communications & networks wpans/wbansahnelson/csce5013/lectures/lecture12.pdf · 2020. 12....
TRANSCRIPT
Communications & Networks –
WPANs/WBANs
Alexander Nelson
October 12, 2020
University of Arkansas - Department of Computer Science and Computer Engineering
Review – Wireless Communication
1
WPAN/WBAN Communications
Low Power – Low Bitrate – Short Range Communication Protocols
Examples:
• Bluetooth
• Bluetooth Low Energy (BLE)
• Zigbee
• Z-Wave
• IrDA (Infrared)
• Thread
2
WPAN Standards
IEEE 802.15 – Working group standardize WPANs
Standards shape the underlying technologies that the high-level
protocols must use
• 802.15.1 – Bluetooth
• 802.15.2 – Coexistence with other WLANs
• 802.15.4 – Low Rate WPAN (ZigBee, Thread, etc..)
• 802.15.5 – Mesh Networking
• 802.15.6 – Body Area Networks
3
Bluetooth
Nils Rydbeck (Ericsson Mobile) & Johan Ullman – Develop
wireless headsets for communication
Operates in the 2.4GHz frequency spectrum
Uses frequency-hopping spread-spectrum communications
4
Bluetooth – Frequency Hopping
Transmitter & Receiver hop channels with a known pseudo-random
code
5
Bluetooth – Coexistence
Coexistence – 2.4 GHz spectrum is unlicensed, & many devices
may use the space
Example – Wi-Fi:
6
Bluetooth – Coexistence
Two strategies:
• Avoid – Attempt to not collide with other communication
• Recover – Detect collision & resend data
Frequency hopping with short windows provide method for recovery
7
Bluetooth – Coexistence
Avoidance can be implemented through intelligent selection of
channels
8
Bluetooth – Specifications
Bluetooth 5.0: 2016/ 50MBps / 50 m range
9
Bluetooth – Scatternet
Bluetooth implements a scatternet topology
Scatternets are groups of piconets
Piconets are small ad hoc networks of up to 7 active clients (up to
255 parked)
10
Bluetooth – Connection & Encryption
1
1https://www.slideshare.net/sara.naseem/bluetooth-2094234 11
Bluetooth – Profiles
Profiles – Protocols built on existing Bluetooth standard to define
data mode
Examples:
• HSP – Headset Profile
• HID – Human Interface Device
• SPP – Serial Port Profile
• A2DP – Advanced Audio Distribution Profile
• AVRCP – A/V Remote Control Profile
These protocols can specify data rate, what specific characters
mean, deadlines, and priorities
12
Bluetooth Low Energy – BLE
Nokia identified usage patterns Bluetooth did not address in 2001
Project MIMOSA released in 2006 under name Wibree
Wibree wrapped back into Bluetooth in 2007, integrated in 2010
Bluetooth SIG released Mesh Profile for BLE in July 2017
13
Bluetooth vs. BLE
14
Bluetooth 5.1
Bluetooth standard updated January 2019
• Angle of Arrival & Angle of Departure for tracking devices
• Advertising Channel Index - Improve advertising channel
selections
• GATT Caching - Faster discovery of devices
• Periodic Advertising Sync Transfer - Devices that never intend
to connect can synchronize advertising packets
15
ZigBee
ZigBee – 915MHz or 2.4GHz spectrum, mesh-capable low-power
WPAN
ZigBee Alliance released Specification 1 in 2005
ZigBee Cluster Library – 2006 Specification to standardize
commands and organize groups
Zigbee PRO – 2007 Specification for ease of use with large
networks
ZigBee Dotdot ‖ : – 2017 Replacement to cluster library, run over
other networks with Internet Protcol and connect with other
specifications such as Thread
16
Z-Wave
Z-Wave – 900 MHz band mesh protocol, primarily for home
automation
Developed in 2001, released first series in 2003
Acquired by Sigma Designs in 2008
As of 2017, 1700 products are certified by the Z-Wave Alliance
Long operating range (300 feet outdoor)
17
Thread
Thread Group alliance founded in 2014
Founded researchers from Nest Labs – now has many large
partners (Google, Samsung, Qualcomm, Silicon Labs, Tyco)
Implements 6LoWPAN with a connecting router (edge router)
Forward end-to-end WWW packets to mesh endpoints
18
OpenThread
Open-source implementation of Thread
19
802.11ah – Wi-Fi HaLow
Wi-Fi powered at lower frequency (900MHz, surprise!)
Signal propagates further & through walls better
Lower-bandwidth, lower power
Added to standard in 2017 – no commercial chipsets available yet
20