Bluetooth & Bluetooth Low Energy internals
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This document discusses Bluetooth technology. It begins with an introduction to Bluetooth, including its history and different flavors such as Classic, High Speed, and Low Energy. It then covers the Bluetooth market, including statistics on device shipments and member companies. The technical side of Bluetooth is explored, including specifications for Basic Rate, Enhanced Data Rate, and Low Energy. Profiles and use cases are also described. Future directions are discussed, such as Bluetooth Mesh networking and the growth of Bluetooth in the Internet of Things. The document concludes with an agenda for questions.
Bluetooth & Bluetooth Low Energy internals
- 1. Bluetooth Ir. Davy Jacops Nov 2015
- 2. Technicolor Intro Bluetooth Market Tech Side Future Q&A Bluetooth: Agenda
- 3. Intro Bluetooth Market Tech Side Future Q&A Bluetooth: Agenda
- 4. Q&A Short range wireless communications technology Personal Area Networking “PAN” Applications Cable replacement Voice & Data access points Ad-hoc networking Key features Robustness Low power Low cost Bluetooth Intro
- 5. Bluetooth Intro: History 1998: BT SIG formed:: Ericsson, Toshiba, Intel, Nokia, IBM Name “Bluetooth” officially adopted 1999: Core spec 1.0 released First BT unplug fest BT technology “Best of show technology award” at COMDEX 2000: First BT enabled mobile phone First BT “single chip” 2001: First BT enabled printer First hands free car kit BT SIG is formed as non profit, non stock corporation 2002: >500 BT qualifed products First BT keyboard & mouse combo 2003: Adoption of core spec 1.2 2004: Adoption of core spec 2.0 + EDR 2005: shipment of 5M BT chipsets per week 2006: First BT enabled watch, > 1B BT devices shipped SIG announces integration of BT and WiMedia UWB 2007: First BT enabled TV shipped 2008: > 2B BT devices shipped in 10 years 2009: BT Core spec 3.0 HS 2010: BT4.0 core spec adopted (BLE) PTS 4.1 launched incl BLE test suites 2011: “BT Smart” & “BT Smart” ready brands 29 new BT 4.0 profiles 2012: new profiles running & cycling data monitoring 2013: BT 4.1: IoT Native BT support in Android 2014 BT 4.2: IP connectivity Core spec 2.772 pages
- 6. Bluetooth Intro: Flavors Flavor Subset name(s) Core spec version Max Data rate Voice Spec Bluetooth “Classic” Basic Rate (BR) 1.x 721.2 kbps V 1999 Enhance Data Rate (EDR) 2.x + EDR 2.1 Mbps V 2004 Bluetooth “High Speed” High Speed (HS) Alternate Mac PHY (AMP) 3.x + HS 54 Mbps (802.11 AMP) V 2009 Bluetooth “Low Energy” Ultra Low Power (ULP) Bluetooth Low Energy (BLE) BT Smart BT Smart Ready (Wibree) 4.x 1 Mbps X 2010
- 7. Bluetooth Intro: “Bluetooth”? The idea for the Bluetooth name came from Jim Kardach of Intel, who was reading a historical novel about Vikings and King Harald Blåtand at the time. The name is the link to the distant past. “Bluetooth” is derived from the nickname of King Harald Blåtand a Dane who (somewhat violently) brought together people in what are now Denmark, Norway, and Sweden into a single kingdom. King Harald reigned from 958 to 986 and got his nickname from his penchant for eating blueberries.
- 8. Intro Bluetooth Market Tech Side Future Q&A Bluetooth: Agenda
- 9. Personal Area Bluetooth Local Area Wi-Fi 802.11 Wide Area Mobile 3G-4G LTE Short range communications such as mobile / PC accessories CABLE REPLACEMENT The center of the connected home / enterprise For applications that demand ubiquitous coverage and high reliability Bluetooth Market Positioning
- 10. 10.000+ new BT enabled products listed in 2014 24% up from 2013 3B devices shipped in 2014 90% penetration in all mobile phones Huge growth Smart home Consumer electronics Bluetooth Market Basic Figures Source: Bluetooth SIG 2014 annual report
- 11. Bluetooth Market Shipments Bluetooth enabled device shipments worldwide (billion units)
- 12. Bluetooth Market Growth Bluetooth Smart growth 2013-2014 Source: ABI Research
- 13. Bluetooth Market SIG member Companies Bluetooth SIG members Monthly increase Source: Bluetooth SIG
- 14. Bluetooth Market Worldwide Press Coverage Source: Bluetooth SIG
- 15. Intro Bluetooth Market Tech Side Future Q&A Bluetooth: Agenda
- 16. Intro Bluetooth Market Tech Side Basic Rate (BR) & Extended Data Rate (EDR) Bluetooth Low Energy Future Q&A Bluetooth: Agenda
- 17. Universal Wireless Standard Small & Cheap Low Power Wireless (<0.1W active power) 2.4GHz ISM band Spread Spectrum Frequency Hopping Avoid interference in ISM 1600 hops/s (625µs time slots) Pseudo random sequence based on master BD address TDD for send / receive Modulation BR: GFSK-Gaussian Frequency Shift Keying EDR: PSK-Phase Shift Keying BLE: GSFK 1 – 100mW Range: up to 100m Voice & Data Secure BD address: 48 bit IEEE registered Bluetooth: Tech Side
- 18. BT SIG documents Core Specification How the tech works Bluetooth protocols Profiles How the tech is used How different parts of the spec shall be used to fulfill a desired function Bluetooth: Tech Side
- 19. Bluetooth Core Specification BR/EDR Piconet Piconet: • Set of devices connected in ad hoc fashion • 1 Master, 1..7 Slaves • Master determining hopping pattern • Slaves have to synchronize • Each piconet has a unique hopping sequence • Participation in piconet = synchronization to hopping sequence • >200 can be parkedM=Master S=Slave P=Parked (deepest sleep) SB=Standby Source: Free University Berlin
- 20. Bluetooth Core Specification BR/EDR Forming a Piconet • Master gives slaves its clock and BD addr. • Hopping pattern: • Determined by master BD (48bit) • Hopping phase determined by clock • Addressing • AMA 3 bit • PMA 8 bit M=Master S=Slave P=Parked (deepest sleep) SB=Standby Source: Free University Berlin
- 21. Bluetooth Core Specification BR/EDR Multi-Slave timing Source: Bluetooth Specification version 4.2
- 22. Bluetooth Core Specification BR/EDR Scatternet • Linking of multiple co-located piconets through sharing of common master or slave devices • Communication between piconets • Devices jumping back and forth between piconets M=Master S=Slave P=Parked (deepest sleep) SB=Standby Source: Free University Berlin
- 23. Bluetooth Core Specification BR/EDR Freq Selection Source: Free University Berlin
- 24. Bluetooth Core Specification BR/EDR ACL Packet Types Source: Bluetooth Specification version 4.2
- 25. Bluetooth Core Specification BR/EDR Link Control Packet Types Source: Bluetooth Specification version 4.2
- 26. Bluetooth Core Specification BR/EDR SCO Packet Types Source: Bluetooth Specification version 4.2
- 27. Bluetooth Core Specification BR/EDR Protocol Stack Source: Free University Berlin • OBEX: Object Exchange • TCS BIN: Telephony Control Binary • BNEP: Bluetooth Network Encapsulation protocol • SDP: Service Discovery Protocol • RFCOMM: Radio freq comm.
- 28. Bluetooth Core Specification BR/EDR Robustness Source: Free University Berlin
- 29. Bluetooth Core Specification BR/EDR Adaptive Freq Hopping Source: Design-Reuse.com AFH Time WiFiBT
- 30. Bluetooth Core Specification BR/EDR Adaptive Freq Hopping Source: Design-Reuse.com AFH Time WiFiBT
- 31. Profiles represent default solutions for a certain usage model Vertical slice through the protocol stack Basis for interoperability Examples Serial Port Profile Headset Profile Dial-up Networking Profile Synchronization Profile … Bluetooth Core Specification BR/EDR Profiles Source: Bluetooth Specification version 4.2
- 32. Bluetooth Core Specification BR/EDR Profiles Example: Headset Source: Bluetooth Developer Portal & Bluetooth Headset Profile Specification V12
- 33. Bluetooth Core Specification BR/EDR Profiles Example: Headset Source: Bluetooth Developer Portal & Bluetooth Headset Profile Specification V12 Example headset scenario: Incoming audio connection In-band ring tone
- 34. Bluetooth Core Specification BR/EDR Profiles List Source: Bluetooth Developer Portal
- 35. Intro Bluetooth Market Tech Side Basic Rate (BR) & Extended Data Rate (EDR) Bluetooth Low Energy (BLE) Future Q&A Bluetooth: Agenda
- 36. BLE targets even more: Ultra-low peak, average and idle mode power consumption (1/2 to 1/100 of BR) Lower memory requirements Ability to run for year(s) on coin cell batteries Lower cost Enhanced Range Drawbacks No voice Lower data rates Bluetooth Core Specification Bluetooth Low Energy - Intro Source: BLE Developers Handbook – Robin Heydon
- 37. BLE – how to reach the cost advantage Low cost ... needs high volume ... needs very successful products ... largest volume consumer electronics is cell phone / smart phone ... reason of success of BT classic …BLE will build on attach rate of BT classic > 1B devices in a couple of years Roll out already ongoing Opens new markets Phone accessories Other devices such as Home Automation, TV, PC, BT classic upgrades Bluetooth Core Specification Bluetooth Low Energy - Intro Source: BLE Developers Handbook – Robin Heydon
- 38. Bluetooth Core Specification Bluetooth Low Energy - Intro Source: BLE Developers Handbook – Robin Heydon
- 39. Bluetooth Core Specification Bluetooth Low Energy - Intro Source: BLE Developers Handbook – Robin Heydon Low Energy: how low is “low”? “Few years on button-cell battery” ~ 230 mAh at 3 V Power a human being for 20s
- 40. BLE Asymmetric Design Central “Bluetooth Smart Ready” – Peripheral “Bluetooth Smart” Advertiser – Scanner Slave – Master Server – Client (Attribute protocol) Advertisers / Slaves / Servers Low memory / processing power / ultra low power consumption / Low cost Bluetooth Core Specification Bluetooth Low Energy - Intro Source: BLE Developers Handbook – Robin Heydon
- 41. BLE – PHY Internals GFSK Clock period = 1𝛍s 40 Channels -20dBm < Tx power < 10dBm Rx sensitivity: -70dBm or better Distance: 2.5m … 40m ... 250m Bluetooth Core Specification Bluetooth Low Energy - PHY Source: BLE Developers Handbook – Robin Heydon
- 42. BLE – Link Layer Standby: Inactive Advertising: Transmit Advertising packets Broadcast packets Scanning: Receive advertising packets Initiating: Initiate a connection Connected: Sub-states: Master or Slave Bluetooth Core Specification Bluetooth Low Energy - LC Source: BLE Developers Handbook – Robin Heydon
- 43. Bluetooth Core Specification BLE – BT Classic Interop Source: BLE Developers Handbook – Robin Heydon
- 44. BLE – Adaptive Frequency Hopping 37 channels Next Frequency: hop = 5…16 Bluetooth Core Specification Bluetooth Low Energy - AFH Source: BLE Developers Handbook – Robin Heydon Hop = 13
- 45. BLE – AFH Adaptive Frequency Hopping Bluetooth Core Specification Bluetooth Low Energy - AFH Source: BLE Developers Handbook – Robin Heydon AFH enabled AFH disabled
- 46. BLE – Connection Setup Connection request packet includes (among others): Access Address to be used in the connection CRC initialization value Transmit window size Transmit window offset Connection interval Slave latency Supervision timeout Adaptive frequency-hopping channel map Frequency-hop algorithm increment Sleep clock accuracy Bluetooth Core Specification Bluetooth Low Energy Source: BLE Developers Handbook – Robin Heydon
- 47. Connectionless model No cable replacement anymore Transient connections Quickly create connection Do something & Disconnect E.g. State notification every 5 minutes Only requires radio activity < 1s per day Radio OFF 99.999% of the time Single connect / data / disconnect in about 3ms Bluetooth Core Specification Bluetooth Low Energy Source: BLE Developers Handbook – Robin Heydon
- 48. Bluetooth Core Specification Bluetooth Low Energy: Architecture Source: BLE Developers Handbook – Robin Heydon Characteristics (UUID) & Services Discovery, connection, bonding, privacy Types of profiles and how they are used Rules for accessing data (att=labeled bits of data) Mux, Flow control HCI Advertising, Scanning, conn mgt, CRC GFSK / 1 bit = 1 us
- 49. Bluetooth Core Specification Implementation: Chipset Solutions Source: BLE Developers Handbook – Robin Heydon Single Chip 2 Chip 2 Chip 3 Chip
- 50. Bluetooth Core Specification BLE: Attribute Protocol Source: BLE Developers Handbook – Robin Heydon
- 51. Bluetooth Core Specification BLE: Attribute Protocol Source: BLE Developers Handbook – Robin Heydon
- 52. Bluetooth Core Specification BLE: Attribute Protocol Source: BLE Developers Handbook – Robin Heydon
- 53. Bluetooth Core Specification BLE Profiles List Source: Bluetooth Developer Portal
- 54. Intro Bluetooth Market Tech Side Future Q&A Bluetooth: Agenda
- 55. “The best way to predict the future is to invent it.” Alan Kay Bluetooth Future Source: Bluetooth Developer Portal
- 56. Bluetooth Future Source: Broadcom CES Blog Jan 2015
- 57. Bluetooth Future: Bluetooth “Smart” “More Than 30 Billion Devices Will Wirelessly Connect to the Internet of Everything in 2020” ABI Research
- 58. Bluetooth Future: Bluetooth 4.x BLE and beyond Source: Bluetooth SIG Brands
- 59. Bluetooth Future: Bluetooth “Smart Ready” Source: Bluetooth SIG: Bluetooth Smart Ready devices …. 39 devices • Apple iPad, iPhone, MacBook, Mac mini • Google OnHub • …
- 60. Bluetooth Future: Bluetooth “Smart” Source: Bluetooth SIG: Bluetooth Smart devices …. 172 devices
- 61. Bluetooth “Mesh” networking Extend range Control up to 64k BLE devices 100m .. Several km Device grouping Proposed by CSR (now Qualcomm) Expected release: 2016 Bluetooth Future: Bluetooth “Mesh” Source: Bluetooth SIG: Bluetooth Smart devices
- 62. Intro Bluetooth Market Tech Side Future Q&A Bluetooth: Agenda
- 63. BT core specification: TODO SIG Annual report 2014: https://www.bluetooth.org/en-us/Documents/Annual_Report_2014.pdf SIG history: http://www.bluetooth.com/Pages/History-of-Bluetooth.aspx ABI research: https://www.abiresearch.com/press/more-than-30-billion-devices-will-wirelessly-conne/ ABI research: https://www.abiresearch.com/market-research/service/internet-of-everything/ Bluetooth Security: https://courses.cs.washington.edu/courses/cse466/01au/Projects/BluetoothSecurity.ppt Bluetooth Low Energy: The Developer’s Handbook – Robin Heydon http://www.amazon.com/Bluetooth-Low-Energy-Developers-Handbook/dp/013288836X Android BLE development API http://developer.android.com/guide/topics/connectivity/bluetooth-le.html iOS BLE development API https://developer.apple.com/library/ios/documentation/NetworkingInternetWeb/Conceptual/CoreBluetooth_concepts References
Editor's Notes
- #5: Q&A Who owns 1 or more BT devices? What do you use it for?
- #11: Yes, 3B devices in 2014 alone
- #14: Membership: Adopter = free (free license tech & trademarks, license PTS) Associate = drive and influence spec through participation in working groups intelligence reports + discount on listing fees
- #18: Universal: France & Japan adapted their rules Secure: topic on its own From the lowest layers, security is embedded Up to 128 bit encryption keys Inadequate for serious security (money transfers), need additional security in higher layers Good enough for non security critical interactions PAN distance reduces risks COST: Low Cost (original target <5$)
- #20: Park; No AM address anymore only listens to beacons (up to 41s) & L2CAP broadcast Must be un-parked Max 4096 parked devices Some interop issues
- #21: AMA = Active member address PMA = parked member address
- #25: Here: ACL BR only Others: SCO, eSCO, ID, NULL, POLL, FHS, some mixed data/voice
- #30: Next frequency calculated based on (BD addr master, current clock, AFH parameters, sequence selection)
- #31: 3 ways to enter AFH Self assessment Host controlled Peer controlled
- #35: Note: HID (now aldo in ULP) A2DP HFP HSP
- #37: Very short packages (8 – 27 bytes) 1 Mbps Advanced sniff sub-rating to achieve ultra low duty cycles AFH (common with BR) Host control: more responsibility to the host Latency: 6ms (conn setup, data transfer) Range: increased modulation index => range > 100m Robustness: CRC 24 bit on all packets Security: AES-128 bit encryption using CCM (encryption & authentication) Topology: 32 bit member address > 4 billion devices
- #39: BLE is SLOW! Reasons: Low cost (extreme high volumes for devices that are not wireless today) ISM band (bad propagation characteristics – water… / body absorption …) but FREE and available No IP licensing cost (FRAND = Fair Reasonable and non discriminatory terms) Ultra low power
- #40: BLE is SLOW! Reasons: Low cost (extreme high volumes for devices that are not wireless today) ISM band (bad propagation characteristics – water… / body absorption …) but FREE and available No IP licensing cost (FRAND = Fair Reasonable and non discriminatory terms) Ultra low power
- #41: Central “Mothership”: Smartphone, notebook, tablet Peripheral: Heart monitor, thermometer
- #43: LC layer
- #44: LC layer
- #46: Channels 0..8 are marked BAD HOP = 13
- #47: Note the AFH algo increment
- #49: Controller = Physical device PHY GFSK (freq shift keying) 1bit = 1 micro-second Link Layer Advertising, scanning Create & maintain connections CRC HOST = SW Stack L2CAP Multiplexing layer Flow control SAR (not used for BLE) Attribute Protocol Set of rules for accessing data on a peer device Attribute = labeled bits of data (ID, type, value) + permissions Attributes can be READ/WRITTEN Both client & server can initiate communication with acked or unacked message Security Manager Security manager protocol Pairing (trust another device) & key distribution (for use when they later reconnect) Generic Attribute Profile Defines the types of profiles and how they are used Generic Access Profile: Defines how devices discover, connect & present useful information to the users How to create a permanent relationship called “bonding” Concept of “privacy” (random addresses in time) Application layer Defines characteristics, service, profile (each built on top of Generic Attributes Profile) Characteristic = a bit of data that has a known format labeled with a UUID (computer readable format) Service = human readable specification of a set of characteristics and their behavior Apps = Applications using the stack
- #50: Single chip: Lowest cost But SW in ROM… so need huge volumes 2 Chip: Cell phones PCs 3 Chip: Development setups
- #55: Note: HID (now aldo in ULP) A2DP HFP HSP
- #60: SMART READY = Backwards compatible with Classic Bluetooth: “Dual mode” radio: BLE + BR/EDR SMART: BLE ONLY “Drones around the mother ship” – peripherals Data collectors Sensors Can remain paired with Smart Ready devices even when not used for hours or days Can remain in sleep indefinitely Can wake from sleep in an instant to share data E.g. heart rate monitor can be worn for hours yet send only data when heart rate reaches certain threshold
- #63: CSR acquired by Qualcomm AUG 13, 2015