2015/07/24 by Hyo Seung Kang, Myung Gil Kang, Kang, Hyo Seung +5
Computer Science · Engineering · Mathematics · #Cognitive Radio Networks and Spectrum Sensing #Cooperative Communication and Network Coding #FOS: Computer and information sciences #Information Theory (cs.IT) #Wireless Communication Security Techniques #cs.IT #math.IT
paper · pdf · doi:10.48550/arxiv.1507.06737
arxiv created 2015/07/24 · openalex publication_date 2015/07/24 · arxiv updated 2015/07/27 · openalex created_date 2022/10/05 · openalex updated_date 2026/07/28
This paper studies the interference channel with a cognitive relay (ICCR) under delayed feedback. Three types of delayed feedback are studied: delayed channel state information at the transmitter (CSIT), delayed output feedback, and delayed Shannon feedback. Outer bounds are derived for the DoF region of the two-user multiple-input multiple-output (MIMO) ICCR with delayed feedback as well as without feedback. For the single-input single-output (SISO) scenario, optimal schemes are proposed based on retrospective interference alignment. It is shown that while a cognitive relay without feedback cannot extend the sum-DoF beyond 1 in the two-user SISO interference channel, delayed feedback in the same scenario can extend the sum-DoF to 4/3. For the MIMO case, achievable schemes are obtained via extensions of retrospective interference alignment, leading to DoF regions that meet the respective upper bounds.