IEEE 802.11n – High Throughput

• Will enable new consumer, enterprise applications• Video distribution, more bandwidth for QoS applications,

greater range, throughput

• High Data rates (64-600Mbps)• A typical 2 transmitter MIMO device will support a 300Mbps data

rate when using 40MHz channel• 144Mbps data rate when using 20MHz channel

• Legacy mode support• Support for Legacy a/b/g, e.g. 802.11n AP and a/b/g STAs• Support for Mixed Mode e.g. 802.11n AP and a/b/g/n STAs

• Green Field 802.11n-only

New components in IEEE 802.11n

• PHY Enhancements, applicable to both 2.4GHz and 5GHz• The new PHY supports OFDM modulation with additional

coding methods, preambles, multiple streams and beam-forming

• Multiple Input Multiple Output (MIMO) Radio Technology With Spatial Multiplexing

• High throughput PHY – 40 MHz channels – Two adjacent 20 MHz channels are combined to create a single 40 MHz channel.

• MAC Enhancements• Two MAC aggregation methods are supported to efficiently

pack smaller packets into a single MPDU• Block Acknowledgement – A performance optimization in which

an IEEE 802.11 ACK frame need not follow every unicast frame and combined acknowledgements may be sent at a later point in time.

What is MIMO?

• Multiple Input Multiple Output (MIMO)• Transmit and Receive with multiple radios simultaneously in same spectrum

channelRadio

Radio

DSP

Bits

TX

Radio

Radio

Radio

DSP

Bits

Radio

RX

• Compare to traditional Single Input Single Output Radio (with optional receive diversity)

channelRadioDSPBits

TXRadio DSP Bits

RX

Spatial Division Multiplexing

Multiple independent data streams are sent between the transmit and receive antennas to deliver more bits in the specified bandwidth

Radio

Radio

DSP

More Bits

TX

Radio

Radio

Radio

DSP

More Bits

Radio

RX

• Cross-paths between antennas are automatically decoded by the receiver, assuming sufficient “richness” in the propagation environment

What Does this Mean to Education

• Pre-N Products will show up in your air– Effective air monitoring & WIDS tools

• Enterprise Draft-N products in 2007– Start pilots for high bandwidth apps– Draft-N clients start to show up in high-end laptops

• Mass adoption in 2008– Standard ratification expected in 1H’2008– Price-performance targets will be met for mass adoption– 802.11n clients will become ubiquitous

• What does this mean to you– Wireless becomes the ONLY connection from PRIMARY– Extending mobile security to legacy wired ports– New high performance 802.11a/b/g/n Access Points– Higher Performance Mobility Controllers

• Control and Data Plane Scaling Intelligence

Agenda

• Introduction to Aruba Networks• 802.11n• Smart Antennas• How Dartmouth Implemented Voice,

Video and Data over Wi-Fi

Smart Antennas for Wi-Fi Stability

Applies MIMO-diversity techniques to standard Wi-Fi

“Intuitive antennas” (continuous learning)

2 to 3X range and performance increase

Active interference rejection

Compatible with all 802.11 standards

Compact internal antenna array Capable of 63 unique antenna patterns

Increased range and better performance in any direction at any time

Expert control software constantly ranks optimum antenna patterns for each receiving device Six high-gain

directional antenna elements

Avoiding Interference with Smart Antennas

Family Room

Bedroom Home office

Kitchen

Interference fromneighboring network

BeamFlexPowered

Set Top Box

Ruckus AP

1

2

3

1

Microwave

2

What Interference Avoidance Looks Like

Ruckus 2900 AP to Off-the-Shelf 802.11g Client Off-the-shelf 802.11 AP to Off-the-Shelf 802.11g Client

Ruckus 2900 AP to Ruckus 2501 Client • 3-minute throughput measurements per test

• Microwave on after 1st minute for 1-minute

AP

Client

Microwave

30 ft

What About 802.11n?

Spatial multiplexing improves top line bandwidth Critical for HD streaming

(WMV-9 at 9-12 Mbps per stream)

Multiple signals increase chance of experiencing interference, decreases the chance of Wi-Fi stability

Streams take different paths making it harder to recover at receiving end

No predictability - at the mercy of wild signal scattering

No inherent QoS

Smart Wi-Fi technology sits on top of 802.11n fixing these problems

More Wi-Fi Capacity is Good but Not Good Enough

Giving 802.11n StabilityData Grade Performance

(@ 50 Percentile of Throughput Distribution)*

Video Grade Performance (@ 99.5 Percentile of Throughput

Distribution)*

Test Environment & Methodology

• 3,000 sq-ft, 2-story US Residential House

• UDP echo test

• 5,000 measurements taken per AP per location at 50ms intervals; measurements sorted by distribution to report the throughput at 50th and 99.5th percentiles

Test Date: May 08, 2006

5 ft, LOS

26 ft, 1

stucco wall

56 ft, 1 stucco

& 1 granite walls

41 ft, 2 stucco

& 2 exterior walls & bathroo

m

40 ft upstairs,

3 stucco

walls and 1 floor

5 ft, LOS

26 ft, 1

stucco wall

56 ft, 1 stucco

& 1 granite walls

41 ft, 2 stucco

& 2 exterior walls & bathroo

m

40 ft upstairs,

3 stucco

walls and 1 floor

Ruckus 2221AP & 2501 Adapter (Atheros 802.11b/g Chipset)

Netgear RangeMax 240 Router & PC Card (Airgo Gen3 MIMO Chipset)

Netgear RangeMax Next Gigabit Edition Router & PC Card (Marvell Draft-N Chipset)

MIMO, Draft-N

BeamFlex on Standard .11G

BeamFlex over .11N