User guide

Deploying a Remote AP Engineering Your RF Communications
150
pmp-0229 (Mar 2013)
Figure 43: Double-hop backhaul links
However, the BHSs can be co-located at the same site only if one is on a different frequency band
range from that of the other or one of the following conditions applies:
• They are vertically separated on a structure by at least 100 feet (30 m).
• They are vertically separated on a structure by less distance, but either
o an RF shield isolates them from each other.
o the uplink and downlink data parameters and control channels match (the Downlink
Data parameter is set to 50%).
The constraints for co-located modules in the same frequency band range are to avoid self-
interference that would occur between them. Specifically, unless the uplink and downlink data
percentages match, intervals exist when one is transmitting while the other is receiving, such that
the receiving module cannot receive the signal from the far end.
The interference is less a problem during low throughput periods and intolerable during high.
Typically, during low throughput periods, sufficient time exists for the far end to retransmit
packets lost because of interference from the co-located module.
Deploying a Remote AP
In cases where the subscriber population is widely distributed, or conditions such as geography
restrict network deployment, you can add a Remote AP to
• provide high-throughput service to near LoS business subscribers.
• reach around obstructions or penetrate foliage with non-LoS throughput.
• reach new, especially widely distributed, residential subscribers with broadband service.
• pass sync to an additional RF hop.
In the remote AP configuration, a remote AP is co-located with an SM. The remote AP distributes
the signal over the last mile to SMs that are logically behind the co-located SM. A remote AP
deployment is illustrated in Figure 44.
CMM
BH
-M-
AP
BH
-S-
CMM
BH
-S-
CMM
BH
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CMM
POP