Spiral modulation startup aims at communications revolution

May 05, 2016 // By Peter Clarke
Astrapi Corp. (Dallas, Texas), a six-year-old startup founded to apply non-periodic signal modulation to communications engineering, has formed a research partnership with TSR Research Lab at the University of the Basque Country (Bilbao, Spain).

The company has a similar research agreement with San Diego State University, in California.

Jerrold Prothero, Astrapi co-founder and CEO, has been working for a number of years on so-called spiral polynomial division multiplexing (SPDM) as an alternative to orthogonal frequency division multiplexing (OFDM). The claim is that the method – based on the use of non-periodic wave forms to create a spiral signal in phase space – exploits an alternative form of orthogonality and has the benefit of minimal power/bandwidth needed to achieve tight and fast synchronization.

Astrapi also claims that OFDM-based systems are sensitive to frequency synchronization and tend to suffer from a poor power amplifier power ratio, providing scope for spiral modulation to improve on the status quo.

Put more generally, Astrapi provides novel ways to build symbol waveforms used to encode digital transmissions. By applying this novel mathematics to signal modulation, Astrapi is able to improve the trade-off between the four fundamental parameters in telecommunications: bandwidth, signal power, data throughput, and error rate. The company claims the resulting efficiency translates into higher spectral performance with more bits available at a lower cost.

Astrapi has over 30 patents issued, pending or filed, and is a member of a United States Department of Defense organization created to optimize defense spectrum. The company is also under consideration for a National Science Foundation Phase I SBIR grant.

The partnership with TSR Research Lab is intended to start building real systems and to explore how spiral-based modulation can increase information transmission rates, mitigate interference, facilitate synchronization, and combat phase impairments.

"This partnership represents a significant technical milestone," said Prothero, in a statement. "The TSR lab is at the point of the spear in researching issues related to the ATSC 3.0 standards, LDM [layer-division multiplexing], and other approaches confronting the broadcast industry."

According to Pablo Angueira of the Department of Communication Engineering at the University of the Basque Country, spiral-based modulation shows