Specifications

15.247 (a) (1) Statement
CETECOM S.A. – ITA team Page 2 of 2 Bluetooth devices
1. Pseudorandom hop selection
The generation of the hopping sequence in connection mode depends
essentially on two input values:
1. LAP/UAP of the master of the connection
2. Internal master clock
The LAP (lower address part) are the 24 LSB’s of the 48 BD_ADDRESS. The
BD_ADDRESS is an unambiguous number of every Bluetooth unit. The UAP
(upper address part) are the 24 MSB’s of the 48 BD_ADDRESS.
The internal clock of a Bluetooth unit is derived from a free running clock which
is never adjusted and is never turned off. For synchronisation with other units
only offset are used. It has no relation to the time of the day. Its resolution is at
least half the RX/TX slot length of 312.5 µs. The clock has a cycle of about one
day (23h 30’). In most case it is implemented as 28 bit counter. For the deriving
of the hopping sequence the entire LAP (24 bits), 4 LSB’s (4 bits) (Input 1) and
the 27 MSB’s of the clock (Input 2) are used.
With this input values different mathematical procedures (permutations,
additions, XOR-operations) are performed to generate the sequence. This will
be done at the beginning of every new transmission. The output constitutes a
pseudorandom sequence covering 79 hop channels.
The exact procedures for the generation of the pseudorandom hopping
sequence can be found in “Bluetooth specification Version 1.1 – Part B –
Baseband Specification – Chapter 11: Hop selection”.
The following is a sample of a pseudorandom hopping sequence of 20 sec.
32000 hops):
34 72 31 69 28 66 25 63 22 60 19 57 16 54 13 51 10 48 07 45 04 42 01 39 77 36 74 33 71 30 68 27 65 24 62
21 59 18 12 20 09 17 61 20 58 17 00 08 76 05 49 08 46 05 67 75 64 72 37 75 34 72 55 63 52 60 25 63 22 60
43 51 40 48 13 51 10 48 31 39 28 36 01 39 77 36 19 27 16 24 68 27 65 24 70 29 55 14 64 23 49 08 58 17 43
02 52 11 37 75 34 72 43 02 28 66 37 75 20 09 17 06 14 03 11 00 22 60 07 45 16 54 01 39 76 65 73 62 70 59
67 56 78 37 63 22 72 31 57 16 66 25 51 10 60 19 45 04 42 01 51 10 36 74 45 04 28 17 25 14 22 11 19 08 30
68 15 53 24 62 09 47 18 56 03 41 12 50 76 35 73 32 03 41 67 26 76 35 59 48 56 45 53 42 50 39 61 20 46 05
55 14 40 78 49 08 34 72 43 02 28 66 25 63 34 72 19 57 28 66 52 62 49 59 46 56 43 53 40 50 37 47 34 44 31
41 28 38 25 35 22 32 19 29 12 50 09 47 61 48 58 45 77 08 09 19 47 06 58 17 67 26 64 23 37 24 34 21 53 63
64 74 23 61 34 72 31 69 14 52 49 59 32 42 19 57 02 40 37 47 20 30 72 31 04 42 11 21 22 32 62 49 59 46 01
39 77 36 58 45 41 28 52 39 35 22 59 69 56 66 29 67 26 64 47 57 44 54 17 55 14 52 35 45 32 42 05 43 02 40
23 33 20 30 72 31 69 28 11 21 08 18 60 19 57 16 78 09 75 06 48 07 45 04 66 76 63 73 36 74 33 71 38 76 21
59 32 70 15 53 26 64 09 47 20 58 03 41 00 38 11 49 73 32 05 43 69 56 66 53 63 50 60 47 69 28 52 11 63 22
46 05 78 37 75 34 44 33 41 30 72 01 77 06 38 76 43 02 60 68 65 73 26 64 31 69 56 64 45 53 22 60 11 49 30
68 27 65 75 64 72 61 24 32 29 37 69 28 74 33 12 20 17 25 57 16 62 21 63 22 60 19 57 16 54 13 37 26 42 31
31 20 36 25 39 77 36 74 33 71 30 68 13 02 18 07 07 75 12 01 15 53 12 50 09 47 06 44 14 52 11 49 59 48 56
45 08 16 13 21 53 12 58 17 75 04 01 09 41 00 46 05 71 00 60 68 37 75 26 64 45 04 42 01 11 00 08 76 39 47
44 52 05 43 10 48 27 35 32 40 72 31 77 36 78 37 75 34 72 31 69 28 52 41 57 46 46 35 51 40 54 13 51 10 48
07 45 04 28 17 33 22 22 11 27 16 30 68 27 65 24 62 21 59 35 73 32 70 29 67 26 64 27 37 32 42 21 31 26 36
15 25 20 30 09 19 14 24 13 51 02 40 56 43 45 32 01 39 69 28 44 31 33 20 60 19 65 24 24 11 29 16 60 70 57
67 24 62 21 59 18 56 15 53 42 52 39 49 73 60 78 65 18 56 23 61 73 32 70 29 18 28 15 25 49 36 54 41 73 32
78 37 51 38 48 35 45 32 42 29 14 52 11 49 38 48 35 45 02 40 78 37 26 36 23 33 69 28 66 25 14 24 11 21 59
46 56 43 53 40 50 37 59 18 48 07 53 12 42 01 35 22 32 19 29 16 26 13 35 73 24 62 29 67 18 56 09 47 06 44
33 43 30 40 76 35 73 32 21 31 18 28 64 23 61 20 09 19 06 16 52 11 49 08 76 07 73 04 42 29 39 26 36 23 33
20 77 06 66 74 43 02 32 70 57 65 62 70 23 61 28 66 39 77 36 74 05 73 02 70 41 49 30 38 07 45 75 34 29 37