Public Land Mobile Network - Specifications

Specifications

A GSM PLMN may be described by a limited set of access interfaces and a limited set of GSM PLMN connection types to support the telecommunication services described in the GSM 02-series of specifications.

PLMN is network that is established and operated by an administration or by a recognized operating agency (ROA) for the specific purpose of providing land mobile telecommunications services to the public. A PLMN may be considered as an extension of a fixed network, e.g. the Public Switched Telephone Network (PSTN) or as an integral part of the PSTN. This is just one view-point on PLMN. PLMN mostly refers to the whole system of networking hardware and software which enables wireless communication, irrespective of the service area or service provider (cf. Internet backbone). Sometimes separate PLMN is defined for each country or for each service provider. Its case is same as that of PSTN. Sometimes it refers to the whole circuit-switched system, or else specific to each country.

PLMN is not a term specific to GSM. In fact GSM can be treated as an example of a PLMN system. These days (as of January, 2006) much discussions are going on to form the structure of UMTS PLMN for the third generation systems. Access to PLMN services is achieved by means of an air interface involving radio communications between mobile phones or other wireless enabled user equipment and land based radio transmitters or radio base stations PLMNs interconnect with other PLMNs and PSTNs for telephone communications or with internet service providers for data and internet access.

A public land mobile network may be defined as a number of mobile services switching centre areas within a common numbering plan and a common routing plan. With respect to their functions, the PLMNs may be regarded as independent communications entities, even though different PLMNs may be interconnected through the PSTN/ISDN for the forwarding of calls or network information. The MSCs of a PLMN can be interconnected similarly to allow interaction. A PLMN may have several interfaces with the fixed network (e.g. one for each MSC). Inter-working between two PLMNs may be performed via an international switching centre. The PLMN is connected via an NCP to the PSTN/ISDN. If there are two mobile service suppliers in the same country, they can be connected through the same PSTN/ISDN.