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Works on Professional Mobile Radio

Works and discussions are taking place currently to study and evaluate the future for Professional Mobile Radio. While current PMR networks are used to essentially carry low throughput voice and data flows, the question arises for the future developments, particularly in the context of wider development of mobile communications networks towards the provision of broadband data transmission services [34].

Several PMR systems are deployed for different applications. We can distinguish two main categories:

  • • The digital technologies with band lower than 25 kHz, providing throughput up to few tens of kbps, for example TETRA technologies TETRAPOL, DMR, dPMR, NXDN;
  • • The digital technologies operating in channels form 50 to 200 kHz, providing throughput up to several hundred kbps, for example TEDS and GSM-R technology.

The evolution of PMR uses to high-speed services raises questions about the technologies that can meet these future new needs. Indeed, the current deployed PMR ensures the voice communication needs and short messages data type. However, the technology does not seem at this stage able to address the problem of high or very high-speed data transfers. It appears that suppliers of “classical” mobile network equipment and PMR specialists actors have entered into partnerships for the development of PMR solutions based on the LTE technology, including communications infrastructure and mobile devices. LTE seems to be one of the possible evolution of technology to meet all or part of PMR needs, with larger bandwidth of 1.4 MHz, 3 MHz or 5 MHz [34].

The AGURRE French organism [35] aims to gather, represent and defend the interests of the major users of PMR in order to define a regulatory framework for the future implementation of broadband networks. AGURRE brings together different stakeholders, such as airline companies, airports, railway or highway operators. The approach consists in the participation in different groups of national and international works that are responsible for establishing a unified technology standard for broadband radio networks. AGURRE ensures that:

  • • All the professional needs are ensured by the standard (transport, security, industry, ...)
  • • The standard is recognized at the world level (Europe, North America, Asia,...)
  • • The standard is part of a common technology for both the mass market and the professional market.

The objective is also to propose a national translation of the technology in France that is suited to the professional world, by the allocation of frequency spectrum bands and the possible use of these bands by users.

The implementation of broadband radio networks aims to ensure functional needs, such as:

  • • Video streams transmission in mobility conditions;
  • • Connection of mobile equipments (vehicles or persons) to a centralized computer application.

The latter application can be used for instance for the transfer of maintenance or for ticketing data. These needs fit naturally into a people and objects connectivity trend that can be generalized to the whole society.

The strategy of AGURRE is to rely on widespread technologies and to offer maximum interoperability at both terminals and network infrastructures. Therefore, the association looks at the LTE technology. Regarding frequency spectrum resource, AGURRE discussions lead to the obtaining of a “principal” frequency band which could be contained in one of these two bands:

  • • The 400 MHz band, currently used by PMR;
  • • The 700 MHz band, which will be released soon (as it will be seen in the following).

Other “secondary” bands could be allocated to answer specific requirements, such as transmission in confined areas such as tunnels, which will need high frequency band (>2 GHz), or transmission on long distances on lower frequency bands

(<380MHz). AGURRE is currently working to evaluate the bandwidth required to ensure functional needs expressed by users.

Finally, it is important to notice that USA Public Safety decided several years ago to adopt LTE 700 MHz as the future of the current TETRA technology. Furthermore, the TETRA MoU promotes the fact that TETRA technology can be maintained as a narrow band technology for critical services and complemented by a LTE providing broadband for complementary non-critical services.

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