Low Power Radio Frequency LPRF
Industrial Scientific Medical ISM
433MHz
688MHz
868MHz
2.4GHz
5.8GHz
915MHz in US
Licence Free – Short Range – Open Standards (i.e. no licenced protocols)
LICENCED PROTOCOLS IN THE LPRF BANDS
ZigBee
BlueTooth
Z Wave
ANT++
WiFi
And so on
........
868 & 2.4 Smart Meters, Health
2.4 Personal Devices
868 Home Automation
2.4 Fitness Market
2.4 Computers
BLUETOOTH – 2.4GHz offering point to point
communciations for commercial products
Hands Free Kit
IT peripherals
Data Streams
OEM Applications
Home entertainment
Serial USB or Analogue (PCM)
RF Data Link
Host computer
or device
HCI
DEVICE 1
DISCOVERABLE
DEVICE 2
DISCOVERY
Sees Board Address
Friendly Name
Device Type
REQUEST TO PAIR
OPTIONAL
ENCRYPTION
AND PIN
NUMBER
REQUEST
ISSUE PIN NUMBER
CREATES LINK
KEY
PAIRED
-------------------------
CREATES LINK KEY
PAIRED
--------------------------------
CONNECTS
CONNECTS
Blue Tooth
Board Address 48 bits (12 HEX)
Friendly Name 18 Characters
Device Type 24 bits (6 HEX)
ZigBee – creates ad-hoc Mesh Networks
known as Personal Area Networks PAN
2.4MHz, 868MHz (EU), 915MHz (USA)
A PAN Id has 24-bits
Each Node has 8-bits
Co-Ordinator Finds free channel and assigns a PAN ID. It also acts as a Router
Nodes request to join – Must be running the correct ZigBee Profile and Application Profile
– they are the allowed to join and are assigned a Node Id. If we are using a Trust Centre
then there is a deeper level of security that must be followed e.g. Smart Energy Profile.
Nodes can act as routers or end-points – thus we create a Tree Network
Co-Ordinator (tree)
1
t1.1
1.2
2
1.3
2.1
2.2
3
2.3
3.1
3.2
Co-Ordinator
(with routing tables)
1
t1.1
1.2
2
1.3
2.1
2.2
3
2.3
3.1
A true Mesh Network,
but with higher
processing overhead
3.2
Z-WAVE
868 & 915
32 bit network or home ID
8 bit node ID
Uses a mesh network with a master and optional secondary controllers
MAX 232 nodes
Each node senses 6 nearest devices and informs controller
No security
Z-WAVE IS WIDELY USED FOR HOME AUTOMATION
Inter-operability
Spread Spectrum Techniques
found in LPRF & GNSS
Bluetooth – Dynamic Frequency Hopping –
to avoid RF collisions
ZigBee – Transformation of bit patterns
from 4 to 32 bits using Modulo-2 Spreading
Code – to provide error detection and
correction
GNSS – Use of modulo-2 Spreading Codes
to achieve Code Division Multiple Access
with a code correlator