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Wireless personal area network
(WPAN), Bluetooth, ZigBee - Coggle Diagram
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Bluetooth
Network topologies
Piconet
- contains one master and at least one slave and that uses the same channel
- Master, controls all of the wireless traffic – only 1
• Slave, takes commands from the master – up to 7
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Bluetooth radio module
– A single radio transciever
– Only hardware required for Bluetooth to function
– Bluetooth 1.1, 1.2 can transmit at a speed of up to 1 Mbps
Bluetooth version 2.1 transmits at 2.1 or 3 Mbps – called
enhanced data rate (EDR) 
Bluetooth power classes and ranges
Power Class 1: 100mW, 330 feet (100m)
Power Class 2: 2.5mW, 33 feet (10m)
Power Class 3: 1mW, 3 feet (1m)
Radio frequency
- uses the same frequency as IEEE
802.11b/g/n WLANs
- Bluetooth version 1.2 adds a feature called adaptive
frequency hopping (AFH) - Further improves compatibility with 802.11 WLANs at
2.4 GHz
Bluetooth RF layer
– Defines how the basic hardware that controls the radio
transmissions functions
– Data bits (0 and 1) are converted into radio signals and
transmitted
– Equivalent to OSI Physical layer
Modulation techniques
- Bluetooth 1.x uses a variation of frequency shift keying
(FSK)
- This variation is called two-level Gaussian
frequency shift keying (2-GFSK)
- Uses two different frequencies
To indicate whether a 1 or a 0 is being transmitted
Version 2.x Bluetooth
- Added 2 modules -Pi/4~DQPSK (2 Mbps)
- 8-DPSK (3 Mbps) : can only be used in ideal conditions
Version 3.0 Bluetooth
- Added low power modes
- 3.0+HS added an alternate MAC/PHY (AMP)
- AMP uses separate radio module for 802.11-like
transmissions
Version 4.0
- introduced Bluetooth low energy (BLE)
How it Works
- sends and receives radio waves in a band of 79 different frequencies (channels) centered on 2.45 GHz
- Bluetooth devices automatically detect and connect to one another and up to eight of them can communicate at any one time.
- To minimize the risks of interference from other electrical appliances (and also to improve security), pairs of devices constantly shift the frequency they're using
- When a group of two or more Bluetooth devices are sharing information together, they form a kind of ad-hoc (piconet)
ZigBee
- contains three different types of devices: a coordinator, routers, and end devices.
- work with each to deliver messages and instructions from the central coordinator out to the individual end devices
- select an appropriate channel by performing a channel scan and finding the most suitable one with the least amount of interference
- assign a unique ID to the network, allocate a unique address to each device within the network
- initiate and transfer the messages