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Questions about Testing the Accuracy of LTE Transmission

Weicheng Bai
Prodigy 90 points

Hi!

We are currently doing some experiments on LTE by using software defined radio. We write our program in CCS 5 and use the Spectrum Digital emulator to test the program.

The boards we are using have already integrated DSP, FPGA, and MCU. We want to send some particular data from eNodeB to UE to test the accuracy of the transmission. We know that the data should be carried in PDSCH. However, we do not know how the DSP can read the data that we define. We believe that FPGA is used for transmitting the data and MCU is used for controlling so DSP should read the user data from MCU. Our questions are as follows.

  1. What can we do in order to let DSP read the specific data that we define from MCU?
  2. We know that in LTE standard, the signal needs to go through some processes like CRC, coder, and modulation. In order to test the accuracy of the transmission, the data in which process should be compared in the transmitter and receiver?

Thanks very much!

  • 0
    TI__Mastermind 37500 points

    Hello,

    The Digital Radio ASIC devices in this forum are in the categories of Digital Up/Down Conversion, Crest Factor Reduction, Digital PreDistortion, Block Up/Down converter.

    We do not internally generate an LTE waveform.  However when we test, we use the Agilent tools (Signal Studio, Advanced Design System, and Vector Signal Analyzer software) to build a Test Model waveform,   The baseband IQ waveform has the component LTE parts.  We then use the Vector Signal Analyzer to demodulate this.  Signal Studio can build the entire waveform, there are ADS files that build the entire waveform, but you can exclude some sections to simplify your testing.

    If you have a specific UE, you could ask the UE vendor for a specific test waveform, and then encode this on the DSP, so that the UE acts as the DL demodulator.  In a loopback sense if you use DSP memory to playback the waveform and the UE can decode it, then your DSP-receiver would have to synchronize, and demodulate the DL section.  note: usually the DL (to UE) and UL (from UE) have different modulations, so this takes several passes to check both links.  You can look under the multicore DSP forum, or search further on LTE in the E2E forum. 

    Some of the HSP DAC products have a digital pattern that is built with the test LTE patterns, you would need to contact your local TI FAE, for a demo, or to access the DAC modulator GUI and data. 

    Regards,

    Radio Joe