802.11h Physical Rates
What are physical rates in the context of 802.11h?
Physical rates refer to the raw data transmission speeds supported at the physical layer of 802.11h devices.
Does 802.11h define new physical rates?
No, 802.11h primarily focuses on regulatory compliance (DFS and TPC) and uses the physical rates defined in 802.11a.
What frequency bands does 802.11h operate in?
802.11h operates mainly in the 5 GHz band, which supports the physical rates defined in 802.11a.
What are typical physical data rates supported under 802.11h?
Rates range from 6 Mbps to 54 Mbps using OFDM modulation as defined in 802.11a.
How does Transmit Power Control (TPC) affect physical rates?
TPC adjusts transmit power but does not directly change physical rates; however, lower power can affect signal quality and thus throughput.
Are physical rates in 802.11h affected by Dynamic Frequency Selection (DFS)?
DFS selects channels to avoid radar, but physical rates on those channels remain consistent with 802.11a standards.
Can devices dynamically change physical rates in 802.11h networks?
Yes, rate adaptation algorithms adjust the physical rate based on link quality and interference.
Does 802.11h specify rate adaptation mechanisms?
No, rate adaptation is handled by implementations and is not defined by 802.11h itself.
Are there any rate limitations imposed by 802.11h regulations?
No direct rate limitations, but power restrictions can indirectly affect achievable throughput.
How do power constraints in 802.11h impact physical rates?
Reduced transmit power may lead to lower signal-to-noise ratio, causing devices to select lower physical rates for reliability.
Are all 802.11a rates supported in 802.11h?
Yes, 802.11h supports the full range of OFDM rates defined in 802.11a.
Does channel switching under DFS impact physical rates?
Channel switching can cause temporary rate drops due to re-association and link adaptation.
Are MIMO or newer physical rate technologies part of 802.11h?
No, 802.11h predates MIMO and focuses on 5 GHz regulatory mechanisms.
Can physical rates be different in various regulatory domains for 802.11h?
The rates are consistent, but allowed transmit power varies by region, impacting effective throughput.
How do environmental factors affect 802.11h physical rates?
Interference, distance, and obstacles influence signal quality, prompting rate adaptation for best performance.
Is there a minimum physical rate defined in 802.11h?
The minimum rate follows 802.11a standards, typically 6 Mbps.
Are control and management frames sent at different physical rates in 802.11h?
Control frames often use lower robust rates to ensure delivery, consistent with 802.11a practices.
Does 802.11h impact data throughput?
Indirectly, through power control and channel management, but it does not specify throughput enhancements.
Topics in this section,
Modulation |
BW |
Tsc |
FSP=BW/Tsc |
Tdata=1/FSP |
GI=Tdata/4 |
Symbol=Tdata+GI |
1/Symbol |
Bits/Symbol |
Code rate |
Usable sc |
Rate |
|---|---|---|---|---|---|---|---|---|---|---|---|
BPSK |
5 |
64 |
78.125 |
12.8 |
3.2 |
16 |
0.0625 |
1 |
1/2 |
48 |
1.5 |
BPSK |
5 |
64 |
78.125 |
12.8 |
3.2 |
16 |
0.0625 |
1 |
3/4 |
48 |
2.25 |
QPSK |
5 |
64 |
78.125 |
12.8 |
3.2 |
16 |
0.0625 |
2 |
1/2 |
48 |
3 |
QPSK |
5 |
64 |
78.125 |
12.8 |
3.2 |
16 |
0.0625 |
2 |
3/4 |
48 |
4.5 |
16-QAM |
5 |
64 |
78.125 |
12.8 |
3.2 |
16 |
0.0625 |
4 |
1/2 |
48 |
6 |
16-QAM |
5 |
64 |
78.125 |
12.8 |
3.2 |
16 |
0.0625 |
4 |
3/4 |
48 |
9 |
64-QAM |
5 |
64 |
78.125 |
12.8 |
3.2 |
16 |
0.0625 |
6 |
2/3 |
48 |
12 |
64-QAM |
5 |
64 |
78.125 |
12.8 |
3.2 |
16 |
0.0625 |
6 |
3/4 |
48 |
13.5 |
BPSK |
10 |
64 |
156.25 |
6.4 |
1.6 |
8 |
0.125 |
1 |
1/2 |
48 |
3 |
BPSK |
10 |
64 |
156.25 |
6.4 |
1.6 |
8 |
0.125 |
1 |
3/4 |
48 |
4.5 |
QPSK |
10 |
64 |
156.25 |
6.4 |
1.6 |
8 |
0.125 |
2 |
1/2 |
48 |
6 |
QPSK |
10 |
64 |
156.25 |
6.4 |
1.6 |
8 |
0.125 |
2 |
3/4 |
48 |
9 |
16-QAM |
10 |
64 |
156.25 |
6.4 |
1.6 |
8 |
0.125 |
4 |
1/2 |
48 |
12 |
16-QAM |
10 |
64 |
156.25 |
6.4 |
1.6 |
8 |
0.125 |
4 |
3/4 |
48 |
18 |
64-QAM |
10 |
64 |
156.25 |
6.4 |
1.6 |
8 |
0.125 |
6 |
2/3 |
48 |
24 |
64-QAM |
10 |
64 |
156.25 |
6.4 |
1.6 |
8 |
0.125 |
6 |
3/4 |
48 |
27 |
BPSK |
20 |
64 |
312.5 |
3.2 |
0.8 |
4 |
0.25 |
1 |
1/2 |
48 |
6 |
BPSK |
20 |
64 |
312.5 |
3.2 |
0.8 |
4 |
0.25 |
1 |
3/4 |
48 |
9 |
QPSK |
20 |
64 |
312.5 |
3.2 |
0.8 |
4 |
0.25 |
2 |
1/2 |
48 |
12 |
QPSK |
20 |
64 |
312.5 |
3.2 |
0.8 |
4 |
0.25 |
2 |
3/4 |
48 |
18 |
16-QAM |
20 |
64 |
312.5 |
3.2 |
0.8 |
4 |
0.25 |
4 |
1/2 |
48 |
24 |
16-QAM |
20 |
64 |
312.5 |
3.2 |
0.8 |
4 |
0.25 |
4 |
3/4 |
48 |
36 |
64-QAM |
20 |
64 |
312.5 |
3.2 |
0.8 |
4 |
0.25 |
6 |
2/3 |
48 |
48 |
64-QAM |
20 |
64 |
312.5 |
3.2 |
0.8 |
4 |
0.25 |
6 |
3/4 |
48 |
54 |
Reference links