Uplink Ranging

In this example, you will set up an uplink signal with ranging bursts and make measurements on that uplink signal with the 89601A.

Part 1: Create Uplink Signal with Ranging

  1. In Signal Studio, select File > New from the menu or click the button in the toolbar to start a new waveform configuration. Leave the instrument settings at the default frequency of 1 GHz and amplitude of –10 dBm. 

  2. Click Waveform Setup in the navigation tree and change Output Mode to Uplink Only (TDD).

  3. Click on Carrier 1 and change the bandwidth to 5 MHz and FFT size to 512.

  4. Click on Uplink Zone #1, PUSC in the navigation tree.  

  5. Change Number of Symbols to 9. Note that this panel has a section titled "Other Region Settings” that summarizes the settings for the fast feedback, ACK region, initial ranging, and periodic ranging regions. Click on "+” next to each heading to show more details of the settings.  

  6. Click Initial Ranging in the navigation tree on the left. On the right, change Ranging State to on to create the region. The number of subchannels for the initial ranging region is a multiple of 6, and the number of symbols is a multiple of 2.

  7. Change Number of Symbols to 4. Ranging regions are usually placed in the upper left portion of the zone at the beginning of the UL-PUSC region, but this is not a requirement.

    Note the message in the status bar stating the initial ranging zone doesn’t satisfy slot boundary. This is because UL-PUSC slots are 3 symbols wide but the 4 symbols in the initial ranging region does not match one of those boundaries. We will take care of this later.

  8. Click to add 2 ranging bursts. Give each burst a code number (0 to 255) and a slot location (0 or 1). Note that ranging bursts are allowed to overlap. This would be the case if multiple subscriber stations are trying to send initial ranging signals to the base station at the same time. The base station distinguishes the signals by the unique code number, similar to CDMA.  

  9. Click Uplink Zone#1, PUSC to view the zone layout. Notice that the 2 symbols that form the rest of the slot boundary for the initial ranging region are crossed out, and user Burst #1 starts on the next slot boundary. We can solve the slot boundary problem either by increasing the size of the initial ranging region, or adding a periodic ranging region. Both types of ranging regions are combined when aligning to slot boundaries. We will choose the second method.

  10. Click Periodic Ranging on the left, and on the right panel, change Ranging State to on and set Number of Symbols to 2 and Symbol Offset to 4.  

  11. Add some ranging bursts and assign a code number and slot location to each.

  12. Click Uplink Zone#1, PUSC and note that the periodic ranging region has satisfied the slot boundary so the symbols with the red cross marks are gone. Add another regular data burst.

  13. Click on Burst #1, change the Data Length to 50 bytes.  

  14. Click Burst #2, change Modulation and Coding to 16QAM (CC) 1/2, Data Length to 150 bytes. Note how the bursts wrap around the ranging region. Generate and download the waveform.

Part 2: Analyze Uplink Signal with Ranging Using VSA.

  1. In the 89601A VSA software, go to File > Preset > Preset Setup.

  2. Configure the proper center frequency, span, and range to measure the instrument's signal.  

  3. Go to MeasSetup > Demodulator > Broadband Wireless Access > 802.16 OFDMA to turn on the demodulator.

  4. Go to MeasSetup > Demod Properties.  

  5. On the Format tab, select Uplink, click on Preset to Standard and select 802.16e 5 MHz.

  6. Next we configure the VSA to measure the UL-PUSC zone. Select the Zone Definition tab and click on the Edit Active Zone button.

  7. Set PermBase to 0 and Length to 9 symbols.  

  8. The VSA does not actually analyze ranging regions, so it can only measure the user bursts. To get the bursts to wrap properly, we still need to configure the ranging region. Delete any existing bursts.

  9. Click New Burst, then change Burst Shape to rectangular and select Burst Type of CDMA.

  10. Configure this burst to include the entire ranging region of 6 symbols by 6 subchannels. This burst will have diagonal lines drawn through it to indicate that it is a special burst, and VSA software will not provide the usual measurements for it such as the constellation or OFDM Syms/Errs. However, you can set the Trace Data type to OFDM Data Burst Info, and the VSA will display the detected CDMA ranging codes along with the power levels, length in symbols, and location (subchannel and symbol)  

  11. Add the two user bursts, selecting the appropriate modulation type and checking the Active box for each burst. Make sure Burst Shape is set to wrapped and Burst Type is normal. When you’re done editing, click OK to exit and make sure the Data Burst Analysis box is checked on the Zone Definition tab and measure the data bursts.