Environmental Telemonitoring: A Flexible GSM-DECT-Based Solution

This paper describes a low-cost standard solution for environmental monitoring. The advent of modern wireless communication technologies has added flexibility to data collection from remotely distributed sensors. In particular, nowadays, wireless Wide Area Networks like the Global System for Mobile communications (GSM) and satellite telephone services are ubiquitous: It has become feasible to collect data from remote sensors at locations which were previously inaccessible due to distance or extremely restrictive conditions. The shortcoming of this approach can be found in the need for a subscription to a telephone service provider. The authors propose to overcome this limitation, realizing a "local" cellular network exploiting a free and standard technology like "Digital Enhanced Cordless Telecommunications" (DECT), typically used for cordless handsets. The link with existing infrastructures can be satisfied with a sort of access point implementing, for example, both the DECT and GSM controllers. Working prototypes have been realized, and some experimental results have been reported. It has been possible to demonstrate the feasibility of a sampling station that is truly autonomous since it is battery powered.