一种移动感知的太赫兹无线局域网定向MAC协议

现有太赫兹无线局域网定向MAC(Medium Access Control)协议中,节点移动情况下PNC(PicoNet)发送beacon帧时存在部分控制字段浪费、CTAP(Channel Time Allocation Period)中PNC与DEV(Device)进行波束赋形开销偏大等问题。为此,提出了一种移动感知的太赫兹无线局域网定向MAC(Mobility-aware Directional MAC,MA-MAC)协议。该协议采用基于卡尔曼算法的节点扇区预测机制对移动节点的扇区范围进行迭代预测,采用基于DEV扇区预测的beacon帧内容填充机制对beacon帧中时隙分配字段进行填充,采用基于节点扇区预测的快速波束赋形机制使得PNC与DEV之间波束赋形操作简化。通过仿真验证,与基于IEEE 802.15.3c的太赫兹无线局域网定向MAC协议和现有协议进行对比,MA-MAC协议下网络吞吐量得到了提升,网络平均时延、网络整体控制开销得到了改善。

高效低时延分级多PAN太赫兹无线网络MAC层优化协议

针对现有分级多PAN太赫兹无线网络MAC(Medium Access Control)协议中存在的子网形成方案不合理以及私有CTA(Channel Time Allocation)与子网内实际负载不匹配等问题,提出了一种高效低时延的MAC层优化协议.该协议采用基于泛听的按需形成子网机制避免了子网分布不均匀以及因子网形成后没有节点加入而造成的私有CTA资源浪费的问题.在子网形成后,子微微网协调器(Piconet Coordinator,PNC)根据子网内实际负载情况自适应选择私有CTA时隙资源优化机制,让有数据传输需求的节点及时将数据发出.仿真结果表明,所提出的方案能有效地降低数据帧平均接入时延,提高吞吐量以及数据帧的传输成功率.

无线和电力线混合通信的MAC层接入算法设计和性能分析

电力线和无线混合通信可以优势互补提升电力物联网室内覆盖的综合性能。针对无线接入和电力线中继的混合通信场景,文章提出一种适用于两跳混合中继的通用MAC层算法。综合考虑物理层信道参数和MAC层的载波侦听多路访问(carrier sense multiple access,CSMA)退避流程,建立了该MAC层算法的跨层性能分析模型,推导了两跳传输系统归一化吞吐量以及系统时延等性能;最后仿真验证了算法有效性和模型准确性,分析了物理层和MAC层关键参数影响系统性能的机理。与Basic-RTS/CTS算法相比,所提算法可有效提升系统吞吐量和时延性能。

认知传感网中基于Transformer网络的MAC协议识别方法

媒体接入控制(Media Access Control,MAC)识别有助于优化认知无线电系统的频谱管理并提高通信质量。已有的基于深度学习的MAC协议识别方法仍存在复杂信道环境的适应性不足、长期依赖关系捕捉能力有限的问题。因此,提出基于Transformer网络的MAC协议识别方法,利用自注意力机制有效捕捉长距离依赖,通过多头注意力机制同时关注输入序列中不同部分的相关性,提升对信号特征和行为的理解。针对认知传感网的特定需求,对传统的Transformer模型结构进行了优化,包括调整模型的深度和宽度以适应信号数据的特性。自注意力机制不仅增强了模型对时间序列数据的处理能力,还通过位置编码保留序列中的位置信息,结合前馈神经网络增强模型的非线性表达能力,并通过层归一化和残差连接机制提高模型的稳定性和训练效率。实验结果表明,所提方法在复杂无线通信环境中具有显著的性能优势,在识别4种主要MAC协议时展现出超过95%的高准确率。

以太网MAC控制器GMII和RGMII接口转换IP设计

阐述RGMII接口是简化的GMII接口,解决GMII接口信号线过多造成的布线复杂和功耗大的问题。首先研究IEEE802.3千兆以太网MAC控制器的GMII接口协议和RGMII接口规范,分析在千兆以太网MAC控制器中两种接口转换的实现方案,包括RGMII正常和延迟模式的实现方案。用Verilog HDL完成代码实现,通过NC-SIM仿真和Quartus-II实现后下载到FPGA板验证,表明功能正确。最后将实现的RGMII应用到某以太网交换芯片。在交换芯片的功能板上两PC机通过RGMII接口和Marvell 88E1145等器件实现数据正确传输。通过这些流程,形成标准接口转换IP,可直接应用于其他产品。

基于FPGA的面向高负载业务的柔性信道预约MAC的设计与实现

针对定向自组织网络中高负载业务的通信需求,提出并实现了一种基于柔性信道预约的MAC协议,可以准确且不受干扰地使用或释放信道资源,保证网络吞吐量和时延要求。该协议主要引入了柔性信道预约机制、自适应MCS调整和自适应帧聚合等功能。整个协议在FPGA上进行设计和实现,并在Xilinx ZYNQ7010开发板上对整机节点业务传输功能进行验证。

基于MEC服务器优先服务的路侧单元MAC层调度策略

针对多接入边缘计算(MEC)服务器高可靠、低时延和大数据量的数据传输要求,基于无冲突接入、优先级架构和弹性服务技术,提出一种适用于车辆边缘计算场景下的媒体访问控制(MAC)调度策略。所提策略由车联网(IoV)路侧单元(RSU)集中协调信道接入权,优先确保车载网络中车载通信单元(OBU)与MEC服务器之间的链路传输质量,以及时传输车辆到网络(V2N)业务数据;同时,对本地OBU之间的业务采取弹性服务方式,增强密集车辆接入时应急消息传输的可靠性。首先,构建调度策略的排队分析模型;其次,根据各时刻系统状态变量的无后效性特点建立嵌入式马尔可夫链,并通过概率母函数的分析方法对系统进行理论分析,得到MEC服务器通信单元和OBU的平均排队队长、平均等待时延和RSU查询周期等关键指标的精确解析表达式。计算机仿真实验结果表明,统计分析结果与理论计算结果一致,所提调度策略在高负载情况下能够提高IoV的稳定性和灵活性。

基于深度强化学习的水声网络公平跨层MAC协议

针对水声通信异构网络中信道分配不公和节点能量受限的问题,基于深度强化学习方法,提出跨层联合优化公平信道接入和功率控制的媒介访问控制(POCL-MAC)协议。根据反馈ACK包获知时延状态下的信道冲突结果和接收机处信噪比,基于深度强化学习的状态、动作和奖励序列自主学习,调整认知用户的接入时隙和发射功率;采用公平函数实现异构网络中认知用户和主用户吞吐量性能的比例公平。设计了一个联合状态序列和独立式奖励函数,在不增加神经网络复杂度的前提下,提高跨层联合优化的子动作决策准确度。仿真结果表明,相比于传统DRL算法,所提算法实现了接近于最优公平性吞吐量性能,同时具有更好的能量利用效率。

Message from Editors

IN recent years,the electrical machines and systems have grown so rapidly with more and more applications in emerging civilian industries as well as cutting-edge areas.A group of novel and exciting technologies have been developed every year.First,the research of motors in new and extreme fields have constantly brought amazing progress to achieve better performance through new technologies such as digitalization,etc.Meanwhile,the fast development of power electronics in recent decades has also changed the overall system to be more flexible,and widely extent our boundary of research area.What is more.

基于IR-UWB的高吞吐量、低延时MAC协议硬件设计

针对IEEE 802.15.4高速数据传输的应用场景,提出一种具有高吞吐量和低延时特性的定制化MAC协议。基于HRP UWB PHY对数据传输模型和吞吐量深入分析,并结合MAC协议的冲突避免载波侦听多路访问(Carrier Sense Multiple Access with Collision Avoid,CSMA-CA)和保障时隙(Guaranteed Timeslot,GTS)实时传输的特性,设计了该机制有效的管理流程。最后在Vivado中使用Verilog HDL对MAC控制器进行硬件设计和验证。仿真结果表明,与经典IEEE 802.15.4 MAC协议相比,该MAC控制器的吞吐量提高了26%,同时数据传输时延降低了17%。

BDSec:Security Authentication Protocol for BeiDou-Ⅱ Civil Navigation Message

Due to the lack of authentication mechanism in BeiDou navigation satellite system(BDS),BD-Ⅱ civil navigation message(BDⅡ-CNAV) are vulnerable to spoofing attack and replay attack.To solve this problem,we present a security authentication protocol,called as BDSec,which is designed by using China’s cryptography Shangyong Mima(SM) series algorithms,such as SM2/4/9 and Zu Chongzhi(ZUC)algorithm.In BDSec protocol,both of BDⅡ-CNAV and signature information are encrypted using the SM4 algorithm(Symmetric encryption mechanism).The encrypted result is used as the subject authentication information.BDSec protocol applies SM9 algorithm(Identity-based cryptography mechanism) to protect the integrity of the BDⅡ-CNAV,adopts the SM2 algorithm(Public key cryptosystem) to guarantee the confidentiality of the important session information,and uses the ZUC algorithm(Encryption and integrity algorithm) to verify the integrity of the message authentication serial number and initial information and the information in authentication initialization sub-protocol respectively.The results of the SVO logic reasoning and performance analysis show that BDSec protocol meets security requirements for the dual user identity authentication in BDS and can realize the security authentication of BDⅡ-CNAV.

无人机群自组网MAC协议综述

近年来,无人机群自组网(UAV Swarm Ad Hoc Network,UAVSNet)的单个UAV不断自主化与智能化,但UAV之间的协同通信仍存在挑战。媒体接入控制(Media Access Control,MAC)协议是其关键技术之一,并成为了新的研究热点。通过概述MAC协议的分类及设计要点,对竞争类MAC协议、非竞争类MAC协议以及混合类MAC协议接入机制、性能表现及不足进行详细综述并提出展望。为UAVSNet的MAC协议的研究和应用提供了理论支持。

Anti-Spoofing:Integrated Information Authentication of BeiDou-ⅡCivil Navigation Message

The BeiDou-Ⅱcivil navigation message(BDⅡ-CNAV)is transmitted in an open environment and no information integrity protection measures are provided.Hence,the BDⅡ-CNAV faces the threat of spoofing attacks,which can lead to wrong location reports and time indication.In order to deal with this threat,we proposed a scheme of anti-spoofing for BDⅡ-CNAV based on integrated information authentication.This scheme generates two type authentication information,one is authentication code information(ACI),which is applied to confirm the authenticity and reliability of satellite time information,and the other is signature information,which is used to authenticate the integrity of satellite location information and other information.Both authentication information is designed to embed into the reserved bits in BDⅡ-CNAV without changing the frame structure.In order to avoid authentication failure caused by public key error or key error,the key or public key prompt information(KPKPI)are designed to remind the receiver to update both keys in time.Experimental results indicate that the scheme can successfully detect spoofing attacks,and the authentication delay is less than 1%of the transmission delay,which meets the requirements of BDⅡ-CNAV information authentication.

Effectiveness of Short Message Service Support on Adherence to Chemotherapy Treatment among Patients Attending Cancer Treatment Facilities in Kenya

Introduction: Cancer is a chronic debilitating disease that unnerves patients, communities, and nations. At some point in cancer patient’s disease experience, chemotherapy is used, and the patient is expected to adhere to treatment to improve survival and quality of life. Methods: This multisite Cluster Randomized Trial (CRT) evaluated the effectiveness of mobile phone Short Message Service (SMS) support on the adherence to treatment schedules among adult cancer patients in Kenya. Data was collected using questionnaires. Ethical approvals were obtained from relevant Ethical Review Boards (ERBs). Results: The mean adherence was 83%. There was a significant difference between treatment arms in relation to the adherence. The intervention arm had a higher mean adherence difference, M = 3.913, 95% CI 2.632-5.193, t (402) = 6.006, p ≤ 0.001), with Cohen’s d = 0.60. Although not significant, (χ2dd = 0.151, df = 1, p = 2.064), more women were perfect adheres than males. Perfect adherers were satisfied with SMS support (χ2dd = 7.620, df = 1, p = 0.06), were in the intervention arm (χ2dd = 22.942, df = 1, p ≤ 0.001), and had trust in the care provider (χ2dd = 10.591 p ≤ 0.001). SMS support was not significant in the multivariate analysis but had an estimated effect size of 0.958 (z = 1.424, p = 0.154, CI = 0.242-3.781), indicating that mean adherence was slightly better in the presence of the intervention. Conclusions: SMS-support intervention has demonstrated superiority in influencing adherence. Further, health system-related factors have a significant influence on the adherence to chemotherapy treatment. Interventions to re-design health systems that are responsive to unmet care needs of cancer patients must be explored. .

Analysis of the Cicatricial Acceleration Method (MAC®) in Skin Repair in Wistar Rattus norvegicus with Induced Chemical Burns

Introduction: The cicatricial acceleration method (MAC®) promotes photobiological effects of an anti-inflammatory and healing nature. Its therapeutic radiation is emitted, producing photobiostimulant effects that result in rapid tissue repair and better tissue quality. The treatment of burns has always been a challenge, which involves both performing surgery and controlling and guiding scar regeneration, avoiding possible morbidities. Objective: To evaluate the effects of applying the MAC methodology with an AlGa (aluminum, gallium arsenide) laser on the time and quality of tissue repair in the skin of rats after induced chemical burns. Method: 22 adult male rats were subjected to a second-degree chemical burn on the back using 50% trichloroacetic acid. After the burns, the animals were randomly separated into 2 groups: control and experimental. The control group (G1) received placebo laser therapy and the laser group (G2) underwent laser irradiation with an energy density of 100 J/cm2. Histological analysis and macroscopic evaluation were carried out by means of the paper template method. Results: Group G1 showed (53%) of the necrosis area and group G2 showed (11%) necrosis area. Conclusion: The cicatricial acceleration method (MAC®) favored the repair of wounds caused by a 2nd-degree chemical burn, optimizing time and improving quality.

Artificial Intelligence-Based Sentiment Analysis of Dynamic Message Signs that Report Fatality Numbers Using Connected Vehicle Data

This study presents results from sentiment analysis of Dynamic message sign (DMS) message content, focusing on messages that include numbers of road fatalities. As a traffic management tool, DMS plays a role in influencing driver behavior and assisting transportation agencies in achieving safe and efficient traffic movement. However, the psychological and behavioral effects of displaying fatality numbers on DMS remain poorly understood;hence, it is important to know the potential impacts of displaying such messages. The Iowa Department of Transportation displays the number of fatalities on a first screen, followed by a supplemental message hoping to promote safe driving;an example is “19 TRAFFIC DEATHS THIS YEAR IF YOU HAVE A SUPER BOWL DON’T DRIVE HIGH.” We employ natural language processing to decode the sentiment and undertone of the supplementary message and investigate how they influence driving speeds. According to the results of a mixed effect model, drivers reduced speeds marginally upon encountering DMS fatality text with a positive sentiment with a neutral undertone. This category had the largest associated amount of speed reduction, while messages with negative sentiment with a negative undertone had the second largest amount of speed reduction, greater than other combinations, including positive sentiment with a positive undertone.

Blockchain-Based Message Authentication Scheme for Internet of Vehicles in an Edge Computing Environment

As an important application of intelligent transportation system,Internet of Vehicles(IoV)provides great convenience for users.Users can obtain real-time traffic conditions through the IoV’s services,plan users’travel routes,and improve travel efficiency.However,in the IoV system,there are always malicious vehicle nodes publishing false information.Therefore,it is essential to ensure the legitimacy of the source.In addition,during the peak period of vehicle travel,the vehicle releases a large number of messages,and IoV authentication efficiency is prone to performance bottlenecks.Most existing authentication schemes have the problem of low authentication efficiency in the scenario.To address the above problems,this paper designs a novel reliable anonymous authentication scheme in IoV for Rush-hour Traffic.Here,our scheme uses blockchain and elliptic curve cryptography(ECC)to design authentication algorithms for message authentication between vehicles and roadside units(RSU).Additionally,we introduce the idea of edge computing into the scheme,RSU will select themost suitable vehicle as the edge computing node for message authentication.In addition,we used the ProVerif tool for Internet security protocols and applications to test its security,ensuring that it is secure under different network attacks.In the simulation experiment,we compare our scheme with other existing works.Our scheme has a significant improvement in computational overhead,authentication efficiency and packet loss rate,and is suitable for traffic scenarios with large message volume.

基于MAC准入控制与网络流量监控的哑终端入网管控系统设计

企业网络中大量哑终端设备的使用,给企业管理带来便利的同时,也带来较大安全隐患。通过分析主流准入控制方式的实现特点及不足,提出一种针对哑终端设备的MAC准入控制方式+网络流量监控相结合的准入控制方法,该方法能够利用2种认证方式的优点,弥补各认证方式自身的不足,使得针对哑终端设备的网络准入控制能够依托于接入交换机的MAC认证机制实现端口级别的管控。同时,根据哑终端设备网络业务流量相对固定的特点,采用网络流量监控的方式,为MAC准入控制方式提供持续性的、更细粒度的准入判决控制。

LSDR-ALOHA-Q:基于强化学习适用于大范围远距离的水下无线传感器网络MAC协议

随着对海洋开发需求的日益增长,水下无线传感器网络成为研究的热点。但由于水下环境信道可用带宽有限,传输速度和传播速度都慢,多普勒效应和多径效应严重等众多不利因素,导致水下网络性能低下。这主要是因为缺少在大范围远距离的水下网络中表现良好的媒体访问控制协议(MAC协议)。提出的LSDR-ALOHA-Q协议以ALOHA-Q协议为基础,该协议采用加入强化学习的方法,以提高信道利用率,同时结合强化学习使得该协议能够适应多变和复杂的水下环境。提出的LSDR-ALOHA-Q协议包括对时隙和帧结构的改造,使其更适合于大范围网络,通过优化时隙数,主动寻找空间复用的机会来增加信道利用率,同时通过提出一个新的退避算法来避免因为优化时隙数量而带来的Q-learning可能无法收敛的问题,即可能存在节点一直无法找到无冲突发送时间的问题。仿真表明当LSDR-ALOHA-Q协议被应用到大规模远距离的网络时可以显著提升信道利用率,同时降低冲突率和平均端到端时延。

Turbo Message Passing Based Burst Interference Cancellation for Data Detection in Massive MIMO-OFDM Systems

This paper investigates the fundamental data detection problem with burst interference in massive multiple-input multiple-output orthogonal frequency division multiplexing(MIMO-OFDM) systems. In particular, burst interference may occur only on data symbols but not on pilot symbols, which means that interference information cannot be premeasured. To cancel the burst interference, we first revisit the uplink multi-user system and develop a matrixform system model, where the covariance pattern and the low-rank property of the interference matrix is discussed. Then, we propose a turbo message passing based burst interference cancellation(TMP-BIC) algorithm to solve the data detection problem, where the constellation information of target data is fully exploited to refine its estimate. Furthermore, in the TMP-BIC algorithm, we design one module to cope with the interference matrix by exploiting its lowrank property. Numerical results demonstrate that the proposed algorithm can effectively mitigate the adverse effects of burst interference and approach the interference-free bound.