Wireless Technologies In The Home – The Invisible Cable

PlantSandy Teger and David J.

WaksSystem Dynamics Inc.

dave@system-dynamics.com

Many Wireless Opportunities

In the home

Public places:HotelsAirportsRestaurants

Outside

To the home

In the Home

• Technologies– Wi-Fi®: IEEE 802.11x– UWB: IEEE 802.15.3a

• Issues– Applications: data, voice, video– Useful range– Speed– Security– Robustness – QoS, reliability

Current Wi-Fi® Status

• Three “flavors” of Wi-Fi– 802.11b: 11 Mbps in 2.4 GHz– 802.11a: 54 Mbps in 5 GHz– 802.11g: 54 Mbps in 2.4 GHz

• Effective maximum speed: ~20 Mbps• Range: comparatively limited at maximum speed,

improving• Security improving – WPA™ and WPA2™• QoS improving - WMM™• Wi-Fi certification will become even more

important – Product complexity is rising– More chip sets and MAC implementations increase

probability of interoperability failure– Cost pressures will impact product quality– Different brands increase interoperability challenge

New Developments

• Focus on 100+ Mbps throughput – many contending technologies including existing wiring and wireless (802.11n, UWB)

• Move to “whole home” networking– Video becoming part of the mix higher speed &

QoS– HDTV and flat screens taking off; new

“entertainment PCs” emerging better use of spectrum

– Digital Living Network Alliance (DLNA, formerly DHWG) developing interoperability standards for integrated networks

Networked Entertainment Issues

•Requirements–Support all media – audio, video, data–Audio and video need QoS–HD video needs high bandwidth–Premium digital content needs DRM

•What media formats supported?•Who supplies what to end user?

Spectrum: 2.4 GHz

• Most consumer products use 2.4 GHz– Shared by 802.11b and 11g– Interference from microwaves, portable

phones, and neighbors

• Most products default to channel 6– One of three non-overlapping channels

• Most products default to maximum transmit power– Maximize potential for interference with

neighbors

Spectrum: 5 GHz

• Why not use 802.11a/5GHz?– 12 non-overlapping channels now, 23

soon– BOM cost differential less than $5– Vendors getting high margins on SME

products

• Microsoft promoting 11a for Media Center 2005– Use Media Center Extender to carry

video from MC PC to large-screen TV

Microsoft Supports 11.a for Video

• “How do I connect my Media Center Extender to my Media Center PC?”

• “There are two main ways—via an Ethernet wired or a wireless connection. The wireless connection works best on 802.11a home networks.”

– Microsoft FAQs

Speed: 802.11n

• Next generation of Wi-Fi®

• 100 Mbps throughput at MAC_SAP layer– 4x-5x faster than 11a and 11g

• Protocol improvements• MIMO antennas

– Multiple Input/Multiple Output

• Projected completion: March 2007• “Pre-11n turbo mode” products appearing

– Wi-Fi Alliance discourages reference to “pre-11n”

Range

• All wireless systems trade range for speed– Multiple modulation schemes (like DOCSIS)– “Loss budget” depends on distance and

obstacles• Most consumer products operate at much

lower transmit power than allowed by FCC• Range is improving

– New chips enable higher power and better receiver sensitivity at consumer pricing

Security: 802.11i and WPA™

• Original WEP (Wired Equivalent Privacy) – Easy to crack, confusing to set up– Most consumer networks operate open

• IEEE 802.11i is new standard for security– Took more than 4 years, published July 2004– Two encryption mechanisms

• WPA (Wi-Fi Protected Access™) – Simpler encryption mechanism– Added to Wi-Fi certification in 2003– In most current products– Download for many earlier WEP products

Security: WPA2™

• WPA2 (Wi-Fi Protected Access version 2™)– More complex encryption – CPU intensive– Generally requires newest chips– Added to Wi-Fi® certification in September

2004– Already included in many products

• Consumer and Enterprise versions– Different authentication methods– Consumer: user-selected “secret” text string– Enterprise: server-based 802.1x/RADIUS– Products can include both

QoS: 802.11e and WMM™

• QoS needed for audio, voice, video• Original Wi-Fi® didn’t have QoS• IEEE 802.11e is new QoS standard

– Still in process after more than 4 years– Both “prioritized” and “guaranteed” QoS

• WMM (Wi-Fi Multimedia)– Prioritized QoS subset of 802.11e draft– Widely accepted by 802.11e members– Added to Wi-Fi certification in September

2004– Already included in some products

WMM™ for Video

Source: Wi-Fi Alliance

QoS: HCCA

• Hybrid Coordination Function Controlled Channel Access– Guaranteed QoS subset of 802.11e draft– Probably needed for HD video– Ongoing debate in 802.11e “dominated

by PC guys”– Planned for 2005 if standard completed

UWB: 802.15.3a and W-USB

• Ultra wideband is coming– FCC approved underlying approach– Chips and products coming to market in 2005

• Standards are uncertain (competing camps)• Complements 802.11

– Short range technology – 10 meters, single room

• Wireless USB is most likely initial application– Replaces wired USB, 480 Mbps goal– Intel, TI and others behind it

• Wireless 1394 is possible follow-on– Replaces existing A/V wiring

Concluding Thoughts

• 100 Mbps is coming soon– 802.11n, UWB, HomePlug AV, etc.

• Need a heterogeneous home network– Wireless is not a complete “whole

home” solution, except maybe in MDUs

• End-to-end QoS is a major challenge– Service providers want it– All QoS efforts appear to be in silos– DLNA is most likely place for resolution

This Home Network of the Future…Is Now

DSL or Cable

High DefinitionDisplay

Standard DefinitionDisplay

Gateway / Router Multimedia

Server

VoWLANHandset /

PDA

Computer

Printer

Ethernet; Cat5 Cable and/or Home Plug

GameConsole

Desktop PC or MACHD/SD Tuners,DVD, DVR, Etc. 11g+11e

2.4 GHz

Video/Audio Source

Computer

UWB

Internet

Source: Bermai

11a+11e5 GHz