Wireless USB Architecture Overview Brad Hosler Intel Corporation
Agenda Devcon goals Radio environment (common platform) High level architecture Compliance environment Intellectual Property Industry Enabling 2
Devcon Goals Jumpstart WUSB product development Get people thinking about WUSB product possibilities Help people understand the architecture and features of WUSB 3
Devcon Schedule Single track for first day and part of second Basic topics that all attendees should hear Split track on second day More focused topics that may not be of interest to everyone 4
Agenda Devcon goals Radio environment (common platform) High level architecture Compliance environment Intellectual Property Industry Enabling 5
UWB Protocol Relationships Various technology solutions running over the common platform Wireless USB IP (WiNet) Other Applications Wireless 1394 Common Ultra-Wideband Radio Platform Convergence Layer WiMedia UWB MAC WiMedia UWB PHY Single Radio In Platform 6
Non-IP Non-IP Peer-to-peer Peer-to-peer (W1394) (W1394) Peripheral Peripheral Interconnect Interconnect (WUSB) (WUSB) Industry Group Structure WiNet USB-IF Convergence Layer WiMedia UWB MAC WiMedia WiMedia UWB Phy 7 IP Networking IP Networking
Agenda Devcon goals Radio environment (common platform) PHY characteristics WiMedia and MAC High level architecture Compliance environment Intellectual Property Industry Enabling 8
UWB Overview UWB is presently legal only in the US Regulatory activity underway in Europe, Japan, and China Emitted Signal Power - 41 dbm/mhz Note: not to scale GPS PCS ISM band 1.6 1.9 2.4 Bluetooth, 802.11b WLAN Cordless Phones Microwave Ovens 3.1 U-NII band 5 Frequency (Ghz) 802.11a WLAN Cordless Phones UWB Spectrum FCC Part 15 Limit 10.6 9
UWB Overview (cont.) High speed at short range 480 Mb/s at ~3m Scaleable performance (Moore s Law radio) 10
Multi-Band Bands Band Group #1 Band Group #2 Band Group #3 Band Group #4 Band Group #5 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 Band #14 3432 MHz 3960 MHz 4488 MHz 5016 MHz 5544 MHz 6072 MHz 6600 MHz 7128 MHz 7656 MHz 8184 MHz 8712 MHz 9240 MHz 9768 MHz 10296 MHz f 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 11
Multi-Band s Band # 1 Band # 2 Band # 3 3168 3696 4224 4752 Freq (MHz) symbol is basic quanta of UWB radio is 312.5ns long Each symbol has 100 data tones, each 4 MHz wide All data rates use same symbol 312.5 ns ns Time Different tone encodings within and between symbols provide different bit rates and different levels of robustness 12
Six Unit 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 different bit rates UWB PHY Baseband 00101001001010001011110100 13
Time Frequency Codes (TFCs) Time Frequency Interleaving (TFI) Band # 1 Band # 2 Band # 3 3168 3696 4224 4752 Freq (MHz) 312.5 ns Time 3168 Fixed Frequency Interleaving (FFI) Band # 1 Band # 2 Band # 3 3696 4224 4752 Freq ( MHz ) Time 14
UWB Packets PLCP Preamble PHY Header Tail Bits MAC Header HCS Tail Bits Pad Bits Frame Payload Variable Length: 0? 4095 bytes FCS Tail Bits Pad Bits PLCP Header 39.4 Mb/s 53.3, 80, 106.7, 160, 200, 320, 400, 480 Mb/s Standard preamble is 9.375 microseconds 30 symbols Burst preamble is 1.875 microseconds Only available for speeds above 200 Mb/s 6 symbols PLCP header is 3.75 microseconds 12 s 15
Inter 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 16
WiMedia 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 17
Agenda Devcon goals Radio environment (common platform) PHY characteristics WiMedia and MAC High level architecture Compliance environment Intellectual Property Industry Enabling 18
WiMedia 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 19
WiMedia 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 20
Agenda Devcon goals Radio environment (common platform) High level architecture Compliance environment Intellectual Property Industry Enabling 21
Technology 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 22
WUSB Topology Hub-and-spoke connection relationship Connection model is a wire replacement Up to 127 devices Point-to-point connections Between WUSB host & peripheral WUSB Cluster WUSB Host with one or more peripherals (up to 127) Host scheduled data communications Dual Role Device connectivity WUSB Clusters may co-exist within an overlapping spatial environment 23
Communication Topology Wireless USB Host Wireless USB Device Delta Change (from USB 2.0) Client SW Function Very Small Change (Isochronous Only) Function Layer USB System SW WUSB Logical Device Device Layer Small Change (Security Framework) WUSB Host Controller WUSB BUS Interface BUS Interface Layer Very Large Change Actual Communications Flow Logical Communications Flow Transmissions Encrypted Secure Relationship 24
Wireless USB Channel Beacon Period t= 0 MBOA MAC DRP WUSB DRP WUSB Beacon Superframe n Superframe n + 1 Period DRP WUSB DRP WUSB DRP WUSB MBOA Physical Layer Channel Time DRP WUSB t= 0 t= 0 Beacon Period M M C M M C M M C M M C M M C M M C M M C M M C M M C M M C Wireless 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 25
TDMA-Based Protocol Super Frame N-1 Super Frame N Super Frame N+1 Distributed Reservation Periods (DRPs) BP Media Access Slots (MAS) MMC MS-CTA 1 MS-CTA n MMC MS-CTA 1 MS-CTAm MMC MS-CTA 1 MS-CTA o Next MMC Next MMC Transaction Group 1 Transaction Group 2..... Next MMC Transaction Group n 26
Transaction Group MMC plus time till next MMC Device Data & Handshake Phase Time Slots (OUT & IN ) HDR MMC Information Elements (W XCTAs ) MMC HDR Micro -schedules sequence (Transaction Group ) Basic structure used to implement Wireless USB Protocol 27
Derived from Wired USB Protocol Classic USB 2 Transaction Prot ocol Propagation delays plus Device Turn Time Token Data Hndsk Token Data Hndsk OUT IN WUSB Transaction Prot ocol HDR Token Out MMC Token In Hndsk Out Data Out Data In Hndsk Out MMC Token In Data In AcK Host Transmission Device Transmission Transaction Group 28
Wireless USB Data Burst Token Phase Data Phase Handshake Phase MMC Data OUT Data X Data X+1 Data X+2 Data X+3 MMC Burst Mode Data Phase (Data Burst) Transaction Group Wireless USB Host Transmission Wireless USB Device Transmission Allows multiple data packets per data phase Extends Efficiency of Transaction 29
WUSB Isochronous Wireless medium requires retries and buffering Host will allocate retry time to meet fixed PER (10-3) Vendors choose amount of buffering More buffering gives more reliable stream USB timebase (1ms) is preserved 30
Device 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) 31
Host 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 32
Interference Mitigation Wireless is not as reliable as a Wire Host has several controls to manage reliability Transmit Power Control (TPC) Transmit Bit Rate Adjustable Packet Payload Change PHY Channel Dynamic Bandwidth Endpoints (Isochronous) 33
Agenda Devcon goals Radio environment (common platform) High level architecture Security and Association Enabling Products Compliance environment Intellectual Property Industry Enabling 34
Security and Association Just As Easy As The Wire 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 Ends define user s connection choice Cable protects data in-transit 35
Security and Association Sample Device Connect WUSB Host 2 Device identifies host from MMC IDENTIFY Device requests association with host (sends unique ID) 1 WUSB Devices 3 5 7 Host sends challenge, encrypted with connection key Host retrieves Response and device Challenge (encrypted w. Connection key) AUTHENTICATE Host Response to device (encrypted w. Connection key) Host queries device acceptance (encrypted w. Connection key) 4 6 AUTHORIZE AUTHORIZE Establish Session Key 36
Security and Association The Connection Context 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 from the host to the device 37
Security and Association Establishing 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 38
Security and Association Cable Model WUSB Host 1 User connect host and device with USB cable. 1 WUSB Devices 2 Host sends Connection Context 39
Security and Association PK Technology WUSB Host WUSB Devices 1 User presses button on 1 host and device to start connection Host and Device generate numeric code and display it 2 3 User compares codes 4 4 User accepts code on host and device. 5 5 Host sends Connection Context to device 40
Security and Association Near Field Communication WUSB Host WUSB Devices 1 User brings device near the host 2 Host and device exchange 2 connection context using NFC 41
Agenda Devcon goals Radio environment (common platform) High level architecture Security and Association Enabling Products Compliance environment Intellectual Property Industry Enabling 42
Host 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 43
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 44
PCI Host Architecture Supports both WUSB and IP Has a common radio control interface All interfaces show up as separate PCI functions NIC Interface PCI or PCIe Radio Control Interface Convergence and MAC HWA Interface PHY 45
USB Host Architecture Supports both WUSB and IP Has a common radio control interface All functions show up as separate USB interfaces NIC Interface USB 2.0 Radio Control Interface Convergence and MAC HWA Interface PHY 46
Device Wire Adapter Looks like a wireless hub Single chip implementations can be integrated directly into devices USB2.0 Device Wire Adapter: DWA 47
Agenda Devcon goals Radio environment (common platform) High level architecture Security and Association Enabling Products Compliance environment Intellectual Property Industry Enabling 48
Compliance Environment USB-IF owns tests for WUSB block WiMedia owns tests for MAC/PHY/Cooperation WiMedia delivers turnkey tests to be used a USB-IF Compliance 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 IP W1394 W1394 Cooperation Layer WiMedia UWB MAC WiMedia UWB Phy WUSB WUSB 49
Agenda Devcon goals Radio environment (common platform) High level architecture Security and Association Enabling Products Compliance environment Intellectual Property Industry Enabling 50
Intellectual 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 WUSB WUSB WiMedia UWB MAC WiMedia UWB Phy 51
Agenda Devcon goals Radio environment (common platform) High level architecture Security and Association Enabling Products Compliance environment Intellectual Property Industry Enabling 52
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) 53
Interop 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 WUSB-PIL@usb.org 54