
•
RIFS (response interframe spacing). When a station waits for a response from
the destination station, the latter waits for a RIFS time of 26 μs before trans-
mitting its response. This RIFS is also used by the stations to change from
sending mode to receiving mode.
•
EIFS (extended interframe spacing). The EIFS corresponds to the maximum
time that is necessary for a station to transmit. It corresponds to the sum of
data frame circulation time in non-ROBO (robust OFDM) mode with its vari-
ous delimiters, of priority intervals of the CIFS, RIFS, and EFG (End of Frame
Gap), which is 1,695 μs. The EIFS time is also used to determine how long the
medium is occupied after a collision and for the FEC (forward error control)
process, it used to check whether or not there are errors in the received data.
The frame length measurement is not determined in a fully robust manner
when listening to the medium using the VCS method.
Table 3.4 summarizes the IFS and time slot values of HomePlug 1.0 and
HomePlug AV.
The AV version of the HomePlug standard has a number of additional IFS com-
pared with version 1.0.
•
AIFS (allocation interframe spacing). Used to separate the TDMA and
CSMA/CA allocation areas from the services reserved for the HomePlug AV
standard.
•
B2BIFS (beacon to beacon interframe spacing). Used to separate the various
beacon frames in the specific TDMA allocation area from HomePlug AV bea-
con frames.
•
BIFS (burst interframe spacing). Used to separate the various MPDU frames
in the case of the bursting type network mode with access to the CSMA/CA
medium.
•
CIFS AV (contention distributed interframe spacing version AV). Used by the
stations that wish to access the medium in order to separate the transmission
Transmission Channel Functionalities 41
Table 3.4 IFS and Time Slot Values According to the
Physical Layer
Homeplug 1.0 Homeplug AV
Time slot 35.84 μs 35.84 μs
CIFS 35.84 μs 100 μs
RIFS 26 μs
30 to 160 μs
140 μs (by default)
EIFS 1,695 μs 2,920 μs
AIFS — 30 μs
B2BIFS — 85 μs
BIFS — 20 μs
CIFS AV — 100 μs
RGIFS — 80 μs
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