This is an implementation of Packet Control Unit (PCU) according to TS 04.60 The PCU is part of BSS, so it connects directly to SGSN. == Current limitations == * No PFC support * No fixed allocation support * No extended dynamic allocation support * No unacknowledged mode operation * Only single slot assignment on uplink direction * No half-duplex class support (only semi-duplex) * No handover support * No measurement support * No TA loop * No power loop * No CS loop * No EGPRS