he world there has been formal adoption of the standard in China and contacts have been let throughout Europe and in the Middle East, Asia, Australia, South America and South Africa, although TETRA is not currently available in North America. TETRA offers various features very useful for PAMR and PMR users that are not available in other standardised current technologies, such as the fast call setup time, excellent group communication sup- port, direct mode operation between radios, high frequency efficiency and excellent security features; furthermore, it also provides packet data and circuit data transfer services. In the current cellular radio systems TETRA is a trunking system from the channel assignment mode of operation point of view. This means that for each cell there is a pool of available traffic channels and each user, in the dedicated mode, have a traffic channel allocated on a call basis. Upon termination of the call, the previously occupied channel returns immediately to the pool of available channels. Using this channel allocation strategy, a large amount of random users can be accommodated in a relatively small number of traffic channels. The TETRA standard has been developed with the aim of supporting international roaming by the provision of national and multinational networks. This means that the TETRA network can be connected various different networks (e.g. PSTN, other TETRA networks, PABX, etc.) and each of them can have a large number of users. Furthermore, the use of shortened identities for intra-TETRA calls is also possible, reducing the signalling information in the call setup messages. Advanced Cellular Network Planning and Optimisation Edited by Ajay R Mishra © 2007 John Wiley & Sons, Ltd TETRA Network Planning TETRA standardisation has reached a mature state. Major future developments are expected to continue with standardisation of the next generation of TETRA release 2 and maintenance of existing TETRA standards. The objective of TETRA release 2 is that EP (ETSI project) TETRA prod