This example uses both channels of USRP® B210, X300 or X310 to receive an LTE downlink signal. LTE Toolbox™ is used to perform the cell search procedure and to decode the MIB and SIB1 messages if present.
LTE Toolbox provides functions and tools to decode LTE waveforms. This example shows how an LTE waveform can be captured with SDR radio hardware such as a USRP®-based radio. The signal can then be analysed and decoded. In this example the captured waveform is searched for the presence of a suitable LTE signal. If found, the MIB and SIB1 messages are decoded.
This example decodes the MIB for a burst of captured frames, and then decodes the control format indicator (CFI) for each subframe, which informs the user equipment (UE) of the size of the control region. The physical downlink control channel (PDCCH) is then decoded. With this information the SIB1 message in the PDSCH is finally decoded.
The example outputs recovered cell wide information including the detected cell identity and checks the SIB1 CRC. The example also plots the signal spectrum, the PDCCH constellation and the magnitude of the channel estimate.
If you have a second SDR platform, a suitable signal can be generated by the companion example Two Antenna LTE SIB1 Transmission using USRP® based Software-Defined Radio (SDR).
This example requires the USRP®-based Radio support package. This can be installed using the Add-On Explorer.
More information about other supported SDR platforms can be found here.
The full example description and source code can be found in the list of examples using USRP® under the name "LTE Cell Search, MIB and SIB1 Recovery with Two Antennas".
Universal Software Radio Peripheral® and USRP® are trademarks of National Instruments Corp.