lectures.alex.balgavy.eu

Lecture notes from university.
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      1 +++
      2 title = "MAC: use in Bluetooth & RFID"
      3 +++
      4 
      5 # MAC: use in Bluetooth & RFID
      6 **Bluetooth**
      7 
      8 - piconet master connected to slave wireless devices
      9 - slaves may be asleep to save power
     10 - two piconets can be bridged through slave to make a scatternet
     11 
     12 ![screenshot.png](4f23b094f7fad480fcbf760ff5304b6d.png)
     13 
     14 - profiles give set of protocols for a given application (and there’s 25 of them WTF)
     15 - radio layer uses adaptive freq hopping in 2.4 GHz band
     16 - link layer uses TDM, links auth via pairing
     17 - frame format:
     18 
     19 ![screenshot.png](a2ee8019c9a5cca230bb3b7b7a6c4732.png)
     20 
     21 **RFID**
     22 
     23 - reader signal powers tags, tags reply using backscatter:
     24 
     25 ![screenshot.png](602a12f8a67d51f5188925a231fb9c13.png)
     26 
     27 - gen 2 tag identification:
     28 
     29     1. Reader sends query and sets slot structure
     30     2. Tags reply in a random slot with possible collisions
     31     3. Reader asks one tag for identifier — acknowledge
     32     4. Process continues until no tags left
     33 
     34 - reader frames vary depending on type, reader sets timing and knows expected format
     35 - tag responses are data only
     36 - frame structure:
     37 
     38 ![screenshot.png](e8fed776415462764a16704acb52b44d.png)