Bluetooth & Bluetooth Low Energy internals

Bluetooth
Ir. Davy Jacops Nov 2015

 Technicolor
 Intro
 Bluetooth Market
 Tech Side
 Future
 Q&A
Bluetooth: Agenda

 Intro
 Tech Side
 Future
 Q&A
Bluetooth: Agenda

 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

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

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

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.

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

 10.000+ 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

Bluetooth Market
Shipments
Bluetooth enabled device shipments worldwide (billion units)

Bluetooth Market
Growth
Bluetooth Smart growth 2013-2014
Source: ABI Research

Bluetooth Market
SIG member Companies
Bluetooth SIG members Monthly increase
Source: Bluetooth SIG

Bluetooth Market
Worldwide Press Coverage
Source: Bluetooth SIG

 Intro
 Tech Side
 Basic Rate (BR) & Extended Data Rate (EDR)
 Bluetooth Low Energy
 Future
 Q&A
Bluetooth: Agenda

 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

 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

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

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
SB=Standby

BR/EDR Multi-Slave timing
Source: Bluetooth Specification version 4.2

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
SB=Standby

BR/EDR Freq Selection

BR/EDR ACL Packet Types

BR/EDR Link Control Packet Types

BR/EDR SCO Packet Types

BR/EDR Protocol Stack
• OBEX: Object Exchange
• TCS BIN: Telephony Control Binary
• BNEP: Bluetooth Network
Encapsulation protocol
• SDP: Service Discovery Protocol
• RFCOMM: Radio freq comm.

BR/EDR Robustness

BR/EDR Adaptive Freq Hopping
Source: Design-Reuse.com AFH
Time
WiFiBT

 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
 …
BR/EDR Profiles

BR/EDR Profiles Example: Headset
Source: Bluetooth Developer Portal & Bluetooth Headset Profile Specification V12

BR/EDR Profiles Example: Headset
Source: Bluetooth Developer Portal & Bluetooth Headset Profile Specification V12
 Example headset scenario:
 Incoming audio connection
 In-band ring tone

BR/EDR Profiles List
Source: Bluetooth Developer Portal

 Intro
 Tech Side
 Basic Rate (BR) & Extended Data Rate (EDR)
 Bluetooth Low Energy (BLE)
 Future
 Q&A
Bluetooth: Agenda

 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 Low Energy - Intro
Source: BLE Developers Handbook – Robin Heydon

 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

 Low Energy: how low is “low”?
 “Few years on button-cell battery”
 ~ 230 mAh at 3 V
 Power a human being for 20s 

 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

 BLE – PHY Internals
 GFSK
 Clock period = 1𝛍s
 40 Channels
 -20dBm < Tx power < 10dBm
 Rx sensitivity: -70dBm or better
 Distance: 2.5m … 40m ... 250m
Bluetooth Low Energy - PHY

 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 Low Energy - LC

BLE – BT Classic Interop

 BLE – Adaptive Frequency Hopping
 37 channels
 Next Frequency:
 hop = 5…16
Bluetooth Low Energy - AFH
Hop = 13

 BLE – AFH
Adaptive
Frequency
Hopping
Bluetooth Low Energy - AFH
AFH enabled AFH disabled

 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 Low Energy

 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 Low Energy

Bluetooth Low Energy: Architecture
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

Implementation: Chipset Solutions
Single Chip
2 Chip 2 Chip
3 Chip

BLE: Attribute Protocol

BLE Profiles List

“The best way to predict the future is to invent it.”
Alan Kay
Bluetooth
Future

Bluetooth
Future
Source: Broadcom CES Blog Jan 2015

Bluetooth Future:
Bluetooth “Smart”
“More Than 30 Billion Devices Will Wirelessly
Connect to the Internet of Everything in 2020”
ABI Research

Bluetooth Future:
Bluetooth 4.x BLE and beyond
Source: Bluetooth SIG Brands

Bluetooth Future:
Bluetooth “Smart Ready”
Source: Bluetooth SIG: Bluetooth Smart Ready devices
….
39 devices
• Apple iPad, iPhone, MacBook, Mac mini
• Google OnHub
• …

Bluetooth Future:
Bluetooth “Smart”
Source: Bluetooth SIG: Bluetooth Smart devices
….
172 devices

 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

 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

Bluetooth & Bluetooth Low Energy internals

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