A base station system comprising: a base station device, a wireless transmission device and a data transfer device, each configured to be installed outdoors, the base station device including: first electronic equipment adapted to function as a base station to relay data between a plurality of mobile stations and a mobile backhaul network; and a first enclosure that is adapted to accommodate the first electronic equipment and provide protection from water and dust ingress necessary for being installed outdoors, the wireless transmission device including: second electronic equipment adapted to function as a radio station to perform wireless transmission connecting the base station device to the mobile backhaul network; and a second enclosure that is adapted to accommodate the second electronic equipment and provide protection from water and dust ingress necessary for being installed outdoors, and the data transfer device including: third electronic equipment adapted to function as a router or a switch to transfer data packets or data frames between the base station device and the wireless transmission device; and a third enclosure that is adapted to accommodate the third electronic equipment and provide protection from water and dust ingress necessary for being installed outdoors, and the first, second, and third enclosures are distinct from one another. a base station device, a wireless transmission device and a data transfer device, each configured to be installed outdoors, the base station device including: first electronic equipment adapted to function as a base station to relay data between a plurality of mobile stations and a mobile backhaul network; and a first enclosure that is adapted to accommodate the first electronic equipment and provide protection from water and dust ingress necessary for being installed outdoors, first electronic equipment adapted to function as a base station to relay data between a plurality of mobile stations and a mobile backhaul network; and a first enclosure that is adapted to accommodate the first electronic equipment and provide protection from water and dust ingress necessary for being installed outdoors, the wireless transmission device including: second electronic equipment adapted to function as a radio station to perform wireless transmission connecting the base station device to the mobile backhaul network; and a second enclosure that is adapted to accommodate the second electronic equipment and provide protection from water and dust ingress necessary for being installed outdoors, and second electronic equipment adapted to function as a radio station to perform wireless transmission connecting the base station device to the mobile backhaul network; and a second enclosure that is adapted to accommodate the second electronic equipment and provide protection from water and dust ingress necessary for being installed outdoors, and the data transfer device including: third electronic equipment adapted to function as a router or a switch to transfer data packets or data frames between the base station device and the wireless transmission device; and a third enclosure that is adapted to accommodate the third electronic equipment and provide protection from water and dust ingress necessary for being installed outdoors, and third electronic equipment adapted to function as a router or a switch to transfer data packets or data frames between the base station device and the wireless transmission device; and a third enclosure that is adapted to accommodate the third electronic equipment and provide protection from water and dust ingress necessary for being installed outdoors, and the first, second, and third enclosures are distinct from one another.