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MODULATION TECHNIQUE
Spread Spectrum (SS) radio transceiver uses two bands: 902-928 MHz ISM license free USA band and Europe-
an CEPT license free 868-870 MHz band. In 902-928 MHz band SS radio uses frequency hopping transmission
techniques. The design is based on high-level modulation techniques which include:
Modulation/ Channel Spacing
902.0-928.0
GMSK – Minimal Shift Keying with Gaussian Filtering
64.0 kbps, 128 *200.0 kHz
The following are its key benefits:
• Ten optimized Frequency Hopping Patterns provides simultaneous operating of several units with min-
imum of mutual interference.
• FEC coding scheme used with GMSK modulation is based on Convolutional code and the Viterbi decoding
algorithm which is the most resource-consuming, but it does Maximum likelihood decoding.
In 868-870 MHz band the design is based on high-level modulation techniques which include:
Modulation/ Channel Spacing
12.5 kHz
25 kHz
GMSK – Minimal Shift Keying with Gaussian Filtering
4.8 kbps
9.6 kbps
The following are its key benefits:
• FEC coding scheme used with GMSK modulation is based on Convolutional code and the Viterbi decoding
algorithm.
• Powerful FEC scheme used with ArWest proprietary frame format improves the tolerance to interference
and ensures the highest link quality at distances range higher than 8 miles (13 km) and roaming speeds of
up to 60 mph (96 km/h).
MANAGEMENT TOOLS
The built-in management tools along with ModemVU (configuration and monitoring software application) will
provide the following benefits:
1. Easy user’s interface for system configuration and monitoring using well developed CLI .
2. An ability to monitor status, alarms and radio performance through the CLI.
3. Software upgrades and improvements can be downloaded from ModemVU to the units connected with
PC/PDA.
SECURITY
The system provides wireless media access protection as well as data scrambling. The following are its key
features and benefits:
1. The Key Sequence generated by Pseudo-random generator scrambles the fully formatted frame (including
Frame’s CRC). This provides the wireless media access protection.
2. User selectable Frequency Hopping Pattern provides another level of the wireless media access protec-
tion.
At the same time it allows operators to increase the number of links deployed in the same location.
