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UBC Theses and Dissertations

Decentralized connectivity-aware computational resource sharing system in the D2D networks Hong, Zhen

Abstract

Device-to-device (D2D) communication and its applications are increasingly important in future networks with the climbing demand for rapid local services. Specifically, resource sharing in the D2D networks is featured by the ubiquitous availability, flexibility, low-latency and low-cost. However, there are challenges when building a satisfactory resource sharing system in the D2D networks, including user mobility and proper incentives for users to share. Previous endeavors typically are not comprehensive over mobility consideration, fairness, and efficiency. In this thesis, we introduce a decentralized connectivity-aware computational resource sharing system in the D2D networks. Three steps are taken towards building such system: 1) an innovative connectivity-aware task scheduling paradigm is proposed to help a user to outsource appropriate amount of computational tasks to appropriate users at appropriate time; 2) a decentralized blockchain-based ledger system is introduced to reduce selfishness; 3) a directed acyclic graph (DAG) based ledger system is proposed to avoid notorious monetary and time costs in a traditional proof of work (PoW) based ledger system, which realizes our decentralized sharing system. Mobility and fairness considerations are formulated as optimization problems with system designs and light-weight algorithms presented. We carried out simulations based on real connectivity traces, and the results show that consideration of mobility can further reduce average task execution time and sacrificing a minor amount of execution time gets major enhance in fairness. High transaction fees, long confirmation time, and thus low efficiency are notorious issues in traditional PoW-based blockchain systems. Many blockchain companies with multi-billion market cap, e.g. IOTA and Nano, believe that properly designed DAG-based ledger systems are the best candidates to achieve very high transaction throughput. Inspired by existing DAG-based ledger technology, our efficiency consideration is mainly a design of a novel decentralized DAG-based ledger system that is suitable to our D2D system for high transaction throughput and solves the aforementioned issues in a traditional PoW-base ledger system. We simulated decentralized systems according to specifications in the IOTA whitepaper, and simulation results show that our system is much more realistic and suitable to a D2D system that needs high throughput, even compared to the leading pioneers like IOTA.

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Attribution-NonCommercial-NoDerivatives 4.0 International

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