5 Layer 1

3GPP43.055Dual Transfer Mode (DTM)Release 16Stage 2TS

Some modifications or extra requirements affect layer 1 areas:

1. Timing advance;

2. Measurement reporting;

3. Power control.

These issues are dealt with in the following clauses.

5.1 Timing advance

A mobile station in DTM shall disable the timing advance features for the GPRS side:

– the mobile station shall inhibit the transmission of timing advance access bursts;

– the mobile station shall ignore the reception of GPRS timing advance messages, if any.

The reporting period and the SACCH message block shall be the same as though the mobile station was in dedicated mode.

5.2 Measurement reporting

The mobile station shall continue to send measurement reports for the circuit switched part, but GPRS measurement reports shall not be sent. The mobile station shall be able to send extended measurement reports when commanded by the network.

5.3 Power control in multislot operation

5.3.1 General

The difference of C/I requirements and the possibility of using different coding schemes in both domains may result in a difference in the power used in adjacent timeslots. This difference in power needs further consideration, which it is done in the following clauses.

5.3.2 Uplink multislot power control

On the network side, there is no restriction for the difference of power received in adjacent timeslots.

On the mobile station side, the power control in different timeslots shall be independent and with no restriction for the difference of power transmitted in adjacent timeslots.

The MS shall measure the signal strength of each radio block monitored by the MS. The C value used for the uplink power control is achieved by filtering the signal strength with a running average filter. Upon the change from one RR mode to another, the filtering shall be restarted if there is no valid C value available. In case the mobile station and the network support enhanced DTM CS establishment procedure, when entering DTM from packet transfer mode, the filtering shall continue from the C value obtained during packet transfer mode (see 3GPP TS 45.008[7]).

In single timeslot operation, the power control for both domains is performed on the SACCH.

5.3.3 Downlink multislot power control

On the network side, there is no restriction for the difference of power transmitted in adjacent timeslots.

As in normal GPRS power control and in addition to the cells present in SI5, the mobile station shall also perform measurements of the serving cell if the FH sequence does not include the BCCH carrier.

In DTM multislot configurations, if the BTS output power for the CS timeslot is not within the range from the maximum downlink power allowed for the MS on the PS timeslot(s) to a power level 10 dB lower, the MS is not required to fulfil the requirements in 3GPP TS 45.005 on the CS timeslot and/or the PS timeslot(s).