802.11r Physical Rates
What are physical rates in 802.11r?
Physical rates refer to the data transmission speeds at the physical layer defined for 802.11r networks.
Does 802.11r specify new physical rates compared to previous standards?
No, 802.11r uses the same physical rates as 802.11a and 802.11g but optimizes roaming processes.
How do physical rates affect fast roaming in 802.11r?
Higher physical rates enable faster exchange of authentication and reassociation frames, reducing roaming latency.
Are physical rates dynamically adjusted in 802.11r?
Yes, 802.11r devices adapt physical rates based on signal quality and environmental factors during roaming.
What modulation schemes correspond to 802.11r physical rates?
802.11r inherits OFDM modulation schemes from 802.11a/g, including BPSK, QPSK, 16-QAM, and 64-QAM.
Is 802.11r limited to certain frequency bands for physical rates?
No, 802.11r operates in both 2.4 GHz and 5 GHz bands, supporting corresponding physical rates.
How does 802.11r handle rate adaptation during fast BSS transition?
Rate adaptation algorithms select optimal physical rates quickly to maintain connection quality during roaming.
Do physical rates impact battery consumption in 802.11r devices?
Yes, higher physical rates can reduce transmission time, potentially saving battery life.
Are there regulatory constraints affecting physical rates in 802.11r?
Physical rates comply with regional regulations on power and channel usage but are not uniquely restricted by 802.11r.
Can physical rates cause roaming failures in 802.11r networks?
Improper rate adaptation or low rates may increase roaming time, but 802.11r mechanisms aim to minimize such risks.
Are physical rates the same for control and data frames in 802.11r?
Control frames often use lower rates for robustness, while data frames use higher rates for throughput.
How does 802.11r support legacy clients with different physical rates?
802.11r networks support a range of rates to accommodate both legacy and 802.11r-capable clients.
Does 802.11r specify minimum physical rates for fast roaming?
No explicit minimum rates are mandated, but practical implementation favors higher rates for speed.
Is MIMO technology used in 802.11r to enhance physical rates?
802.11r itself doesn’t define MIMO but can operate alongside 802.11n/ac standards that use MIMO.
How are physical rates negotiated during the reassociation process in 802.11r?
Physical rates are negotiated based on AP and client capabilities and current radio conditions during reassociation.
Do physical rates affect the security handshake in 802.11r?
Physical rates impact the speed of handshake frame exchanges but do not affect security mechanisms directly.
Can 802.11r physical rates vary across different vendors?
Physical rates follow standard modulation and coding schemes, but vendor optimizations may affect actual performance.
Are there tools to measure physical rates in 802.11r deployments?
Yes, network analyzers and Wi-Fi testing tools can monitor and analyze physical rates during operation.
How does 802.11r enhance user experience through physical rates?
By optimizing physical rates during roaming, 802.11r reduces latency and improves throughput continuity.
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