4RF Limited SRN0400025A ユーザーズマニュアル
16 | About the Radio
Aprisa SR User Manual
Product Overview
Network Coverage and Capacity
In a simple point-to-multipoint network, an Aprisa SR, configured as a base station, will communicate with
multiple remote units in a given coverage area. With a link range of up to 60 km a typical deployment will
have 30 – 50 remote stations attached to the base station. However, geographic features, such as hills,
mountains, trees and foliage, or other path obstructions, such as buildings, tend to limit radio coverage.
Additionally, geography may reduce network capacity at the edge of the network where errors may occur
and require retransmission. However, the Aprisa SR uses Forward Error Correction (FEC) which greatly
improves the sensitivity performance of the radio resulting in less retries and minimal reduction in
capacity.
multiple remote units in a given coverage area. With a link range of up to 60 km a typical deployment will
have 30 – 50 remote stations attached to the base station. However, geographic features, such as hills,
mountains, trees and foliage, or other path obstructions, such as buildings, tend to limit radio coverage.
Additionally, geography may reduce network capacity at the edge of the network where errors may occur
and require retransmission. However, the Aprisa SR uses Forward Error Correction (FEC) which greatly
improves the sensitivity performance of the radio resulting in less retries and minimal reduction in
capacity.
Ultimately, the overall performance of any specific network will be defined by a range of factors including
the geographic location, the number of remote stations in the base station coverage area and the traffic
profile across the network. Effective network design will distribute the total number of remote stations
across the available base stations to ensure optimal geographic coverage and network capacity.
the geographic location, the number of remote stations in the base station coverage area and the traffic
profile across the network. Effective network design will distribute the total number of remote stations
across the available base stations to ensure optimal geographic coverage and network capacity.
Remote Messaging
On start-up, the remote station transmits a registration message to the base stations which responds with
a registration response. This allows the base station to record the details of all the remote stations active
in the network.
a registration response. This allows the base station to record the details of all the remote stations active
in the network.
If a remote station cannot register with the base station after multiple attempts (RF LED flashing red)
within 10 minutes, it will automatically reboot. If a remote station has registered with the base station
but then loses communication, it will automatically reboot within 6 minutes.
within 10 minutes, it will automatically reboot. If a remote station has registered with the base station
but then loses communication, it will automatically reboot within 6 minutes.
There are two message types in the Aprisa SR network, broadcast messages and unicast messages.
Broadcast messages are transmitted by the base station to the remote stations and unicast messages are
transmitted by the remote station to the base station.
Broadcast messages are transmitted by the base station to the remote stations and unicast messages are
transmitted by the remote station to the base station.
All remotes within the coverage area will receive broadcast messages and pass them on to either the
Ethernet or serial interface. The RTU determines if the message is intended for it and will accept it or
discard it.
Ethernet or serial interface. The RTU determines if the message is intended for it and will accept it or
discard it.
Only the base station can receive the unicast messages transmitted from the remote station. Unicast
messages are ignored by other remote stations which may be able to receive them.
messages are ignored by other remote stations which may be able to receive them.