Wireless Service engineering
Bluetooth
Widely supported
Built-in on many PDA's, mobile phones and some laptops
Several embedded solutions exist
keyboards, mouse, head sets, printers, serial line replacement…
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Adding the capability to the device
PCMCIA cards
CF cards
USB dongle
Power class | Output power | Range |
Class 1 | 100 mW | 100 meters |
Class 2 | 2.5 mW | 10 meters |
Class 3 | 1 mW | 1 meter |
Access points
Omnidirectional RF
Class 1 devices have ethernet connection to bridge TCP/IP connections
Many models are running embedded linux
Many brands to choose from
Do it yourself with PC and Bluetooth dongle?
Full protocol stack from link to application layer.
HCI is the interface used to communicate with Bluetooth hardware
Newer BNEP protocol can be used instead of RFCOMM and PPP under IP
The way to use these protocols on different types of products is defined in profiles
On what layer you should start creating your application?
Connectivity with Bluetooth
1. Device discovery (Inquiry)
The initiator sends inquiry messages in order to find devices in it's proximity
Devices in discoverable mode reply with their BD ADDR
Inquiry in Bluetooth 1.1 takes 10.24 seconds and still might not find all devices on proximity (~90% success)
Enhanced inquiry in Bluetooth 1.2 requires maximum of 5 seconds and is almost 100% reliable
2. Connecting devices (paging)
The initiator pages the device it wants to connect at (BD ADDR)
Takea average of 1.28 seconds and maximum of 2.56 seconds
Interlaced page scan of Bluetooth 1.2 halves the time
3. Service discovery
Service Discovery protocol is used to discover the capabilities of the device that the basic data connection is formed at.
More information at the service discovery lecture
Specification gives no roaming support
Want to create Bluetooth games?