Home Rf

HomeRFHomeRF

Bringing Wireless Connectivity Home

ContentsContentsIntroduction to Wireless Home Networking

Brief History of HomeRFHomeRF Technology- SWAPSummary

Overview of HomeRF Overview of HomeRF A next step wireless networking optimized for home/office environment

Provides Data and Voice communication between devices such as PC’s, Cordless Phones and DSL Modems etc.

Uses SWAP-CA Technology

What is Home What is Home Networking ?Networking ?The distribution of information(Audio,

Video, & Data) around the home and their interface with attached devices and external services.

The interconnection and interoperation of

- Home appliances- Entertainment devices - PC hardware- Telecommunication devices- Security lighting and environmental

control systems

Wireless TechnologyWireless Technology• Infrared-Line-of-Sight Technology• Radio Frequency

HomeRF WG(Working HomeRF WG(Working Group) Group) Formed in 1997 with 85+ membersEnable existence of a broad range

of interoperable consumer devices bringing information services to each part of the home

Establish an open industry specification for unlicensed RF digital communications for PCs and consumer devices anywhere in and around the house

Initiating members: Compaq, Ericsson, HP, IBM, Intel, Microsoft…

HomeRF VisionHomeRF Vision

HomeRF Technology HomeRF Technology SWAP (Shared Wireless Access Protocol)

Derived from extension of existing cordless Telephone (Digital Enhanced Cordless Telephone) and wireless LAN technology

HomeRF Technical Goals HomeRF Technical Goals Low cost and voice support of DECT

– Adapted to 2.4GHz band– Client call services well defined

TCP/IP support of IEEE 802.11– Relaxed specs to lower cost– Use existing 2.4GHz support (FH)

HomeRF OriginsHomeRF Origins

802.11Uses CSMA/CA Good for data

DECTUses TDMA Good for voice

SWAPTDMA+CSMA/CA

Good for voice and Data Optimized for small networks(in home)Simplified Radio & Protocol to reduce costBoth Data & Voice are important for

HomeRF

SWAPSWAPHomeRF SWAP specification– Designed for both data & voice wireless

communication– Defines interoperation of PSTN &

Internet Operates in the 2.4GHz band– Uses digital frequency hopping spread

spectrum radio Derived from extensions of existing

cordless telephone (DECT) & wireless LAN technology

– Enables new class of home cordless services

IP Data at up to 2 Mbps & support cordless telephony

SWAP supports SWAP supports TDMA– Time Division Multiple Access– Provides delivery of interactive voice & other time critical service

CSMA/CACarrier Sense Multiple Access/Collision Avoidance

– Service for delivery of high speed packet data

Capabilities of HomeRFCapabilities of HomeRFUp to 150 foot rangeNetworks up to 50 PCs Work with dial-up, DSL, and

cable modems Work through walls & floorsData secured through unique

network IDRobust & reliable & minimizes

the impact of radio frequenciesIncludes support of near line

quality voice & full telephony

Data Service TypesData Service Types Isochronous (I Node)– Used mainly to carry interactive voice Minimum latency Requires the presence of a Connection

Point– Example: cordless telephones Asynchronous (A Node)– Used for data networking - TCP/IP traffic– Example: fridge pad I Nodes get priority on bandwidth CP - connection point– Can manage a network or act as an A node– Can be USB, PCI, PC-Card, Device Bay– CP can place calls even when PC is down

Frequency HoppingFrequency HoppingIt works very much like its name implies-Data signal is modulated with a

narrowband carrier signal that hops from frequency to frequency as a function of time over a wide band of frequencies

-Hopping pattern is known to both transmitter & receiver To properly receive the signal the receiver must be set to the same hopping code & listen to the incoming signal at the right time & correct frequency

Unintended receiver see FH to be short-duration impulse noise

Network Layers of Network Layers of HomeRFHomeRF

Network TopologyNetwork TopologySWAP system supportsSWAP system supports Ad-Hoc Network– Only data communication is

supported– All stations are equal– Control of the network is distributed

between the stationsManaged network under the control

of a CP– Ideal for isochronous data and power

savings– Such as time critical communications

such as Interactive voice– Provides gateway to PSTN

UsesUsesPC Enhanced Cordless TelephonyMobile Internet viewingPC resource sharing

Comparative study Comparative study

Technical SummaryTechnical SummaryHybrid TDMA/CSMA frameFrequency Hopping: 50 hops/secRange up to 50 meters indoorsSpeed: dual speed– 1 or 2 Mb/sec– Also supports TCP/IP voiceVoice: High quality voice

channels with retransmission– High quality cordless telephones– Voice recognition

ReferencesReferencesXILINX HomeRF TutorialWPAN-HomRF Tutorial from

Intel’s Labhttp://www.palowireless.com/ho

merf/about.asphttp://en.wikipedia.org/wiki/

HomeRF