2008/02/13 by K. Sreeram, Sreeram, K., S. Birenjith +3 · 4 citations
Computer Science · Engineering · Mathematics · #Advanced MIMO Systems Optimization #Cooperative Communication and Network Coding #FOS: Computer and information sciences #Full-Duplex Wireless Communications #Information Theory (cs.IT) #cs.IT #math.IT
paper · pdf · doi:10.48550/arxiv.0802.1888
arxiv created 2008/02/13 · openalex publication_date 2008/02/13 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/29
We consider single-source single-sink (ss-ss) multi-hop networks, with slow-fading links and single-antenna half-duplex relays. We identify two families of networks that are multi-hop generalizations of the well-studied two-hop network: K-Parallel-Path (KPP) networks and layered networks. KPP networks can be viewed as the union of K node-disjoint parallel relaying paths, each of length greater than one. KPP networks are then generalized to KPP(I) networks, which permit interference between paths and to KPP(D) networks, which possess a direct link from source to sink. We characterize the DMT of these families of networks completely for K > 3. Layered networks are networks comprising of relaying layers with edges existing only within the same layer or between adjacent layers. We prove that a linear DMT between the maximum diversity dmax and the maximum multiplexing gain of 1 is achievable for fully-connected layered networks. This is shown to be equal to the optimal DMT if the number of layers is less than 4. For multi-antenna KPP and layered networks, we provide an achievable DMT region. For arbitrary ss-ss single-antenna directed-acyclic full-duplex networks, we prove that a linear tradeoff between maximum diversity and maximum multiplexing gain is achievable. All protocols in this paper are explicit and use only amplify and forward (AF) relaying. We also construct codes with short block-lengths based on cyclic division algebras that achieve the optimal DMT for all the proposed schemes. Two key implications of the results in the paper are that the half-duplex constraint does not entail any rate loss for a large class of networks and that simple AF protocols are often sufficient to attain the optimal DMT.