Creating a CDMA2k Waveform

RFmx Waveform Creator 19.1 Help

Edition Date: October 2019

Part Number: 377064G-01

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RFmx Waveform Creator 19.1 Help
RFmx Waveform Creator 20.0 Help

To create a new CDMA2k waveform,

  1. Select the Modulation menu.
  2. Click CDMA2k.

    The New Settings File window appears.

  3. Click OK in the New Settings File window.

    The CDMA2k settings window appears.

Note: If CDMA2k does not appear in the Modulation menu, use the Tools menu to add Registered Plugins niCdma2000GenPlugin.dll.

If example settings are available, you are offered a choice to create a New Default Settings and select an Example Settings.



Fig. 4-12 CDMA2k settings window


This window has tabs for Modulation, Filter, IQ Impairments, and Graphics settings. These tabs are the same as those found in other modulations.

Setting the Modulation Parameters

This section describes the general settings available for CDMA2k and how you can modify them. The above figure shows the default settings that appear when you open a CDMA2k settings window. The spreading rate is direct mode. The chip rate is set to 1.2288 MHz when the spreading rate is x1 and 3.6864 MHz when the spreading rate is x3. The following parameters can be set:

Link Direction

Select the link direction you require using the Link Direction drop-down menu.

Spreading Rate

Select the required spreading rate using the Spreading Rate drop-down menu. You have the choice of x1 or x3. This selection affects the type and number of radio configurations that are available.

Number of Frames

You can select a value in the Number of Frames combo-box to change the number of frames that you want to generate. The length of the resulting waveform is shown in brackets.

Oversampling Factor

The default value is 4. If you want to enter a different value, unselect the Auto checkbox.

Radio Configuration

There is a total of nine radio configurations available.

When the Link Direction is set to Up/Reverse, radio configurations 1 to 4 are allowed if the spreading rate is x1, and radio configurations 5 to 6 are allowed with a spreading rate of x3.

When the Link Direction is set to Down/Forward, radio configurations 1 to 5 are allowed if the spreading rate is x1, and radio configurations 6 to 9 are allowed with a spreading rate of x3.

When you select a radio configuration, the types of channel available to you are presented in the Channel table.

Creating a Reverse Link

Once you have set the general parameters, you can define the reverse channel(s) for your configuration.

Radio Configurations 1 and 2 (RC1 and RC2)

If you have selected either radio configuration 1 or 2 you are only able to define either an Access or Traffic channel. Select the type of channel using the Select Channel combo box. If you select the Access channel you are presented with the settings shown in the following figure.



Fig. 4-13 Settings for RC1 Access Channel


If you selected a Traffic channel the settings are as shown in the following figure. The settings are the same for both RC1 and RC2. Note that because RFmx Waveform Creator does not currently support data encoding, the implementations of RC1 and RC2 are identical.


Fig. 4-14 Settings for RC1 Traffic Channel


You are able to set the Long Code Mask, relative power level of the channel and the data source. The Long Code Mask is a hex number that defines 42 bits. The default value for the access channel is 31E00000000. (For the FCH channel it is 30000000000).

Channel Properties

You can modify the properties of the channel by clicking on any of the editable cells in the table. The channel type, and symbol rate properties are not editable, and are shown with a shaded gray background.

Power

This controls the level of the specific channel. The range is 0 to -60 dB. The default is 0dB

Data Source

This controls the data payload of the channel. Refer to Selecting the Data Source topic for more information on data source.

State

This controls whether the channel will be transmitted or not.

Radio Configurations 3 and 4 (RC3 and RC4)

If you have selected either radio configuration 3 or 4 you are only able to define an Enhanced Access, Common Control or Traffic channel. Select the type of channel using the Select Channel combo box.

If you select an Enhanced Access channel, you are presented with the settings shown in Fig. 4-133.



Fig. 4-15 Enhanced Access Channel settings for RC3


The settings for the Common Control and Traffic channels are shown in the following figures. Once again, because RFmx Waveform Creator does not currently support data encoding, the implementations of RC3 and RC4 are identical.



Fig. 4-16 Common Control Channel settings for RC3




Fig. 4-17 Traffic Channel settings for RC3


For each of the channel types you are able to set the long code mask used for scrambling the data as indicated in the block diagram. The value is entered in hex in the Long Code Mask edit box.

Configuring the Enhanced Access Channel

The enhanced access channel consists of a pilot channel (PICH) and the enhanced access channel (EACH). You are able to set the channel state, power level and data source as described previously for each of the channels. Note that the data source for the pilot channel is PRBS Again, you are able to edit a channel by double-clicking on the cell of interest.

You are able to change the data source and power level. The Walsh Code and symbol rate are fixed and are not editable, shown with a gray background. Again, the power level is limited to the range of 0 to –60 dB. The data source is configured as before.

Configuring the Common Control Channel

The common control channel consists of a pilot channel (PICH) and the common control channel (CCCH). You are able to set the channel state, power level and data source as described previously for each of the channels. Note that the data source for the pilot channel is fixed to zeros. As with the other described channels, you can edit any parameters of interest by clicking on the parameter you wish to modify.

Configuring the Traffic Channel

The traffic channel consists of a pilot channel (PICH), dedicated control channel (DCCH), fundamental channel (FCH), and supplemental channels 1 and 2 (SCH1 and SCH2). You are able to set the channel state, power level and data source as described previously for each of the channels. For the SCH1 and SCH2 channels you are also able to set the spreading factor, Walsh code and symbol rate. Again, the data source is fixed to zeros for the pilot channel. Editing a channel is the same as before. Select the parameter of interest and double-click.

In addition to the power and data source parameters, you are able to set the symbol rate and spreading factor. The Walsh code changes to 1 if you set a spreading factor of 2. The relationships between symbol rate, spreading factor and Walsh code are given in Appendix B. Note that SCH1 and SCH2 support different data rates and can have different Walsh codes.

Radio Configurations 5 and 6 (RC5 and RC6)

You are only able to select the radio configurations 5 and 6 if the spreading rate has been set to x3. You are able to define an Enhanced Access, Common Control or Traffic channel. Select the type of channel using the Select Channel combo box. Once again, because RFmx Waveform Creator does not currently support data encoding, the implementations of RC5 and RC6 are identical. The method of defining and editing the channels is the same as that described for RC3 and RC4. Again, refer to Appendix B to obtain the relationships between data rates, symbol rates, Walsh codes and spreading factor.

Generating a Waveform

Once you have set up the reverse channel and channel filter to suit your needs, you generate the waveform in the same way as for other modulation schemes. Select the Save Waveform File menu and proceed as described in the Getting Started Manual.

Creating a Forward Link

Once you have set the general parameters to your liking, you can define the forward channels for your configuration. Refer to the section ‘Setting the Modulation Parameters’, starting on page 1-12, on how to do this.

Radio Configurations 1 and 2 (RC1 and RC2)

Selecting either radio configuration 1 or 2 presents you with the link configuration set up shown in Fig. 4-136. The settings page is the same for both RC1 and RC2. From here, you are able to set the Pilot PN Offset and configure the forward channels. The Pilot PN Offset is used to set the offset of the scrambling codes. Typically, each base station is assigned its own offset. Valid values are 0 to 511.

The default table shows the Pilot (PICH) and Sync (SYNCH) channels. In general, you would want to turn these channels on. To do this, move your mouse over the State and required channel cell and double-click the left-hand button. Select On to turn the channel on. The spreading factor (SF), Walsh code and symbol rate are fixed for the PICH and SYNCH channels. You can set the relative power level for both channels and the data source type for the SYNCH channel. To set the power level, double-click the left-hand mouse button while the cursor is over the Power and selected channel cell. You can then enter a value between 0 and –60 dB. To select a data source, once again double-click the left-hand mouse button while the cursor is over the Data Source and selected channel cell. On doing this, you are presented with the standard data source dialog, from which you can select the data source required.



Fig. 4-18 Settings for a RC1 forward link


You can use the table to directly edit any of the parameters, although in some situations not all parameters are editable. In such situations, the background color of the table will be shown as light gray.

Symbol Rate

This is the symbol rate used for the particular channel. This is not editable for PICH, SYNC, PCH, and QPCH. As traffic channels are split into sub channels, symbol rate is not applicable.

Spreading Factor

This is the spreading factor for the specified channel. This is derived from the symbol rate of the channel and is for display purposes only.

Walsh Code

This specifies the Walsh code of the given channel. The valid range is 0 to 63. For PICH and SYNC channels, this value not editable. The default value is 0.

Data Source

This defines the data payload of the specific channel. This can either be All zeros, All ones, PRBS, Random, Repeating Pattern, or User defined. The default is a PN 9 sequence for editable Channels.

For PICH channels, the data source is fixed to All Zero’s.

Power

This changes the relative power of the channel within the signal. The allowed range is -60dB to 0dB. The default value is 0dB.

State

This changes whether the channel is transmitted. All default channels are turned off.

To edit any of the parameters; you can click on any of the items within the table.

For traffic channels, you may select the specific channel by pressing the left-hand mouse button when the cursor is on the required channel row. On doing so, the Edit… button at the bottom of the screen will be enabled appropriately. To edit the specific channel, press the Edit… button which will present the dialog shown in the following figure. This dialog will allow you to modify all the properties described above for the component channels within the traffic channel.



Fig. 4-19 Editing a traffic channel


You can add more channels by pressing the Add… button. On doing so, you are presented with the dialog box shown in the following figure. From here, you can add all the channels supported in RC1 and 2 as indicated in Table 4-39. Remove channels by selecting the channel in the table and pressing the Remove… button.



Fig. 4-20 Add channel dialog


The default Add Channel dialog shows the settings for adding a traffic channel. For radio configurations 1 and 2, a traffic channel can consist of one fundamental channel and up to seven supplemental channels. In all cases, the spreading factor is fixed at 64. The Channel State combo box selects the state of the traffic channel. This lets you turn off a traffic channel without having to turn off channels within the traffic channel.

You are able to set the channel state, Walsh code, power level and data source type for each of the allowed channels within a traffic channel. This can be done by selecting the channel of interest and double-clicking the left-hand mouse button when the cursor is over the parameter cell as described to set the channel state Seen in the following figure. You can set the Walsh code, power level and data source type. Note that you are unable to define long code masks. RFmx Waveform Creator currently does not support this in the forward link.



Fig. 4-21 Edit dialog for traffic channels


The Walsh code for a channel is entered into the Walsh Code edit box. Allowed values are 0 to 63. Note that if you choose a code that is either already in use or that is not orthogonal to another that is in use, the channels that are in conflict with each other will be highlighted in red, as indicated in the following figure. This warning appears only when the channel has been turned on.



Fig. 4-22 Walsh code conflict


If you wish to add channels other than a traffic channel click on the combo box Select Channel Type. The available channels are: BCCH, CACH, CCCH, PCH, and QPCH. Add channel dialog. The parameters and how to change them are again straightforward. With these channels, you are able to change the symbol rate. For the PCH and QPCH channels the symbol rate is fixed and it cannot be changed.

In all cases, RFmx Waveform Creator limits the number of channels that you can add. The number of available Walsh codes limits the number of traffic channels.

Radio Configurations 3, 4, and 5 (RC3, RC4, and RC5)

Selecting one of radio configuration 3, 4, or 5 presents you with the link configuration setup shown in the following figure. The settings page is the same for all three radio configurations. From here, you are able to set the Pilot PN Offset, the Quasi-Orthogonal set, and configure the forward channels. Again, the Pilot PN Offset is used to set the offset of the scrambling codes. Typically, each base station is assigned its own offset. Valid values are 0 to 511. The Quasi-Orthogonal set defines the Walsh Rotation bits and QOF values that are used to modify the Walsh code. Valid values are 0 to 3.

The default channel table shows the Pilot (PICH) and Sync (SYNCH) channels. In general, you would want to turn these on. The channel state and other parameters that can be changed within the table are altered as described earlier.



Fig. 4-23 Forward link configuration for RC3, RC4 and RC5


To add a channel press the Add… button beneath the table. On doing so, you are presented with the dialog shown in the following figure. The default channel is again the traffic channel. For RC3, RC4, and RC5 the traffic channel consists of up to two SCHs, a DCCH and a FCH. You can edit and alter parameters as for RC1 and RC2.



Fig. 4-24 Add channel dialog for RC3, RC4 and RC5


If you would like to add another type of channel, click the Select Channel Type combo-box. Again you are allowed to choose one of the following channels: BCCH, CACH, CCCH, PCH, and QPCH. You set these channels up in the same way as for RC1 and RC2. Walsh code conflicts. As for RC1 and RC2, RFmx Waveform Creator limits the number of channels that you can add. The number of available Walsh codes limits the number of traffic channels.

Generating a Waveform

Once you have set up the forward channel, select the filter tab to set the channel filter. For the forward link you would generally select either the CDMA2k. If you are happy with your choices, select the Save Waveform File menu and proceed as described in the Getting Started Manual.

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