2016 ASEE Annual Conference & Exposition

With the significant growth in the number of users using various types of portable devices on diverse real and non-real time, high and low data rate applications, future wireless communication systems are expected to operate under the strict constraint of limited spectrum to provide ubiquitous communications in a heterogeneous environment composed of sophisticated digital communication systems, infrastructures, and services.

To meet the future wireless communications requirements, software-defined radio (SDR) and cooperative transmit beamforming have been proposed to be the key techniques that future graduating communication engineers should be capable of designing and implementing. SDR, a flexible platform whose functionality can be changed on the fly by software on a computer or embedded system, can cope with the broad range of wireless standards, frequency bands, and user requirements. Cooperative transmit beamforming, a promising technique for high frequency and power efficiency, enables increased coverage range, increased data rate, or decreased net transmit power for a fixed desired received power. In cooperative transmit beamforming, a number of distributed transmit nodes, each equipped with single antenna, cooperatively organize themselves into a virtual antenna array and focus their transmissions in the direction of the intended receiver, such that, after propagation, the signals combined constructively at the receiver.

Despite the compelling needs of SDR and beamforming expertise in the wireless industry, few schools are offering undergraduate courses on these advanced topics. This paper describes a Research Experience for Undergraduate (REU) project that implements and evaluates a cooperative wireless communication system with SDR and beamforming techniques. A hands-on design project for Communication Systems course has been developed based on the experiences and observation from this project. The student learning outcomes and assessment rubrics are also presented in the paper. The cooperative communication system for image transmission is implemented with universal software radio peripherals (USRPs) and the open source GNU radio software development toolkit. A group of single antenna transmitter collaborate together to synchronize their carrier frequencies, phase and time so that the transmitted image packets can reach the desired receiving direction with significant level of power improvement. The performance of the system is evaluated through the received signal power at the desired receiving direction; the interferences towards other directions; and the subjective evaluations of the received images based on different viewers' opinion scores.

Through the proposed design project, the students will not only gain valuable knowledge of the state-of-art beamforming technique, SDR concepts, and the USRP platform, but also improve their creative thinking ability, and hands-on and programming skills. Feedbacks from preliminary evaluations were positive and encouraging. Students were highly interested and excited about learning SDR and beamforming techniques by following the procedures developed in the REU project. The from-research-to-teaching paradigm in this work is expected to blaze a path for integrating other emerging communication systems techniques in undergraduate Electrical Engineering education.