A Software-Defined Radio implementation of an 802.11 OFDM Physical Layer transceiverProceedings of 2012 IEEE 17th International Conference on Emerging Technologies & Factory Automation (ETFA 2012)

This work presents our effort in developing a complete, real-time, Software-Defined Radio implementation of an OFDM transceiver, compliant with the IEEE 802.11 Physical Layer specifications. All the baseband components in both the transmitter and the receiver are implemented with fast software functions, running on a General Purpose CPU. Real-time operation is achieved on a modern CPU by means of extensive code optimization, mostly using the SIMD instruction sets which are widely available on almost every modern CPU

IEEE 802.11p Transmission Using GNURadio

In this work we present an implementation of a fully functional IEEE 802.11p transmitter in software-defined radio. We describe the rapid-prototyping methodology that was used to implement the frame-encoder within the open-source GNU Software Radio (GNURadio) platform [1]. The encoder generates OFDM frames in digital complex base-band representation and uses the USRP2 [2] as digital-to-analog front-end for up-conversion and final transmission. Since the actual encoding process involves a large number of complex steps we split the development approach into three sequential stages. First, a reference-encoder in a high-level language (MATLAB) is derived from the IEEE standard documents. Second, the individual blocks of the MATLAB encoding chain are progressively ported to GNURadio, cross-checking with the reference after each step. Finally, standard compliance is verified by conducting comparative over-the-air measurements with an early prototype of a commercial 11p transceiver. Initial measurement results indicate that the fidelity of the resulting GNURadio implementation is on par with non-software-defined radio industry solutions and capable of generating truly standard-compliant OFDM frames. The encoder presented here has been released under GPLv3 and is also capable of encoding frames according to the 11a and 11g amendments, thus making it a valuable building block for upcoming software-defined radio projects