Résumé
In telecommunications, point-to-multipoint communication (P2MP, PTMP or PMP) is communication which is accomplished via a distinct type of one-to-many connection, providing multiple paths from a single location to multiple locations. Point-to-multipoint telecommunications is typically used in wireless Internet and IP telephony via gigahertz radio frequencies. P2MP systems have been designed with and without a return channel from the multiple receivers. A central antenna or antenna array broadcasts to several receiving antennas and the system uses a form of time-division multiplexing to allow for the return channel traffic. In contemporary usage, the term point-to-multipoint wireless communications relates to fixed wireless data communications for Internet or voice over IP via radio or microwave frequencies in the gigahertz range. Point-to-multipoint is the most popular approach for wireless communications that have a large number of nodes, end destinations or end users. Point to Multipoint generally assumes there is a central base station to which remote subscriber units or customer premises equipment (CPE) (a term that was originally used in the wired telephone industry) are connected over the wireless medium. Connections between the base station and subscriber units can be either line-of-sight or, for lower-frequency radio systems, non-line-of-sight where link budgets permit. Generally, lower frequencies can offer non-line-of-sight connections. Various software planning tools can be used to determine feasibility of potential connections using topographic data as well as link budget simulation. Often the point to multipoint links are installed to reduce the cost of infrastructure and increase the number of CPE's and connectivity. Point-to-multipoint wireless networks employing directional antennas are affected by the hidden node problem (also called hidden terminal) in case they employ a CSMA/CA medium access control protocol.
À propos de ce résultat
Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.