System Architecture

The ACeS System offers connections between:

• The ACeS User Terminal and terrestrial telephone networks (PSTN/PLMN)
• The User Terminal and other User Terminals

Using a geosynchronous satellite, the ACeS System provides security and privacy for users, infrastructure to produce billing data (invoices) and an interface with the customer service system & call center, and is compatible with GSM networks. It delivers a Supplementary Service like the GSM standard fax (2.4 kbps), and data (2.4 kbps) between the User Terminal and terrestrial telephone networks (PSTN/PLMN) and between one User Terminal and another.

Special Feature of ACeS

• High Penetration Alerting (HPA)
  The call signal from the satellite for an incoming call is very powerful. So even if the User Terminal is currently located in a "weak signal" area, inside a building for example, it can still pick up the signal.
  
  
• Optimal Control Routing (Long Haul Routing)
  For each outgoing call from a User Terminal, the network can select the closest Gateway to the call destination.
  
  
• Outgoing Call between User Terminal with "Single Hop" through Satellite
  The system’s capacity allows a User Terminal to send a voice signal direct to another User Terminal via satellite without going through a Gateway, minimizing delay and echo effects.

Fixed Ground Segment Key 

The ACeS ground system serves as a link between the ACeS system and terrestrial networks (PSTN/PLPM). The system comprises a number of gateways, or interconnection nodes, between the ACeS system and terrestrial networks, and a Network Control Center to regulate and monitor the Gateways and the network as a whole. The Fixed Ground Segment is designed to GSM specifications with slight modifications to accommodate satellite transmission.

Gateway 

Gateways function as interconnection nodes with the terrestrial telecommunications networks (PSTN/PLMN) in each country. Each Gateway also processes voice, data, and so on to make them compatible with the PSTN/PLMN network, conducts electronic authentication/verification at the beginning of each call to prevent unauthorized use of SIM cards, and makes a record of each call (CDR : Call Detail Record) so that bills can be produced for each user. Every gateway has its own customers and keeps a database of their customers.  

Network Control Center (NCC) 

The NCC functions as a resource distributor between Gateways (frequency and time), regulates and monitors each job, sets up each call, and records the satellite airtime for each Gateway, enabling it to produce individual bills.

Garuda Spacecraft Main Features

The Garuda satellite is the communications link between a User Terminal and the NCC for signaling, a User Terminal and a Gateway for voice and signaling, the NCC and the respective Gateway for signaling, and between one Gateway and another for signaling.

The Garuda satellite has 2 L-band antennae with a diameter of 12 m to communicate with User Terminals (Asia-Pacific coverage area with 140 spotbeams). In addition, it has a 3 m C-Band antenna to communicate between the Gateways and the NCC. The satellite has an in-orbit lifetime of 12 years, and will spend the first 3.7 years in an "inclined" orbit. With a dry mass of approximately 2700 kg, it has a dual power source, namely a solar array that converts solar energy into electricity, and a battery, used when the solar array is in the earth’s shadow. The satellite’s initial orbit is 123° East longitude, plus or minus 3° North and South, and it will be stable at 0° (the equator) when their age is more than 3.7 years

For further information please download this Adobe Acrobat™ File : Overview.pdf (761 kb)

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