ASCOM VoWiFi System System Description page 13

System Description
Ascom VoWiFi System
The 802.11n standard defines Modulation and Coding Scheme (MCS), which is combinations
of modulation, Forward Error Correction (FEC) coding, and number of spatial streams. The
maximum data rate depends on the MCS, channel bandwidth, and GI length. There are 77
MCS values from 0 to 76. The first 32 MCSs are shown below. The rest are mixed
combinations that can be used to modulate two to four streams. 802.11n stations must
support values 0–7, and 802.11n APs must support MCS values 0–15.
MCS Number of
Index streams
0 1
1 1
2 1
3 1
4 1
5 1
6 1
7 1
8 2
9 2
10 2
11 2
12 2
13 2
14 2
15 2
16 3
17 3
18 3
19 3
20 3
21 3
22 3
23 3
24 4
25 4
26 4
27 4
28 4
29 4
30 4
31 4
802.11n is backwards compatible with existing 802.11a/b/g networks (legacy networks).
However, mixing 802.11n devices with legacy devices will result in a significant reduction in
throughput for the 802.11n devices.
7 September 2011 / Ver. G
Modulation and Data Rate (Mbps)
FEC Coding 20 MHz Channel
GI=800 ns GI=400 ns GI=800 ns GI=400 ns
BPSK 1/2 6.50
QPSK 1/2 13.00
QPSK 3/4 19.50
16-QAM 1/2 26.00
16-QAM 3/4 39.00
64-QAM 2/3 52.00
64-QAM 3/4 58.50
64-QAM 5/6 65.00
BPSK 1/2 13.00
QPSK 1/2 26.00
QPSK 3/4 39.00
16-QAM 1/2 52.00
16-QAM 3/4 78.00
64-QAM 2/3 104.00
64-QAM 3/4 117.00
64-QAM 5/6 130.00
BPSK 1/2 19.50
QPSK 1/2 39.00
QPSK 3/4 58.50
16-QAM 1/2 78.00
16-QAM 3/4 117.00
64-QAM 2/3 156.00
64-QAM 3/4 175.50
64-QAM 5/6 195.00
BPSK 1/2 26.00
QPSK 1/2 52.00
QPSK 3/4 78.00
16-QAM 1/2 104.00
16-QAM 3/4 156.00
64-QAM 2/3 208.00
64-QAM 3/4 234.00
64-QAM 5/6 260.00
Data Rate (Mbps)
40 MHz Channel
7.20 13.50
14.40 27.00
21.70 40.50
28.90 54.00
43.30 81.00
57.80 108.00
65.00 121.50
72.20 135.00
14.40 27.00
28.90 54.00
43.30 81.00
57.80 108.00
86.70 162.00
115.60 216.00
130.00 243.00
144.40 270.00
21.70 40.50
43.30 81.00
65.00 121.50
86.70 162.00
130.00 243.00
173.30 324.00
195.00 364.00
216.70 405.00
28.90 54.00
57.80 108.00
86.70 162.00
115.60 216.00
173.30 324.00
231.10 432.00
260.00 486.00
288.90 540.00
TD 92313EN
15.00
30.00
45.00
60.00
90.00
120.00
135.00
150.00
30.00
60.00
90.00
120.00
180.00
240.00
270.00
300.00
45.00
90.00
135.00
180.00
270.00
360.00
405.00
450.00
60.00
120.00
180.00
240.00
360.00
480.00
540.00
600.00
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