Single-Symbol, Preamble-Free Communications

Tech ID: 21-007

Inventor: Thomas Pratt, Thomas Fuja, Joseph Loof, Eric Jesse, Xiaobin Wu

Date Added: October 19, 2020


Innovative method for OFDM-based modulation/demodulation scheme that enables preamble-free communications

Technology Summary

Wireless communications have permeated almost every sector of life. As wireless communications grow more ubiquitous, the demands placed upon technology efficiencies increases. In many cases, information about the data is provided at the transmitter in order to ensure an accurate and secure data estimate at the receiver. One method of providing this accuracy is a preamble, which provides information to synchronize transmission timing between two or more systems.  However, the added information provided by preambles affects the energy and spectral efficiency, especially when short data payloads are conveyed.

Researchers at the University of Notre Dame have developed a preamble-free communications technology based on Polarization Shift Keying (PolSK), in which information is imparted into the polarization state of the electromagnetic field. The specific technology proposes an orthogonal frequency-division multiplexing (OFDM)-based modulation/demodulation scheme using polarization-state modulation and hybrid modulation without a preamble to improve energy and spectral efficiency.  This signal processing method would be most beneficial in cases where short messages are sent, maximizing the system’s valuable data transmission and minimizing energy consumption.

Market Advantages

  • Energy efficiency: A single OFDM symbol is transmitted; demodulation occurs without need for a preamble, leading to energy efficient operation
  • Spectral efficiency: hybrid modulation is employed to achieve high spectral efficiency
  • Useful for small data payloads

Market Opportunities

  • Short message communications for government or military applications
  • Efficient communications for distributed sensor networks 

Technology Readiness Level

TRL 4 – Technology Validated in Lab

Intellectual Property Status



  • Four-Dimensional Hybrid Constellations for Dual-Polarized Wireless Communications     DOI: 10.1109/ICC.2018.8422468
  • Preamble-Free Binary Polarization Shift Keying in Frequency Selective Channels     DOI: 10.1109/RWEEK.2018.8473551


Richard Cox