05 ble intro
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This document provides an introduction to Bluetooth low energy technology. It discusses the basics of Bluetooth standards and terminology. It then describes the key aspects of Bluetooth low energy including its architecture, features, physical layer, link layer, attribute protocol, generic attribute profile, generic access profile, and example application profiles. The document also discusses Bluetooth qualification requirements and provides an overview of operating system support for Bluetooth low energy.
05 ble intro
- 1. Introduction to Bluetooth® low energy A brief insight into the ultra low power technology at the core of the nRF51 series October 2012Vinayak Kariappa Chettimada
- 2. 2Introduction to Bluetooth low energy Bluetooth: essentials Standard for Personal Area Network based on Ericsson research Short range, low-power Frequency hopping spread spectrum (FHSS) 2.4 GHz ISM band Bluetooth Special Interest Group formed in 1998 16000+ SIG member companies Billions of products shipped Nordic Semiconductor is one 9 SIG Board members
- 3. 4Introduction to Bluetooth low energy Bluetooth: terminology Term Introduced Means BR 1.1 (2002) Basic Rate (1 Mbit/s) EDR 2.0 (2004) Enhanced Data Rate (2 and 3 Mbit/s) HS 3.0 (2009) High Speed (Alternate MAC/PHY) LE 4.0 (2010) Low Energy (1 Mbit/s ultra low power) Bluetooth Smart 4.0 Single-mode, LE-only radio Bluetooth Smart Ready 4.0 Dual-mode, BR/EDR and LE dual radio nRF51 Series
- 4. 5Introduction to Bluetooth low energy Bluetooth: configurations BR/EDR/HS 1.1, 2.0, 3.0 Link Manager BR/EDR PHY L2CAP SPP RFCOMM BR/EDR 4.0 Dual Mode (+LE) L2CAP GATT ATTSMP GAPSPP RFCOMM Link LayerLink Manager BR/EDR + LE PHY LE 4.0 Single Mode GA P GATT ATTSMP L2CAP GAP Link Layer LE PHY
- 5. 6Introduction to Bluetooth low energy Bluetooth LE: key features Following goals and rules of ULP wireless pioneered by Nordic PHY compatible with all 4.0 Bluetooth devices Ultra Low Power Small packets Short RX and TX windows Race to idle Turn radio on as seldom as possible Turn radio off as soon as possible Coin-cell battery 1+ year Low memory footprint Fast connection in 6 ms and teardown Simple stateless operation, data in form of parameter-value
- 6. 7Introduction to Bluetooth low energy Bluetooth LE: architecture Host GAPGATT ATT SMP L2CAP Controller Host Controller Interface (HCI) Link Layer (LL) Physical Layer (PHY) … Profiles HIDoverGATT Proximity Battery Thermometer HeartRate BloodPressure Speed&Cadence
- 7. 8Introduction to Bluetooth low energy 2.4 GHz free ISM band 1 Mbit/s signalling rate GFSK modulation Up to 4 dBm maximum transmit power 40 RF channels 3 advertising channels reserved for: Discover Connect Broadcast 37 data channels PHY Overview … ControllerHostProfiles GAPGATT ATT SMP L2CAP Host Controller Interface (HCI) Link Layer (LL) Physical Layer (PHY) HIDoverGATT Proximity Battery Thermometer HeartRate BloodPressure Speed&Cadence
- 8. 9Introduction to Bluetooth low energy Advertising: connectable and non-connectable Scanning: active or passive Slave: connection role Master: connection role 31 bytes advertising payload size 27 bytes maximum payload size per packet AES-128 built-in encryption CCM Counter with Cipher Block Chaining Message Authentication Code Link Layer Overview … ControllerHostProfiles GAPGATT ATT SMP L2CAP Host Controller Interface (HCI) Link Layer (LL) Physical Layer (PHY) HIDoverGATT Proximity Battery Thermometer HeartRate BloodPressure Speed&Cadence
- 9. Scanning on channel 37 0 ms S 25 ms 50 ms 100 ms75 ms 125 ms 150 ms Scanning on channel 38 Scanning on channel 39 Advertising on 37, 38 and 39 0 ms 20 ms 40 ms 60 ms 80 ms 100 ms 120 ms 140 ms A 10PRESENTATION TITLE Scanner scan interval = 50 ms Scanner scan window = 25 ms Link Layer Overview: Advertising and Scanning Advertiser advertising interval = 20 ms
- 10. 11PRESENTATION TITLE Link Layer Overview: Topology Master Advertiser SlaveConnection Request Scanner BR/EDR BR/EDR Slave Scanner Slave Slave Advertiser
- 11. 12PRESENTATION TITLE Selectable Connection Interval: 7.5 ms to 4 s Radio Idle Radio Idle Radio Idle Radio Idle Link Layer Overview: Connection T X T X Slave connection interval T X T X Master R X R X R X R X connection interval connection interval T X T X R X R X T X T X R X R X ... ...
- 12. 15Introduction to Bluetooth low energy Attribute Protocol Mandatory and used for all data transfers in BLE Fast, simple, independent of connection logic Client – Server architecture Server stores data Client requests data Server initiates Notifications and Indications Supports for fine-grained security ATT Overview … ControllerHostProfiles GAPGATT ATT SMP L2CAP Host Controller Interface (HCI) Link Layer (LL) Physical Layer (PHY) HIDoverGATT Proximity Battery Thermometer HeartRate BloodPressure Speed&Cadence
- 13. 16Introduction to Bluetooth low energy ATT Transaction Client ATT Request PDU ATT Response PDU ATT HVN/HVI PDU(on update) Server Attr. Attr. Attr. Attr. Handle UUID Permissions Value Attribute Handle – Index in the ATT Table, used in ATT transaction PDU UUID – Universal Unique Identifier Permissions – Read, Write, Authenticated, Encrypted etc. Value – data read/written by Client
- 14. 18Introduction to Bluetooth low energy Generic Attribute Profile Mandatory for all BLE profiles Procedures for attribute discovery and access Models the ATT Table layout 16-bit (SIG Assigned) and 128-bit (Proprietary) UUIDs Hierarchial classification of Attributes Services Characteristics Descriptors GATT Overview … ControllerHostProfiles GAPGATT ATT SMP L2CAP Host Controller Interface (HCI) Link Layer (LL) Physical Layer (PHY) HIDoverGATT Proximity Battery Thermometer HeartRate BloodPressure Speed&Cadence
- 15. 19Introduction to Bluetooth low energy GATT Overview Handle UUID Value 0x0005 CHAR HSL 0x0006 HSL FINGER 0x0002 CHAR HRM 0x0003 HRM 80bpm 0x0001 SERVICE HRSService Permissions READ READ READ READ/NOTIF READ 0x0004 DESC NOTIFYREAD Characteristic Characteristic Descriptor Attribute
- 16. 21Introduction to Bluetooth low energy Generic Access Profile Common to BR/EDR and BLE Mandatory for all BLE profiles Procedures to discover, and connect to devices Roles Peripheral (Slave) Central (Master) Broadcaster (Advertiser) Observer (Scanner) Security Creating bonds with peer devices Attribute access security requirements Privacy and address control Advertising data format GAP Overview … ControllerHostProfiles GAPGATT ATT SMP L2CAP Host Controller Interface (HCI) Link Layer (LL) Physical Layer (PHY) HIDoverGATT Proximity Battery Thermometer HeartRate BloodPressure Speed&Cadence
- 17. 22Introduction to Bluetooth low energy Vertical slice across protocol stack Selects required features from the stack Describes a particular use case Requires a particular set of GATT services Defines Roles Procedures Security Key to inter-operability Profiles overview GAPGATT ATT SMP L2CAP Profile Services … ControllerHostProfiles GAPGATT ATT SMP L2CAP Host Controller Interface (HCI) Link Layer (LL) Physical Layer (PHY) HIDoverGATT Proximity Battery Thermometer HeartRate BloodPressure Speed&Cadence
- 18. 23Introduction to Bluetooth low energy Profiles overview: Examples and roles HID over GATT: Wireless Human Interface Devices Host (PC, tablet, phone) Device (keyboard, mouse, trackpad, …) Heart Rate: Both sport and medical Heart Rate transmission Collector (PC, tablet, phone) Sensor (Heart Rate belt or similar) Proximity / Find Me: Locate devices and detect presence Monitor (PC, tablet, phone) Reporter (keyfob, phone)
- 19. 24Introduction to Bluetooth low energy All Bluetooth products must be qualified End Product Listing is the goal Requires an EP-QDL (Qualified Design Listing) Nordic can help! We will provide an EP-QDL for nRF51 No qualification fees Only RF-PHY retesting required Qualification
- 20. 25Introduction to Bluetooth low energy Qualification RF-PHY (Component) Link Layer (Component) Host (Component) nRF51 (EP-QDL) nRF51 Profiles (Subsystem) Internal Nordic Qualifications (Not intended to be used by customers) Publicly Available Qualifications (Intended to be used by customers) nRF51 End Product (EPL) End product (Listed by the product manufacturer) Subset
- 21. 26Introduction to Bluetooth low energy Annex: Operating System support today Microsoft Windows: Windows XP, Vista and 7: 1.1 – 2.1 BR/EDR only Additional full replacements commonly shipped by OEMs Windows 8: 4.0 BR/EDR and low energy natively supported Apple Mac OS X (10.6 and above): 4.0 BR/EDR and low energy iOS (5 and above): 4.0 BR/EDR and low energy GNU/Linux: Vanilla BlueZ (~4.93 and above): 4.0 BR/EDR and low energy Android: BR/EDR only as of 4.1 (Jelly Bean) Several vendors offer patched versions with 4.0 LE support
- 22. Thank you for your attention Questions October 2012Vinayak Kariappa Chettimada