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CDMA2000 Measurements
R&S
®
CMW-KM8xx/-KS8xx
730
User Manual 1173.9511.02 ─ 12
Radio Configuration
Spreading Rate
Modulation
5
3
H-PSK
6
3
H-PSK
The R&S
CMW supports only spreading rate 1 (also called 1x). Spreading rate 3 (3x) is
not supported.
For spreading rate 1 the reverse CDMA channel uses a carrier with a chip rate of
1.2288 Mcps.
5.2.5.3
Channelization
CDMA2000 channels are spread using orthogonal Walsh functions W
n
N
defined in
terms of the order N of the function and the index n ranging from 0 to –1. This index is
also called channelization code number. The Walsh functions are serially constructed
from a N x N Hadamard matrix, generated by means of the following recursive proce-
dure 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:
The OVSF spreading factor SF corresponds to the Walsh function order N. For a given
spreading factor SF, Walsh codes and OVSF codes can be derived from each other
via the binary representation of the channelization code numbers. The Walsh code with
code number n is equal to the OVSF code with code number m, where m has the
General Description
深圳德标仪器
135-1095-0799