Hardware Setup

As shown in above figure, the hardware setup includes two desktop PCs. One of them is connected with a web camera, which captures images. The captured images are then encoded into H.264 bitstreams in real time. This PC is also connected with a Universal Software Radio Peripheral (USRP) board through USB2 interface. The USRP board acts as the RF transmitter. Packets from the host PC will be sent over the air.

Another desktop PC is connected with the second USRP board. This board picks up signals transmitted from the first USRP and hands them to the host PC for demodulation and depacketization. An H.264 decoder on this PC will decode the packets and display video in real time. 


Software Setup

Above figure shows the software setup of our testbed. Both desktop PCs have Linux OS. GNU radio and FFmpeg are installed on two PCs. On the first PC, FFmpeg and x264 perform the image capturing and H.264 encoding work. GNU Radio gets encoded packets and then performs packet header assembling and modulation before sending the packets to USRP board. On the second PC, GNU radio receives packets from USRP board. Before sending the information to FFplay, the H.264 decoder, GNU radio demodulates and dissembles the packets.

The communication between FFmpeg/FFplay and GNU radio is through UDP sockets.