LTE Signaling
R&S
®
CMW-KM5xx/-KS5xx
54
User Manual 1173.9628.02 ─ 16
2.2.14.1
Fixed CQI Channels
For fixed CQI channels, option R&S CMW-KS510 is required.
The downlink channel is configured via a set of parameters:
●
Channel bandwidth
●
Number of allocated Resource Blocks (RB)
●
Position of the first allocated RB
●
CQI index
All parameters except the channel bandwidth can be configured individually for each
downlink subframe (TTI) of a radio frame.
The allocated resource blocks are contiguous and the position of the first RB can be
configured. The configuration rules are the same as for user-defined downlink chan-
nels, see
chapter 2.2.13.1, "Supported Number of RB / Position of First RB (DL)"
The CQI index determines also the modulation scheme and the channel code rate. The
code rate is defined as the number of downlink information bits (including CRC bits)
divided by the number of physical channel bits on the PDSCH. The relation is defined
in 3GPP TS 36.213, table 7.2.3-1 as follows.
CQI Index
Modulation Scheme
Target Code Rate
1
QPSK
0.07617
2
0.11719
3
0.18848
4
0.30078
5
0.43848
6
0.58789
7
16-QAM
0.36914
8
0.47852
9
0.60156
10
64-QAM
0.45508
11
0.55371
12
0.65039
13
0.75391
14
0.85254
15
0.92578
The modulation scheme is selected automatically according to the table. Indirectly, the
table also determines the transport block size. The transport block size is selected
automatically so that the resulting effective channel code rate approaches the listed
General Description
深圳德标仪器
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