM, 64-QAM

Has from 12 to 23 nonoverlapping channels (FCC) Has up to 19 nonoverlapping channels (ETSI) Regulations different across countriesTransmit (Tx) power control and dynamic frequency selection required (802.11h)CCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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5-GHz Channels with 802.11h

802.11h implements TPC and DFS. With 802.11h in February 2004, the FCC added 11 channels.

23 channels in the United States (FCC) 19 channels in Europe (ETSI) UNII-3 band currently not allowed in most of Europe



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802.11a Channel Reuse802.11h DFS not available Manual channel assignment required 802.11h DFS implemented Channel assignment done by Dynamic Frequency Selection (DFS) Only frequency bands can be selected



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802.11 Standards Comparison



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802.11 RF Comparison802.11b 2.4 GHz Most commonly deployed WLAN standard

802.11g 2.4 GHz Higher throughput OFDM technology reduces multipath issues

802.11a 5 GHz Highest throughput OFDM technology reduces multipath issues Provides up to 23 nonoverlapping channels

Pro

Co n

Lower market Interference and noise penetration Interference and noise from other services in from other services in the 2.4-GHz band the 2.4-GHz band Only three Only 3 nonoverlapping nonoverlapping channels channels Distance limited by Throughput degraded in multipath issues the presence of 802.11b clients 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public


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802.11 Standards Comparison

802.11b Ratified Frequency band No of channels Transmission Data rates [Mbps] Throughput [Mbps] 1999 2.4 GHz 3 DSSS DSSS

802.11g 2003 2.4 GHz 3 OFDM

802.11a 1999 5 GHz Up to 23 OFDM

1, 2, 5.5, 11 1, 2, 5.5, 11 Up to 6

6, 9, 12, 18, 24, 6, 9, 12, 18, 24, 36, 48, 54 36, 48, 54 Up to 28

Up to 22



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WLAN Industry StandardsNetwork Radio SpeedsIEEE 802.11n Multichannel Greater Than 100 Mbps IEEE 802.11g 2.4 GHzOFDM Up to 54 Mbps IEEE 802.11a 5 GHzOFDM Up to 54 Mbps IEEE 802.11b 2.4 GHzDS Up to 11 MbpsProprietary 1999CCNAW_80211_A_P_S3_v2

IEEE 802.11a/b Ratified 2001 2002 2003Cisco Public

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Range Comparisons



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Ratified IEEE 802.11 Standards802.11: WLAN 1 and 2 Mbps at 2.4 GHz 802.11a: WLAN 54-Mbps at 5 GHz 802.11b: WLAN 11-Mbps at 2.4 GHz 802.11d: Multiple regulatory domains 802.11e: Quality of service 802.11f: Inter-Access Point Protocol (IAPP) 802.11g: WLAN 54-Mbps at 2.4 GHz 802.11h: Dynamic Frequency Selection (DFS) Power Control (TPC) at 5 GHz 802.11i: Security 802.11j: 5-GHz channels for Japan Transmit



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802.11n The New Standard More to Come



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Antennas for Rugged Access Points 802.11n options for ceilings and walls



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Guide to Antenna part numbers



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MIMO Ceiling Antenna 2.4 GHz

AIR-ANT2430V-R (3 dBi ceiling mount Omni)

Antenna has three monopole elements



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MIMO Ceiling Antenna 5 GHz

AIR-ANT5140V-R (4 dBi ceiling mount Omni)

Antenna has three monopole elements



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AIR-ANT2451NV-R

Hz (2.5 dBi) & 5 GHz (3.5 dBi) dual band ceiling omni

Six leads - 5 GHz antennas have blue markings (shrink wrap)



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AIR-ANT2460NP-R

4 GHz 6 dBi Three Element Patch



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AIR-ANT5160NP-R5 GHz 6 dBi Three Element Patch



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AIR-ANT2450NV-R= & AIRANT5140NR-R

MIMO Multi-mount Omni 2.4 GHz and 5 GHz New 3 in 1 Antenna for 2.4 GHz and 5 GHz. Gain should be 4 dBi for each antenna but may be higher depending on how much gain we can achieve.



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New Cisco Antenna part numbers



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Complex Modulation SchemesRadio technology has a lot in common with that old twisted pair phone line that started out at 300 baud and then quickly increased In order to get faster data rates, (throughput) into the radio signal, complex modulation schemes as QPSK or 64 bit QAM is used. Generally speaking, the faster the data rate the more powerful the signal needs to be (at the receiver) to be successfully decoded. Take-away here is that 802.11n is a method of using special modulation techniques and *not* specific to a frequency like 2.4 or 5 GHz 802.11n can be used in either bandCisco Public

Example of 802.11n Modulation Coding Schemes

QAM or Quadrature Amplitude Modulation is one of the fastest modulation types actually sending two signals that are out of phase with each other and then somehow putting all the pieces back together for even greater throughput. This is one of the advantages of 802.11n



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Understanding 802.11 MIMO terminologyMIMO (Multiple-Input-Multiple-Output)Some RF components of 802.11n include: MRC Maximal Ratio Combining a method that combines signals from multiple antennas taking into account factors such as signal to noise ratio to decode the signal with the best possible Bit Error Rate. TxBF Transmit beam forming The ability to transmit independent and separately encoded data signals, socalled streams from each of the multiple transmit antennas. Channel Bonding Use of more than one frequency or channel for more bandwidth. Spatial Multiplexing A technique for boosting wireless bandwidth and range by taking advantage of multiplexing which is the ability within the radio chipset to send out information over two or more transmitters known as spatial streams. Note: Cisco 802.11n Access Points utilize two transmitters and three receivers per radio module.

MIMO is pronounced My Moe not to be confused with this Moe.

CCNAW_80211_A_P_S3_v2 Presentation_ID 2006 Cisco Systems, Inc. 2010 Cisco and/or its affiliates. All rights reserved. All rights reserved. Cisco Confidential

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Technical Elements of 802.11nMIMO 40Mhz Channels Packet Aggregation Backward Compatibility

MIMO

40Mhz Channels

Packet Aggregation

Backward Compatibility



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Aspects of 802.11nMIMO 40Mhz Channels Packet Aggregation Backward Compatibility

MIMO (Multiple Input, Multiple Output)

With Beam Forming

Transmissions Arrive in Phase, Increasing Signal Strength

Without Beam FormingTransmissions Arrive out of Phase and signal is weaker

Performed by Transmitter (Talk Better)

Ensures Signal Received in Phase

Increases Receive Sensitivity

Works with non-MIMO and MIMO Clients

Beam FormingCCNAW_80211_A_P_S3_v2

Maximal Ratio CombiningCisco Public

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Aspects of 802.11n40Mhz Channels Packet Aggregation Backward Compatibility

MIMO (Multiple Input, Multiple Output)Without MRCMultiple Signals Sent; One Signal Chosen

With MRCMultiple Signals Sent and Combined at the Receiver Increasing Fidelity

MIMO AP Performance

Performed by Receiver (Hear Better)

Combines Multiple Received Signals

Increases Receive Sensitivity

Works with non-MIMO and MIMO Clients





Aspects of 802.11n40Mhz Channels Packet Aggregation Backward Compatibility

MIMO (Multiple Input, Multiple Output)

Information Is Split and Transmitted on Multiple Streamsstream 1

MIMO AP

stream 2 Performance

Transmitter and Receiver Participate

Concurrent Transmission on Same Channel

Increases Bandwidth

Requires MIMO Client






MIMO (Multiple Input, Multiple Output) 40Mhz Channels Moving from 2 to 4 Lanes

20-MHzGained Space

40-MHz

20-MHz

40-MHz = 2 aggregated 20-MHz channelstakes advantage of the reserved channel space through bonding to gain more than double the data rate of two 20-MHz channelsCCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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Packet Aggregation 40Mhz Channels Carpooling Is More Efficient Than Driving AloneWithout Packet Aggregation 802.11n Overhead Data Unit Packet 802.11n Overhead Data Unit Packet 802.11n Overhead Data Unit Packet

802.11n Overhead

Data Unit Packet Packet Packet

With Packet Aggregation



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BackwardAggregation Packet Compatibility 2.4GHz 11n Operates in Both Frequencies 5GHz

802.11ABG Clients Interoperate with 11n AND Experience Performance ImprovementsCCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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Understanding MCS rates and Channel Bonding40MHz 802.11n channel1 2 3 4 5 6Channel Bonding: Wider channels means more bandwidth per AP

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2.402 GHzMCS rates 0-15 apply Regardless of channel Bonding.

20 MHz channel

2.483 GHz

MCS 0-7 is one Spatial Stream When you bond a channel You have a control channel and a data (extension) Channel Legacy ABG clients use control channel for communication



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2.4 GHz, 40 MHz Bandwidths

Tip: Channel bonding in 2.4 GHz should be avoided in enterprise deployments Tip: Use 5 GHz as there are noCCNAW_80211_A_P_S3_v2 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public

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Example UNII-3 Channel Bonding

In 40-MHz you define the control channel this is the channel that is used for communication by Legacy .11a clients. The Extension channel is the bonded channel that High Throughput HT 802.11n clients use in 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public


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Channel Bonding - Subcarriers802.11n uses both 20-MHz and 40-MHz channels. The 40-MHz channels in 802.11n are two adjacent 20-MHz When using the bonded channels, 40-MHz bonded channel, 802.11n takes advantage of the fact that each 20-MHz channel has a small amount of the channel that is reserved at the top and bottom, to reduce interference in those together. adjacent channels.When using 40-MHz channels, the top of the lower channel and the bottom of the upper channel don't have to be reserved to avoid interference. These small parts of the channel can now be used to carry information. By using the two 20-MHz channels more efficiently in this way, 802.11n achieves slightly more than doubling the data rate when moving from 20-MHz to 40-MHz channels



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The guard interval that is Understanding part of each OFDM symbol is a period of time that is used to minimize intersymbol interference. This type of interference is caused in multipath environments when the beginning of a new symbol arrives at theCCNAW_80211_A_P_S3_v2

Guard Interval


Default mode for 802.11n is 800 nanoseconds If you set a shorter interval it will goCisco Public

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802.11n OperationThroughput improves when all things come together802.11a/g AP (non-MIMO) MRC TxBF Spatial Multiplexing 802.11a/g client (non-MIMO)54 48 36 24 Mbps

MRC

802.11n AP (MIMO) TxBF Spatial Multiplexing

54 Mbps

802.11a/g client (non-MIMO)

MRC TxBF Spatial Multiplexing

802.11n AP (MIMO)

300 Mbps

Channel Bonding 802.11n client (MIMO)



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MCS index of 802.11n rates



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CCNAW 80211 Antenna Protocol S3 C5-6 v2

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Transcript of CCNAW 80211 Antenna Protocol S3 C5-6 v2