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-Network Topology -Remote Gateway
-Meg@ctive Hub -Network
Management System (NMS)
System
Overview
The Meg@ctive system is a Two-Way Multimedia Interactive System over satellite,
that provides a cost-effective, reliable and immediate deployable solution for servicing
broadband applications such as Internet Access, Distance Learning, Teleconferencing,
Direct Video Broadcasting (DVB-S) and more. This is achieved by incorporating satellites
to divert the transmission to/from different destinations, over large territories,
bypassing the bottlenecks of the terrestrial infrastructure.
Meg@ctive system offers multiple users to
enjoy multimedia applications at unprecedented speeds, by incorporating forward link
DVB-S/MPEG-2 technology, a full 36 MHz transponder can allow 30Mbps of outbound data rate
transmission, achieving an Inbound data rate of TCP/IP protocol of 1.6Mbps per session.
The return path from the Remote Gateway to the central Hub, also via satellite, offers
data rates of up to 384Kbps. Using the DVB-S technology for the forward link enhances the
efficiency of the space segment usage due to the natural feature of broadcasting
information to multiple users. Also, it is very efficient in the way in which it monitors
and controls the remote sites as they receive the DVB-S channel continuously. The DVB-S
forward channel is dynamically time-shared between the users according to their actual
needs, thus providing an optimal usage of resources. The following table summarizes the
Meg@ctive system characteristics.
The Network operates in star topology.
The Meg@ctive consists of a Meg@ctive Central Hub and Meg@ctive Remote Gateways located at
the customer sites.
The Meg@ctive Hub includes the network management software and hardware, broadcasting and
receiving via satellite capabilities, and Internet Service providing software and
hardware.
The Remote Gateway includes all the software and hardware to support full Internet
Protocol (IP) based connectivity via satellite using customer standard equipment and
Meg@ctive communication schemes.
The Remote Gateway receives the signal from
the Meg@ctive Hub using the DVB-S forward channel and transmits to the Hub using SCPC
Traffic Channels as assigned by the Network Management System (NMS).
Remote Gateway
The Remote Gateway is composed of indoor and outdoor
units. The indoor unit is an Industrial PC based unit, including a DVB-S receiver with LAN
processor, a SR256 L-band modulator and the supporting units like power supply and 10MHz
reference for the outdoor unit, Ethernet LAN with 10/100BaseT interface. It can receive
data rates of up to 53 Mbps (data rate per TCP/IP session of up to 1.6Mbps) and transmits
data rates of up to 384 Kbps. The outdoor unit consists of a Block up-converter, a
standard TVRO down-converter and an optional antenna.
Meg@ctive Remote Gateway provides a complete
solution to provide Internet/Intranet applications based on standard DVB-S/MPEG-2
protocol. The terminal supports high-speed data communications for fast, secure and
reliable TCP&UDP over IP applications. Residing on an Ethernet network, the terminal
offers multiple users to enjoy multimedia applications at unprecedented speeds, increasing
work productivity and enhancing remote communication. On reception, the user terminal
performs DVB-S demodulation, FEC decoding, PID de-multiplexing and filtering. The
Meg@ctive Remote Gateway reconstructs IP datagrams from DVB-S/TS cells and routes them to
the appropriate PCs on the shared LAN. On transmission, the terminal collects IP datagrams
from all the PCs and processes and transmits via the outdoor unit to the Hub.
The modulator at the Remote Gateway uses advanced
Digital Signal Processing (DSP) technology and advanced algorithms, housed on a small
compact digital board. The unique L-band interface (950-1535 MHz) reduces RTs cost
and allows the achievment of an exceptional price-performance ratio.
Meg@ctive Hub
The indoor portion of a Hub with minimal configuration
is composed of a DVB-S broadcast server, DVB-S modulator, bank of receivers, two NMS
servers, and a router with WAN interface toward the Internet backbone. The equipment is
connected via a 100BaseT Ethernet LAN. The DVB-S modulator supports transmission rates of
up to 53 Mbps. Each receiver of an inbound channel supports data rates of up to 384Kbps.
Network Management System (NMS)
The Network Management and Control
System are responsible
for the following:
* Bandwidth allocation.
* Power control.
* Transmission control.
* Conditional access.
* Channel and user monitoring.
The system dynamically assigns bandwidth to the
subscribers according to their needs. The space segment resources are exploited
efficiently and the subscribers cost is reduced accordingly. Indications on the received
power at the hub are transmitted via the outbound channel to the subscribers for adjusting
their transmitted power level. Transmission from the remote is conditioned on receiving
the outbound signal at the remote and on subscribers authorization. The system
manages the subscribers database which includes the remote site parameters (i.e.
antenna size power amplifier modem data rates. etc.) and the access rights of the
subscribers. |