数据在短距离无线传输中的信道编码研究

介绍了工程机械设备监测数据在远程故障诊断无线传输过程中组建的短距离无线通信系统的信道编码方案,较好的解决了实际应用中误码率高、数据帧丢失的技术难题,并在MATLAB环境下进行仿真实现,得出了在不同信噪比下的误码率曲线,为短距离无线通信系统中的数据可靠传输提供了一种新方法。     

超宽带无线传感器网络的一种节能误码率门限设置策略

为了优化网络性能和延长传感器节点寿命,结合超宽带信号的特点研究了物理层接收机处的误码率门限与传感器节点的无线通信能耗之间的关系,建立了物理层能耗优化模型并提出了使得传输每比特信息平均能耗最小化的误码率门限设置策略(BER-TSS)。由BER-TSS设置的最优误码率门限可较好地在传输能耗与出错信息重传能耗之间进行平衡,从而使得每比特信息平均传输能耗最小。仿真结果表明,在不同的无线信道条件下,BER-TSS可较大幅度削减每比特信息平均传输能耗,并且必须结合网络业务的时延要求适当地设置接收信号BER门限。     

汽车胎压监测系统无线传输的研究

汽车胎压监测系统轮胎漏气和低气压状态进行报警的一项提高汽车安全性的新技术。本文通过工作原理,确定好无线通信方案,利用FSK调制和BCH编解码减少系统传输的误码率,提高系统的稳定性和抗干扰能力。     

美国研讨无线通信标准

无线通信在迅速地向前发展,越来越多的用户在引入新产品和新服务,可是很多竞争者在推行专用接口,以迫使用户只能用一家设备,从而减小用户的选择性,把他们束缚于较高价格的设备和服务上。为了消除这方面问题,美国摩托罗拉蜂窝结构系统集团泛美销售分部建议采用无线网络标准——"A 接口"。此标准规定了无线系统管理模、数通信的方     

基于认知无线电网络的协作中继资源分配算法

频谱资源紧张己经成为制约下一代无线通信系统发展的主要因素之一.认知无线电技术通过大力发掘授权频谱的复用潜力,可有效解决频谱紧缺问题.本文把协作中继传输技术引入到认知网络中,建立了配置双天线的次用户帮助主用户传输的协作模型,基于此提出了基于译码转发的协作功率及频谱资源分配算法,并进行了详细的理论分析.仿真结果表明,本文提出的协作传输策略能够在保障主用户正常传输情况下提高次用户的传输机会并减小中断概率.     

传输斜移对同步并行光传输系统性能的影响

针对一个具体的链路模型,通过计算机仿真分析了传输斜移对同步并行光传输系统性能的影响.光纤中的信号分析在频域中通过快速傅立叶变换(fast fourier transform,FFT)进行.分别计算了单信道误码率以及没有传输斜移和有传输斜移时并行信道总的误码率.计算结果表明,在噪声不是影响系统性能的主要因素时,传输斜移是决定并行光传输系统最大同步传输速率和传输距离的一个重要因素.     

接入网技术在城市4G无线通信中的应用

城市4G无线通信作为下一代通用无线通信系统,在具有很多优势的前提下,4G无线网络作为其核心的安全认证协议就显得更为重要,并且安全接入技术需要具备更高的安全性能。文章针对现有4G无线网络接入安全研究存在的问题与城市4G无线通信的应用特点,演绎设计了接入网技术在城市4G无线通信中的应用体系,提供不可否认服务和身份隐私性,确保了接入的安全性与可靠性,同时提高了移动终端的接入效率。     

基于QoS升降级的无线异构网动态带宽分配策略研究

利用异构无线网络环境下实时多媒体业务传输带宽可变的特点,提出一种基于服务质量(QoS)升降级的动态带宽分配策略。该策略针对系统带宽资源不足的情况,给出基于信道容量对多媒体用户进行平缓QoS升降级的方法,使系统在用户可接受的降级程度内接入更多的呼叫,进一步,为得到满意的服务等级(GoS),设置一个限制新呼叫接入的带宽阈值,并基于Markov模型给出该阈值的计算方法。与固定划分降质水平的带宽分配策略比较的结果表明,上述带宽分配策略能有效降低新呼叫阻塞率(CBP)与切换呼叫中断率(HDP),同时能明显提高带宽资源利用率。     

基于DM调制的Chirp超宽带通信系统性能研究

基于线性调频脉冲(Chirp)信号良好的自相关性以及匹配滤波后尖锐的时域特性,将线性调频脉冲扩频技术用于高速的超宽带无线通信,设计Chirp-DM调制的超宽带通信系统。DM方式传输速率较快,而且误码率较低,但是实现复杂。首先对DM调制方式给出理论分析,然后再进行性能仿真。     

交互设计中的用户控制感研究

将心理学中关于控制感的研究引入交互设计中,结合交互设计的目的和心理学中控制感的运行模式及结果,提出了保护用户控制感的方法即系统模型与用户模型匹配原则和构建标准化、系统化操作符号系统、交互系统与现实世界匹配的原则。     

A Robust Resource Allocation Scheme for Device-to-Device Communications Based on Q-Learning

One of the most effective technology for the 5G mobile communications is Device-to-device (D2D) communication which is also called terminal pass-through technology. It can directly communicate between devices under the control of a base station and does not require a base station to forward it. The advantages of applying D2D communication technology to cellular networks are: It can increase the communication system capacity, improve the system spectrum efficiency, increase the data transmission rate, and reduce the base station load. Aiming at the problem of co-channel interference between the D2D and cellular users, this paper proposes an efficient algorithm for resource allocation based on the idea of Q-learning, which creates multi-agent learners from multiple D2D users, and the system throughput is determined from the corresponding state-learning of the Q value list and the maximum Q action is obtained through dynamic power for control for D2D users. The mutual interference between the D2D users and base stations and exact channel state information is not required during the Q-learning process and symmetric data transmission mechanism is adopted. The proposed algorithm maximizes the system throughput by controlling the power of D2D users while guaranteeing the quality-of-service of the cellular users. Simulation results show that the proposed algorithm effectively improves system performance as compared with existing algorithms.     

宽带CDMA无线多媒体接入系统的研究

提出了可变传输速率的宽带CDMA扩频调制方法、非平衡功率控制算法以及自适应接入速率的无线接入方法。基于上述技术,给出了由基站和多媒体终端组成的实验系统参数。该系统实现了舆速率分别为8kbp和144skbps的语音和数据通信。     

Directional Antenna Intelligent Coverage Method Based on Traversal Optimization Algorithm

Wireless broadband communication is widely used in maneuver command communications systems in many fields, such as military operations, counter-terrorism and disaster relief. How to reasonably formulate the directional antenna coverage strategy according to the mobile terminal dynamic distribution and guide the directional antenna dynamic coverage becomes a practical research topic. In many applications, a temporary wireless boardband base station is required to support wireless signal communications between many terminals from nearby vehicles and staffs. It is therefore important to efficiently set directional antenna while ensuring large enough coverage over dynamically distributed terminals. The wireless broadband base station mostly uses two rotatable conical-polarized directional antennas with a coverage angle of 80 degrees. In this paper, we study this directional antenna coverage problem and propose a new solution by using three-dimensional coordinate transformation, provides wireless signal coverage schemes for point-to-point and point-to-region, determined the required horizontal rotation angle and pitch rotation angle of the directional antenna intelligent coverage, which lays the foundation for the performance of the wireless broadband communication in the maneuver command communication system.     

An Optimized Algorithm for Resource Allocation for D2D in Heterogeneous Networks

With the emergence of 5G mobile multimedia services, end users’ demand for high-speed, low-latency mobile communication network access is increasing. Among them, the device-to-device (D2D) communication is one of the considerable technology. In D2D communication, the data does not need to be relayed and forwarded by the base station, but under the control of the base station, a direct local link is allowed between two adjacent mobile devices. This flexible communication mode reduces the processing bottlenecks and coverage blind spots of the base station, and can be widely used in dense user communication scenarios such as heterogeneous ultra-dense wireless networks. One of the important factors which affects the quality-of-service (QoS) of D2D communications is co-channel interference. In order to solve this problem of co-channel interference, this paper proposes a graph coloring based algorithm. The main idea is to utilize the weighted priority of spectrum resources and enables multiple D2D users to reuse the single cellular user resource. The proposed algorithm also provides simpler power control. The heterogeneous pattern of interference is determined using different types of interferences and UE and the priority of color is acquired. Simulation results show that the proposed algorithm effectively reduced the co-channel interference, power consumption and improved the system throughput as compared with existing algorithms.     

Multi-Gigabit CO-OFDM System over SMF and MMF Links for 5G URLLC Backhaul Network

The 5G cellular network aims at providing three major services: Massive machine-type communication (mMTC), ultra-reliable low-latency communications (URLLC), and enhanced-mobile-broadband (eMBB). Among these services, the URLLC and eMBB require strict end-to-end latency of 1 ms while maintaining 99.999% reliability, and availability of extremely high data rates for the users, respectively. One of the critical challenges in meeting these requirements is to upgrade the existing optical fiber backhaul network interconnecting the base stations with a multigigabit capacity, low latency and very high reliability system. To address this issue, we have numerically analyzed 100 Gbit/s coherent optical orthogonal frequency division multiplexing (CO-OFDM) transmission performance over 400 km single-mode fiber (SMF) and 100 km of multi-mode fiber (MMF) links. The system is simulated over optically repeated and non-repeated SMF and MMF links. Coherent transmission is used, and the system is analyzed in a linear and non-linear regime. The system performance is quantified by bit error ratio (BER). Spectrally efficient and optimal transmission performance is achieved for 400 km SMF and 100 km MMF link. The results designate that MMF links can be employed beyond short reach applications by using them in the existing SMF infrastructure for long haul transmission. In particular, the proposed CO-OFDM system can be efficiently employed in 5G backhaul network. The multi-gigabit capacity and lower BER of the proposed system makes it a suitable candidate especially for the eMBB and URLLC requirements for 5G backhaul network.     

水声通信系统中分布式空时分组码的研究

协作传输可以获得无线信道内在的空间分集,有效改善通信系统的性能,增加通信系统的覆盖范围。对水声通信系统中两中继节点协作的译码转发方案进行了研究,提出了基于译码转发协议(DF)的分布式空时分组扩频编码(DSTBSC)方案,该方案可以克服多径衰落对分布式空时分组码(DSTBC)信号正交性的影响。给出了DSTBSC方案的系统模型,着重分析了在采用两中继译码转发时,中继节点的误码对水声通信系统性能的影响。在接收端不考虑信号冲突的情况进行仿真,结果表明,与直接传输方案相比,采用两中继节点、译码转发的DSTBSC方案,在两中继节点处均无误码和一个中继有误码时在相同的比特误码率(BER)条件下均可获得约4dB的分集增益,增加了传输距离。     

Game theoretic approach for channel assignment and power control with no-internal-regret learning in wireless ad hoc networks

In wireless ad hoc networks, co-channel interference can be suppressed effectively through proper integration of channel assignment (CA) and power control (PC) techniques. Unlike centralised cellular networks where CA and PC can be coordinated by base stations, the integration of CA and PC into infrastructureless wireless ad hoc networks where no global information is available is more technically challenging. The authors model the CA and PC problems as a non-cooperative game, in which all wireless users jointly pick an optimal channel and power level to minimise a joint cost function. To prove the existence and uniqueness of Nash equilibrium (NE) in the proposed non-cooperative CA and PC game (NCPG), the authors break the NCPG into a CA subgame and a PC subgame. It is shown that if NE exists in these two subgames, the existence of NE in the NCPG is ensured. Nonetheless, due to unpredictable network topology and diverse system conditions in wireless ad hoc networks, the NCPG may encounter the dasiaping-pongdasia effect that renders NE unattainable. By incorporating a call-dropping strategy and no-internal-regret learning into the NCPG, an iterative and distributed algorithm that ensures convergence to NE is proposed. It is shown through simulation results that the proposed approach leads to convergence and results in significant improvements in power preservation and system capacity as compared with the popular distributed dynamic CA technique incorporated with PC.     

WiFi6 Dynamic Channel Optimization Method for Fault Tolerance in Power Communication Network

As the scale of power networks has expanded, the demand for multi-service transmission has gradually increased. The emergence of WiFi6 has improved the transmission efficiency and resource utilization of wireless networks. However, it still cannot cope with situations such as wireless access point (AP) failure. To solve this problem, this paper combines orthogonal frequency division multiple access (OFDMA) technology and dynamic channel optimization technology to design a fault-tolerant WiFi6 dynamic resource optimization method for achieving high quality wireless services in a wirelessly covered network even when an AP fails. First, under the premise of AP layout with strong coverage over the whole area, a faulty AP determination method based on beacon frames (BF) is designed. Then, the maximum signal-to-interference ratio (SINR) is used as the principle to select AP reconnection for the affected users. Finally, this paper designs a dynamic access selection model (DASM) for service frames of power Internet of Things (IoTs) and a scheduling access optimization model (SAO-MF) based on multi-frame transmission, which enables access optimization for differentiated services. For the above mechanisms, a heuristic resource allocation algorithm is proposed in SAO-MF. Simulation results show that the method can reduce the delay by 15% and improve the throughput by 55%, ensuring high-quality communication in power wireless networks.     

Remote Sensing and Control of an Irrigation System Using a Distributed Wireless Sensor Network

Efficient water management is a major concern in many cropping systems in semiarid and arid areas. Distributed in-field sensor-based irrigation systemsoffer a potential solution to support site-specific irrigation management that allows producers to maximize their productivity while saving water. This paper describes details of the design and instrumentation of variable rate irrigation, a wireless sensor network, and software for real-time in-field sensing and control of a site-specific precision linear-move irrigation system. Field conditions were site-specifically monitored by six in-field sensor stations distributed across the field based on a soil property map, and periodically sampled and wirelessly transmitted to a base station. An irrigation machine was converted to be electronically controlled by a programming logic controller that updates georeferenced location of sprinklers from a differential Global Positioning System (GPS) and wirelessly communicates with a computer at the base station. Communication signals from the sensor network and irrigation controller to the base station were successfully interfaced using low-cost Bluetooth wireless radio communication. Graphic user interface-based software developed in this paper offered stable remote access to field conditions and real-time control and monitoring of the variable-rate irrigation controller.     

Resource Allocation in Edge-Computing Based Wireless Networks Based on Differential Game and Feedback Control

In this paper, we have proposed a differential game model to optimally solve the resource allocation problems in the edge-computing based wireless networks. In the proposed model, a wireless network with one cloud-computing center (CC) and lots of edge services providers (ESPs) is investigated. In order to provide users with higher services quality, the ESPs in the proposed wireless network should lease the computing resources from the CC and the CC can allocate its idle cloud computing resource to the ESPs. We will try to optimally allocate the edge computing resources between the ESPs and CC using the differential game and feedback control. Based on the proposed model, the ESPs can choose the amount of computing resources from the CC using feedback control, which is affected by the unit price of computing resources controlled by the CC. In the simulation part, the optimal allocated resources for users’ services are obtained based on the Nash equilibrium of the proposed differential game. The effectiveness and correctness of the proposed scheme is also verified through the numerical simulations and results.