scope:

The present document specifies the minimum performance parameters for terrestrial fixed service radio communications equipments operating in the frequency range 24,50 GHz to 29,50 GHz and contains a revision from the previous version, 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 and related categories of equipment classes of spectral efficiency;

- additional systems with higher spectrum efficiency in the new class 4 systems;

- change of spectrum mask and adjacent channel selectivity of STM-0 systems in 28 MHz channel spacing to align to EN 300 639 [34];

- introduction of new spectrum efficiency class 5 for STM-1 capacity for 28 MHz Adjacent Channel Alternate-Polarization (ACAP as class 5a) and Adjacent Channel Co-Polarization (ACCP as class 5b), see examples of the spectrum usage in figures 1.1a and 1.1b;

- change to spectrum mask for class 4 (140 Mbit/s to 155 Mbit/s) at "f5" to align with the mask used in the 23 GHz and 38 GHz standards;

- technical specifications relevant to the EMC Directive, detailed in annex B.

NOTE: In a previous version (ETS 300 431), there was provision for:

- further options for Grade A digital radio systems (with 112 MHz Channel separation);

- specific antenna radiation patterns (now superseded by EN 300 833 [3]).

These options are not reprinted in the present document as they are considered to be no longer of interest for ETSI members. However, for regulatory purposes, they may still be referenced from ETS 300 431.

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 the Synchronous Transport Module, level 1 (STM-1).

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 either:

- to separate antennas; or

- to separate polarizations of the same antenna.

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, STM-0 and STM-1 Synchronous Digital Hierarchy (SDH) transmission systems. Antenna/feeder system requirements are covered in EN 300 833 [3].

For digital systems, with capacities up to 34 Mbit/s, for class 2 equipment there are also two types of equipment specified:

- grade A equipment, intended for applications where moderate frequency congestion is envisaged;

- the deployment of Grade A equipment in new links will be limited and stopped over a period of time. Therefore, it is likely that provision for Grade A equipment will be removed from the present document during the next revision;

- grade B equipment, intended for applications where higher nodal capacity is required.

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 [2].

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

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);

class 5: equipment spectral efficiency based on typically 64 or 128-states modulation scheme (e.g. 64-QAM, 128-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 will not be considered in the present document. However compliance to EN 60950 [35] will be required to comply with Directive 1999/5/EC [36] (R&TTE).

Technical background for most of the parameters and requirements referred in the present document may be found in TR 101 036-1 [21].