Comparing Home Networking Technologies Comparing Wireless Networking Technologies for the Broadband Internet Home Dr. Kevin J. Negus Chief Technical Officer

Comparing Home Networking Technologies

Comparing Wireless Networking Technologies for the Broadband

Internet Home

Dr. Kevin J. NegusDr. Kevin J. Negus

Chief Technical OfficerChief Technical Officer

Proxim, Inc.Proxim, Inc.

November 27, 2001November 27, 2001


Some Useful Acronyms• Bluetooth

– The Special Interest Group or the Technical Spec

• HomeRF– The Working Group or the Technical Spec

• IEEE802.11 – Family of WLAN “standards”– 802.11 “MAC” – original MAC layer based upon 802.3– 802.11FH – now obsolete freq hopping PHY layer– 802.11DS – original 1997 direct sequence PHY (1,2 Mb/s)– 802.11a – ratified 5 GHz OFDM PHY layer (up to 54 Mb/s)– 802.11b – ratified high rate direct sequence PHY layer (5.5,11

Mb/s)– 802.11e – MAC enhancement for QoS under development– 802.11f – AP-AP communication– 802.11g – higher rate “direct sequence” PHY layer– 802.11h – DFS/TPC enhancements for 5 GHz operation– 802.11i – MAC security improvement under development


Agenda

• Broadband Internet Home

• Candidate Wireless Home Networking Technologies

• Introduction to HomeRF Technology

• Comparison of Candidate Technologies

• Summary


US Broadband Internet Households

0

5

10

15

20

25

30

1998 1999 2000 2001 2002 2003 2004

Source: The Strategis Group (2000)

Ho

use

hold

s (M

)

TOTAL

Other

Wireless

DSL

Cable


Desired Services US Consumers want from a “Telecom Bundle”

84%

78%

71%

58%

53%

35%

2%

7%

0% 10% 20% 30% 40% 50% 60% 70% 80% 90%

Local Phone

Long Distance

Cable TV

Internet

Cellular

Paging

Satellite TV

Not Interested

Source: The Strategis Group (2000)

High-speed data is not enough – MUST support toll-quality voice and streaming media services.

High-speed data is not enough – MUST support toll-quality voice and streaming media services.


Candidate Wireless Home Networking Technologies

• IEEE 802.11b (or “WiFi”)– Wireless “equivalent” of Ethernet

• HomeRF– Wireless Ethernet plus multi-line toll-quality cordless

voice and multiple streaming media sessions– Addresses the major interference and security

problems consumers have with 802.11b at home

• Bluetooth– Much lower power draw for ad hoc connectivity– Not a candidate for “backbone” home network– But, consumers will still want to operate Bluetooth

devices in their homes – so operation in presence of multiple Bluetooth devices is important


HomeRF 2.0 Capabilities Summary

• 10 Mb/s peak data rate with fallback modes of 5 Mb/s, 1.6 Mb/s and 0.8 Mb/s

• Powerful and effective security measures against eavesdropping, service denial and unauthorized access

• Up to 8 simultaneous prioritized streaming media sessions for audio and video

• Up to 8 simultaneous toll-quality two-way cordless voice connections (based on DECT)

• Active interference avoidance and mitigation techniques


HomeRF Capabilities Roadmap

EnhancedEnhanced VideoVideo

Voice/AudioVoice/Audio Basic VideoBasic Video

DataData

‘ ‘20002000 ‘2001 ‘2001 ‘2002 ‘20021.6 Mbps1.6 Mbps 10 Mbps 10 Mbps 20+ Mbps 20+ Mbps

• GatewaysGateways• Music DevicesMusic Devices• Web TabletsWeb Tablets• Cordless PhonesCordless Phones

• Video TabletsVideo Tablets• Set Top BoxesSet Top Boxes

InternetInternet


HomeRF Network TopologyBroadband Internet

Control Point(CP Class 1)

Laptop(A-node)

Internet Appliance(SA-node)

Audio Player(S-node)

Cordless Handset(I-node)

Wired network


Existing Upper Layers

TCP UDP

IPDECT

HomeRF MAC Layer

HomeRF PHY Layer

“Ethernet”Data Path

StreamingMedia Path

Toll-QualityVoice Path

CSMA/CA PriorityCSMA TDMA

Network Layer View of HomeRF


HomeRF – 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


HomeRF/Bluetooth PHY Layer Basics and Commonality

• Band and Channel Access– 2.4 GHz, frequency hopping

• Modulation and Transmitter– FSK, direct conversion, constant envelope– Nominally 100 mW saturated output power

• Transceiver Architecture– ~ 200 us turnaround using standard synthesizers on a

single VCO

• Single-chip PHY CMOS RFIC– Practical today for either HomeRF or Bluetooth or

dual-mode for both


Key Comparison Attributes

• Voice Support– Consumer voice revenues are >10X data revenues– Cordless phones outsell wireless data devices >50X

• Streaming Media Support– Internet audio and video are key apps for broadband

• Interference Immunity and Scalability– Bluetooth, cordless phones, microwave ovens– High density housing with many adjacent networks

• Security– PHY/MAC attributes are critical since end-end

solutions are generally not available in the home


Voice Support

• IEEE802.11b has no explicit voice support– No prioritization for voice, no bounded latency

mechanism for voice, no standard software stacks for voice features

• HomeRF was designed to support high quality, multi-line cordless telephony– Up to 8 simultaneous voice connections– 10 ms bounded latency– Frequency diversity and hopset adaptation provides

high quality even with severe interference– Maps directly into DECT for full CLASS features– A ratified global standard for multi-line cordless

telephony (and much more)


Streaming Media Support

• IEEE802.11b has no explicit streaming media support– Demos work fine, but network loading can wreak

havoc on VoIP phones or streaming videos– Interference and scalability issues not withstanding,

802.11e should eventually address this issue

• HomeRF was designed to support multiple prioritized streaming media sessions– Up to 8 consecutively prioritized levels– One-way (audio/video) or two-way (VoIP/videophone)– Frequency diversity and flexible re-try buffer length

provides high quality even with severe interference


Interference Immunity and Scalability

• 802.11b has only 3 wide, static channels– Channel bandwidth ~ 17 MHz, fixed location– Only interference avoidance mechanism is time

diversity (wait for the interferer to leave)– Fast hopper like Bluetooth is devastating– DS cordless phones can shut entire network down– Always shares the bandwidth with foreign networks

• HomeRF has narrower, dynamic channels– Channel bandwidth ~ 1.0/3.5 MHz (low/high rate)– Employs frequency and time diversity as well as

hopset adaptation with static interferers– Ignores foreign networks for graceful degradation in

high network density environments


Security

• 802.11b has 3 well publicized security flaws– Weak encryption with poor 24 bit IV management– “Open” network access– Trivial mass denial of service susceptibility

• HomeRF addresses all 3 concerns– 128 bit encryption standard with tamper-resistant 32

bit initialization vector– No equivalent of the 802.11 “open” access mode

and spec-compliant devices cannot pass promiscuous packets above the MAC

– Mass denial of service virtually impossible due to frequency hopping PHY and ignoring foreign NWIDs


Other Comparison Attributes

• Cost– HomeRF starts from a cordless telephone cost basis– BUT the market sets the price!!

• Range– HomeRF and 802.11b are roughly similar

• Peak Data Throughput– HomeRF and 802.11b are roughly similar

• Power Consumption– HomeRF power-savings devices have < 10 mW

standby with full TCP/IP connectivity

• Network Topology– HomeRF uniquely supports host/client and peer-peer

simultaneously


What about IEEE802.11a or HiperLAN2 for the home?

• Much higher peak data rates

• More Bandwidth, “Cleaner” Bandwidth

• MAC layer Considerations– 802.11a same as 802.11b for MAC

• Lacks explicit voice and streaming media support• Relies on upper layers for strong security solution

– HiperLAN2 has excellent QoS capable of supporting voice and streaming media

• But as yet, no cordless telephony infrastructure with range, power and features comparable to DECT or HomeRF

• Limited silicon availability at low cost

• Conclusion – Ideal solution for the enterprise– Far greater system capacity than 802.11b


What about DECT “plus Data” for the home?

• DECT is the world’s most successful multi-user cordless phone standard

• DECT performance sets the expectation for any competitive voice networking technology

• DECT can support credible data extensions– ~3 Mb/s performance demonstrated– Probably sufficient for many home applications– BUT, as currently specified DECT “plus Data” has:

• Limited interference mitigation for global 2.4 GHz band operation

• No available silicon• Unclear roadmap to competitive higher data rates

• Conclusion – HomeRF = DECT “plus Data”


Market Positioning

Business MarketBusiness Market[802.11a/HL2 centric][802.11a/HL2 centric]

• Wireless EthernetWireless Ethernet• PerformancePerformance• RoamingRoaming

Home MarketHome Market[HomeRF centric][HomeRF centric]

• Low Cost, SecureLow Cost, Secure• Toll-Quality VoiceToll-Quality Voice• Streaming MediaStreaming Media

Mobile MarketMobile Market[Bluetooth centric][Bluetooth centric]

• Ad Hoc ConnectivityAd Hoc Connectivity• Low PowerLow Power• Low CostLow Cost


Summary

• HomeRF combines 10 Mb/s data, toll-quality voice and streaming media for the Broadband Internet home

• HomeRF is uniquely optimized for the Broadband Internet home

• More information at www.HomeRF.org

Documents

Comparing Home Networking Technologies Comparing Wireless Networking Technologies for the Broadband Internet Home Dr. Kevin J. Negus Chief Technical Officer