scope:

The present document specifies the minimum performance parameters for terrestrial digital fixed service radio communications equipments operating in the 55 GHz frequency band and is a complete revision of the existing ETS 300 407 (March 1997) specification in the areas of:

- introduction of unique system type codes for regulatory reference to the various system types detailed in the present document, refer to new annex C (normative) and related categories of equipment classes of spectral efficiency;

- additional systems with higher spectrum efficiency in the new classes 1 to 4;

- removal of Analogue services;

-digital services restricted to frequency division duplex (FDD) operation only;

- technical specifications relevant to the EMC Directive, detailed in annex B (normative);

- specific antenna radiation patterns (now superseded by EN 300 833 [12]).

Harmonized channel spacings lower than 14 MHz are not defined in the 55 GHz band at the drafting date of the present document as there is still a pending decision on the WRC2000 agenda item 1.4. However the present document includes 7 MHz and 3,5 MHz channel spacings and can only be considered as a guideline until a decision at WRC2000 is taken and ERC harmonized channel arrangements would possibly be enlarged to include those smaller channel spacings.

Digital systems are intended to be used for point-to-point connections in local and regional networks at data rates between 2 Mbit/s and Synchronous Transport Module, level 1 (STM-1).

Digital systems considered in the present document will be able to meet the error performance objectives of the ITU-R national portion of the reference path, i.e. ITU-R Recommendation F.1189 [19] and the error performance objectives detailed in ITU-T Recommendation G.826 [26].

The parameters to be specified fall into two categories:

a) those that are required to provide compatibility between channels from different sources of equipment on the same route, connected to separate antennas;

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

The present document deals with Radio Frequency (RF) and baseband characteristics relevant to low, medium and high capacity Plesiochronous Digital Hierarchy (PDH) transmission systems, and STM-0 and STM-1 Synchronous Digital Hierarchy (SDH) transmission systems. Antenna/feeder system requirements are covered in EN 300 833 [12].

The present document does not contain aspects related to test procedures and test conditions however they are to be found in EN 301 126-1 [3].

As the maximum transmission rate in a given bandwidth depends on system spectral efficiency, different equipment classes are defined:

Class 1: equipment spectral efficiency based on typically 2-states modulation scheme (e.g. 2-FSK, Gaussian Minimum Shift Keying (GMSK) with discriminator detection, or equivalent);

Class 2: equipment spectral efficiency based on typically 4-states modulation scheme (e.g. 4-FSK, 4-QAM, or equivalent);

Class 3: equipment spectral efficiency based on typically 8-states modulation scheme (e.g. 8PSK, or equivalent);

Class 4: equipment spectral efficiency based on typically 16 or 32-states modulation scheme (e.g. 16- QAM, 32-QAM, or equivalent). The above classes are indicative only and do not imply any constraint to the actual modulation format, provided that all the requirements in the present document are met.

Safety aspects are not considered in the present document. However compliance to CENELEC EN 60950 [34] will be required to comply with the 99/5/EC [35] Directive (R&TTE). Technical background for most of the parameters and requirements referred in the present document may be found in TR 101 036-1 [14]