TABLE OF CONTENTS Playing an increasingly more important role in technology, as well as in daily life, wireless communication systems from the very beginning have also been used for data transmission in distributed measurement systems. Wireless transmission is the only possible transmission method in systems where the object of measurement is moving (e.g., a vehicle), or is a large distance away from the measurement system center (e.g., radar sondes or spatial bodies), or is hardly accessible. When deployment or operating costs of a telephone or measurement line are high, wireless measurement systems can provide an alternative to their wired counterparts. Wireless data transmission is serial only, even in multichannel systems.
There are three types of measurement systems with wireless data transmission:
Distributed measurement systems with data transmission through a cellular telecommunication network (mobile telecommunications);
Distributed measurement systems with data transmission through dedicated (nontelephone) radio channels;
Measurement systems with short distance wireless data transmission through infrared or radio frequency link.
The first two types of measurement systems are distributed within the coverage of communications systems, and thus their range can be practically global. In particular, such systems can involve spatial objects as well.
In contrast to the mobile phone network-based systems, principally designed for audio signal (mainly voice) transmission, and in which data transfer is just one of several functions, distributed systems using dedicated radio channels are designed and constructed for digital data transmission exclusively. A radio-transmission system comprises transmitters, receivers, a set of radiomodems, and measurement units.
