Specifications

The effect of using Redline’s proprietary encryption was investigated as well. The results show
little difference if it is on or off. For all of these results the modulation format was set to be
adaptive with a maximum bit rate of 54Mbps with a step size of two levels. This proved to give
better results than any of the attempts to have a fixed level of modulation.
Encryption Throughput (Mbps)
On 19.48
Off 19.94
Fig 5.10 The Effect of Encryption on Throughput.
6. Conclusions
The Redline communications equipment and the 802.16 standard that they are based have been
demonstrated to be able to provide a reliable telemetry link. Although the specified throughput
of 48Mbps at the Ethernet port was not attainable the system sill performed well. The highest
throughput measured was 44 Mbps at the Ethernet under ideal conditions. The radio performed
well in the presence of adjacent channel interference, likely due to the use of the adaptive
modulation, error correction and the use of OFDM. The long-range test showed that the system,
when properly configured, quickly and easily establishes a link that performs well. With the first
attempt at antenna alignment done purely by visual reference the link became operational as soon
as both units were powered on.
The range of an 802.16 radio can be extended by the use of advanced receiver and transmitter
antenna design and signal processing. Future work on this project involves integrating an
adaptive antenna with an IEEE 802.16 radio transceiver. The antenna will provide for higher on
axis gain, as well as being more directional so that interference from off axis sources will be
minimized. This will aid in both system security and throughput.
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