Initial scrambler state, specified as an integer in the interval [1, 127], or the
corresponding binary-valued column vector of length 7.
Section 17.3.5.5 of [1]
specifies the scrambling and descrambling process applied to the transmitted data. The
header and data fields that follow the scrambler initialization field (including data
padding bits) are scrambled by XORing each bit with a length-127 periodic sequence
generated by the polynomial S(x) = x7
+ x4 + 1. The octets of the PSDU are placed into a bit stream, and, within each
octet, bit 0 (LSB) is first and bit 7 (MSB) is last. This figure demonstrates the
sequence generation and XOR operation.
Conversion from integer to bits uses left-MSB orientation. For example,
initializing the scrambler with decimal 1
, the bits map to these
elements.
Element | X7 | X6 | X5 | X4 | X3 | X2 | X1 |
---|
Bit Value | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
To generate the bit stream equivalent to a decimal, use the int2bit
function. For example, for decimal
1
:
int2bit(1,7)'
ans =
0 0 0 0 0 0 1
Example: [1; 0; 1; 1; 1; 0; 1]
conveys the scrambler
initialization state of 93 as a binary-valued column vector.
Data Types: double