The present document specifies the minimum performance parameters for terrestrial digital fixed service radio
communications equipments operating in the 15 GHz to 38 GHz frequency band intended to be used for point-to-point
connections in local and regional networks at data rates between 2 × STM-1 (transported by one carrier) and 4 × STM-1
or STM-4 (transported by two 2 × STM-1 carriers).
Harmonized channel spacings of 56 MHz are not available in frequency bands below 15 GHz at the drafting date of the
present document. However, the present document can be considered as a guideline where national frequency plans
allow the use of 55/56 MHz channel spacing in other frequency bands, or where an allocation of two contiguous
28 MHz channels is possible.
The maximum transmission rate in a given bandwidth depends on system spectral efficiency, a single equipment class is
defined:
Class 5: equipment spectral efficiency based on typically 128-states modulation scheme (e.g. 128-QAM,
or equivalent).
However, for addressing different market requirements, the systems are further subdivided in two grades:
a) Adjacent Channel Alternate Polarization (ACAP as class 5a).
b) Adjacent Channel Co-Polarization (ACCP or CCDP as class 5b).
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.
Examples of the spectrum usage are given in figure 1.
The 4 × STM-1 or STM-4 connection is achieved by two 2 × STM-1 carriers. The two carriers can be arranged in three
configurations:
a) Adjacent Channel Alternate Polarization for which ACAP, class 5a is applicable.
b) Adjacent Channel Co-polarization for which ACCP, class 5b is applicable.
c) Co-Channel Dual Polarization for which CCDP, class 5b is applicable. For this configuration, XPIC may be
used.
Examples of the three spectrum usage of a 4 × STM-1 or STM-4 (...abbreviated)