The present document specifies the minimum performance parameters for terrestrial fixed service digital radio
communications equipments operating in the 13 GHz, 15 GHz and 18 GHz frequency bands.
Digital Radio Relay Systems (DRRS) are used for point-to-point connections in local, regional and national networks at
data rates between 2 Mbit/s and 34 Mbit/s.
As harmonized channel spacings lower than 13,75 MHz are not available in the 18 GHz frequency band at the drafting
date of the present document, capacities lower than 2 x 8 Mbit/s are consequently not considered in this frequency band.
However the present document can be considered as a guideline when national frequency plans based on a 3,5 MHz
channel spacing exist.
Systems considered in the present document are able to respect ITU-R Recommendation national or international grade
performance objectives, i.e. ITU-R Recommendations F.1189-1 [9] for national, ITU-R Recommendation F.1092-1 [8]
for international and ITU-T Recommendation G.826 [11]. Maximum hop lengths of about 35 km are normally
achievable according to the considered frequency bands.
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 and medium
capacity Plesiochronous Digital Hierarchy (PDH) transmission. Antenna/feeder system requirements are covered in
EN 300 833 [18].
As the maximum transmission rate in a given bandwidth depends on system spectral efficiency, different classes are
defined:
Class 1: equipment based on a minimum 4-state modulation scheme (e.g. 4-FSK, 4-QAM, or equivalent).
Cl (...abbreviated)