CDMA2000 Generator
R&S
®
CMW-KG8xx/-KM8xx/-KS8xx
930
User Manual 1173.9511.02 ─ 11
structed from a
N x N
Hadamard matrix, generated by means of the following recursive
procedure defined in 3GPP2 C.S0002:
For the spreading operation the binary symbols of the Walsh function are mapped as
follows:
0
is mapped to
+1
and
1
is mapped to
-1
.
Orthogonal Variable Spreading Factor (OVSF) codes provide an alternative scheme of
generating codes that preserve orthogonality between channels. They are derived from
a hierarchical tree:
Channelization codes are used to separate different physical channels of the same
carrier frequency, cell and user. They are defined in terms of the spreading factor (SF)
and a code number
m
ranging from
0
to SF
–1
. The codes c
SF,m
are called Orthogonal
Variable Spreading Factor (OVSF) codes and are derived from a hierarchical tree:
The following rule has to be observed for assignment of channelization codes in order
to avoid code conflicts: Within each branch only one code can be used at the same
time. This means:
●
1. Other codes on the path between the code and the root of the tree must not be
used.
●
2. Codes in sub-branches of the code (to the right of the code) must not be used.
For an example see the figure below. The red parts are blocked when c
4,3
is used.
General Description
深圳德标仪器
135-1095-0799