The aim of SANSA project is to improve the capacity, resilience, and coverage of mobile backhaul networks while maximizing their spectral and energy efficiency, in order to meet the Digital Agenda 2020 for European Union growth requirements. In particular, the specific objectives of SANSA project, which are perfectly aligned with the objectives set in the H2020-ICT6-2014 call, are:
- To increase the mobile backhaul networks capacity in order to avoid the so-called "capacity crunch"
The changes in user trends and the appearance of new applications in recent years resulted in a huge increase of mobile traffic worldwide. For instance, mobile video traffic exceeded 53% of the total traffic in 2013, which in part caused a global traffic increase of 81% with respect to 2012. In order to face the unprecedented traffic demand predictions, the industry and research communities have targeted a 1000x capacity increase by 2020. Therefore the aim of SANSA is to contribute to this 1000x capacity increase by conceiving novel backhaul solutions which will allow supporting the ever increasing mobile traffic in access networks. In these sense, the proposed self-organizing hybrid backhaul network will allow much higher exploitation of all deployed resources by evenly balancing the load among terrestrrial and satellite links.
- To drastically improve backhaul network resilience against link failures and congestion
Besides the aforementioned traffic demand increases, mobile users require high Quality of Service (QoS) independent from their location, their context or the status of the network. This not only imposes some requirements on the access networks but also on the resilience of backhaul ones. For example, in traditional daisy-chain terrestrial networks, the network is as robust as it is one of their links, so the failure or congestion of one link causes the fall of the whole network. SANSA inherently provides a twofold solution for this issue. On one side, the capability of reconfiguring the terrestrial network topology will allow skipping failed or congested links. On the other side, the satellite provides a new path for the mobile traffic that could be accessed from different nodes of the terrestrial network. It is worth mentioning that this architecture can be very useful in disaster relief situations where parts of the terrestrial network may have been defected.
- To facilitate the deployment of mobile networks both in low and highly populated areas
One of the main challenges that mobile network operators (MNO) are facing is the cost of deploying new network infrastructures in both low and high populated areas. In rural or remote areas, there is a scarcity of network infrastructure that requires a big CAPEX for the MNO. The use of satellite backhauling is a virtuous solution that has been considered in other European funded research projects such FP7-BATS. However, the objectives of SANSA go well beyond this, since it also provides low cost deployment solutions in highly populated areas. In these scenarios, installing optical fiber could become extremely expensive (particularly when considering massive deployment of small cells in lampposts or building façades), whereas the use of high frequency high capacity wireless links requires line-of-sight (LOS) operation, which often results in wireless repeaters, and good antenna pointing at installation. Usually an exhaustive radio planning is needed, and once the network is deployed no changes can be done. SANSA provides a straightforward solution to these issues, due to the capability of reconfiguring the network topology, which is based on the deployment of terrestrial nodes equipped with smart antennas with beam-steering capabilities. Thanks to their self-pointing features, these antennas substantially ease installation cost by not requiring highly qualified personnel in the process. In summary, SANSA will demonstrate that ubiquitous backhauling with an affordable CAPEX is possible by employing an integrated terrestrial-satellite network.
- To improve the spectrum efficiency in the extended Ka band for backhaul operations
In Europe, current CEPT recommendations assign the frequency bands of 19.7-20.2 GHz and 29.5-30 GHz for exclusive Space-to–Earth and Earth-to-Space satellite communications, respectively. The band from 17.7-19.7 GHz is shared between Space-to–Earth satellite communications and terrestrial services (which corresponds to the usual 18 GHz backhaul frequency band). In this band, satellite receivers cannot claim for protection against terrestrial interferences. As a result, satellite operators use their exclusive bands for their uncoordinated user links and reserve the shared bands for feeder links, since there are fewer stations and have better isolation capabilities, due to their large reflector antennas. In contrast, the band from 27.5-29.5 GHz is split into several sub bands allowing either exclusive satellite (Earth-to-Space) or terrestrial (usual point-to-multipoint 28 GHz band) communications. The objective of SANSA is to develop novel interference mitigation techniques that will allow deploying satellite terminals dedicated to backhaul operations in the 17.7-19.7 GHz band without the need of occupying part of the satellite exclusive bands. In a similar way, they will be also deployed in the exclusive terrestrial sub-bands within the 27.5-29.5 GHz. This is well aligned with the actual trend of satellite systems of moving the feeder links to Q/V bands and using the Ka band for user links. The Ka band is targeted in SANSA since it currently allows the spectrum coexistence on a coprimary basis between both segments, but the results obtained in the project will be useful for other potential sharing bands as well. Specifically, SANSA will contribute the 10-fold spectral efficiency improvement targeted in the H2020 2014-015 work programme.
- To reduce the energy consumption of mobile backhaul networks
Communication network infrastructure represented around the 11% of the ICT carbon footprint in 2011, and the figures keep on growing, so novel techniques are needed to make the communication infrastructures more sustainable. The objective of SANSA is to develop ground-breaking traffic management algorithms for its self-organizing hybrid network, enabling selective node sleep modes and improving the energy efficiency of the whole backhaul network. SANSA will develop solutions to contribute to energy efficiency improvements of up to 30%.
- To strengthen European terrestrial and satellite operators market and their related industries
European satellite operators have been successful in providing broadcast services (e.g. satellite TV), but they have not been able to obtain a relevant position in the mobile communication market, though several attempts have been performed at research and commercial levels. The objective of SANSA is to demonstrate that satellite segment is essential in mobile backhaul networks, and to provide a roadmap for bringing SANSAs’ solutions to the real world. This will not go in detriment of the revenue of current terrestrial operators. In fact, SANSA envisages a win-win collaboration among both segments that will reinforce the position of European satellite and terrestrial operators in the world. Terrestrial operators will be able to cope with the increase of traffic demands and will share part of the band licensing costs with satellite operators, whereas the latter will take part of the mobile backhaul market. As a consequence, secondary markets related to the operators such as terrestrial equipment manufacturers or satellite terminal and network manufacturers, will also benefit from the new business opportunities created by SANSA. Finally, these new business opportunities will create new job openings that will benefit the European society.