Ground Technology
The IPSTAR system is comprised of a gateway earth station communicating over the Thaicom-4 (IPSTAR) satellite to provide broadband packet-switched communications to a large number of small terminals with network STAR topology configuration.
A wide-band data link from the gateway to the user terminal utilizes an Orthogonal Frequency Division Multiplexing (OFDM) with a Time Division Multiplex (TDM) overlay. These forward channels employ highly efficient transmission methods including Turbo Product Coding (TPC) and higher order modulation (L-codes) for increased system performance.
In the terminal-to-gateway direction or return link, the narrow-band channels employ the same efficient transmission methods. These narrow-band channels operate in different multiple-access modes based on bandwidth usage behavior, including ALOHA and TDMA on the STAR return link waveform.
IPSTAR Gateway System
The IPSTAR air interface is designed for mass broadband applications. The IPSTAR gateway provides packet-switched broadband communications to a large number of small terminals or Customer Terminal Equipment (CTE). IPSTAR terminals work in conjunction with the satellite and gateway. The air interface employs advanced waveforms on the forward and return channels, and is optimized for overall system efficiency.
The IPSTAR gateway incorporates proprietary Adaptive Coding and Modulation (ACM) for an efficient use of RF power and bandwidth allowing high transmission rates in conjunction with small antennas (84–120 cm.) and transmitters. The interface between the IPSTAR gateway to any device or network is based on the industry standard Internet Protocol (IP) to ensure seamless integration of existing applications, hardware, and systems. The IPSTAR gateway and terminals can interface with any device or network that is based on the industry standard Internet Protocol, which ensures seamless integration of applications, hardware and software. Network configuration is based on gateway STAR topology: a user terminal receives/transmits signals from/to a beam, which connects to the IPSTAR gateway that is linked to other networks, such as the Internet backbone or telephone networks.
A wide-band data link from the gateway to the user terminal utilizes an OFDM with TDM overlay. The forward channel employs highly efficient transmission methods, including TPC and higher order of modulation (L codes) for increased performance. The waveform of the forward channel is based on TDM-OFDM technology that utilizes bandwidth and power more efficiently. The forward channel is optimized to accommodate multiple data rates and forward error correction coding. The return channel is based on MF-TDMA technology to offset bursty traffic and to accommodate applications that require higher bandwidths. The waveform is fixed to a more robust modulation to ensure high link availability at low transmission power. The narrow-band channel operates in multiple access modes based on bandwidth usage behavior, such as ALOHA and TDMA.
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