- was once called Bluetooth Smart
- the best learning resource is an old hacker talk about how ridiculous the BLE security is. … obviosly
- some other resource: https://academy.nordicsemi.com/courses/bluetooth-low-energy-fundamentals/
general
-
es gibt server
- ein server hat services … mit UUID = Universally Unique Identifier
- ein service kann dann mehrere Werte haben, die man lesen oder schreiben kann
- ein Gerät kann mehrere server haben
- that’s not actually a BLE thing … but a ATT = Low Energy Attribute Protokoll thing
-
connection setup can be done in under 3ms … and a whole sending can be done in as little as 6ms
-
ein “LE-Coded” Burst besteht aus 3 Blöcken
PHY
- GFSK = Gaussian Minimum Shift Keying
- spectrum divided into 40 channels with 2MHz
- 3 of those are Advertising Channel (BLE)
- 37 used for Data connections
- hopping (Frequency hopping, FH-SS = Frequency Hopping Spread Spectrum)
- just increment the channel number by an amount specified by the connection master … you will loop through all channels, because 37 is a Prime Number
- hopp occoures after one transmission from the master and one from the slave
- there is a waiting time (specified by the master)
Link Layer
- Preamble: 10101010