基于设备能耗分簇的M2M通信随机接入方法

针对机器对机器(Machine to Machine, M2M)通信设备数量的持续增大导致M2M通信在当前蜂窝网络架构下会产生网络拥塞和接入成功率下降的问题,提出了一种基于设备能耗率分簇的M2M通信随机接入方法。该方法中M2M通信设备根据自身能量消耗率划分优等簇,即能耗率越大其优等级越高,优等级高的簇内设备享有随机接入资源的优先分配权,其随机接入资源由每簇的簇头代表簇接收,并在簇内设备之间通过随机接入竞争过程实现分配。仿真结果表明,相对于接入级限制(Access Class Barring, ACB)方法,该方法在接入成功率方面提升约5%,在延迟方面降低约10 s,能够有效降低设备能耗,提高设备接入的成功率。     

LTE TDD系统随机接入过程研究

随机接入技术是移动通信系统中UE与网络建立连接,进行通信的首要步骤,设计一种快速有效的随机接入过程将对系统的性能具有重要的意义。首先对LTE系统随机接入技术的进展情况进行了介绍,然后重点介绍一种基于LCR TDD帧结构的随机接入过程,给出接入流程。最后对碰撞概率进行定量分析。     

一种H2H和M2M混合场景下的前导码资源动态分配机制

在H2H和M2M混合场景下,随着大规模M2M(Machine-to-Machine)设备接入网络,受限于有限的接入前导码资源,H2H(Human-to-Human)用户的接入成功率会大幅降低。针对此问题,提出了一种H2H和M2M混合场景下的前导码资源动态分配机制。在满足H2H平均接入时延要求的情况下,动态调整分配给M2M设备的前导码资源数量,然后根据分配的资源数量,自适应调整每个随机接入子帧内参与竞争的M2M设备数量,最大化M2M设备的接入效率。对M2M设备接入成功率及H2H平均接入时延进行仿真,结果表明所提方法相比固定资源分配机制,在H2H平均访问时延较低的情况下,明显提高了M2M设备的接入成功率。     

基于M2M平台的J2ME应用程序的研究与设计

1M2M平台综合了电信和信息技术,能够使业务流程自动化,集成公司IT系统的资产,并创造增值服务。这项平台能够在广泛的应用和解决方案环境中运行,如自动读取停车表、安全设施、自动扶梯控制、车队管理、自动售货机和电动设备等都是其大显身手的应用环境。本文从其概念及应用出发,提出了其与J2ME移动应用相结合的实现策略、实际系统开发设计方案与影响其发展与应用的因素。     

M2M物联网在电力系统信息采集终端中的应用

电力系统信息采集终端的要求主要体现在智能化、移动化、高可靠性、网络化等方面,本文根据电力系统信息采集终端的要求,从功率控制、节点分簇、网络部署等众多角度出发,研究了基于M2M协议的无线传感器网络拓扑控制方法,将某些复杂的网络动力学特征加以简化,使无线传感器网络拓扑成为无标独特性,最终使电力系统信息采集终端组网实现高可靠性和抗毁性。     

物联网M2M的安全分析及策略

物联网M2M的先进理念引来了新一轮的无线革命,也暴露出物联网的安全隐患。在此以M2M的前端传感器及设备、网络和末端IT系统三个部分为出发点,提出了从十三个方面来分析物联网所面临的安全隐患问题,并大胆提出了相应的解决策略。     

改进PBFT算法的配电物联网接入认证方法

随着物联网与配电网深度融合,海量终端设备接入系统给配电物联网安全稳定运行带来巨大挑战。针对传统身份认证方式过于中心化且无法承载大规模终端等现状,设计一种基于区块链共识机制的配电物联网终端接入认证方法。由配电物联网网关负责对待接入终端节点登记注册,采用共识算法进行分布式认证,将合法终端上链存储。在传统PBFT算法的基础上,设计了配电物联网终端共识算法。该算法引入权重机制,根据终端节点权重选取认证节点,缩小共识规模;引入可验证随机函数增强主节点安全,避免启动视图切换协议,提高共识效率;结合实际应用场景优化一致性协议,降低通信开销。实验分析表明该方法可有效规避多种网络攻击,通信开销和吞吐量优于其他方法,系统抗攻击性较强,满足配电物联网对认证效率和系统可靠性等要求。     

基于M2M平台的无线传感网的研究

M2M技术的先进理念引来新一轮“无线革命”，而近期高速率和低速率的无线个域网（WPAN）技术因为巨大的市场需求成为一个新的研究热点。高速率的WPAN技术主要用在数字多媒体设备互连中，而低速率的WPAN技术主要应用在传感器网络、自动化控制中。简单介绍了M2M的概念，讨论了M2M技术应用于无线传感网的前景，最后给出了一个基于M2M平台的无线传感网的主要用于解决软硬件兼容设计的实现方案。     

基于LTE的物理随机接入信道前导检测研究

LTE系统中,物理随机接入信道(PRACH)的前导检测是整个随机接入过程的关键,提高前导检测的正确性是随机接入的主要任务之一。基于LTE FDD系统采用不同的子帧配置来提高物理随机接入信道前导检测的正确概率。仿真实验结果表明,不同的子帧配置能够影响正确检测概率,但要达到一定的信噪比时才能够得到给定的正确检测概率,从而满足用户所需的随机接入性能要求。     

基于终端分组的非正交随机接入资源分配方案

为了解决机器到机器(Machine to Machine,M2M)通信中的冲突碰撞、资源短缺等问题,提出了基于终端分组的非正交随机接入和数据传输(Non-Orthogonal Random Access and Data Transmission based on Terminal Grouping,TG-NORA-DT)方案。首先,根据能量消耗速度对机器类型通信设备(Machine Type Communication Devices,MTCDs)进行分组,并对组设定优先级,优先级高的组MTCDs优先分配接入资源。其次,利用到达时间的差异,识别出选择相同前导码的多个MTCDs,且在随后的接入过程中实现冲突MTCDs的功率复用。最后,基于TG-NORA-DT方案,提出一种资源分配方法,以实现在物理随机接入信道(Physical Random Access Channel,PRACH)和物理上行共享信道(Physical Uplink Shared Channel,PUSCH)间的资源合理分配。仿真结果表明,与正交随机接入数据传输协议(Orthogonal Random Access and Data Transmission Protocol,ORADTP)和非正交随机接入的数据传输(Non-Orthogonal Random Access-Data Transmission,NORA-DT)方案相比,TG-NORA-DT方案提高了系统吞吐量和资源利用率,降低了前导码冲突概率,其中资源利用率提高了20%以上。     

Dynamic LTE resource reservation for critical M2M deployments

Machine-to-machine (M2M) communications are envisioned to be major contenders for long term evolution (LTE) cellular resources in the time of fifth generation (5G) wireless communications and beyond. They will be used for a variety of applications on which users will rely for managing many aspects of their daily life. One of the promising fields in which M2M communications can play a major role is the field of emergency services. In such situations, it is crucial to ensure the reliable allocation of communication resources to M2M communications to ensure the right decisions and actions are taken in a timely manner. One of the techniques that could be used to ensure sustained and reliable resource allocation is to use an LTE-based virtual resource-slicing scheme. This scheme ensures a dynamic and an uninterrupted allocation of the resources dedicated to M2M communications in such a way that accommodates the changing needs of the emergency operations. In this paper, we introduce two schemes to allocate LTE resources to M2M emergency deployments in an adaptive manner. These schemes ensure that the resource allocation responds to the changing needs of the underlying emergency application. The adaptation period is also varied in response to the speed of change of the allocation requirements. This is done to ensure that the devices involved in critical missions are not competing for resources with the rest of network clients. We conduct several experiments to assess the success of the proposed schemes in responding to the needs of emergency M2M deployments.     

基于Cortex-M3的M2M监控终端

在对物联网在工业监控领域的应用研究后,针对目前工业监控终端体积大、容量小、功能简单等问题,设计并实现了一种微型化、大容量、强实时、多参数的M2M监控终端。该终端设计了基本的监控模块,且针对不同的应用环境预设了可配和选择模块,使适用范围更广。实现了网络动态配置接口,提高了终端的通用性。并借鉴传统数据采集模式,设计一种数据采集和数据传输优化方案,并对优化算法进行探讨,经应用结果分析,对系统开销、数据传输等指标有显著的改进。     

Efficient cooperative access class barring with load balancing and traffic adaptive radio resource management for M2M communications over LTE-A

We propose two efficient cooperative access class barring with load balancing (CACB-LB) and traffic adaptive radio resource management (TARRM) schemes for M2M communications over LTE-A. The proposed CACB-LB uses the percentage of the number of Machine-Type Communication (MTC) devices that can only access one eNB between two adjacent eNBs as a criterion to allocate those MTC devices that are located in the overlapped coverage area to each eNB. Note that an eNB is a base station of LTE-A. In this way, the proposed CACB-LB can achieve better load balancing among eNBs than CACB, which is the best available related work. The proposed CACB-LB also uses the ratio of the channel quality indication that an MTC device received from an eNB over the number of MTC devices that attach to the eNB as a criterion to adjust the estimated number of MTC devices that may access the eNB. As a result, the proposed CACB-LB can have a better set of barring rates of access class barring than CACB and can reduce random access delay experienced by an MTC device, which is also applicable to user equipment (UE). After an MTC device successfully accesses to an eNB, the eNB needs to allocate radio resources for the MTC device. In addition, the proposed TARRM allocates radio resources for an MTC device based on the random access rate of the MTC device and the amount of data uploaded and downloaded by the MTC device in a homogeneous MTC device network, and the priority of an MTC device in a heterogeneous MTC device network. Furthermore, we use the concept from cognitive radio networks such that if there are unused physical resource blocks (PRBs) of UEs, an eNB can schedule MTC devices to use these PRBs to enhance the throughput performance. Simulation results show that either in a homogeneous MTC device network or in a heterogeneous MTC device network, the proposed CACB-LB’s average access delay of UEs/MTC devices and average throughput from UEs/MTC devices are better than CACB’s. The proposed CACB-LB with TARRM’s average throughput from UEs/MTC devices is also higher than CACB’s. Therefore, the proposed CACB-LB with TARRM is feasible for M2M communications over LTE-A.     

一种高速场景中的前导序列设计与检测方案

针对高速移动场景下的随机接入过程中大多普勒频移导致系统解调性能恶化的问题,提出一种随机接入前导序列设计与检测方案。该方案利用频率偏移引起的相关函数峰值偏移距离与Zadoff-Chu(ZC)序列根索引的关系,将两个共轭对称的前导序列组合为一个新的随机接入前导序列,并针对该序列进行两级联合检测。仿真结果表明,与传统LTE标准中使用的限制集相比,该方案不仅提高了可用前导序列数量,还可有效地避免了整数倍频偏对定时估计误差的影响,增强了在高载波频率及高速移动场景下的随机接入检测性能。     

10/100M自适应端口LANE业务的设计与实现

该文介绍了传统局域网接入ＡＴＭ网的实现方案,提出了一种具有本板交换功能的１０Ｍ／１００Ｍ自适应多端口的ＬＡＮＥ业务实现方案,并给出了软、硬件的设计实现。     

基于Cortex M3的RFID以太网接入系统

随着RFID和以太网的普及,RFID技术和以太网技术的结合将是RFID应用的一个很好的发展方向。因此,本文提出了一种基于CortexM3[1]的RFID读写器的以太网接入方案。本方案实现的系统分为两部分：RFID读写器和以太网接入器,RFID读写器利用STC89C52RD2作为处理器,通过MFRC500实现对IC卡的基本操作以及提供基本的串口通信功能;以太网接入器利用LPC1766[1]（内核为CortexM3）作为处理器进行串行网络与以太网网络的协议转换,实现RFID读写器的以太网接入。     

A novel distributed scheduling scheme for OFDMA uplink using channel information and probabilistic transmission

Distributed uplink scheduling in OFDMA systems is considered. In the proposed model, mobile terminals have the responsibility of making their own transmission decisions. The proposed scheme is based on two dimensional reservation in time and frequency. Terminals use channel state information in order to favor transmissions over certain subchannels, and transmission is done in a probabilistic manner. The proposed approach provides more autonomy to mobile devices in making transmission decisions. Furthermore, it allows avoiding collisions during transmission since it leads to collision detection during the resource reservation phase. The proposed approach is compared to other random access methods and shown to be superior in terms of increasing sum-rate, reducing the number of users in outage, and reducing the collision probability in the reservation phase.