Special Technologies


Adaptive Satellite Access Technology (A-SAT-IITM)

The A-SAT-IITM technology allows the same modem to operate 3 different access wave forms, and achieve the most efficient bandwidth utilization possible:

  • A-SAT-IITM capability modem with triple access mode


Data-Over-Cable Service Interface Specification (DOCSIS)

Data Over Cable Service Interface Specification (DOCSIS) is an international telecommunications standard that permits the addition of high-bandwidth data transfer to an existing cable TV (CATV) system. It is employed by many cable television operators to provide Internet access over their existing hybrid fiber-coaxial (HFC) infrastructure. The version numbers are sometimes prefixed with simply "D" instead of "DOCSIS" (e.g. D3 for DOCSIS 3).


NovelSat NS4

NovelSat NS4 is the satellite industry’s newest 4th generation transmission waveform. Already, NovelSat NS4 is the waveform of choice for broadcasters and data networks around the globe. As worldwide demand for data and content continues to grow rapidly, the need for even more bandwidth-efficient satellite transmission solutions is ideally addressed by NovelSat NS4.


ViaSat ArcLight Technology

ArcLight enables users to combine traditional VSAT applications and interactive broadband IP data into a single network, dramatically expanding the number of applications where VSATs are economical. The ArcLight subscriber terminal also costs less than today's typical TDM/TDMA terminal. Each remote terminal in an ArcLight network shares data downloads at speeds up to 45 Mbps and transmits data at up to 512 kbps.

ArcLight features two to three times the bandwidth efficiency of a traditional TDMA VSAT. The technology behind the new network is Paired Carrier Multiple Access (PCMA), a patented ViaSat signal processing technique that enables both send and receive signals to occupy the same satellite frequency. Using PCMA technology, ArcLight "piggybacks" multiple subscriber return channels on top of a high speed DVB forward channel to maximize bandwidth efficiency.

The improvement in bandwidth efficiency is essential for broadband services because these services can consume vastly more transponder space than traditional VSAT applications. As a result, ArcLight can support virtual circuits for enterprise wide area networks at a price comparable to terrestrial frame relay service. The ArcLight system includes a hub and comprehensive network management system.


ViaSat Code Reuse Multiple Access (CRMA)

Code reuse multiple access (CRMA) is a new communication technique (patent pending) that employs direct sequence spread spectrum signaling for the access channel. It is similar to the spread ALOHA CDMA (SA/CDMA) and spread ALOHA multiple access (SAMA) multiple access techniques. The value of CRMA is that it improves on the multiple access collision performance of SAMA without the additional complexity required for SA/CDMA. It also removes some of the limitations of SAMA, since the spreading codes are not required to be maximal length codes of data symbol length.


ViaSat Paired Carrier Multiple Access (PCMA)

PCMA pairs forward and return channels in ths same bandwidth.PCMA (Paired Carrier Multiple Access) - a patented Viasat technology - is a frequency re-use technique for two-way satellite communications. It enables two different earth stations to use the same frequency, time slots, and/or CDMA code at the same time.

Using PCMA, you can choose the system benefit that's best for you:

  • More capacity to serve more customers in the same bandwidth
  • Reduce bandwidth requirements/costs to save money
  • Allocate more bandwidth per customer to improve service levels with no increase in costs

This technique can be applied with any of the commonly-used multiple access techniques such as FDMA, TDMA, or CDMA. PCMA may also be applied independently of the modulation and coding technique for the link. PCMA is used in addition to -- not instead of -- other bandwidth and power efficient modulation, coding and multiple access techniques.The benefit of PCMA is that it may effectively double the throughput of satellite systems in terms of bits/sec/Hz, with a minimal impact on the Eb/No required to achieve a desired Bit Error Rate.