De-interleaving stream – Wavecom W-BitView V2.5.00 User Manual

Page 40

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34

Function Library

BitView Manual V2.5.00 WAVECOM W-BV

Function:
Change the bit order according to the settings of Block length, Frame length and Interleaving
distance
. The easiest way to understand the de-interleaving function is a closer look at the examples
below (imagine that the bit stream is written horizontally into the buffer and read out vertically):

Example:

#1

#2

Block Length

12

16

Frame Length

1

2

Interleaving Distance

3

2

Input

000111000111

0011001111100010

Matrix

000
111
000
111

00 11
00 11
11 10
00 10

Output

010101010101

0000110011111010

De-Interleaving Stream

In: Bit stream
Out: Bit stream

Function:
Change the bit order according to the settings of Offset into Bit Buffer, Output frame length and
Interleaving distance.
The Offset into Bit Buffer tells the function where to start the de-interleaving function. Is Offset into
Bit Buffer
for example set to 3, then the first 3 bits will not be used for calculation of the output data.
According to the Output frame length setting, the output data will be less than the input data. The
easiest way to understand the de-interleaving stream function is a closer look at the example below
(imagine that the bit stream is written horizontally into the buffer and read out vertically):
Example 1:
Offset into Bit Buffer = 0
Interleaving distance = 15
Output frame length = 4

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