JPL's Wireless Communication Reference Website

Chapter: Network Concepts and Standards


Paging

Paging is a wireless service to send simple messages to a mobile subscriber. The message can be a simple 'beep', a number or an alphanumerical message. CCIR Recommendation 584 (1982) defines
Paging
is a non-speech, one-way, personal selective calling system with alert without message or with defined message such as numeric or alphanumeric
In 1995, 31 Million people used pagers. Paging is a cheap service and can enhance the use of CT2 cordless phones that can make calls, but not receive calls.

There two main paging standards:

Increasingly, subcarrier signals added to FM radio broadcasts are used to support paging services.

POCSAG

ERMES

European Radio Message Service (ERMES) is a European common standard for paging developed by ETSI, supporting ERMES uses a network of terrestrial base station transmitting on 16 channels between 169 and 170 MHz. The channel bandwidth is 25 kHz. The modulation method is 4-PAM FM at 6.25 kbit/s. The pager only needs to listen to one channel at a time.

Data Format

30 bits form a code word, that is transmitted in 4.8 msec. 18 out of these 30 bits carry user data, 12 bits of redundancy allow forward error correction. ERMES signals are transmitted as batches, lasting about 750 msec. One batch contains

Hierarchy

ERMES systems became operational in February 1996.

New proprietary systems are also proposed, for instance the FLEX system designed by Motorola.



JPL's Wireless Communication Reference Website Jean-Paul M.G. Linnartz, 1993, 1995.