Consensus protocol is a key technology enabling blockchain to provide secure and trustful services in wireless networks. However, most previous study on blockchain consensus protocols for wireless networks relies on reliable message transmissions and honest leaders. In practice, wireless blockchains inherently suffer from limited physical resources and unreliable wireless channels due to environmental noises and adversary attacks. This paper studies the design of Byzantine fault tolerant consensus protocol for blockchain in single-hop wireless networks subject to signal-to-noise constraint. For this purpose, we propose a low-latency and reliable Byzantine fault-tolerant consensus protocol LRBP, which incorporates the following three designs: 1) Randomized credit-based block proposer selection, which can prevent adversary corruption and improve the system throughput, 2) Enhanced threshold Boneh-Lynn-Shacham signature based voting mechanism, which can achieve communication-efficient block validity voting by using piggyback-based acknowledgment and criticality-based adaptive channel accessing probability adjustment, and 3) Random linear network coding based batch forwarding, which supports reliable block transmissions. We derive the consensus success probability and consensus time complexity of LRBP. We prove that LRBP simultaneously satisfies the properties of persistence and liveness. It is resistant to the 51% attack, Sybil attack, double-spending attack, and jamming attack. Simulation results show the high efficiency of LRBP as compared with existing work.

Scalable consensus protocol is essential for providing high-throughput and secure blockchain services in wireless networks. In this article, we propose a scalable credible-committee-based blockchain consensus (SCBC) protocol for resource-limited multihop wireless networks, which contains the following key designs: 1) credit-based committee selection algorithm, which improves the system security by selecting credible committee members; 2) scalable credible-committee-based consensus algorithm, which supports efficient consensuses using small-sized committee and threshold signatures; and 3) criticality-based localized broadcast algorithm, which is designed to suppress broadcast redundancy and further improves the consensus efficiency. Thorough security analyses show that SCBC satisfies both safety and liveness properties, and can resist more attacks than traditional Byzantine fault-tolerant consensus protocols. We deduce the message complexity of SCBC. Extensive simulation results demonstrate that our proposed protocol SCBC outperforms existing work in terms of throughput and consensus latency.

unmanned aerial vehicles (UAVs) enabled mobile edge computing (MEC) has been an attractive paradigm for providing flexible and high-quality offloading services to ground users. In this article, we study a hierarchical aerial MEC network architecture for improved Quality of user Experiences. Specifically, we study a bilevel UAV-enabled MEC network where a fixed-wing UAV (F-UAV) and multiple rotor UAVs (R-UAVs) are jointly deployed to provide continuous MEC services to ground users with dynamic demands. We formulate a long-term optimization problem for minimizing the utility of all users while considering the stability of task queue backlogs and energy consumption budgets at users and R-UAVs, where user utility measures the per-slot task processing performance at user side. We apply Lyapunov optimization technique to decompose the original problem into deterministic per-slot optimization subproblems. We derive the optimal offloading conditions at different types of edge nodes. We accordingly propose a Bilevel UAVs based online task processing and resource allocation algorithm (BOTRA) for determining the offloading and local processing profiles at users. Extensive simulation experiment results show the high performance of the proposed BOTRA algorithm compared with benchmark algorithms.

With the development of big data, people focus on data security and privacy, blockchain has been paid more and more attention. Compared to pre-2013, the number of blockchain literature publications has increased. Scholars from different research fields have deeply explored blockchain technology. In this paper, we collected blockchain literature data from 2013 to 2020, and then we conducted a quantitative analysis of publications, author groups, research content and future research content. For the current research status, we also discussed the problems facing blockchain. We started by mining representative authors, and revealed current status of blockchain research, author’s team cooperation, and blockchain’s development content. We can provide research objectives and inspiration for new researchers, and give research routes for the future development of blockchain.