The satellite industry is known for its flexibility and adaptability; reason why satcom is often used in different ways for filling in gaps left by lack of readily available terrestrial alternatives. Yet, there are also times when market disruptions coupled with creative technology foster uses with wide appeal and impact on the larger telecom space.
This could indeed be the case for the emergence of cellular backhaul offload and overflow networks, which might soon become new industry buzzwords as a number of conditions appear to be coming together for satcom to seize the opportunity and to offer the mobile sector new complementary solutions.
From 2G Backhaul to 3G Backhaul and Beyond
The development of satellite-based 2G cellular backhaul solutions in the mid 2000s has helped mobile operators extend their service footprint into underserved, low-density and remote locations, particularly in the developing world.
The shift from a voice-centric to a data-centric mobile environment has more recently focused the attention on 3G backhaul but lower data ARPU has brought challenges for closing the business case over conventional FSS capacity. HTS (high throughput satellite) platforms worldwide are coming to the rescue of the 3G backhaul business model, bridging the economic gap assisted by use of advanced satellite transport and backhaul optimization.
The next phase in cellular backhaul via satellite will be about intelligently routing traffic based on mobile service and traffic volume in hybrid (terrestrial + satellite) backhaul environments. The key ingredients fostering satcom offload / overflow are the exponentially-growing data traffic (see Ericsson Chart) , the proliferation of HTS platforms and development of intelligent backhaul optimization technology. These last two combine low-cost edge CAPEX, bandwidth costs comparable to terrestrial and smart ways for managing “on demand” traffic carried over both terrestrial and satellite links.
Total (uplink + downlink) Mobile Monthly Traffic (PetaBytes) – Source: Ericsson Mobility Report August 2013
Offload and overflow have been hot topics in the mobile space but mainly in the context of last-mile (RAN) environments. The rapid surge of mobile data is putting a strain on cellular networks, a situation that has prompted cellular operators to implement cellular offload strategies such use of WiFi and additions of femtocells. But there is another story developing behind the scene, which is about how the traffic surge is affecting demands for backhaul networks in urban, suburban and remote locations.
Mobile operators are pragmatically adopting a number of strategies to mitigate these issues but the challenge to maintain user´s quality of experience increases from urban to suburban and remote locations, as expanding backhaul capacity becomes less economically attractive.
Satellite vs Traditional Mobile Backhaul Solutions: CAPEX and OPEX
Uses of satellite offload/overflow could find great receptiveness in areas that make extensive use of traditional mobile backhaul solutions, effectively extending the satellite backhaul market beyond the hard-to-reach remote locations. Upgrading traditional backhaul networks, such as microwave links, to support a higher traffic volume is manageable for voice but the rapid demands for mobile data and its inherent lower revenue make the backhaul upgrade process more economically challenging for operators. Increasing the speed of legacy or traditional backhaul links typically involves adding communication equipment at multiple locations (e.g., end points and repeaters), costing tens of thousand of dollars in CAPEX. A single satellite terminal can absorb traffic peaks (overflow) and even intelligently route user traffic (offload) based on the application, such as bandwidth-hungry video intelligently routed over satellite while delay-sensitive voice routed over terrestrial backhaul paths.
Offload and overflow networks via satellite will be shaped by the following industry trends:
- Globalization of HTS : With success stories in North America, Asia Pacific and Europe, HTS platforms are proliferating worldwide and in a variety of ways: from fully-integrated systems (e.g. Hughes or ViaSat) to open platforms (e.g. Intelsat EpicNG). Such variety will enable a number of uses and business models.
- Cellular Shift to IP: The inevitable shift to mobile IP is making satellite backhaul services more “virtualizable”, effectively enabling uses of third-party satellite delivery platforms.
- Exponential growth of mobile data: Satellites have historically benefited from disruptions in traffic demands as distance-indifferent satellite communications can flexibly support bandwidth needs. Even in high population density areas, it takes time to resolve backhaul congestion problems but a solution based on satcom equipment can be rapidly (less than a day) installed at the base stations. This enhances the user experience (immediately eliminates backhaul congestion) while giving the operator time to engineer and deploy a terrestrial backhaul solution in the urban area.
- Low cost, high-speed terminals: Primarily driven by large volume consumer markets, manufacturing of HTS terminals have reached scale to support high-speed connectivity at a low CAPEX. Terminals cost only hundreds of dollars, a negligible cost when seen in the picture of a macrocell and within the range of femtocell deployments.
- Cross-beam HTS bandwidth pooling: HTS platform operators have the capability to provision aggregate bandwidth that can be dynamically assigned to different beams on an on-demand basis, effectively extending HTS economics to wider geographic areas and eliminating the need for the mobile operator to lease a fixed amount of bandwidth per beam.
- Developments in intelligent optimization technology: Cellular optimization has come a long way and currently supports both 2G and 3G with double-digit savings in backhaul capacity. Offload/overflow technology will extend such capabilities and offer dynamic allocation of bandwidth in hybrid terrestrial-satellite environments.
In a nutshell, there will be a number of scenarios where the satellite OPEX will largely be justified by the savings in network CAPEX that would be otherwise necessary to manage traffic peaks and increasing demands of backhaul capacity. In context of an industry diversifying uses (and the customer base) of HTS systems beyond consumer broadband, offload/overflow satellite backhaul networks could eventually become instrumental in driving growth in sales of HTS terminals, intelligent optimization gear and cross-beam aggregate capacity.
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