7 DTM operation

03.553GPPDual Transfer Mode (DTM)Release 1999Stage 2TS

Once the mobile stations enters the DTM, the existent RLC/MAC procedures apply, with the exception of the case of an exclusive allocation of an uplink PDCH (including the PDHC/H of a "TCH/H + PDHC/H" configuration). In that case, the mobile station is always granted the transmission of uplink RLC/MAC blocks, which keep the current format. Thus, the mobile station will ignore the USF mechanism or the allocation bitmap for dynamic or fixed allocation, respectively.

Other exceptions to the existent RLC/MAC procedures are:

  • The mobile station shall not accept a packet assignment command (addressed to it on the PACCH) that changes the frequency definition of the PDCH. Such change shall be done by means of a DTM Assignment Command message on the main DCCH (changing both TCH and PDCH configurations). A modification of the timeslot allocation may occur by means of a Packet Assignment message. Any violation of the frequency restrictions or the multislot class of the mobile station (taking both TCH and PDCH resources into account) shall be treated as an abnormal case and the TBF(s) shall then be aborted.

NOTE 1: the PCU should know that the mobile station is in dual transfer mode and therefore format the messages correctly.

  • When all TBFs have been released (or aborted), the mobile station returns to dedicated mode.
  • When the mobile station is in dual transfer mode, it shall ignore a Packet Cell Change Order or a RR-Cell Change Order message and shall remain in dual transfer mode.

NOTE 2: the PCU should know that the mobile station is in dual transfer mode and therefore not send these messages.

  • When a mobile station in dual transfer mode receives a valid RRBP field in a downlink RLC/MAC block, if it has been assigned PDCH/H, the mobile station shall use normal bursts and not access bursts to transmit the Packet Control Acknowledgement message, irrespective of the value of the CONTROL_ACK_TYPE field received in the DTM Assignment Command message or Packet Assignment message. If the mobile station has not been assigned PDCH/H, it shall transmit the Packet Control Acknowledgement message according to the value indicated by CONTROL_ACK_TYPE field received in the DTM Assignment Command message or Packet Assignment message.

The mobile station remains in DTM until the CS connection or all the TBFs are released.