WARF: P00232US

Method and System for Multi-Carrier Multiple Access Reception in the Presence of Imperfections


Akbar Sayeed, Tamer Kadous

The Wisconsin Alumni Research Foundation (WARF) is seeking commercial partners interested in developing an improved receiver for multi-carrier code-division multiple access (MC-CDMA) in wireless communication systems.
OVERVIEWHigher bandwidths are needed for existing and emerging wireless personal communications services. Code division multiple access (CDMA) systems, one of the leading technologies, allow multiple users to access wireless communication systems at the same time. However, conventional systems are limited in their ability to deliver high data rates, making them unsuitable for “bandwidth on demand” multimedia applications.

To accommodate these greater bandwidth applications, a multicarrier CDMA (MC-CDMA) has been proposed, which is similar to orthogonal frequency-division multiplexing (OFDM). Although this system is superior to conventional CDMA systems, its implementation critically depends on orthogonality between subcarriers. In practice, non-ideal conditions in wireless channels, such as frequency offsets, phase noise and Doppler shifts, destroy the orthogonality between subcarriers.
THE INVENTIONUW–Madison researchers have now developed a system that addresses current limitations of multicarrier modulation schemes by using a universal receiver structure. This system processes signals from multiple users in a manner that compensates for imperfections, and in fact exploits some of these imperfections to significantly improve the accuracy of received data.
  • Wireless communications
  • Reception of multicarrier signals is carried out such that it is less sensitive to imperfections in the communications channel and local oscillators.
  • Improves accuracy of the received and decoded data
  • Can employ low-cost tuners, which reduces the cost of the portable unit
  • Can receive higher data rates with simple processing
  • Achieves higher level of performance under lower power levels, resulting in longer battery life
  • Combats fading
  • Compensates for phase noise and frequency offsets
  • Exploits Doppler effects for improved performance against fading
For More Information About the Inventors
Contact Information
For current licensing status, please contact Jeanine Burmania at or 608-960-9846.
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