From Design to Implementation

 Wireless Team Wins David Tuma Undergraduate Laboratory Award

June 14, 2005

At the beginning of the semester, when ECE students Jesse Vizcaino, Kermin Fleming, and Muhammed Wahabsuhaili brainstormed about building a hardware and software prototype for a wireless intercom system for their Digital Communications and Signal Processing Systems Design course, they had lots of ideas, but no inkling they were award winners in the making. It was only after hours of hard work and creative problem-solving that the trio was invited to the ECE Diploma Ceremony to accept the David Tuma Undergraduate Laboratory Award for the most outstanding student project. Established in 1985, the award pays tribute to the late Professor David Tuma, acknowledging his dedication to undergraduate education and his commitment to practical laboratory experiences.

"This project was one of the key factors in helping me to distinguish myself while I was going through the job interviewing process," said Jesse, who is interning this summer at DRS Signal Solutions. "There is no doubt in my mind that this project's success will showcase my abilities as an engineer to future employers and my peers."

The capstone design project started as Jesse's brainchild, but evolved into a coordinated effort that called upon the strengths of all three. Jesse focused on the communications portion, including the wireless channel simulation, while Muhammed handled voice compression. Kermin tied the project together with his knowledge of embedded software and hardware, and also worked on programming, encryption, and error correction. Their goal was to enable different users to communicate over a wireless network over short distances (such as small office spaces) using a secure encrypted link without installing complicated infrastructure.

"This project was clearly quite challenging and required the students to acquire and use knowledge on such diverse topics as speech compression, wireless communications, error correcting codes, and encryption schemes, plus understanding the intricacies of the digital signal processing hardware on which the system needed to be built," wrote professors David Casasent and Rajeev Gandhi in their nomination letter. The Tuma award recipients are chosen from nominations submitted by faculty.

Along the way to success, the students faced two major challenges: the hardware they wanted to buy was too expensive and although they wrote an extensive amount of code, the embedded hardware board had a limited memory. But instead of giving up their idea or settling for a less difficult version of their plan, they made it work.

"I learned a lot about how engineers make design decisions and the engineering process as a whole, such as how hardware limitations affect system choices," explained Jesse, who researched and designed the skeleton of the communications model. He added updates with each test to improve reliability and meet their initial specifications, watching the communication theory he had learned about in action.

Classmate Muhammed also valued the practical experience: "Sometimes the only way to learn something new is to actually do it and learn from the experience itself," he discovered.

Muhammed studied commonly used voice compression algorithms as well as freely available code, examining the trade-offs of using their own system versus one that was ready-made. He fed their code into a Digital Signal Processor (DSP) from Texas Instruments (TI), modifying it so their data would transfer from the DSP to a PC (where the wireless channel simulation code resided) and back. Then, the group optimized the code for speed, using techniques they learned in class and by delving through the DSP manuals. Over the semester, Muhammed noticed his programming skills improve and his knowledge of signals and embedded systems increase. At first, he had little experience with the DSP, but it wasn't long before he became the group's expert on DSP errors.

"It's a good feeling to know that you are needed and that your group-mates are confident in your abilities. That to me is what a team is all about," Muhammed summarized. "This for me has all been a good exposure to real-world life endeavors where we need to work in teams and interaction with others is essential."

Facilitating that interaction, Kermin recalls supporting Jesse and Muhammed wherever he was needed: "For example, initially, Jesse was having trouble with data loss over the channel, so I came up with algorithms to boost his accuracy," he offered. "When Husni [Muhammed] had trouble getting code to operate fast on the DSP card, I read the TI manuals and figured out how to make critical parts of the code run faster given the system limitations."

Motivating his peers and learning about communications software as he worked, Kermin took the time to familiarize himself with all aspects of the project from programming and debugging to simulating. He was ready to share his hardware expertise: "Sometimes the answers he gave to my questions were more than I asked for, but they were exactly what I needed," reported Muhammed.

"Kermin was the glue binding this project together... Ultimately, he was the guy in the background that did the tuning up to make sure the project met its goals," Jesse added.

Casasent and Gandhi's nomination described the project as using a code-excited linear prediction (CELP) voice compression algorithm to reduce the amount of transmitted data. It employed error-correction coding, phase shift keying modulation and code division multiple access (CDMA) for the different users. CDMA allows multiple users to communicate simultaneously without interfering with each other's data and is implemented through spread spectrum systems. In their architecture, the students used a direct sequence spectrum system. To protect against information compromise due to eavesdropping, they exploited encryption algorithms for communication between sender and receiver.

The course assignments aimed to prepare the pupils for the steps involved in real-world engineering group projects, including budgets, reports, and presentations. In all, Jesse, Kermin, and Muhammed submitted a one page proposal; a written and oral proposal including a schedule, milestones, and the division of tasks between the three members; an email status update; an oral update; a final oral presentation; a real-time laboratory demonstration on digital signal processing hardware; and a written final report. All of their oral presentations were given to the entire class, allowing the professors to judge their team dynamics, oral, and writing skills.

Muhammed graduated this May and will start working for Telekom Malaysia (a telecommunications company that sponsored his education at Carnegie Mellon) this summer. Kermin and Jesse will be seniors in the fall, and Kermin will research new hardware for next year's Digital Communications and Signal Processing Systems Design course, as well as help to prepare protoboards for Fundamentals of Computer Engineering. He is also interning this summer for Lexmark, and works for them remotely over the academic year.

ECE students Kermin Fleming (left) and Muhammed Wahabsuhaili (right) accept the Tuma Award from David Casasent, George Westinghouse Professor of ECE (center). Jesse Vizcaino also won the award.

Jesse Vizcaino

Muhammed Wahabsuhaili

Kermin Fleming

Headshot of David Casasent

Headshot of Rajeev Gandhi

Related People:

David Casasent

Rajeev Gandhi