scope:

This European Telecommunication Standard (ETS) specifies the minimum performance parameters for terrestrial fixed services radio communications equipment, as given below, for operation in the 13 GHz, 15 GHz and 18 GHz frequency bands (12,75 to 13,25 GHz, 14,50 to 15,35 GHz and 17,70 to 19,70 GHz).

This ETS covers equipment for the transmission of sub Synchronous Transport Module level-1 (STM-1) digital signals with a VC3 payload capacity. The standardisation of sub STM-1 radio systems for 13 GHz, 15 GHz and 18 GHz bands has been prepared to ensure the compatibility with the existing plesiochronous and the new synchronous systems concerning frequency plans and performance. The architecture and functional aspects should be in accordance with CCIR Recommendation 750 [9] and transmission characteristics and performance requirements in accordance with CCIR Recommendation 751 [10].

The application of these digital radio-relay systems is anticipated to be for point-to-point links in local, regional and national networks, mobile base station connections and customer access links. Consideration has to be given to special requirements of the local network, e.g. simple towers with less space for antenna, different network structures with high density nodes.

The systems considered shall operate in these networks having regard for existing hop lengths, which are considered to be normally up to about 15 km for the 18 GHz band, 20 km for the 15 GHz band and 30 km or more for the 13 GHz band.

Systems considered in this standard should be able to respect performance objectives, i.e. CCIR Recommendations 634 [5], 557 [3]' 696 [7], 697 [8]' ITU-T Recommendation G.821 [20], ITU-T Recommendation G .826 [21],

The parameters to be specified fall into two categories:

a) those that are required to provide compatibility between RF channels occupied by different sources of equipment on the same route connected either to:

- separate antennas; or to

- separate polarisation of the same antenna;

b) parameters defining the transmission quality of the proposed system.

The standardisation deals with Intermediate Frequency (IF), Radio Frequency (RF) and baseband characteristics relevant to sub STM-1 Synchronous Digital Hierarchy (SOH) transmission. Spurious emissions and Electro Magnetic Compatibility (EMC) requirements are also included in this ETS.