Reaching Out Via Satellite Backhauling - Page 2 of 3

Serving The Unserved

In January, ViaSat Inc. and Verso Technologies announced they had tested a satellite-based GSM backhaul system in Papua New Guinea, for Telikom PNG Ltd. The network combines ViaSat LinkStar satellite and Verso NetPerformer A-bis-over-IP optimizer software technology, and Telikom PNG plans to deploy 50 GSM-over-satellite remote sites. According to Moorthy Hariharan, CTO for ViaSat VSAT Networks, VSAT systems integrated with IP-based transceiver link optimizers like NetPerformer can offer competitive and efficient backhaul extensions for cellular networks. Besides packetizing network traffic — reducing bandwidth requirements by as much as 50 percent without affecting voice quality — and dynamically assigning bandwidth based on voice and signaling traffic volumes, this DVB-S2 solution uses ViaSat technology that includes advanced bandwidth allocation techniques to assign features that prioritize calls and data traffic. Verso NetPerformer ensures that legacy voice and data traffic can share the same network infrastructure along with traffic flowing from Wi-Fi and WiMax hotspots.

“The level of aggregation and peak-to-average traffic variations in end points drive the design choices for backhaul,” says Hariharan. “The continuing evolution in mobile and wireless networking standards makes it extremely important that operators and service providers implement scalable, extensible and upgradable backhaul systems. Adopting packet-switched IP for transport makes upgrading the system for advanced services a lot easier as well.”

In Nicaragua, Empresa Nicaraguense de Telecomunicaciones, a subsidiary of Mexico’s America Movil, added GSM satellite backhauling to its rural telephony network using Gilat’s SkyAbis solution, which is a demand assign multiple access-based solution. With a Gilat SkyEdge hub in place, Empresa Nicaraguense deployed SkyAbis on top of the SkyEdge system, which can dynamically adjust bandwidth depending on real-time requirements at each transceiver.

According to Daniel Enns, senior vice president strategic marketing & business development for Comtech EF Data, successful satellite backhauling requires bandwidth-efficient and scalable solutions for cellular operators. “Cellular backhaul-enabled satellite modems are capable of delivering optimal performance and spectral utilization at multiple layers,” says Enns, who adds that this is about selecting the right combination of forward error correction, modulation formats and code rates in order to simultaneously optimize satellite transponder power and bandwidth.

A combined Memotec and Comtech EF Data solution called AbisXtender includes an A-bis-over-IP optimization platform and bandwidth-efficient, IP-enabled modems. The solution can eliminate a GSM operator’s dependence upon fixed lines and generate cost savings in low-traffic zones such as remote transportation routes. “Space segment costs are typically the most significant operating expense for GSM service providers considering satellite-based services,” says Enns. “Satellite transmission backhaul costs can represent up to 40 percent of the total operating expense related to [transceiver] deployment. Therefore, careful satellite network design and selection of the right technologies have a direct impact on the viability and profitability of the service.”