User's Manual
AppendixD:GlossaryofTerms
3Com®AirProtectPlannerUserGuide
114
MCS
Modulation and Coding
Schemes
IEEE 802.11n draft 2.0 defines 77 MCS based on
the modulation technique, coding rate, number of
spatial streams, channel width, and guard
interval. The mandatory settings of 20 MHz
channel width, 800 ns guard interval, and up to
two spatial streams gives a total of 16 mandatory
schemes (MCS 0 to 15).
Frame aggregation
Frame aggregation is introduced in IEEE 802.11n
for improving the protocol efficiency. Aggregation
is defined at two levels: Medium Access Control
(MAC) and physical (PHY) layers. At the MAC
layer, Multiple MAC Service Data Units (MSDUs) or
subframes are aggregated and an aggregated
MSDU (A-MSDU) is delivered to the PHY layer for
transmission. The maximum A-MSDU size can be
set to 4KB or 8KB; the maximum MSDU size
carried in each subframe is limited to 2304 bytes.
At the PHY layer, Multiple Protocol Data Units
(MPDUs) or subframes can be aggregated into an
aggregated MPDU (A-MPDU). The maximum size
of an A-MPDU is 64 KB or 64 subframes,
whichever limit is reached first. The maximum
MPDU size carried in each subframe of an A-MPDU
is limited to 4065 bytes.
Regulatory Domain
Compliance
Different countries have regulatory agencies
permitting a select number of channels for device
protocols. Hence, the power values of the devices
placed on the floor map will operate only on those
power values that match that of the respective
country where you are planning.
While specifying the desired power range for each
protocol, ensure that the values are complaint
with the regulatory domain for a particular
country for which you are performing planning.
If you create a .spm file in one location and forget
to send the device information along with the
.spm to another location, then the Client at the
second location will not be able to view the device
information of the previous location. In such a
case, Planner assigns the default device, as
defined by you, in the .spm. If this device has
power values conflicting with the regulatory
domain compliance of the region, then Planner
assigns the factory default device, which is
regulatory domain complaint for any region.