scope:

The present document specifies parameters for digital radio-relay systems with Transport Module-level 4, (1 x STM-4), interface, and in addition, optional 140 Mbit/s PDH interfaces.

The present document is applicable to systems carrying an STM-4 signal over a pair of RF channels each with a capacity of 2 x Synchronous Transport Module-level 1, (2 x STM-1), designed to operate in defined bands utilizing 40 MHz between adjacent cross-polar channels. Optionally, a single RF channel can be used to transport 2 x Synchronous Transport Module-level 1, (2 x STM-1), signals.

The parameters specified fall into two categories:

a) those 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. This category also includes parameters providing compatibility with the existing radio-relay network;

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

Compatibility requirements with analogue and digital systems on the same hop and at nodes are examined. However, they can not be defined with exactness due to the fact that analogue systems and some digital systems are not standardized. Compatibility requirements are, therefore, limited to allowing the operation of digital and analogue channels on separate ports of the same antenna (see annex B). The standardization includes the following specifications:

a) transmitter and receiver characteristics;

b) baseband and Radio Frequency (RF) interface characteristics;

c) diversity system characteristics;

d) STM-4, or STM-1 baseband transport interface;

e) PDH baseband transport interfaces mapped onto an SDH frame.

Baseband interfaces have to be considered for STM-4 signals and STM-1 signals are in accordance with ITU-T Recommendations G.957 [37] and G.707 [33] respectively.

Safety aspects are outside the mandate of ETSI and they will not be considered in the present document.