Motorola PTP 400 Series - Manual (Page 37)

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4 Product Architecture
The PTP 400 Series Bridge consists of an identical pair of unit’s deployed one at each end of
the link. The radio link operates on a single frequency channel in each direction using Time
Division Duplex (TDD). One unit is deployed as a master and the other as a slave. The
master unit takes responsibility for controlling the link in both directions.
The non-line-of-sight (NLOS) aspects of the product are provided by Multiple-Input Multiple-
Output (MIMO), coupled with Orthogonal Frequency Division Multiplexing (OFDM)
modulation.
The PTP 400 Series Bridge has been developed to operate within a selection of frequency
bands.
The current product range supports:
• USA 4.9 GHz National Public Safety Band (4.940-4.990 GHz) - 49400
• ETSI 5.4 GHz license exempt band B (5.470-5.725 GHz) - 54400
• ETSI 5.8 GHz license exempt band C (5.725-5.850 GHz) and the USA 5 GHz ISM band
(5.725-5.850 GHz) - 58400
The PTP 400 Series Bridge has been designed to coexist with other users of the band in an
optimal fashion using a combination of Transmit Power Control (TPC), Planned Frequency
Allocation or Dynamic Frequency Selection (DFS) and antenna beam shape.
In order to maintain link availability, the product employs adaptive modulation techniques that
dynamically reduce the data rate in severe or adverse conditions. To the data network the
PTP 400 Series Bridge is implemented as a learning bridge. A learning bridge builds up a
picture of which addresses are connected to which port. This means that it will not bridge a
packet if it knows that the destination address is connected to the same port on which the
bridge saw the packet. Figure 10 illustrates the PTP 400 Series Bridge layer diagram.