In certain rural or remote areas, backhaul networks can constitute bottleneck facilities. In areas where mobile traffic is low, the full backhaul capacity may lie unused, making it ideal for sharing among different operators. Accordingly, where passive or active infrastructure is shared on a tower or rooftop, operators may also share backhaul facilities. Backhaul sharing can be achieved either through fibre cables or microwave links.
Regulatory or licensing conditions may preclude operators from sharing backhaul facilities, however, especially when spectrum is employed (as with microwave links). This is often the case in rural or remote areas. For example, sharing of radio backhaul is not permitted under the licensing conditions of mobile operators in India. When backhaul radio facilities cannot be shared, operators have to install separate antennas on the towers, in addition to the antennas used to communicate with handsets. This increases the weight of the antenna on the tower, requiring higher and heavier towers, increasing the cost of construction and adding to visual intrusion. Therefore, it may be more practical to share fibre and limit the sharing of radio backhaul facilities to low-traffic regions. In addition, regulators and policy makers intending to foster wireless broadband deployment may wish to encourage mobile operators to replace microwave links with fibre links to add greater bandwidth.