Talk: Farzin Salek (August 10, 2016 at 11:00 am, LNT Seminar Room N2408)


On August 10, 2016 at 11:00 am, Farzin Salek from Tehran will be giving a talk in the LNT Seminar Room N2408 about "A Distributed Opportunistic MAC Protocol for Multichannel Wireless Networks".

A Distributed Opportunistic MAC Protocol for Multichannel Wireless Networks

Farzin Salek


We propose a distributed opportunistic medium access control (MAC) scheme for maximizing the expected aggregate throughput in a multichannel wireless network such as a clustered orthogonal frequency division multiple access (OFDMA) network. In our proposed scheme, each user attempts to send only on its best channel and transmits if the best-channel gain is higher than a given threshold, which is dynamically updated depending on previous idle and collision situations. In this way, with our proposed scheme, in a homogeneous system where the channel fading distribution is identical for all users, the best user for each channel is obtained in a distributed manner. We also obtain the optimal values of the thresholds so that the probability of successful transmission is maximized and a minimal number of transmission opportunities are wasted (e.g., due to collision or idle transmissions). In the asymptotic limit of a large number of users and sufficiently long transmission slot duration, we show that, in comparison with the optimal centralized scheme, the throughput loss for our proposed scheme goes to zero. Furthermore, we extend our distributed opportunistic MAC scheme for a homogeneous system to that for a heterogeneous system where the channel fading distribution is heterogeneous across users. Throughput performances and signaling overhead are analyzed for the proposed distributed MAC schemes and compared with those of the existing schemes. Simulation results show that our proposed schemes significantly improve the average aggregate throughput when compared with the existing schemes.


Farzin Salek received the M.Sc. degree (with honors) in electrical engineering from Tarbiat Modares University, Tehran, Iran, in 2014; (a joint work with Sarif University of Technology including a TA position at Sharif University of Technology). Then he joined Wireless Innovation lab. at the same university as a research assistant. During Nov. 2015 – Jun. 2016 he was a visiting scholar with the information theory and coding group at the department of communication and information technologies, Pompeu Fabra University, Barcelona, Spain. He was a recipient of TMU fellowship through exceptional talents program. His research interests include network information theory and its applications to wireless networks.