User guide

45 Mbps Backhaul User Guide
Issue 3, December 2004 Page 19 of 113
4.1.4 Aggregate Ethernet throughput rate v maximum link loss
The equipment capability is given in Table 2. It gives the Ethernet throughput rate vs link loss for 45 Mbps
Backhaul in both modes. Adaptive modulation will ensure that the highest throughput that can be achieved
instantaneously will be obtained taking account of propagation and interference. The calculation of Equation 1
needs to be performed to judge whether a particular link can be installed. When the link has been installed web
pages provide information about the link loss currently measured by the equipment both instantaneously and
averaged. The averaged value will require maximum seasonal fading to be added and then the radio reliability
of the link can be computed.
Aggregate Ethernet Throughput Rate
(Mbps)
1
Maximum path
budget
2
(dB)
0-5km
(0-3 miles)
Mode
0-40km
(0-25 miles)
Mode
0-100km
(0-62 miles)
Mode
0-200km
(0-124 miles)
Mode
33.75
31.59
28.46
24.43
138.1
28.92
27.07
24.39
20.94
142.8
25.71
24.06
21.68
18.61
144.7
19.28
18.05
16.26
13.96
150.1
12.86
12.03
10.84
9.30
154.6
8.57
8.02
7.23
6.20
159.2
6.43
6.02
5.42
4.65
161.3
3.21
3.01
2.71
2.33
166.5
Table 2 Aggregate Ethernet throughput rate v maximum link loss
The full calculation is relatively complicated, and so a link estimator tool is available that calculates the radio
propagation and reliability of NLOS links using the 45 Mbps Backhaul equipment.
4.2 Collocating Backhauls
The Canopy 45 Mbps Backhaul can be collocated on the same mast or tower or building as other Canopy
modules operating in the 5.7 GHz frequency band. Following only three design rules will often give full
performance. Additional interference mitigation design may be needed in some cases, depending on the RF
environment.
1
Throughput based on 1518 Byte Ethernet Packets on a symmetrical link.
2
AMOD link margin of 1.5 dB applied.