Specifications

3.Test Bed

3.1 Test Bed Objectives: A test bed for evaluating a high-speed radio link is required. This test

bed should be able to simulate a real world link and as many of the parameters that a real world

system has to face as possible. The test bed also has to be able to generate and monitor the

traffic on the link.

The link that is to be tested is a high speed RF link between remote terminals. Each terminal

accepts standard RJ-45 Ethernet inputs and has an IF output that goes to a transceiver unit that up

converts to the 5.8GHz band. This output has a standard N-type male connector. The antenna

connects to this port. In lab based testing the antennas weren’t used, but instead the RF ports on

the transceivers were connected together with cables, running through other equipment as

necessary.

The test bed had to be able to do testing of throughput vs. received signal strength, throughput

vs. signal to noise and distortion ratio, throughput vs. packet size, as well as throughput as a

function of configuration settings on the terminal itself.

The RF portion of the test bed had to be able to allow for easy reconfiguration of the test

configuration. The test bed had to be able to create values of added noise, loss, and interference

that would be able to simulate different types of link conditions. The noise value should range

from thermal up to a value that makes the link inoperable. Loss had to be able to be variable so

that the input power of the receive transceiver could be varied between the extremes of saturation

and minimum sensitivity. Both the noise and the loss should be finely adjustable, on the scale of

1-db steps. Interference should be adjustable as well so that strong and weak interferers could

both be simulated.

The interconnects for the test bed had to be able to meet certain requirements as well. The RF

interconnects had to be able to have a low loss at the operating frequency of 5.8GHz. This is so

that the loss over the cable itself is negligible compared to the other losses in the system. High