Communication Technology

m Sequence (MLS : Maximum Length Sequence)

m-Sequence is a kind of (special kind of) LFSR sequence. So in order for you to understand m-sequence, first you need to understand the concept of LFSR sequence.

What is so special about m-sequence comparing to typical LFSR ? If you generate a sequence with LFSR, the output eventually repeats itself. But in most of the application, the purpose is to generate the longest possible non-repeating sequence with a given number of shift registers (Taps). m-Squence is a special type of LFSR which gives the longest non-repeating sequence for each give number of taps. The well-known m-sequence for various taps is shown in the following table.

 No of Taps Generator Polynomial 2 [2 1 0] 3 [3 2 0] 4 [4 3 0] 5 [5 3 0] 6 [6 5 0] 7 [7 6 0] 8 [8 6 5 4 0] 9 [9 5 0] 10 [10 7 0] 11 [11 9 0] 12 [12 11 8 6 0] 13 [13 12 10 9 0] 14 [14 13 8 4 0] 15 [15 14 0] 16 [16 15 13 4 0] 17 [17 14 0] 18 [18 11 0] 19 [19 18 17 14 0] 20 [20 17 0] 21 [21 19 0] 22 [22 21 0] 23 [23 18 0] 24 [24 23 22 17 0] 25 [25 22 0] 26 [26 25 24 20 0] 27 [27 26 25 22 0] 28 [28 25 0] 29 [29 27 0] 30 [30 29 28 7 0] 31 [31 28 0] 32 [32 31 30 10 0] 33 [33 20 0] 34 [34 15 14 1 0] 35 [35 2 0] 36 [36 11 0] 37 [37 12 10 2 0] 38 [38 6 5 1 0] 39 [39 8 0] 40 [40 5 4 3 0] 41 [41 3 0] 42 [42 23 22 1 0] 43 [43 6 4 3 0] 44 [44 6 5 2 0] 45 [45 4 3 1 0] 46 [46 21 10 1 0] 47 [47 14 0] 48 [48 28 27 1 0] 49 [49 9 0] 50 [50 4 3 2 0] 51 [51 6 3 1 0] 52 [52 3 0] 53 [53 6 2 1 0]