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Technical Overview

This presentation is provided by the HomeRF Working Group.Direct questions or requests for softcopy to:

Info@homerf.org, 503-291-2563Or contact HomeRF Communications Chairman, Wayne Caswell

(wayne.caswell@icm.siemens.com, 512-335-6073)

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Technical Overview Topics

• Toll-quality Voice & Streaming Media

• Data Throughput, Range & Attenuation

• Security & Interference Immunity

• Power Consumption & Form Factor

• Cost

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HomeRF Node Types

Laptop(A-node)

asynchronous

Cordless Handset(I-node)

isochronous

Internet Appliance(SA-node)

Audio Headset(S-node)streaming

Broadband Internet

Control Point(CP Class 1)

Wired network

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OSI 7-Layer Network Stack Model

7. Application

6. Presentation

5. Session

4. Transport

3. Network

2. Data Link (MAC)

1. Physical (PHY)

HomeRF Specification uses, references, or “maps into” existing network layers.

{HomeRF Specification modifies existing technology

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Network Layer View

Existing Upper Layers

TCP UDP

IPDECT

HomeRF MAC Layer

HomeRF PHY Layer

CSMA/CAPriorityCSMA TDMA

“Ethernet”Data Path

StreamingMedia Path

Toll-QualityVoice Path

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HomeRF Specification Basics

Contention-based “Wireless Ethernet” Reserved time TDMA

MAC Layer

Beacon

HomeRF Frame

Plus priority access and time reservation

Plus re-transmission option

PHY Layer

0.8, 1.6, 5, 10 Mbps data rates

2.4 GHz FH

Constant envelope FSK modulation

Conventional synthesizer

BACKUP

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MAC Layer Basics

time

Data Networking

Bulk of time is allocated to data networking

1 2Priority Streams

Within data networking time, streaming media sessions get priority access

Voice Calls

Reserved time period based on number of active voice calls

Hop Re-Transmit

If voice packets fail, they can be re-transmitted at the start of the next frequency

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20 ms

fN+5 Data#8Hop

Ack#8

Data#10 Ack#10

Data#9 Ack#9

20 ms

fN Data#1Hop

Ack#1

Data#2 Ack#2

Data#3 Ack#3

All asynchronous traffic

fN+1 Dn#1

Up#1

Data#4BHop

Ack#4

10 ms

Beacon is added for Isochronous traffic and frame length is reduced to 10ms

fN+3 Up#3

Up#1

Data#6BHop

Ack#6

Dn#3

Dn#1

Second call is added

BHop

10 ms

Dn#1

Up#1

Data#5 Ack#5fN+2

BHop

Dn#3

Up#3

Data#7 Ack#7

First call ends. Frame reordered.fN+4

Superframes and Subframes

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Bandwidth Requirements

Application Speed RequiredText 300 bpsTelephone (QoS, Latency) 8 – 64 KbpsColor Image 25 – 2,500 K bytesDigital Photo 1,000 – 10,000 K bytesDigital Music (QoS) 128 – 700 KbpsVideo Conferencing 384 – 2,000 KbpsMPEG-4 SDTV VoD (QoS, jitter) 250 – 750 KbpsMPEG-4 HDTV VoD 720p (QoS, jitter) 4,500 KbpsMPEG-2 HDTV 1080i (QoS, jitter) 20,000 Kbps

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Technical Overview Topics

• Toll-quality Voice & Streaming Media

• Data Throughput, Range & Attenuation

• Security & Interference Immunity

• Power Consumption & Form Factor

• Cost

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Wideband Frequency Hopping

f1 MHz

Base Channel

5 MHz Superchannel

75 1 MHz channels for 1.6 Mbps data and all voice communications

15 5 MHz channels for 5 and 10 Mbps data modes

HomeRF improves performance of 802.11 FHEnabled by FCC rule change in August 2000, ETSI rule change in December 2001

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0’ 85’ 130’ 150’

RANGE: Signal Strength Diminishes with Distance

Throughput

~5 Mbps

~2.5 Mbps

~0.4-0.8 Mbps

0.8-1.6 Mbps

5 Mbps

AdvertisedRange

150’Advertised Data Rate: 10 Mbps

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Performance over Distance

Broadband/ MPG 4 Video

0

1

2

3

4

5

6

10' 20' 30' 40' 50' 60' 70' 80' 90' 100' 110' 120' 130' 140' 150'

No

min

al t

hro

ug

hp

ut

(Mb

ps)

Source: Practical and Theoretical Calculations

HomeRF provides real-time media streaming to more nodes over a greater distance.

Dial-up / MP3 Audio

MPEG2 Video

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Attenuation: Signal Strength Diminishes through Materials

BU

ILD

ING

WA

LL

Wood and plaster Walls or Floors are OK. Even Brick.

Metal and thick rock block the RF signals.

The Higher the Frequency, the more signal loss.

5 GHz is worse than 2.4 GHz.

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Multi-path in Homes: More Absorption, Less Reflection

Signals can arrive at different times and cancel each other out.

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Technical Overview Topics

• Toll-quality Voice & Streaming Media

• Data Throughput, Range & Attenuation

• Security & Interference Immunity

• Power Consumption & Form Factor

• Cost

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is Secure and Reliable

• Frequency Hopping Spread SpectrumFrequency Hopping Spread Spectrum– Invented for the US Military to avoid jamming,

denial of service, and eavesdropping

• Performance with InterferencePerformance with Interference– Microwave ovens, cordless phones,

baby monitors, video senders, neighbors– High Density Apartments

• Security LayersSecurity Layers• Application Layer Security Option• 128-bit Encryption Option • Standardized Teach/Learn• 24-bit Network ID• Random Frequency Hopping• Spread-Spectrum• Digital

BU

ILD

ING

WA

LLTypical Wi-Fi configuration with

3 non-overlapping channels.

is Secure and Reliable

BEWARE: RF signals can penetrate walls

Access from car or

hilltop ???

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Interference:HomeRF hops around it

FHSS DSSS

TimeTime

Fre

qu

en

cy

IEEE 802.11b waits for Interference to go away

2.4 GHz

2.5 GHz

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p Spectral / Temporal Characteristics of Microwave Ovens

Frequency

PowerSpectralDensity

Used ISM band (75 MHz)

Average Power Spectrum(10 to 30 MHz)

Next

hop

clear

Next

hop

clear

Next

hop

clear

Next

hop

clear

Next

hop

clear

Active Interference Avoidance

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10 ms

Active data traffic

Hop BeaconfN Data 1 Ak1

Active calls

Dn5 Up5

Normal calls continue

Dn5 Up5Dn2 Up2

Data packet succeeds on retry

Ak2Data 2Hop BeaconfN+1

Control point allocatesretry of up/down 2

Data 2 Dn2 Up2

Latency is bounded to 10 ms even in the presence of interference

Active Interference Avoidance

Interference 1contacts fN

Dn2 Up2

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IEEE 802.11b

802.11b – DSSS using channel 3 (static frequency)

Source: Celerity Digital Broadband Test

2.4 2.5 GHz

Signal Strength

2.40 GHz

2.50 GHz

0 250 500 s

2.45 GHz

Frequency over Time

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Bluetooth™

Bluetooth Headset signal31.25 µs between pulse pairs125 µs between pulse sets

Source: Celerity Digital Broadband Test

2.4 2.5 GHz

Signal Strength

2.40 GHz

2.50 GHz

0 250 500 s

2.45 GHz

Frequency over Time

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2.4 GHz Cordless Phone

Multiple Channel Cordless TelephoneTransmit Receive on separate channelsChannel selection is arbitrary

Source: Celerity Digital Broadband Test

2.4 2.5 GHz

Signal Strength

2.40 GHz

2.50 GHz

0 250 500 s

2.45 GHz

Frequency over Time

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Coexistence within ISM band

WLAN 802.11bBluetooth™Cordless Telephone

Source: Celerity Digital Broadband Test

2.4 2.5 GHz

Signal Strength

2.40 GHz

2.50 GHz

0 250 500 s

2.45 GHz

Frequency over Time

802.11b politely waits for interference to go away – potentially a very long time with cordless phones.

Bluetooth interference, at 1600 hops/sec can also be severe.

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Technical Overview Topics

• Toll-quality Voice & Streaming Media

• Data Throughput, Range & Attenuation

• Security & Interference Immunity

• Power Consumption & Form Factor

• Cost

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p • Smallest WLAN form factor• 1.6 Mbps and full home coverage• < 10mW standby power draw• Full TCP/IP connectivity• Ideal for handheld Internet appliances,

personal imaging and audio devices

Specifications:Physical• Type II size, < 20 grams• 0 – 40 degree C operation• CE, EMC-EEC 89/336 CompliantElectrical• 3.3 V, 120mA Rc; 250mA Tx modes• 3mA standby mode

Simple Design: enables small form factor for embedded apps

Up

dat

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r 2.

0?

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Hand Held Trends

• Larger, higher resolution Displays with more Colors

• More Performance, Less Cost

– e.g. Video streaming

• Better Text rendering

• Wireless (WAN, WLAN, PAN)

• PDA becomes Phone, MP3…

• Phone becomes PDA, MP3…

• Digital Imaging

• PocketPC gains some ground – Palm still has >70% share

With Microsoft ClearType, palm-sized devices can act as eBooks.

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Technical Overview Topics

• Toll-quality Voice & Streaming Media

• Data Throughput, Range & Attenuation

• Security & Interference Immunity

• Power Consumption & Form Factor

• Cost

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Cost Roadmap parallels DECT

• DECT is a leading indicator for HomeRF– 6 generations of architecture evolution– HomeRF comes in well down the learning curve

• Complexity is similar– HomeRF Baseband ROM/Flash about 2X DECT– Radio will reuse Bluetooth/DECT Low-IF IP

• HomeRF BOM cost will approach DECT at same volumes– Basic HomeRF functionality (voice + 10Mbps)– Additional SW & HW depends on product features

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Cost Synergies

• Easy compatibility with OpenAir– HomeRF and OpenAir share a common PHY

(dual MAC client devices available now)– OpenAir has over 1M devices from over 20

different vendors already deployed in the field

• Multi-mode client devices with Bluetooth– HomeRF and Bluetooth have similar PHY

(multi-MAC client devices, such as a PCMCIA or Compact Flash card, are feasible and expected in 2002)

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Cost Synergies, cont.

• Multi-mode / Multi-band clients– PCS / GSM phones– 802.11b / .11g (DSSS / OFDM)– 802.11b / Bluetooth (DSSS / FHSS)– 802.11b / .11a (2.4 / 5 GHz)– WLAN / WAN (for mobile workers)– Easy to include support for HomeRF

• Adds much needed Flexibility– Automatically sense and adapt to networks

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Bottom Side

IntegratedBaseband

RFIC

Flash

Simple Design: enables Inexpensive 2-chip solutions

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Summary

• Ideal for the Broadband (voice, data, entertainment)– Blends several technologies to enable Digital Convergence– Broadband data at Ethernet speeds “plus” toll-quality voice

and streaming media

• Designed and optimized for Households & SOHO:– Simplicity, Security/Privacy, Interference, Cost, Applications

• Smooth roadmap to 20 Mb/s and beyond – Multi-band support for 2.4 GHz and 5 GHz (802.11a)

• More information at www.HomeRF.org– Learning Center for W.Papers, Presentations, etc.

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Wireless Choices for the Broadband Internet home

- Advantage ~ - Adequate X - DisadvantageLegend:

X ~

X ~

Roaming Outside the Home ~ ~ ~

ATTRIBUTE HomeRF Bluetooth 802.11b

Cost

Security

Interference Immunity

Toll-Quality Voice Support

Streaming Media Support

Data Throughput

Range

Power Consumption

Form Factor

Network Topology

~ X

~ X

~

X

X

X ~

X ~

~ ~

~