DxWiFi

Skills Learned: 802.11 MAC, Atheros AR9271 Driver/Firmware Development, libpcap Packet capture library, Forward Error Correction

Built With: C, libpcap, Cmake5

OreSat Live is tasked with the mission of streaming images of Oregon from low earth orbit (~400km) to DIY Handheld ground stations built by high-school students with cheap, COTS WiFi adapters. The 802.11 WiFi standard was designed for reliability over a Local Area Network in mind, and has some significant shortcomings when it comes to long range transmission. DxWiFi attempts to surmount these shortcomings by leveraging packet injection and monitoring. Typically used by security researchers (or nefarious hackers), packet injection and monitoring has seen extensive use in the testing (and breaking) of 802.11 protocols. With packet injection we can send custom raw data frames over the air without the need of a network connection or an expectation of a positive ACK from the receiver. Likewise, receivers enabled in monitor mode can “promiscuously” scan and capture any packet regardless of destination. Combining injection and monitoring enables DxWiFi to achieve true unidirectional communication without the need for control packets or ACKs.

Check out the full repository here