802.11u Physical Rates
What frequency bands does 802.11u support for physical rates?
802.11u primarily operates on the 2.4 GHz and 5 GHz bands as defined by underlying 802.11 PHYs.
Does 802.11u define new physical layer rates?
No, 802.11u is an amendment focused on network interworking, using existing PHY rates from standards like 802.11a/b/g/n.
How does 802.11u affect rate adaptation algorithms?
It does not directly modify rate adaptation but supports features that improve network selection based on PHY rates.
Are the physical rates in 802.11u dependent on underlying 802.11 standards?
Yes, 802.11u uses physical rates defined by the underlying standard (e.g., 6-54 Mbps for 802.11a).
What modulation schemes correspond to physical rates in 802.11u?
Modulation schemes like BPSK, QPSK, 16-QAM, and 64-QAM from the underlying PHY standards are used.
Can 802.11u devices dynamically change rates during communication?
Yes, rate adaptation is inherited from underlying PHY implementations.
How does 802.11u improve throughput with physical rates?
By enabling intelligent network selection and interworking, devices may connect to networks supporting optimal PHY rates.
Does 802.11u specify channel widths for physical rates?
No, channel widths are defined by the underlying PHY, such as 20 MHz or 40 MHz in 802.11n.
Are MIMO and beamforming part of 802.11u physical rate enhancements?
No, these features are part of later standards like 802.11n/ac, not 802.11u.
How does 802.11u interact with Quality of Service (QoS) regarding physical rates?
While 802.11u manages network access and selection, QoS and rate prioritization are handled by other amendments like 802.11e.
Can 802.11u enable faster physical rates in public networks?
Indirectly, by allowing seamless roaming to networks that support higher PHY rates.
What is the maximum physical rate supported when using 802.11u?
It depends on the underlying PHY; for example, up to 54 Mbps in 802.11a/g or higher in 802.11n/ac.
How are physical rates advertised in 802.11u?
Through management frames from the underlying PHY standard, not specifically by 802.11u.
Does 802.11u require new hardware for physical rate support?
No, it leverages existing hardware compliant with underlying PHY standards.
Are physical rates affected by network interworking features of 802.11u?
Physical rates themselves are not affected but interworking can influence which network a device chooses based on rates.
How do physical rates in 802.11u affect roaming?
Devices may select networks offering higher physical rates, improving user experience during roaming.
Does 802.11u support dual-band operation affecting physical rates?
Yes, through underlying dual-band capable PHYs, enabling operation in 2.4 GHz and 5 GHz bands.
What factors influence physical rate selection in 802.11u networks?
Signal quality, interference, network policies, and device capabilities all play a role.
Where can I find detailed physical rate specifications for 802.11u?
In the underlying PHY standards referenced by 802.11u such as 802.11a/b/g/n documents.
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