Real-time media or multimedia services in 3GPP GSM/EDGE-compliant mobile radio networks call for reducing the actual latency of transmissions. Resources are assigned by the network to set up or reconfigure a TBF associated to the uplink/downlink transmission of radio blocks from/to an MS. A 5-bit "Coding" field is configured in the header of the involved RLC/MAC messages to select the transmitting/receiving window size. An additional signaling bit, also called scaling bit, is asserted/negated according to two opportunities offered by the new MAC protocol to properly select the window size. Thanks to the introduction of the scaling bit a subdivision of the time windows for type of services is made possible. Non real-time services, e.g. file transfer, all of standard window sizes for MSs with multistat capability, as reported in 3GPP TS 44.060, V7.3.0 (2006 February), Release 7, subclause 9.1.9, for EGPRS TBFs. Delay-sensitive services, e.g. media or multimedia real-time transmissions, avail of new window sizes with scaled down values remapped to start from 1 to (maximum) 64 RLC/MAC blocks. The scaling bit is asserted or negated by BSC accordingly. Both peer entities comprised in a TBF are receiving the RLC/MAC messages with the proper setting of the scaling bit and the 5-bit coding IF; these entities decode the scaling bit and behave accordingly. The behavior includes either assuming the standard window size or scaled window size addressed by the same predetermined 5-bit "coding" information element.