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Product Features
Introduction
Modulation Technique
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1.1.2. Modulation Technique
The design is based on high-level modulation techniques which include:
The following are its key benefits:
• Provides an excellent spectral efficiency (up to 2.3 bps/Hz for D16QAM), it is better than
any product available on the market.
• FEC coding scheme used with GMSK and 4FSK modulations is based on Hamming Code
known as Perfect Codes. Although Hamming Codes are not very powerful, they are easy
to implement and do not require much DSP resources.
• More powerful Reed-Solomon FEC coding 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).
1.1.3. Media Access Control (MAC)
The following Media Access protocols are available for AW400Tx modem:
1. Simplex protocols (Simplex Base, Simplex Remote, and Repeater) are developed prima-
rily for GNSS applications.
2. Half Duplex protocols (Half Duplex Base, Half Duplex Remote and Repeater) are the
alternative to Simplex protocols that provide bidirectional link with the dynamic band-
width allocation.
Note:
Repeater decreases the user data rate. The user data rate in the link with the repeaters is equal to
C /[(n+1]), where C is a link throughput determined by the modulation technique and n is a
number of repeaters in the chain. Half duplex Base, Half duplex Remote and repeater are not
supported in current release.
3. Sleep mode is an investment provided by MAC sub-layer that provides additional power
saving. The wakeup from Sleep mode is user selectable either by an internal real-time
Modulation/ Channel Spacing 6.25 kHz 12.5 kHz 20 kHz 25 kHz
DBPSK – Differential Binary Phase Shift Keying 2.4 kbps 4.8 kbps 7.5 kbps 9.6 kbps
DQPSK – Differential Quadrature Phase Shift Keying 4.8 kbps 9.6 kbps 15 kbps 19.2 kbps
D8PSK – Eight Phase Shift Keying 7.2 kbps 14.4 kbps 22.5kbps 28.8 kbps
D16QAM – Sixteen Quadrature Amplitude Modulation 9.6 kbps 19.2 kbps 30 kbps 38.4 kbps
GMSK – Minimal Shift Keying with Gaussian Filtering 2.4 kbps 4.8 kbps 7.5 kbps 9.6 kbps
4FSK- Four Level Frequency Shift Keying
N/A
1
1. N/A – Not Applicable
9.6 kbps 15.0 kbps 19.2 kbps