SkyHopper PRO - PTP (Point-to-Point) Configuration; PTP Link Step-by-Step Configuration

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6 TDMA
Time Division Multiple Access(TDMA) is achannel access methodfor shared medium networks. It allows several units to share
the samefrequency channelby dividing the signal into different time slots. The units transmit and receive on the same frequency
in a synchronized manner. Every unit transmits in its own dedicated time slots. On the other time slots said unit receives the trans-
mission sent by the other units that are members of the same network (which are also transmitting on their own dedicated slots).
TDMA requires a synchronization system. The system is synchronized internally, externally or via GPS (synchronization varies
between topologies and method used).
The SkyHopper PRO unit uses TDMA regardless of the application type, PTP or PTMP.
7 PTP (Point-to-Point)
A PTP network is a radio link between 2 SkyHopper PRO units. The conguration (frequency and prole) of both units must be
the same with only one difference - one unit is congured as a Remote Unit while the other unit is congured as a Controller Unit.
The Remote Unit works with its internal clock and synchronizes the Controller Unit. After power-up, the Remote Unit starts trans-
mitting regardless of link status. The Controller Unit however, does not transmit and stays in Rx mode, trying to acquire synchroni-
zation by nding a preamble (synchronization pattern). As soon as the Controller Unit recognizes the pattern, it starts to transmit
according to its allocated time slot.
The transmission bandwidth ratio is predened as part of the prole conguration. It can be symmetric when full duplex commu-
nications are required (50% to each unit) or asymmetric up to 10% to one unit (remote or controller) and 90% to the other unit.
Downlink 10% = 0.6 Mbps
Downlink 90% = 5.4 Mbps
Uplink 10% = 0.6 Mbps
Uplink 90% = 5.4 Mbps
Aerial Unit
Ground Unit
Total
Network BW
6 Mbps
TX TX TX TX
Power
up
Remote Unit
Controller Unit
t
TX TX TX
Power
up
Preamble
Received
t
Figure 5: Transmit frames of the remote unit and controller unit from Power Up
► Note: A viewer unit acts like a Controller unit but with one major change, it does not transmit
and only receives.
7. 1. PTP Link Step-by-Step Conguration
In order to build a PTP link, two SkyHopper PRO units are required. One unit acts as a remote unit, while the other as a
controller unit.
1. Connect antennas to RF1 and RF2 connectors, and power up the unit.
! CAUTION – Powering up a unit without connecting the antennas can cause irreparable damage to the unit.
2. Connect the unit to a PC using a standard Ethernet Cat 5 cable.