Mr. Ammar Ahmad has successfully defended his Ph.D. dissertation, “Strategies for Radar-Communication Spectrum\u00a0Sharing,” on February 15, 2021. Because of the COVID pandemic, the dissertation presentation was delivered virtually through Zoom.<\/p>\n
Ammar\u2019s dissertation focuses on spectrum sharing which has become increasingly important since the past decade due to the ongoing congestion of\u00a0spectral resources. Higher data rates in wireless\u00a0communications require expansion of existing frequency\u00a0allocations. Significant research efforts have been made\u00a0in the direction of cognitive radio to effectively manage\u00a0the existing frequency usage. Recently, coexistence of\u00a0multiple platforms within same frequency bands is\u00a0considered effective to mitigate spectral congestion. The\u00a0coexistence of radar and communication platforms in the same frequency bands requires both systems to work\u00a0collaboratively to mitigate their mutual interference. This\u00a0challenge can be significantly simplified if both systems are controlled by a joint control entity. Joint radar-communication (JRC) system is such an example where radar and communication system objectives are achieved\u00a0by the same physical platform.\u00a0In Ammar’s dissertation, three different types of JRC systems are investigated and novel signal processing techniques are developed to optimize their performance. These JRC systems respectively exploit a single transmit antenna, an antenna array for beamforming, and a distributed JRC network.<\/p>\n
In addition to his work on spectrum sharing and JRC, Ammar has performed extensive work on over-the-horizon radar and sparse array signal processing that generated many publications. His work was supported in part by the Air Force Research Laboratory. Ammar received the Best Student Paper Award (Third Place)<\/a> at the 2017 IEEE Radar Conference for his work on “Effective nested array design for fourth-order cumulant-based DOA estimation”<\/span>. He is a coauthor of paper “DOA estimation exploiting interpolated multi-frequency sparse array” that received the Best Student Paper Award<\/a> at the 2020 IEEE Sensor Array and Multichannel Signal Processing Workshop.<\/p>\n Ammar’s Ph.D. studies were supported by the Air Force Research Lab.<\/p>\n