Abstract-One challenge in delay tolerant networks (DTNs) is efficient routing, as the lack of contemporaneous end-to-end paths makes conventional routing schemes inapplicable. Many existing DTN routing protocols adopt multi-copy replication and/or are incognizant of mobility models. Hence they are not suitable for networks with extremely stringent resources and time-varying mobility models such as underwater sensor networks. In this paper, we propose a generic prediction assisted single-copy routing (PASR) scheme that can be instantiated for different mobility models in underwater sensor networks. PASR employs an effective greedy algorithm which captures the features of network mobility patterns, and provides guidance on how to use historical information. We demonstrate the superior performance of PASR through simulation.
This article examines the implications of the Chinese-led Belt and Road Initiative (BRI) for Africa’s connectivity. The BRI seeks to rebuild the ancient Silk Road trade route with the overall goal of opening global markets, thus creating a trade and investment network involving three continents: Africa, Asia, and Europe. Using secondary data, this article assesses the opportunities and potential challenges of the BRI for Africa with a special focus on various BRI national projects. It concludes that China’s involvement in infrastructure projects in Africa and the BRI’s vision for increased connectivity among beneficiary countries can lead to integrated and streamlined economic and infrastructure development in Africa, while improving China’s corporate and product image, generating mutual benefits to both China and Africa. This article also argues that for those BRI-based benefits to materialize, certain challenges need to be dealt with, particularly security risks and corruption, which could increase the long-term costs of infrastructure projects for countries involved.
An intermediate node in an inter-flow network coding scheme needs to know exactly which are the previous hop and next hop of a packet before coding. It is difficult to incorporate inter-flow network coding into opportunistic routing (OR) because the next hop of a packet in OR can't be determined in advance. Codingaware opportunistic routing (CAR) is proposed in this paper to address this problem on fixed wireless mesh networks (WMNs). Meanwhile, it aims to maximize the number of native packets coded in each single transmission. It dynamically selects a route for a given flow according to the real-time coding opportunities. There are no control packets in CAR, which greatly reduces the overhead costs. CAR gives the coded packet that consists of a larger number of native packets with a smaller forwarding delay. The forwarder with the largest number of native packets coded together is ultimately selected to send data. Simulations demonstrate that CAR achieves significantly better throughput gains and derives a reasonable end-to-end delay in both cross topology and mesh topology under both transmission control protocol (TCP) and user datagram protocol (UDP) traffic, as explained below. CAR achieves more than 35 % throughput improvement under TCP traffic and more than 15 % throughput improvement under UDP traffic, compared to other state-of-art protocols in cross topology, respectively. CAR also provides a several-fold increase in throughput in a large scale network (mesh topology). In a word, CAR significantly improves network performance of a WMN.
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