of tall buildings provides coverage there, but the signal will be too weak to reach the street level. Picocells are one way to resolve these issues. Hospitals and hotels, which need coverage for visitors, are prime examples of organizations that need additional cellular coverage within their facilities. A network of picocells or a distributed antenna system can solve the problem. Distributed antenna systems for in-building coverage are described in the next section. Picocells within office buildings, hotels, or healthcare facilities consist of many base stations with antennas (picocells) located 300 to 900 feet apart. Picocells can be the size of a sheet of letter paper or as small as a Rubik's Cube. The picocells are connected to the location's wired broadband connection via its Local Area Network (LAN) for traffic back to the mobile providers. Traffic carried back to the carrier con- sists of Internet traffic and calls to people on the Public Switched Telephone Network (PSTN) or on other providers' mobile networks. Picocells used for outdoor coverage can be attached to light poles and even low- rise buildings in densely populated areas with high concentrations of mobile traffic. The Microcell Technology of Picocells and Femtocells This solution is an inexpensive way to gain capacity by reusing a carrier's spectrum within a smaller area than that covered by larger macrocells. A macrocell site is a cell site with a larger antenna and a controller that covers a larger area and can handle more traffic. Picocells require local electricity and connections back to the mobile carrier's equipment. Picocell Technology with Centralized Management Capability and Multisite Distribution New systems for in-building coverage are suitable for enterprises that want uniform coverage for multiple sites. These systems have centralized controllers that track all mobile devices and manage the handover between antennas when employees move about the building. The local antennas and central controller are connected together by the LAN a