Interference Mitigation and Resource Allocation for Underlay Cognitive Radio Networks

Speaker: Shailesh Chaudhari
Affiliation: Ph.D. Candidate - UCLA

Abstract:  Due to ever-increasing usage of wireless devices and data hungry applications, it has become necessary to improve the spectral efficiency of wireless networks. Underlay cognitive radio network improves the spectrum efficiency by allowing unlicensed secondary users (SUs) to utilize the spectrum in the same time-frequency block as the licensed primary users (PUs). The SUs in such network use spatial dimension provided by multiple antenna techniques, such as MIMO, to achieve the objective of satisfying its own QoS requirements while protecting PUs from interference. A judicious resource allocation is required at the SUs for this purpose.

We present two aspects of resource allocation and interference mitigation in underlay CR networks. First, a new optimization framework is proposed to serve maximum number of SUs in the same time-frequency slot from a massive MIMO secondary base station in downlink transmission. The proposed framework satisfies the QoS requirements of SUs, while keeping the interference to PUs below a specified limit. Secondly, we analyze various power control and frequency band selection policies for a SU that utilizes MIMO beamforming to maximize its own QoS. We propose low-complexity user selection and frequency band selection approaches for the two scenarios. The analysis shows that the performance gap between the optimal and the proposed low-complexity algorithms closes when the number of antennas at SUs are order of magnitude larger than the number of PUs. Thus, the proposed approaches improve the efficiency of wireless networks by maximizing QoS of SUs in the same time-frequency slot as PUs without causing harmful interference to PUs.

Biography:  Shailesh Chaudhari is a Ph.D. candidate in the research group of Prof. Danijela Cabric at the UCLA ECE Department. He received B. Tech. degree in Electronics and Telecommunications from College of Engineering, Pune (India) in 2010 and M.S. in Electrical Engineering from UCLA in 2013. During his Ph.D., he held a summer internship in Qualcomm Technologies, Inc. in San Jose.

For more information, contact Prof. Danijela Cabric ()

Date(s) - Apr 24, 2018
12:00 pm - 2:00 pm

E-IV Maxwell Room #57-124
420 Westwood Plaza - 5th Flr. , Los Angeles CA 90095