802.11 Protocol Architecture
FIGURE 2.9
EIFS Reference Chart
802.11 FH
Section 14.9 FH PHY characteristics:
aSlotTime:
50 µs
aSIFSTime:
28 µs
aPreambleLength:
96 µs
aPLCPheaderLength:
32 µs
EIFS:
28 + 112 + 96 + 32 + 28 + 100 = 396 µs
802.11 DS
Section 15.3.3 DS PHY characteristics (long preamble):
aSlotTime:
20 µs
aSIFSTime:
10 µs
aPreambleLength:
144 µs
aPLCPheaderLength:
48 µs
EIFS:
10 + 112 + 144 + 48 + 10 + 40 = 364 µs
802.11a
Section 17.4.4 OFDM PHY characteristics:
aSlotTime:
9 µs
aSIFSTime:
16 µs
aPreambleLength:
20 µs
aPLCPheaderLength:
4 µs
EIFS:
16 + 112 + 20 + 4 + 16 + 18 = 186 µs
802.11b
Section 18.3.4 DS High Rate PHY characteristics (long preamble):
aSlotTime:
20 µs
aSIFSTime:
10 µs
aPreambleLength:
144 µs
aPLCPheaderLength:
48 µs
EIFS:
10 + 112 + 144 + 48 + 10 + 40 = 364 µs
or
Section 18.3.4 DS High Rate PHY characteristics (short preamble):
aSlotTime:
20 µs
aSIFSTime:
10 µs
aPreambleLength:
72 µs
aPLCPheaderLength:
24 µs
EIFS:
10 + 112 + 72 + 24 + 10 + 40 = 268 µs
802.11g
Section 19.8.4 OFDM Extended Rate PHY characteristics:
aSlotTime:
20 µs (long slot time)
aSIFSTime:
10 µs
aPreambleLength:
20 µs
aPLCPheaderLength:
4 µs
EIFS:
10 + 112 + 20 + 4 + 10 + 40 = 196 µs
or
Section 18.3.4 DS High Rate PHY characteristics (short preamble):
aSlotTime:
9 µs (short slot time)
aSIFSTime:
10 µs
aPreambleLength:
20 µs
aPLCPheaderLength:
4 µs
EIFS:
10 + 112 + 20 + 4 + 10 + 18 = 174 µs
In 802.11g basic service sets where legacy (NonERP) stations are
present, 20µs slot times are used for backwards compatibility.
