Set the controls in these sections and those found in the Link Parameters section with the following guidelines in mind:Įnter the two IP addresses associated with the NI USRP transceivers in each of the Tx and Rx pairs. The Tx Settings and Rx Settings sections contain the parameters for the Tx and Rx pairs of NI USRP transceivers, respectively. On the front panel of the example (Figure 2), click the System Parameters tab. The System Parameters Tab on the Front Panel of the 2x2QAMAlamouti VI zip file to a new folder and open 2x2QAMAlamouti with BER.vi in LabVIEW.įigure 2.
This 2 × 2 MIMO example is a LabVIEW application that requires the following software components: For the same reason, space the receivers apart the same way.Ģ × 2 MIMO System: Software Configuration To allow the MIMO system to fully exploit the diversity of the separate channels, space the transmitters apart by at least half a wavelength of the carrier frequency used. Each transceiver has one antenna connected to either port (NI recommends RX1/TX1 for simplicity). 2 × 2 MIMO Hardware Setup Diagramįigure 1 shows the configuration you can use to synchronize the Reference Clock sources between both transmitters and the Reference Clock sources between both receivers. Connect the third transceiver directly to the switch using Ethernet and connect the fourth transceiver to the third using the MIMO cable.įigure 1. Two transceivers configured as receivers.Connect the first transceiver directly to the switch using Ethernet and connect the second transceiver to the first using the MIMO cable. Two transceivers configured as transmitters.One gigabit Ethernet switch connected to the PC.One PC with a free gigabit Ethernet port.NI recommends the following configuration: Refer to External Link: Alamouti code for more information about the Alamouti scheme.Ģ × 2 MIMO System: Hardware Configuration This matrix repeats for every consecutive pair of transmit symbols. The rows represent the different transmit antennas, and the columns represent consecutive time slots. The first two symbols (s1 and s2) are converted into a 2 × 2 matrix. The combination of the two techniques exploits the full diversity available to a 2 × 2 MIMO system.Īt the transmitter, symbols are encoded with the Alamouti scheme. The MIMO system described here uses Alamouti space-time block coding on the transmitter side and MRC on the receiver side. When you use multiple antennas, the transmitted signal progresses through different wireless channels (from the transmitter antennas to the receiver antennas) and creates a capacity gain by exploiting channel diversity. With MIMO, you can increase wireless system performance without increasing power consumption.
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