Product Manual

Applications | 65
Aprisa SR+ Product Description 1.5.0
Multi-hop Daisy Chain Repeaters in LBS Mode Application
This application is used for daisy chain repeaters when remote stations are very far from base station
coverage. Daisy chain repeaters can only be used in LBS channel access mode (and future release in AR
mode).
In the figure example below, the Base Station can communicate with any of the far remotes via the daisy
chain repeaters. The SCADA master will communicate with RTU 2 using a source and destination IP address
and the underlining SCADA protocol.
On the downstream, the SCADA master would like to communicate with RTU-2 and sends a packet
destined to RTU-2 (using RTU 2 destination address). This packet received by the Base Station will then
broadcast OTA to Repeater 1.
Repeater 1 will store-and-forward the received packet and re-transmit the packet to Repeater 2 and back
to the Base Station, which will drop the duplicate packet as this packet is its own forward.
Repeater 2 will store-and-forward the packet to the local Ethernet port to RTU 3 (which will drop the
packet due to destination address mismatch) and it will also re-transmit the packet OTA to Repeater 3,
Remote 1 and back to Repeater 1, which will drop the duplicate packet as this packet is its own forward.
Remote-1 will forward the packet to its local Ethernet port and RTU-1 will drop the packet due to
destination address mismatch.
Repeater 3 will store-and-forward and re-transmit the packet OTA to Remote-2 and back to Repeater 2,
which will drop the packet as duplicate packet as this packet is its own forward.
Remote 2 will then forward the packet to its local Ethernet port and RTU 2 as the destined address which
will process the packet accordingly.
On the upstream, RTU 2 will send a packet to the SCADA master, and the radio network from Remote 2
sending a unicast packet destined to Base Station which will act with the same process mechanism as
described above for downstream path.