一种基于信誉值拍卖的区块链下的感知收益分配机制

实现频谱共享,需要以实时准确地掌握主用户的频谱占用情况以及频谱交易信息为前提.为此,在利用群智感知以及区块链的前提下,提出了三层式的基于区块链的认知无线电系统,即物理层、传输层以及应用层.其中区块链网络位于传输层,用以记录交易信息,并利用区块链的去中心化以及去信任化特性以保证交易的安全性与可靠性.特别地,为了激励系统中...     

面向数字孪生边缘网络的区块链分片及资源自适应优化机制

为了解决数字孪生边缘网络数据共享面临的隐私和安全问题,提出一种基于区块链分片的数字孪生边缘网络数据安全共享机制。考虑动态时变的数字孪生边缘网络和边缘网络孪生模型与物理网络映射误差,建立联合多播簇头选择、本地基站（BS）共识接入选择、频谱和计算共识资源分配的自适应资源优化模型,实现最大化区块链分片交易吞吐量的目标。在数字孪生边缘网络环境下,提出双层近端策略优化（PPO）算法,求解自适应资源优化问题。仿真结果表明,所提算法可以有效改善区块链分片交易吞吐量。同时,在适应映射误差方面优于传统深度强化学习算法。     

一种金融级安全的区块链资产交易系统

提出了一种基于同态加密和环签名的区块链资产交易系统,通过同态加密技术可以对用户交易信息进行加密,使其对其他用户不可见,而环签名可以对同态加密后的密文进行业务合法性校验,保证交易合法性。该方法可以使区块链上原本公开透明的用户资产交易信息得到保护,具有去中心化、安全可靠和易用性高的特点,可以有效地起到保护用户隐私的作用,有利于促进增强区块链在金融资产交易场景中的用户交易信息隐私保护功能,有利于促进区块链隐私保护技术在金融场景中的落地和发展。     

基于区块链技术的跨域认证方案

针对现有交互频繁的信息服务信任域（PKI域和IBC域）之间不能实现信息服务实体（ISE）安全高效的跨域认证的问题,提出一种基于区块链的跨异构域认证方案.在IBC域设置区块链域代理服务器参与SM9（国产标识密码）算法中密钥生成,并与PKI域区块链证书服务器等构成联盟链模型,利用区块链技术去中心化信任、数据不易篡改等优点保证模型内第三方服务器的可信性.基于此设计了跨域认证协议与重认证协议,并进行SOV逻辑证明.分析表明,与目前相关方案相比,协议在满足安全需求的前提下,降低了用户终端的计算量、通信量和存储负担,简化了重认证过程,实现域间安全通信,在信息服务跨异构域身份认证过程中具有良好的实用性.     

基于代理重加密的区块链数据受控共享方案

区块链以分布式共享全局账本的形式存储交易数据，数据共享难以实现隐私保护和可用性之间的平衡，现有的区块链数据共享方案在进行隐私保护的同时可用性较低，有效实现区块链数据访问权限的动态调整是一个挑战性问题.为此，本文提出基于代理重加密的区块链数据受控共享方案.首先，基于SM2构造代理重加密算法，并借此设计区块链数据受控共享方案，利用代理重加密保护交易数据隐私实现数据安全共享.其次，提出用户权限动态调整机制，区块链节点分工代理并对重加密密钥参数分割管理，实现用户访问权限确定性更新，交易数据的可见性得到动态调整.最后，安全性和性能分析表明，本方案可以在保护交易隐私的同时，实现区块链数据动态共享，并且在计算开销方面具有优势，更好地适用于区块链数据受控共享.     

基于联盟区块链的高效性能优化中间件研究

区块链已成为现代甚至未来众多应用程序中最具吸引力的技术之一.目前Fabric是实现企业级区块链的开源联盟区块链,其性能的不足一直是区块链的瓶颈,其大规模数据运行的性能并不理想,本论文对区块链进行区块交易解析并设计了一种多链架构,基于HASH取模算法和Merkle Tree从交易到查询研究设计了页面与区块链的一致性验证的...     

用于图片交易的混合共识机制

随着信息技术的发展,越来越多的用户通过线上网站传输图像、浏览照片、交易版权。近年来,由于元宇宙概念逐渐引发热议,通过区块链进行的图片交易越来越多。区块链是一种分布式的数据库账本,拥有去中心化、防篡改、不依赖可信第三方等优良特性,但现有的区块链共识方案在处理图片交易时,存在奖励单一,过程复杂等不足。本文研究改进了工作量证明算法与实用拜占庭算法,并设计了基于工作积分的节点分级机制用于沟通公有链和联盟链;提出了基于双链的混合共识机制,以弥补现有共识机制在处理图片交易时节点选举随意,缺少奖惩机制的不足。实验表明,新的混合共识机制在处理图片交易时减少了通信开销,提高了交易速度。     

一种高效的联盟链网络构建设计

区块链已经成为了下一代最有前途的技术之一,以联盟链为主的区块链项目正不断应用落地.不同于比特币、以太坊等公链设施,联盟链多用于建立商业组织之间的信任.在联盟链网络中,所有节点必须经过授权才能加入网络,因此,其网络性能很大程度上依赖于网络的规模和消息传播机制.为了提高联盟链网络性能,文中提出了一种高效的联盟链网络构建设计...     

基于Fisco-Bcos平台的区块链系统性能精确分析模型

为了解决区块链系统实际部署面临的性能难以估计、所需的硬件设施性能难以确定等问题，建立了不同网络结构下基于模型和数据融合的区块链网络吞吐量精确表达模型。通过分析实用拜占庭容错（practical Byzantine fault tolerance,PBFT）算法区块链系统的交易流程，综合考虑网络拓扑结构、采用的共识算法、节点的通信方式等状况，基于大量实际数据建立了Fisco-Bcos区块链平台的交易吞吐量（transaction per second,TPS）精确表达模型。实际的区块链系统测试结果表明，本文建立的TPS预测模型可以在不同的网络结构下保持较高的预测精确度。     

区块链异常交易检测系统方案设计与分析

为解决区块链交易安全问题,基于智能合约交易等区块链相关业务的安全态势感知方法,提出了一种基于交易数据分析的异常交易检测系统,通过构建地址和实体交易图,联合特征和机器学习进行交易实体识别,并基于交易数据分析提取多粒度交易模式和用户画像,对区块链中的异常交易进行及时可靠的检测,可提高监管部门的监管效率,保障区块链交易安全。     

Consortium blockchains-based deep deterministic policy gradient algorithm for optimal electricity trading among households

To achieve higher energy utilization and lower generation cost for renewable sources ( e. g. , wind and solar energy), much work hasbeen focusedon demand response in smart grid (SG). Nonetheless, most existing studies consider energy trading with utility company which results in high energy loss from high voltage to low voltage and privacy leakage. Besides, there are relatively few researches devoted to electricity scheduling and price optimum among households without a third party. To cope with these issues, a novel deep deterministic policy gradient (DDPG)-based energy trading method with consortium blockchain (DETCB) is introduced. Firstly, in order to enhance system security, executing energy transaction among households is on the basis of consortium blockchain, which leads to not only anonymous trade but also public account. Moreover, the primary target from the aspect of the system is apparently the maximal social welfare, thus exploiting an iterative decision-making method combined with DDPG algorithm by non-profit controllers to obtain optimal trading prices and carry out optimal electricity allocation. To this end, security analysis demonstrates that DETCB contributes to creating a secure, stable and trustful environment. Furthermore, the excellent performance concerning social welfare, algorithm efficiency, and transaction energy sum is shown by numerical results.     

Energy Efficiency and Superlative TTT for Equitable RLF and Ping Pong in LTE Networks

Mobile Networks and Applications - Data hungry users engage radio resources over long periods of time thus resulting into higher energy consumption by Base Stations (BSs). Mobile operators’...     

Electronic medical record data sharing scheme based on searchable encryption via consortium blockchain

Considering that it was difficult to share medical record data among different medical institutions in cloud storage,an electronic medical record data sharing scheme based on searchable encryption on blockchain was proposed.In order to realize the secure storage and sharing of electronic medical records in the scheme,the patient’s electronic medical record ciphertext was stored in the hospital server,the ciphertext hash value was stored in the private blockchain,and the keyword index was stored in the consortium blockchain.Searchable encryption was used to implement secure search of keywords in the consortium blockchain,and proxy re-encryption technology was used to realize the sharing of electronic medical records of patients by other data users.Security analysis shows that the proposed scheme can achieve ciphertext security and keyword security.Moreover,the performance of the scheme was analyzed by function analysis,computational efficiency analysis and numerical simulation.The performance analysis shows that the scheme can achieve high computational efficiency.     

LTE系统中BSR和SR发送问题的改进

调度是LTE(长期演进)系统中基站为用户分配资源的重要环节和关键技术。UE(用户终端)一般通过BSR(缓存状态报告)和SR(调度请求)获得无线资源。文章针对BSR和SR同时存在时造成资源浪费的问题,通过不同的参数设置设计了解决方案,并且提出了一种在半静态调度下判断触发BSR和SR的方法以及解决填充BSR和其他BSR冲突的方法,有效地提高了资源利用率和系统稳定性。     

Downlink Radio Resource Allocation for Multi-Cell OFDMA System

This paper presents a radio resource control (RRC) scheme for OFDMA systems where dynamic resource allocation is realized at both a radio network controller (RNC) and base stations (BSs). The scheme is semi-distributed in the sense that the RRC decision is split between RNC and BSs. RNC makes decision on which channel is used by which BS at super-frame level and BSs then make decision on which user is assigned to which channel at frame-level. Two optimization problems for RNC and BSs are formulated and computationally efficient algorithms that perform the function of interference avoidance and traffic/channel adaptation are developed. Numerical analysis is performed under several cell configurations to show tradeoffs between sector interference suppression and dynamic interference avoidance. The results indicate that with reasonable signaling overhead, the protocol and the associated algorithms yield excellent performance for both real-time and non real-time services, even under fast fading     

LTE切换自优化算法进展综述

LTE是新一代通信技术的代名词,它对现有3G系统的网络结构和无线接入方式都有较大改进.在简要介绍LTE系统的网络架构及切换功能的基础上,重点介绍并比较了2种LTE切换自优化算法：常见的用户速度的负载均衡算法有效地降低了系统的掉话率,使系统的整体性能得到提高,但没有考虑到目标小区资源变化的情况;基于RSRP/RSRQ负载均衡算法综合考虑了源小区和目标小区的RSRP（参考信号接收功率）和RSRQ（参考信号接收质量）,降低了系统的切换失败率,同时减少了不必要的切换,但没有考虑用户运动方向的影响.综合加权考虑多种因素,如用户的移动方向以及小区资源的变化等对切换的影响等方面均有待深入开展研究.     

Resource allocation algorithm for LTE networks using fuzzy based adaptive priority and effective bandwidth estimation

In this paper, we propose a scheme to allocate resource blocks for the Long Term Evolution (LTE) downlink based on the estimation of the effective bandwidths of traffic flows, where users’ priorities are adaptively computed using fuzzy logic. The effective bandwidth of each user traffic flow that is estimated through the parameters of the adaptive β-Multifractal Wavelet Mode modeling, is used to attain their quality of service (QoS) parameters. The proposed allocation scheme aims to guarantee the QoS parameters of users respecting the constraints of modulation and code schemes (modulation and coding scheme) of the LTE downlink transmission. The proposed algorithm considers the average channel quality and the adaptive estimation of effective bandwidth to decide about the scheduling of available radio resources. The efficiency of the proposed scheme is verified through simulations and compared to other algorithms in the literature in terms of parameters such as: system throughput, required data rate not provided, fairness index, data loss rate and network delay.     

Economic Approaches for Cognitive Radio Networks: A Survey

Efficient resource allocation is one of the key concerns of implementing cognitive radio networks. Game theory has been extensively used to study the strategic interactions between primary and secondary users for effective resource allocation. The concept of spectrum trading has introduced a new direction for the coexistence of primary and secondary users through economic benefits to primary users. The use of price theory and market theory from economics has played a vital role to facilitate economic models for spectrum trading. So, it is important to understand the feasibility of using economic approaches as well as to realize the technical challenges associated with them for implementation of cognitive radio networks. With this motivation, we present an extensive summary of the related work that use economic approaches such as game theory and/or price theory/market theory to model the behavior of primary and secondary users for spectrum sharing and discuss the associated issues. We also propose some open directions for future research on economic aspects of spectrum sharing in cognitive radio networks.     

Resource scheduling in downlink LTE-advanced system with carrier aggregation

In this paper,we focus on the resource scheduling in the downlink of long term evolution advanced (LTE-A) assuming equal power allocation among subcarriers.Considering the backward compatibility,the LT...