Transcript Comparing Home Networking Technologies

Comparing Wireless Networking
Technologies for the Broadband
Internet Home
Dr. Kevin J. Negus
Chief Technical Officer
Proxim, Inc.
November 27, 2001
Comparing Home Networking Technologies
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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”
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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
Comparing Home Networking Technologies
Agenda
• Broadband Internet Home
• Candidate Wireless Home Networking
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Technologies
Introduction to HomeRF Technology
Comparison of Candidate Technologies
Summary
Comparing Home Networking Technologies
US Broadband Internet Households
30
25
Households (M)
20
TOTAL
Other
Wireless
DSL
Cable
15
10
5
0
1998
1999
2000
2001
Source: The Strategis Group (2000)
Comparing Home Networking Technologies
2002
2003
2004
Desired Services US Consumers
want from a “Telecom Bundle”
Not Interested
Satellite TV
High-speed data is not
enough – MUST
support toll-quality
voice and streaming
media services.
7%
2%
35%
Paging
53%
Cellular
58%
Internet
71%
Cable TV
78%
Long Distance
84%
Local Phone
0%
10%
20%
30%
40%
50%
60%
Source: The Strategis Group (2000)
Comparing Home Networking Technologies
70%
80%
90%
Candidate Wireless Home
Networking Technologies
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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
Comparing Home Networking Technologies
HomeRF 2.0 Capabilities Summary
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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
Comparing Home Networking Technologies
HomeRF Capabilities Roadmap
Enhanced
Video
Voice/Audio
Basic Video
Data
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• Video Tablets
• Set Top Boxes
Gateways
Music Devices
Web Tablets
Cordless Phones
Internet
‘2000
1.6 Mbps
‘2001
10 Mbps
Comparing Home Networking Technologies
‘2002
20+ Mbps
HomeRF Network Topology
Broadband Internet
Wired network
Laptop
(A-node)
Internet Appliance
(SA-node)
Control Point
(CP Class 1)
Audio Player
(S-node)
Cordless Handset
(I-node)
Comparing Home Networking Technologies
Network Layer View of HomeRF
Existing Upper Layers
UDP
TCP
IP
DECT
HomeRF MAC Layer
CSMA/CA
Priority
CSMA
TDMA
HomeRF PHY Layer
“Ethernet”
Data Path
Streaming
Media Path
Toll-Quality
Voice Path
Comparing Home Networking Technologies
HomeRF – MAC Layer Basics
Bulk of time is allocated
to data networking
time
Data Networking
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Voice Calls
Hop
Re-Transmit
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Priority Streams
Within data networking time,
streaming media sessions
get priority access
Reserved time period
based on number of
active voice calls
Comparing Home Networking Technologies
If voice packets fail, they can
be re-transmitted at the start
of the next frequency
HomeRF/Bluetooth PHY Layer
Basics and Commonality
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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
Comparing Home Networking Technologies
Key Comparison Attributes
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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
Comparing Home Networking Technologies
Voice Support
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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)
Comparing Home Networking Technologies
Streaming Media Support
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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
Comparing Home Networking Technologies
Interference Immunity and
Scalability
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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
Comparing Home Networking Technologies
Security
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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
Comparing Home Networking Technologies
Other Comparison Attributes
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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 peerpeer simultaneously
Comparing Home Networking Technologies
What about IEEE802.11a or
HiperLAN2 for the home?
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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
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• 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
Comparing Home Networking Technologies
What about DECT “plus Data” for
the home?
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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:
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• 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”
Comparing Home Networking Technologies
Market Positioning
Home Market
[HomeRF centric]
• Low Cost, Secure
• Toll-Quality Voice
• Streaming Media
Business Market
[802.11a/HL2 centric]
Mobile Market
• Wireless Ethernet
• Performance
• Roaming
[Bluetooth centric]
• Ad Hoc Connectivity
• Low Power
• Low Cost
Comparing Home Networking Technologies
Summary
• HomeRF combines 10 Mb/s data, toll•
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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
Comparing Home Networking Technologies