Digital mobile communication is widely thought to be synonymous with cellular telephony. In fact, the spectrum includes not only GSM, but also broadcast-type networks. Accordingly, the German Federal Communication Network Agency assigns frequency bands for trunked radio and paging in addition to digital cellular networks. The chart below illustrates the various technologies in use.
A network architecture oriented towards two-way communication, and primarily used for individual mobile communications. Characteristics include the need for reusable frequencies, upstream transmission by the mobile user device, and often sharing of frequency bands between different user groups. Cellular networks include the GSM and UMTS-based networks as well as the MPT1327, TETRA, and TETRAPOL trunked radio networks. The architecture of cellular networks does not permit guaranteed delivery times for short-message services (SMS, SDS).
Networks with stationary or mobile user equipment in which a given message can be sent to any number of user devices at once. The transmission cost is independent of the number of users who receive the information. Such networks include broadcast radio and television networks, as well as paging networks.
The wireless transmission of coded signals or short messages to a mobile receiver, called a pager. Depending on the pager’s configuration, it can receive a sound, several sounds, a number, or any alphanumeric text of a limited length. Paging systems also support group calls, in which one and the same message is sent to many users at once.
In a study by RWTH Aachen University, Prof. Bernhard Walke compares paging with cellular telephony networks and digital radio services. “Paging services”, the study concludes, “have undeniable advantages over all other wireless communication technologies, whether cellular telephony, satellite radio, or wireless access to terrestrial networks.” With paging technology, the users remain reachable almost all the time. Paging is also superior to other wireless systems — drastically in some cases — for fast and reliable alerting of individuals and groups.
Among the outstanding advantages of paging are nationwide coverage, long battery life, low latency, group call capability, and a high location and time probability. Unlike cellular phone networks, the number of users that can be addressed by a single base station is unlimited. Only paging makes point-to-multipoint applications with several hundred or even thousands of users economically feasible. According to the RWTH study, paging systems have a “substantial development potential”. Integration in hybrid systems, for example, leads to completely new areas of application.