Isolated Rural Communities can be classified in three large blocks according to its location: forest communities, high mountain communities, and communities placed in great desert plains or savannahs. In all these cases population density is very low, economic capacity is limited and the absence of roads makes deployment of terrestrial infrastructure difficult. These are scenarios with their own particularities, and characteristic radio propagation conditions.
Figure 2. Overview of the TUCAN3G reference scenarios, where access to the 3G operator core network is done through a WiLD backbone.
Forest communities are placed next to the major rivers and depend on fluvial communications, which are slow and also very expensive due to fuel consumption. Moreover, distances between communities are enormous. Wireless networks in these areas will follow a linear architecture, linking small communities until reaching a large city that is usually placed in the river mouths.
High mountain communities are located in deep valleys and are communicated by small paths or roads. Straight line distances are not long, but the time needed to traverse the roads is large. Wireless deployment in these areas will be based on a backbone between summits, and will enlighten valley communities from the top hill.
Figure 3. Overview of the TUCAN3G reference scenarios, where access to the 3G operator core network is done through a WiLD backbone connected to a VSAT gateway.
Finally, interconnection of isolated rural communities in desert plains or savannahs can also be complicated. The lack of mountains where antennas could be placed makes terrestrial communications difficult, and a satellite link to establish connection with outer world is required in many cases.
TUCAN3G aims to provide high rate connectivity to sparsely populated areas where the deployment of conventional communication infrastructure (3G macro base stations with wired backhaul) is not economically viable. We envision a scenario where the access network consists of femto base stations that are connected to a wireless transport network with tree-like topology.
While the access network is based on 3G or LTE technologies, the transport network can be based on WiLD (see Figure 2 as a possible real example for 15 small communities in the jungle) or a combination of WiLD and WiMAX (see Cuzco network in Figure 4 as a possible real example for 11 villages in a mountain area). The connection to the outer world is envisioned though either a VSAT connection (as in the Putumayo network that can be seen in Figure 3) or through fibber to the operator's core network, when one of the ends of the transport network is close to a densely populated area (see Figure 2 and Figure 4). Both have different tradeoffs in operating costs, bandwidth and delay. These scenarios are representative for the situation found in a lot of rural areas of developing countries.
Figure 4. Overview of the TUCAN3G reference scenarios, where access to the 3G operator core network is done through a heterogeneous WiMAX-WiLD backbone.