User's Manual Part 1

20
4.1.4 Aggregate Ethernet throughput rate v maximum link loss
The equipment capability is given in Table 3. It gives the Ethernet throughput rate vs link loss
for OS-Gemini 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)
2
Maximum path budget
3
(dB)
0-5km Mode 0-40km Mode 0-130km Mode
33.61 31.46 27.02 138.1
28.81 26.97 23.16 142.8
25.61 23.97 20.58 144.7
19.21 17.98 15.44 150.1
12.81 11.99 10.29 154.6
8.54 7.99 6.86 159.2
6.40 5.99 5.15 161.3
3.20 3.00 2.57 166.5
Table 3 Aggregate Ethernet throughput rate v maximum link loss
The full calculation is relatively complicated and thus Orthogon Systems have supplied a link
estimator that calculates the radio propagation and reliability of NLOS links using the OS-
Gemini equipment.
2
Throughput based on 1518 Byte Ethernet Packets on a symmetrical link.
3
AMOD link margin of 1.5 dB applied.