Extended site sharing is when operators share not only the passive elements of a site, but also active equipment such as antennas, combiners and transmission links. In extended site sharing arrangements, operators may also share the TRX (transmitter and receiver). This requires parties to share the spectrum, as well. Spectrum sharing is technically possible, but it can raise regulatory challenges because of rules dealing with spectrum optimization. Nevertheless, the Brazilian regulatory ANATEL has expressly allowed spectrum sharing in case operators decide to share their networks in order to provide coverage in rural or remote areas (communities with less than 30,000 inhabitants).
The extended site-sharing option may increase capital and operating savings when compared with simple site sharing. The amount of additional savings may be limited, however, because the additional costs of antennas and transmission equipment are relatively small.
While it is technically possible for operators using different frequencies to share an antenna, this option poses some technical challenges. It may particularly difficult when radio optimization strategies are not aligned among the operators. While an antenna can be shared, it is usually kept in a certain position, based on the operator’s own radio optimization strategy. The optimization strategy of the sharing operator may require changing the antenna position – something that may be difficult or impossible when the antenna is shared.
Nevertheless, certain equipment manufacturers supply antennas that are adequate for antenna sharing.[1] This equipment includes Multi-Operator Radio Access Network (MO-RAN) technology. Where MO-RANs are deployed they allow for two operators to share the same base station and to share the radio network controller which directs the voice and data traffic back to the operator's own core network.
[1] Nokia, for example, is an equipment manufacturer and supplier that provides equipment intended for network sharing.