AN2254 Freescale Semiconductor / Motorola, AN2254 Datasheet - Page 4

• Manufacturer Part Number: AN2254
• Description: Scrambling Code Generation for WCDMA
• Manufacturer: Freescale Semiconductor / Motorola

Scrambling Codes for WCDMA
These 25-degree generator polynomials are truncated to the 10 ms frame length that results in 38400 chips at the
rate of 3.84 Mcps. The long scrambling sequences, c
sum of 38400 chip segments of the two binary m-sequences. The two binary m-sequences are constructed using the
following primitive polynomial over GF(2), as show in Figure 3. Furthermore, sequence c
delayed version of sequence c
Let x, and y be the two m-sequences that are constructed from primitive polynomials of Equation 2 and Equation
3, respectively. The resulting sequences constitute segments of a set of Gold sequences. Now, let n
24-bit binary representation of the scrambling sequence number n with n
sequence depends on the chosen scrambling sequence number n and is denoted as x
x
constructed as follows:
4
n
(i) and y(i) denote the i:
1.
2.
Initial conditions:
Recursive definition of subsequent symbols:
MSB
Scrambling Code Generation for WCDMA on the StarCore™ SC140/SC1400 Cores, Rev. 1
th
symbol of the sequences x
1,n
Figure 3. Uplink Long Scrambling Code Generator
.
X
x n (0) = n 0 , x n (1) = n 1 , ..., x n (22) = n 22 , x n (23) = n 23 , x n (24) = 1
y(0) = y(1) = ... = y(23) = y(24) = 1
X
25
25
+ X
+ X
3
3
+ 1
+ X
2
+ X + 1
1,n
n
and c
and y, respectively. The m-sequences x
2,n
, are constructed from a position-wise modulo 2
0
LSB
as the least significant bit. The x
n
in the sequel. Furthermore, let
2,n
Freescale Semiconductor
is a 16,777,232 chip
n
and y are
C
C
23
1,n
2,n
... n
Equation 2
Equation 3
Equation 4
Equation 5
0
be the