We organize the seminar of Prof. Seong-Lyun Kim, who is a professor at Yonsei University, Korea. He will speak on Random MAC and Opportunity Detection in Dynamic Spectrum Access.

We welcome your participation.

  • Date: November 6, 2017 (Monday)
  • Time: 16:00-17:30
  • Place: S3-201 seminar room (O-okayama South 3, 2F)
  • Speaker: Prof. Seong-Lyun Kim,
  • School of Electrical & Electronic Engineering, Yonsei University, Korea

TITLE: Random MAC and Opportunity Detection in Dynamic Spectrum Access

ABSTRACT: The huge demand for wireless services has been supported by enhanced spectral efficiency, massive spectrum reuse and new frequency spectrum bands. Among others, spectrum sharing is a fundamental item in commercial wireless systems to cope with the limited radio resource. It is implemented in all levels of the systems, from media access control (MAC) design, up to coexistence of heterogeneous networks, where mutual interference is cancelled, mitigated, avoided or sometimes even shared by the multiple systems. For the shared radio access, sensing based approach (e.g., CSMA/CA, Cognitive Radio) has been used effectively; on the other hand, there are still issues remained in detecting errors such as hidden and exposed node problems. In this talk, we start with prediction of reception quality at the receiver, whereas the sensing of the channel is done in a separate position, e.g., by transmitters or independent sensing devices. Measuring the interference levels at remote devices, the transmitter tries to predict the SINR at the corresponding receiver to reduce opportunity-detection errors. In line with this, the talk illustrates how the random ALOHA MAC behaves when its transmission probability is linearly proportional to the probability of the “predicted”・opportunity at the receiver. Finally, the talk ends with the flexible duplex prototype that are currently under investigation in Yonsei university.

Prof. Seong-Lyun Kim’s BIO