Downlink user allocations (LTE)

You can have the demodulator autodetect allocations by modulation type or by decoding PDCCH Physical Downlink Control Channel, or you can define user mappings manually.

Configure decoded PDCCH autodetection
Configure power-based autodetection
Configure user allocations manually

You can interact with the allocations in the RB Mapping grid below by clicking on them. Clicking selects an allocation. Dragging will reposition an allocation, and dragging the circular handles at the corners will resize an allocation.

When Auto-detect Power Levels selected, the Edit User Mapping... button will be disabled.

For downlink signals, auto detection supports only PDSCH Physical Downlink Shared Channel allocations transmitted on C-RS Cell-specific RS antenna ports.

To set parameters for Decoded PDCCH RB autodetection:

Select RB Auto Detect
Set RB Auto Detect Mode to Decoded PDCCH
Set Expected Num. of Users
Configure codeword power detection

Select Auto-detect Power Levels

-or-

Clear Auto-detect Power Levels, and then specify codeword powers (CW0 Power and CW1 Power) for each user in the LTE Long Term Evolution Allocation Editor. Alternately, you can select Use Per-antenna EPRE and specify the EPRE parameter. Then click OK to save changes and close the LTE Allocation Editor.

To set parameters for power-based RB autodetection:

Select RB Auto Detect
Open the LTE Allocation Editor

Click MeasSetup > LTE Demod Properties > Profile Tab > Edit User Mappings...
Set RB Auto Detect Mode to Power Based
Configure codeword power detection

Select Auto-detect Power Levels

-or-

Clear Auto-detect Power Levels, and then specify codeword powers (CW0 Power and CW1 Power). Alternately, you can select Use Per-antenna EPRE and specify the EPRE parameter. Then click OK to save changes and close the LTE Allocation Editor.
Select the codewords to include in analysis by selecting the check boxes to the left of CW0 Mod Type and CW1 Mod Type.
Set MIMO Multiple Input, Multiple Output: A physical layer (PHY) configuration in which both transmitter and receiver use multiple antennas. parameters for multiple-antenna signals. These parameters apply to all three autodetected modulation groups (QPSK Quadrature phase shift keying, 16QAM, and 64QAM).
1. Select Precoding type to detect
2. Specify No. Layers
3. Specify No. Codewords
4. Specify Codebook Idx
5. Specify CDD
Click OK to save changes and close the LTE Allocation Editor.

To define user mappings manually:

Open the LTE Allocation Editor

Click MeasSetup > LTE Demod Properties > Profile Tab > Edit User Mappings...
Clear RB Auto Detect
Configure multi-frame analysis (optional)

For single-antenna TDD Time Division Duplex: A duplexing technique dividing a radio channel in time to allow downlink operation during part of the frame period and uplink operation in the remainder of the frame period. signals, you can define allocations for two different frames. To configure the demodulator for multi-frame analysis:
1. Make sure Input > Channels is set to a single-channel configuration
2. Select Multi-Frame Analysis
3. Set the frame to show on the RB Mapping graph in the lower section of the LTE Allocation Editor using the Show Mapping parameter
Add a user
1. Click the Add button next to the list of users
2. Configure User-specific Reference Signal settings
  1. Set RNTI
  2. Select UE-specific RS Present
  3. Select UE-specific RS Include
  4. Specify UE-specific RS Power (dB)
  5. Specify UE User Equipment (e.g. cell phone)-specific RS Port and n_SCID
Set the MIMO parameters for the user
1. Select Precoding type for this user
2. Specify No. Layers
3. Specify No. Codewords
4. Specify Codebook Idx
5. Specify CDD
Configure user resource block allocations
1. Select the codewords to include in analysis by selecting the check boxes to the left of CW0 Mod Type and CW1 Mod Type.
2. Add a resource block allocation for each rectangular section of the LTE frame that the user has been assigned by clicking the Add button next to the slot allocations.
3. Set the resource block and slot boundaries for each allocation (RB Start, RB End, Slot Start, and Slot End).
4. Set the codewords' modulation types (CW0 Mod Type and CW1 Mod Type).
5. Set codeword powers (CW0 Power and CW1 Power)
  or
  Select Use Per-antenna EPRE and specify the EPRE parameter.
6. (TDD only, single antenna) When performing multi-frame analysis, specify which frame contains the allocation using the Frame Index parameter.
When a parameter is different for each allocation, clear the check box to the right of the parameter, and set the parameter for each allocation separately.
Repeat steps 4-6 to add more users
Click OK to save changes and close the LTE Allocation Editor.

For more information about the parameters, see LTE Allocation Editor.