This Recommendation covers definitions, architectures and services in Public Land Mobile Networks.The definition section is subdivided into basic,roaming and handover subheadings.The architecture section covers examples of Public Land Mobile Network architecture in roaming and handover situations.The services section covers introductory descriptions of basic and supplementary services that can be provided to the user.
ITU-T Q.1001-1988 history
1988ITU-T Q.1001-1988 GENERAL ASPECTS OF PUBLIC LAND MOBILE NETWORKS