Cambium Networks cnWave, User Manual

Page: 85 / 248

System Planning 85
Perform a survey to identify all the obstructions (such as trees or buildings) in the path and to assess the
risk of interference. This information is necessary to achieve an accurate link feasibility assessment. The
60 GHz cnWave radios are designed to operate in Line-of-Sight (LoS) environments.
The 60 GHz cnWave radios operate at ranges from 15 m (49 ft) to 2000 m (1.2 miles). The operation of
the system depends on the frequency channel chosen.
Path loss
Path loss is the amount of attenuation the radio signal undergoes between the two ends of the link. The
path loss is the sum of the attenuation of the path if there were no obstacles in the way (Free Space Path
Loss), the attenuation caused by obstacles (Excess Path Loss) and a margin to allow for possible fading
of the radio signal (Fade Margin). The following calculation needs to be performed to judge whether a
particular link can be installed:
Table 34: Input details for the link calculation
Where: Is:
L
free_space
Free Space Path Loss (dB)
L
excess
Excess Path Loss (dB)
L
fade
Fade Margin Required (dB)
L
seasonal
Seasonal Fading (dB)
L
capability
Equipment Capability (dB)
At 60 GHz cnWave the oxygen absorption is a key component of the free space path loss and varies
substantially depending on the frequency channel selected. Use LINKPlanner to calculate the oxygen
absorption component for the required path and frequency channel.
Data network planning
This section describes factors to be considered when planning 60 GHz cnWave data networks.
60 GHz cnWave network can be deployed as point-to-point backhaul-bridge, Point-to-Multipoint
coverage network and mesh network that provide network rebound. Regardless of the network
topology, the underlining routing protocol between cnWave radios is always IPv6 with OpenR routing
protocol.
By default, the cnWave operates in IPv6 layer 3 network mode, requiring IPv6-based routing gears etc.
While underlying routing in the cnWave network relies on IPv6 OpenR routing, the network can be
designed to operate in pure IPv4 network mode, transporting layer 2 traffic (VLAN tagged and
untagged) with GRE tunnels built-in by the system.
There is no fundamental difference between configurations of PTP vs. PMP vs. Mesh because the
underlying routing mechanism of the cnWave network is always IPv6-based OpenR routing.
In a PTP network, you have one PoP DN and a CN to form a link. In a PMP network, you have one PoP DN
and multiple CNs (up to 30 CNs if V5000 is used) to form a PMP cluster. You can have multiple PMP
clusters to form a coverage area network.