Downlink Dual Carrier

Downlink Dual Carrier

Last updated: May 31, 2010

This section is applicable to the EGPRS lab application and test application with a required feature license.

The Downlink Dual Carrier (DLDC) assigns PDTCH resources to a mobile on two different carriers. With DLDC-based transfer, the downlink throughput theoretically scales linearly with the total number of timeslots allocated to a downlink TBF.

DLDC Assignment Types

Any changes to the connection state, the DLDC state or the PDTCH parameters in the test set may result in the mobile receiving an assignment message (e.g. Packet Uplink/Downlink Assignment) with updated ASSIGNMENT TYPE IE field and CARRIER ID IE field, indicating that the assignment is an `Assignment on single carrier only', `Dual Carrier Assignment' or `Modification of existing assignment' by carrier ID.

The following table outlines the Assignment Type and Carrier ID that included in the assignment message associated with the actions.

Note: PDTCH1 specifies PDTCH resource on `Carrier ID 0' and PDTCH2 specifies PDTCH resource on `Carrier ID 1'.

Current PS State

Current DLDC State


Assignment Type

Carrier ID

Packet Idle On Start Data Connection Dual Carrier Assignment


Packet Transfer


Change DLDC State to ON

Modification of Existing Assignment

Carrier ID = 1

Packet Transfer


Change DLDC State to OFF

Single Carrier Assignment

Carrier ID = 0
Packet Transfer On

Change one of the following parameters on PDTCH1:


- P0

- PDTCH Band



- PDTCH Multislot Config

- Custom PDTCH Multislot Config

- PDTCH Frequency Hopping State

Modification of Existing Assignment

Carrier ID = 0

Packet Transfer


Change one of the following parameters on PDTCH2:

- Multislot Config

- Custom Multislot Config

- P0

- Frequency Hopping State



Modification of Existing Assignment

Carrier ID = 1

Packet Transfer


Change one of the following parameters:

- TTI Mode


- PDTCH MS Output Power Control

- PDTCH MS Tx or Gamma Levels

- Downlink MCS

- Uplink MCS

- MA Table


Dual Carrier Assignment


DLDC Uplink Carrier Control

When DLDC is enabled, the Assigned DLDC Uplink Carrier(s) parameter allows configuration of which PDCH carriers are assigned to the DUT during uplink TBF establishment/reassignment (therefore specifying which carrier(s) the DUT must monitor for USF allocation). When this parameter is set to `PDTCH 2' and Downlink Dual Carrier state is enabled, if an uplink TBF is established the assignment parameters shall be those associated with PDTCH2; when this parameter is set to `Both' the Allocated DLDC Uplink Carrier parameter further qualifies which of the assigned uplink PDCH carriers is currently being granted a USF.

Due to the limitation of receiver in the test set, when the Allocated DLDC Uplink Carrier is modified during uplink TBF transfer where both DLDC carriers are assigned, there shall be a short (transient) period of time where USFs are not allocated to the DUT (during which the uplink channels are reconfigured within the test set), it requires several frames to perform.

Note: when a DUT is polled, the DUT will respond to the poll on the carrier on which the block specifying a poll response was received. If the currently allocated uplink carrier is changed before an outstanding poll response has been received, the poll response shall be lost.

Constrains on PDTCH Configuration

When setting the PDTCH configuration for DLDC Configuration, the following overriding restrictions apply:

Configurable Parameters

The DLDC settings are as shown in the table below:


GPIB Command

Downlink Dual Carrier State CALL:(PDTChannel|PDTCH):DLDCarrier[:STATe]

Deferred Downlink Dual Carrier State


DLDC UL Carrier(s) Assigned


DLDC UL Carrier Allocated


Optional Dual Carrier Reassignment State


PTR for TBF Establishment State


Legacy IEs For Single Carrier Assignment State


Deferred DLDC UL Carrier(s) Assigned


Deferred DLDC UL Carrier Allocated


PDTCH2 Traffic Channel CALL:(PDTC2|PDTCH2|PDTChannel2):ARFCn[:SELected]

PDTCH2 Frequency hopping state





PDTCH2 Power Reduction Level


PDTCH2 Power Reduction Level Burst <1-5>


PDTCH2 Downlink MCS Burst <1-5>




PDTCH2 MCS/PS Burst <2-5> CALL:(PDTC2|PDTCH2|PDTChannel2):MCSCheme:EBPTest:BURSt<2|3|4|5>

PDTCH2 Multislot Config


PDTCH2 Custom Multislot Config


How to set the DLDC mode?

The following procedure details how to access and configure the DLDC mode.

  1. Press CALL SETUP .
  2. Press the More key on the lower right corner to display the PDTCH parms (3 of 3).
  3. Press DLDC Mode ( F8 ) to display the DLDC Setup menu. Use the knob to select the parameter that you want to set.

Operating Considerations

The DLDC mode is only available in the Active Cell(EGPRS) and EGPRS BCH+PDTCH operating mode. However, parameters associated with DLDC can be changed in other operating modes, but do not effect the test set's operation until the operating mode is changed to the above values.

When the DLDC mode is enabled, performing the following measurements when the data connection type is ETSI-B or SRB loopback will result in the measurement returning an `Unsupported Configuration' integrity indicator value:

Continuous Timing Advance restrictions: Due to hardware limitations, when a dual carrier configuration (i.e. two different PDCH carriers assigned) is currently in use and the allocated(i.e. demodulated) uplink carrier is set to PDCH carrier 2, it will not be possible to demodulate the PTCCH/U on PDCH carrier 1, then test set shall implicitly ignore the lack of PTCCH/U bursts (also timeout warnings) and transmit the PTCCH/D as normal. the PTCCH/D shall still be received as part of the continuous timing advance procedure correctly, but the test set will not be able to discern (or report) whether the MS correctly transmitted RACH bursts on the PTCCH/U

Related Topics

TTI Mode Configuration