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Generating a Multi-Standard Radio (MSR) Waveform

This process enables you to generate Multi-Standard Radio (MSR) waveforms using exported Signal Studio component waveforms. Below is a list of the Signal Studio component waveforms that can be imported into the MSR feature for LTE signals.

N7600B Signal Studio for W-CDMA/HSPA+
N7601B Signal Studio for cdma2000/1xEV-DO
N7602B Signal Studio for GSM/EDGE/Evo
N7612B Signal Studio for TD-SCDMA/HSDPA
N7617B Signal Studio for WLAN^a
N7624B Signal Studio for LTE/LTE-Advanced FDD (non-MSR waveforms)^b
N7625B Signal Studio for LTE/LTE-Advanced TDD (non-MSR waveforms)^c

Supports high-resolution waveform export, providing better signal quality in the resulting MSR waveform. Requires minor enhancement update (MEU) N7617B-U02 or greater to playback MSR waveforms using the high-resolution component waveform.
Supports high-resolution waveform import and export, providing better signal quality in the resulting MSR waveform. Requires minor enhancement update (MEU) N7624B-U04 or greater to playback MSR waveforms using the high-resolution component waveform.
Supports high-resolution waveform import and export, providing better signal quality in the resulting MSR waveform. Requires minor enhancement update (MEU) N7625B-U04 or greater to playback MSR waveforms using the high-resolution component waveform.

Requirements

Licensing

Library Waveforms that are used with the MSR feature must have proper Signal Studio licensing. The MSR waveform comprises all the license requirements for each of the component waveform-types used.

The maximum number of component waveforms that can be imported into an MSR composite waveform is limited by the number of unique licenses required to generate the MSR waveform. For example:

3 Basic waveforms + 1 W-CDMA waveform = 4 waveform component licenses

Typically, up to approximately 11 waveforms can be used in a MSR waveform. If the number of waveforms exceeds the MSR feature's limits, an Closed error message will be displayed.

If your equipment setup requires an E4438C, Option N7624B-Hxx is required. E4438C with Options 400, 401, 402, and 411 are not a substitute for Option N7624B-Hxx licensing for the MSR feature.(Additionally, to use the Waveform Library Manager feature with your Basic MSR LTE and LTE-A waveforms, Options N7624B-Jxx and N7624B-Txx are required.) Using any waveform with the N7624B's MSR feature requires all of that imported waveform's licensing.

Connectivity

To use the MSR feature, you must have the correct waveform options and the correct instrument connectivity.

Example: Using a Basic N7602B waveform with the N7624B's MSR feature requires connectivity with an MXG signal generator (Options N7602B-3xx and N7624B-3xx) and the basic waveform options (Option N7602B-Exx and N7624B-Hxx). Additionally, using the Waveform Library Manager with your MSR LTE and LTE-A waveforms requires Option N7624B-Jxx.

For additional hardware requirements, refer to the "Hardware and System Requirements for the Multi-Standard Radio (MSR)" in the System Requirements.

Memory

Each waveform sample point requires about 25 bytes of hard drive space, so a 1 GSa waveform requires 25 GB of available drive space.

MSR Waveform Generation Procedure

Using the N7600B, N7601B, N7602B, N7612B, N7617B, N7624B or N7625B software, export each of the required component waveforms using the exported waveform settings below. Refer to your component waveform's help for more information.

Waveform Type	Waveform Length (Recommended) ^{a, c} (N = integer)	Oversampling Rate (OSR) – (Recommended) ^{b, d}	Notes ^h
N7600B W-CDMA/ HSPA+	10 msec * N repetitions (Basic) Number of msec or Number of frames * N repetitions (Advanced)	8x or AUTO (Basic) AUTO (Advanced Single Carrier)	Avoid exporting the PRACH and CELL_FACH carriers. Avoid exporting Multicarrier waveforms. Instead, export the Advanced carriers individually and then import the single carriers using the N7624B, to create a Multicarrier waveform.
N7601B cdma2000/ 1xEV-DO	26.6666 msec * N repetitions (Basic C2K and 1xEV-DO)	25x or AUTO (Basic)	Advanced 1xEV-DO is not recommended (240 msec x N repetitions). Avoid using 26.6666 msec * 4 repetitions. Avoid exporting Multicarrier waveforms. Instead, export the Advanced carriers individually and then import the single carriers using the N7624B, to create a Multicarrier waveform.
N7602B GSM/EDGE/ Evo	60 msec * N repetitions (Basic and Advanced)	128x or AUTO (Basic) AUTO (Advanced Single Carrier)	Default or integer multiple of 13 frames (60 msec) is required to import basic carrier waveform file. Avoid exporting the Control channel carrier. Avoid exporting older default GSM/EDGE 4 frame waveforms (≤ v2.x). Avoid exporting Multicarrier waveforms. Instead, export the Advanced carriers individually and then import the single carriers using the N7624B, to create a Multicarrier waveform.
N7612B TD-SCDMA/ HSDPA	5 msec * N repetitions	24 is recommended (1.28 * 24 = 30.72)	Default or integer multiple of 5 ms is required to import basic carrier waveform file.
N7617B WLAN	10 msec * N repetitions	Set the Oversampling Ratio (located under Waveform Setup) to adjust the ARB Sample Clock value so it is close to an integer multiple of 30.72 Msps (LTE software's base sample rate). This improves waveform quality.	Waveform signal length needs to be integer multiple of 10 msec by adjusting parameters “Idle Interval” and “# of frames" when generating from N7617B. (RF burst + idle interval) x (# of frame) = waveform signal length. Note: “waveform signal length” needs to be integer multiple of 10 msec (in actual time length). “RF burst” length changes by various WLAN parameters including bandwidth. Waveform signal length (in “actual time length”) = (total sample points) / (ARB sample clock) Note: ARB sample clock is affected by bandwidth.
N7624B LTE/LTE-Advanced FDD	For N7624B waveforms: non-MSR (external) waveform files can be imported.	Set the Oversampling Ratio (located under Waveform Setup > Carrier n) to adjust the Waveform Sampling Ratio so it is an integer multiple of 30.72 Msps (LTE software's base sample rate). This is required for the waveform data to be imported into MSR and improves waveform quality. The Waveform Sampling Ratio updates after each waveform generation to show the actual value, so you can use that to fine tune.	To prevent recursive imports, no external MSR files of any type, can be imported.
N7625B LTE/LTE-Advanced TDD	For N7625B waveforms: non-MSR (external) waveform files can be imported.	Set the Oversampling Ratio (located under Waveform Setup > Carrier n) to adjust the Waveform Sampling Ratio so it is an integer multiple of 30.72 Msps (LTE software's base sample rate). This is required for the waveform data to be imported into MSR and improves waveform quality. The Waveform Sampling Ratio updates after each waveform generation to show the actual value, so you can use that to fine tune.	To prevent recursive imports, no external MSR files of any type, can be imported.

ARB Sample Clock ≥ 100 MHz can be used, but performance may be degraded. The ARB Sample Clock parameter is displayed under the Instrument node. It is automatically calculated by the software based on the signal generator's ARB Sample Clock settings. The ARB Sample Clock should be < 100 MHz. If a Frequency Offset is applied to a waveform, the settings should be compatible with the ARB Sample Clock settings on the signal generator.
Higher OSR values will degrade performance once the waveforms are imported into the N7624B's MSR waveform. For Advanced N7600B or N7601B carriers, OSR's = 1 are not recommended while Signal Studio is in Simulation Mode (e.g. use AUTO).
The waveform length is dependent on the resampling ratio:
- The source waveform clock > baseband sampling clock; source waveform will be decimated. This is typically not desirable, but will decrease waveform size.
- The source waveform clock < baseband sampling clock; source waveform will be oversampled. This is typically acceptable, but will increase waveform size.
- Waveform Quality will always degrade on resampling.
The MSR waveform requirements (source wavelength * baseband sampling clock) should be ≥ 1024 sample points and ≤ 1024e6 sample points.
For all of the component waveforms, set the Frequency Offset to 0. Frequency Offset can be set in the N7624B software, after importing all of the waveforms.
For the N7600B, N7601B, N7602B, N7612B, N7624B and N7625B software, to better understand the carrier power level calculations for an exported waveform, refer to Output Power Calculation (Downlink) and Output Power Calculation (Uplink).
Size of exported file must be ≤ 1024 Msa. If the waveforms exceed the maximum allowable, the System Message window is displayed.
There are three different descriptions for the various waveform setups:
- The recommended waveform settings yield the best overall performance with the MSR feature (i.e. faster waveform loading times, minimal intermodulation products, and minimal EVM).
- The waveform settings that are not recommended will work, but with reduced waveform performance (i.e. increased waveform loading times, increased intermodulation products, and degraded EVM).
- The waveform settings that are to be avoided may not work as desired or have some other unpredictable behavior.
The maximum number of component waveforms that can be imported into an MSR composite waveform are limited by the number of unique licenses required to generate the MSR waveform. For example:

3 Basic waveforms + 1 W-CDMA waveform = 4 waveform component licenses

Typically, up to approximately 11 waveforms can be used in a MSR waveform. If the number of waveforms exceeds the MSR feature's limits, an error message will be displayed.

Import the individual component waveforms into your MSR composite waveform using the imported waveform settings below.

In the Carrier n node, click Source Waveform File Name > <enter a Closed path of the file to be imported>.

MSR Waveform Setting Levels	Baseband Sampling Rate ^{a, b}	Frequency Offset ^a	Power (Offset)	Notes
Recommended	AUTO, 61.44 MHz	as required	as required	Where the Frequency Offset = 0, a Baseband Sampling Rate of 30.72 MHz can be used to decrease waveform build time.
Allowable	184.32 MHz	as required	as required	Possible degradation in waveform generation time and in waveform performance quality.

After importing the waveforms into the MSR waveform, the default Baseband Sampling Rate is set to 61.44 MHz. This value is required for non-zero Frequency Offsets and optional for 0 Hz Frequency Offsets. If the Frequency Offset is set to 0 Hz in the N7624B, the Baseband Sampling Rate can be set to 30.72 MHz and the waveform build-time will be faster. The Baseband Sampling Rate of 184.32 MHz can be used, but the waveform's performance may be degraded. The Baseband Sampling Rate = (chip rate * oversampling ratio). For best results, the Baseband Sampling Rate should be < 100 MHz.
To avoid degradation of the signal, in the N7624B software, do not use the default oversampling rate of 1 with MSR waveforms. For best results, use AUTO for the OSR value.
The MSR waveform requirements (source wavelength * baseband sampling clock) should be ≥ 1024 sample points and ≤ 1024e6 sample points.

After all of the component waveform files have been imported, generate and download the waveform by choosing the correct file path for the MSR waveform file. The new multicarrier waveform comprises all the license requirements for each of the component waveform types used. Here is an example of an MSR waveform with five component carriers.
In the MSR composite waveform, the waveforms that have narrower bands — like CW and EDGE waveforms — are displayed with higher power levels. This is because the waveforms' power is defined by its integrated power and not by its power spectral density (PSD).
To minimize spurious images, optimize the channel waveform filtering and frequency offsets for the imported component waveforms. Refer to MSR: Applying a Waveform Channel Filter.

After generating the MSR carriers, to enable faster measurements particularly where ongoing changes are required for the Baseband Sampling Rate and Filter Ratio, refer to the MSR: Using the Waveform Library Manager and Library Waveform Carrier topics.