Wireless USB Architecture Overview Brad · PDF fileWireless USB Architecture Overview Brad...

Wireless USB Architecture Overview Brad Hosler

Intel Corporation

2

AgendaAgenda

• Devcon goals• Radio environment (common platform)• High level architecture• Compliance environment• Intellectual Property• Industry Enabling

3

Devcon GoalsDevcon Goals

• Jumpstart WUSB product development• Get people thinking about WUSB

product possibilities• Help people understand the architecture

and features of WUSB

4

Devcon ScheduleDevcon Schedule

• Single track for first day and partof second

• Basic topics that all attendees should hear

• Split track on second day• More focused topics that may not be of

interest to everyone

5

AgendaAgenda


6

UWB Protocol RelationshipsUWB Protocol Relationships

Wire

less

US

B

IP (W

iNet

)

Oth

er A

pplic

atio

ns

Wire

less

139

4Various technology Various technology solutionssolutions

running over the running over the common platformcommon platform

Common Common UltraUltra--Wideband Wideband Radio PlatformRadio Platform

WiMedia UWB PHY

WiMedia UWB MAC

Convergence Layer

Single RadioSingle RadioIn PlatformIn Platform

7

Industry Group StructureIndustry Group Structure

Convergence LayerConvergence Layer

WiMedia UWB Phy

WiMedia UWB MAC

WiNet USB-IF

WiMedia

IP N

etw

orki

ngIP

Net

wor

king

Non

-IP

Peer

-to-p

eer

(W13

94)

Non

-IP

Peer

-to-p

eer

(W13

94)

Perip

hera

l In

terc

onne

ct

(WU

SB)

Perip

hera

l In

terc

onne

ct

(WU

SB)

8

AgendaAgenda

• Devcon goals• Radio environment (common platform)

• PHY characteristics• WiMedia and MAC

• High level architecture• Compliance environment• Intellectual Property• Industry Enabling

9

UWB OverviewUWB Overview

• UWB is presently legal only in the US• Regulatory activity underway in Europe,

Japan, and China

1.61.61.6 1.91.91.9 2.42.42.4

Bluetooth,Bluetooth,802.11b WLAN802.11b WLANCordless PhonesCordless PhonesMicrowave OvensMicrowave Ovens

PCS

PCS

555

802.11a WLAN802.11a WLANCordless PhonesCordless Phones

-- 41 dBm/Mhz41 dBm/Mhz“FCC Part 15 Limit”“FCC Part 15 Limit”

Frequency (Ghz)Frequency (Ghz)

EmittedEmittedSignalSignalPowerPower

10.610.610.63.13.13.1Note: not to scaleNote: not to scale

UWB SpectrumUWB Spectrum

UUU--- N

II ba

ndN

II ba

nd

ISM

ban

dIS

M b

and

GPS

GPS

10

UWB Overview (cont.)UWB Overview (cont.)

• High speed at short range• 480 Mb/s at ~3m

• Scaleable performance (Moore’s Law radio)

11

Multi-Band OFDM BandsMulti-Band OFDM Bands

f3432MHz

3960MHz

4488MHz

5016MHz

5544MHz

6072MHz

6600MHz

7128MHz

7656MHz

8184MHz

8712MHz

9240MHz

9768MHz

Band #1

Band #2

Band #3

Band #4

Band #5

Band #6

Band #7

Band #8

Band#9

Band #10

Band #11

Band #12

Band #13

10296MHz

Band #14

Band Group #1 Band Group #2 Band Group #3 Band Group #4 Band Group #5

• Fourteen bands, grouped in five Band Groups• Each band is 528 MHz

• Each band is capable of 480 Mb/s• First WUSB products will use Band Group 1

12

Multi-Band OFDM SymbolsMulti-Band OFDM Symbols

• OFDM symbol is basic quanta of UWB radio• Symbol is 312.5ns long• Each symbol has 100 data ‘tones’, each 4 MHz wide• All data rates use same symbol

• Different tone encodings within and between symbols provide different bit rates and different levels of robustness

OFDMSymbolOFDM

Symbol

OFDMSymbolOFDM

Symbol

OFDMSymbolOFDM

Symbol

OFDMSymbolOFDM

Symbol

OFDMSymbolOFDM

Symbol

OFDMSymbolOFDM

Symbol

312.5 ns

OFDM Symbol

TimeFreq (MHz)

3168

3696

4752

4224

Band # 1

Band # 2

Band # 3

OFDM Symbol

OFDM Symbol

OFDM Symbol

OFDM Symbol

OFDM Symbol

312.5 ns

13

Six Symbol UnitSix Symbol Unit

UWB PHYBaseband

“00101001001010001011110100”

• Six consecutive symbols make base data unit

• All packets are some integral number of six symbols in length (1.875us)

• PHY baseband converts to bits

• Different tone codings and interleaving produce differentbit rates

OFDMOFDMSymbolSymbol






14

Time Frequency Codes (TFCs)Time Frequency Codes (TFCs)

OFDMSymbolOFDMSymbol






TimeFreq ( MHz )

3168

3696

4752

4224

Band # 1

Band # 2

Band # 3OFDMOFDMSymbolSymbol






OFDMSymbolOFDM

Symbol

OFDMSymbolOFDM

Symbol

OFDMSymbolOFDM

Symbol

OFDMSymbolOFDM

Symbol

OFDMSymbolOFDM

Symbol

OFDMSymbolOFDM

Symbol

312.5 ns

OFDM Symbol

TimeFreq (MHz)

3168

3696

4752

4224

Band # 1

Band # 2

Band # 3

OFDM Symbol

OFDM Symbol

OFDM Symbol

OFDM Symbol

OFDM Symbol

TimeFrequencyInterleaving

(TFI)

FixedFrequencyInterleaving

(FFI)

15

UWB PacketsUWB Packets

PLCP Preamble PHY Header

MAC Header HCSTail

BitsTailBits

PadBits

39.4 Mb/sPLCP Header

Frame PayloadVariable Length: 0 ? 4095 bytes

PadBits

TailBitsFCS

53.3, 80, 106.7, 160, 200, 320, 400, 480 Mb/s

• Standard preamble is 9.375 microseconds• 30 OFDM symbols

• Burst preamble is 1.875 microseconds • Only available for speeds above 200 Mb/s• 6 OFDM symbols

• PLCP header is 3.75 microseconds• 12 OFDM Symbols

16

Inter Packet SpacingInter Packet Spacing

• Short Interframe Spacing (SIFS)• 10 microseconds• Used anytime there is Transmitter change

• Minimum Interframe Spacing (MIFS)• 1.875 microseconds• Only used when same transmitter

17

WiMedia PHYWiMedia PHY

• Required speeds• 53.3, 106.7, 200 Mbps• Other speeds (80,160,320,400, and 480)

are optional

• Band group 1 required• Three low bands

• TFI and FFI• PHY required to support both• How each will be used still to be decided

18

AgendaAgenda

• Devcon goals• Radio environment (common platform)

• PHY characteristics• WiMedia and MAC

• High level architecture• Compliance environment• Intellectual Property• Industry Enabling

19

WiMedia MACWiMedia MAC

• 64K microsecond superframes• Supports TDMA capabilities

• WUSB uses this feature

• All WUSB products need to be good MBOA citizens

• Primarily a responsibility of WUSB hosts• WUSB devices can be MBOA-unaware

20

WiMediaWiMedia

• Focused on making sure multiple devices can coexist

• Fairness policies• How much bandwidth can devices uses• When/how is bandwidth given up

• Policies are implemented by WUSB hosts• Devices generally don’t have to worry

about them

21

AgendaAgenda


22

Technology FeaturesTechnology Features

• Bandwidth • 480Mbps @ ~3 meters• Scalable architecture & protocol (up to1Gbps and beyond)

• Power management (battery preservation)• Sleep/Listen/Wake, Conserve under operation• Tx/Rx power management

• Security (secure connection)• Device secure association & authentication • Low overhead, minimize performance impact• Encryption through application

• Ease of Use (similar to wired USB)• Easy installation & setup• Backward compatible to wired USB• Low cost implementation

23

WUSB TopologyWUSB Topology

• Hub-and-spoke connection relationship

• Connection model is a wire replacement

• Point-to-point connections

• Between WUSB host& peripheral

• WUSB Cluster• WUSB Host with one or

more peripherals (up to 127)

• WUSB Clusters mayco-exist within an overlapping spatial environment

Dual Role Device connectivity

Up to 127 devices

Host scheduled data communications

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24

Communication TopologyCommunication Topology

Client SW Function

USB System SW

WUSB Host Controller

WUSB Logical Device

WUSB “BUS” Interface

Function Layer

Device Layer

“BUS” Interface Layer

Actual Communications Flow

Logical Communications Flow

Transmissions Encrypted

Secure Relationship

Wireless USBHost

Wireless USBDevice

Delta Change(from USB 2.0)

Very Small Change (Isochronous Only)

Small Change(Security Framework)

Very Large Change

25

Wireless USB ChannelWireless USB Channel

• The Wireless USB Channel is encapsulated by the MBOA channel

• Uses MBOA PHY/MAC compliant components

• MBOA PHY signaling and frames

• MAC Headers, Security Encapsulation, etc.

• Wireless USB channel is continuous sequence of linked control packets transmitted by Host during reserved time

• WUSB time is reserved from MBOA channel time (DRPs)

• Called MMCs – Micro-schedule Management Commands

• All Wireless USB Data communications are over Wireless USB Channel

MBOA Physical Layer Channel Time

MMC

MMC

MMC

MMC

MMC

MMC

MMC

MMC

MMC

MMC

Wireless USB Channel

BeaconPeriod

BeaconPeriod

DRPWUSB

DRPWUSB

DRPWUSB

t= 0

DRPWUSB

DRPWUSB

DRPWUSB

Superframe n Superframe n + 1

t= 0 t= 0MBOA MAC

BeaconPeriod

26

TDMA-Based ProtocolTDMA-Based ProtocolM

MC

MS-

CTA

1

MS-

CTA

n

MS-

CTA

1

MS-

CTA

m

MM

C

MS-

CTA

1

MS-

CTA

o

BP

Super Frame N Super Frame N+1Super Frame N-1

Distributed Reservation Periods (DRPs)

Transaction Group 1 Transaction Group 2 . . . . .Transaction Group n

Media Access Slots (MAS)

MM

C

Next MMCNext MMCNext MMC

27

Transaction GroupTransaction Group

• MMC plus time till next MMC

• Basic structure used to implement Wireless USB Protocol

MMC

HDR

MMC

Micro -schedules sequence (Transaction Group )

InformationElements

(W XCTAs ) HDR

Device Data & Handshake Phase Time Slots (OUT & IN )

28

Derived from WiredUSB ProtocolDerived from WiredUSB Protocol

Token Data Hndsk Token Data Hndsk

Propagation delays plus Device Turn Time

OUT IN

MMC

Toke

nO

u t

HDR

Hnds

kO

ut

Data Out

Toke

nIn

Data In

‘Cla

ssic

’USB

2T r

ansa

ctio

nPr

otoc

olW

USB

T ran

sact

ion

Prot

ocol

MMC

Transaction Group

Host Transmission

Device Transmission

Toke

nIn

Data In AcK

Hnd

skO

ut

29

Wireless USB Data BurstWireless USB Data Burst

MMCData OUT

MMC

Transaction Group Wireless USB Host Transmission

Wireless USB Device Transmission

DataX DataX+1 DataX+2 DataX+3

Burst Mode Data Phase (Data Burst)

Token Phase

Data Phase

Handshake Phase

• Allows multiple data packets per data phase• Extends Efficiency of Transaction

30

WUSB IsochronousWUSB Isochronous

• Wireless medium requires retriesand buffering

• Host will allocate retry time to meetfixed PER (10-3)

• Vendors choose amount of buffering• More buffering gives more reliable stream

• USB timebase (1ms) is preserved

31

Device Power ManagementDevice Power Management

• Devices and their drivers own device PM• Hosts don’t need to manage devices to save host power• Just like the wired case for selective suspend

• Three ways to save power• Conserve during normal operation

• Shut down radio between MMCs or whatever else makes sense• Host is unaware of any device PM activities

• Devices goes to sleep• Extended periods where device won’t respond• Host is aware and doesn’t schedule traffic

• Device disconnects• Host is aware (explicit)

32

Host Power ManagementHost Power Management

• Two cases• Case 1: WUSB channel (linked MMCs) is maintained

• Saving power while system is operational• Devices are unaware of host PM activities

• Case 2: WUSB channel is interrupted• System going to suspend (S3 or lower)• Radio is shut down for extended period• Host notifies devices that channel is stopping

• Remote Wake• Host restarts WUSB channel at least every 4 seconds• Devices use ‘Remote Wake’ notification to tell host to wake up

33

Interference MitigationInterference Mitigation

• Wireless is not as reliable as a Wire• Host has several controls tomanage reliability

• Transmit Power Control (TPC)• Transmit Bit Rate• Adjustable Packet Payload• Change PHY Channel• Dynamic Bandwidth Endpoints (Isochronous)

34

AgendaAgenda

• Devcon goals• Radio environment (common platform)• High level architecture

• Security and Association• Enabling Products

• Compliance environment• Intellectual Property• Industry Enabling

35

Just As Easy As The WireJust As Easy As The WireSecurity and AssociationSecurity and Association

• Association’s job:• Connect the owner’s devices the way the

owner wants them connected (IAA)

• Security’s job:• Match the security afforded by the USB wire• Protect data in-transit

Cable protects datain-transit

Cable Ends define user’s connection choice

36

Security and AssociationSecurity and Association

Sample Device ConnectSample Device Connect

WUSB Host 1

Device requests association with host

(sends unique ID)

2

4

5

Host sends challenge, encrypted with connection key

6

Device identifies host from MMC

Establish Session Key

7

WUSB Devices

3

Host Response to device(encrypted w. Connection key)

Host retrieves Response and device Challenge (encrypted

w. Connection key)

Host queries device acceptance (encrypted w.

Connection key)

IDENTIFYIDENTIFY

AUTHENTICATEAUTHENTICATE

AUTHORIZEAUTHORIZE

http://computers.cnet.com/hardware/0-2709830-404-20033518.html?tag=topfive

http://www.sherlocksystems.com/sherdvd/images/Dzmv100a.gif

http://images.amazon.com/images/P/B00006412G.01.LZZZZZZZ.jpg

37

The Connection ContextThe Connection ContextSecurity and AssociationSecurity and Association

128 bits 128 bits 128 bits

Host ID Device ID Connection Key

• Contains everything needed to set up secure communication

• Unique for each host-device pairing• Always generated on the host• Needs to be downloaded to device

Association gets the CC fromAssociation gets the CC fromthe host to the devicethe host to the device

38

Establishing the Connection ContextEstablishing the Connection Context


• Passing Connection Context to device is the challenge

• Must be a secure mechanism

• Three mechanisms are being considered• Use a cable• Use UWB radios with PK technology and

user authorization• Use Near Field Communication

39


Cable ModelCable Model

WUSB Host WUSB Devices

User connect host and device with USB cable.

11

Host sends Connection Context2



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http://images.amazon.com/images/P/B00006412G.01.LZZZZZZZ.jpg

http://images.google.com/imgres?imgurl=www.cwol.com/usb/images/3000le.jpg&imgrefurl=http://www.cwol.com/usb/maxtor-3000le-120gb-usb-hard-drive.htm&h=160&w=279&prev=/images%3Fq%3Dusb%2Bhard%2Bdrive%26start%3D20%26svnum%3D10%26hl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3DUTF-8%26sa%3DN

40


PK TechnologyPK Technology

User compares codes3

Host sends Connection Context to device

5 5


User presses button on host and device to start

connection

1 1

Host and Device generate numeric code and display it

2

User accepts code on host and device.

4 4



41


Near Field CommunicationNear Field Communication


User brings device near the host

1

Host and device exchange connection context using

NFC

2 2



42

AgendaAgenda




43

Host Radio SolutionsHost Radio Solutions

• PCI (or PCIe) based solution• Can go in an addin card slot• Cardbus or ExpressCard solutions

• Wired USB dongle• Cabled ‘base station’ variety• Small ‘key’ solutions

44

Wireless Host Controller Interface (WHCI)Wireless Host Controller Interface (WHCI)

• Being defined now• Similar to EHCI• Special interface for radio control

• Rev 0.9 release targeted for Q3’05• Requires signed license agreement

45

PCI Host ArchitecturePCI Host Architecture

NICInterface

RadioControl

Interface

HWAInterface

Convergence and MAC

PHY

PCI or PCIe• Supports both WUSB and IP• Has a common radio control

interface• All interfaces show up as

separate PCI functions

46

USB Host ArchitectureUSB Host Architecture

NICInterface

RadioControl

Interface

HWAInterface

Convergence and MAC

PHY

USB 2.0• Supports both WUSB and IP• Has a common radio control

interface• All functions show up as

separate USB interfaces

47

Device Wire AdapterDevice Wire Adapter

• Looks like a wireless hub• Single chip implementations can be integrated directly into devices

USB2.0

Device Wire Adapter: DWA

48

AgendaAgenda




49

Compliance EnvironmentCompliance Environment

• USB-IF owns tests for WUSB block• WiMedia owns tests for

MAC/PHY/Cooperation• WiMedia delivers turnkey tests

to be used a USB-IFCompliance Workshops

• Complete testing (including WiMedia) for WUSB products will be done at Compliance Workshops

• Or independent test houses

• Single logo for WUSB• Logo usage requires passing WUSB

and WiMedia tests

Cooperation LayerCooperation Layer

WiMedia UWB Phy

WiMedia UWB MAC

IPIP

W13

94W

1394

WU

SBW

USB

50

AgendaAgenda




51

Intellectual PropertyIntellectual Property

• All levels of the stack have RAND licensing terms

• Not aware of any company planning royalties

• Whatever happens, we will strive to make it easy WiMedia UWB Phy

WiMedia UWB MAC

WU

SBW

USB

52

AgendaAgenda




53

Peripheral Developers Kit (PDK)Peripheral Developers Kit (PDK)

• Provides host radio and SW solution to enable early peripheral development

• PCI addin card• Microsoft software stack• Some simple tools

• Will be available at end of Q2• Limited quantities• They won’t be free (probably about $4K)• Order through usb.org (not live yet)

54

Interop LabInterop Lab

• Provides early debug and interop help• Access to tools, other products, and experts

• Available to early developers• By appointment• For multiple days, if needed

• Hosted at Intel in Oregon• Opens on 6/20• Contact [email protected]

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