2020/01/09 by Sarthak Jain, Jain, Sarthak, Soheil Mohajer +3
Computer Science · Engineering · #Cooperative Communication and Network Coding #FOS: Computer and information sciences #Full-Duplex Wireless Communications #Information Theory (cs.IT) #Wireless Communication Security Techniques
paper · pdf · doi:10.48550/arxiv.2001.02851
openalex publication_date 2020/01/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
This paper considers Gaussian half-duplex diamond n-relay networks, where a source communicates with a destination by hopping information through one layer of n non-communicating relays that operate in half-duplex. The main focus consists of investigating the following question: What is the contribution of a single relay on the approximate capacity of the entire network? In particular, approximate capacity refers to a quantity that approximates the Shannon capacity within an additive gap which only depends on n, and is independent of the channel parameters. This paper answers the above question by providing a fundamental bound on the ratio between the approximate capacity of the highest-performing single relay and the approximate capacity of the entire network, for any number n. Surprisingly, it is shown that such a ratio guarantee is f = 1/(2+2cos(2π/(n+2))), that is a sinusoidal function of n, which decreases as n increases. It is also shown that the aforementioned ratio guarantee is tight, i.e., there exist Gaussian half-duplex diamond n-relay networks, where the highest-performing relay has an approximate capacity equal to an f fraction of the approximate capacity of the entire network.