Machine-to-Machine Content Retrieval in Wireless Networks

Wireless Personal Communications - Machine-to-Machine (M2M) communication is a distinct capability that enables communications with anything. With the expected connection among several tens of...     

Quality of Protection in Cloud-Assisted Cognitive Machine-to-Machine Communications for Industrial Systems

Cloud-assisted cognitive machine-to-machine co- mmunications (CM2M) is a new paradigm to improve the mobile services, which have drawn considerable attention in industry and academia. In this paper, we consider the quality of protection (QoP) of information transmission in cloud-assisted CM2M communications. In such an environment, the secondary M2M system intends to share the primary spectrum on the condition that the secondary transmitter (ST) has to relay the primary message. However, the ST is a low-energy device which adopts the energy harvesting technique to power itself. In particular, we focus on secure information transmission for the primary system when the secondary users (SUs) are the potential eavesdroppers. We aim to jointly design power splitting and secure beamforming to maximize the secondary M2M system data rate subject to the secrecy requirement of the primary system and the ST power constraint. To solve this non-convex problem, we propose a computationally efficient two-stage optimization approach. Simulation results demonstrate that our proposed scheme achieves a significant transmission rate of the secondary M2M system while provides a high secrecy rate for the primary system compared to the scheme without energy harvesting.     

Cross-Layer Collaborative In-Network Processing in Multihop Wireless Sensor Networks

Emerging wireless sensor network (WSN) applications demand considerable computation capacity for in-network processing. To achieve the required processing capacity, cross-layer collaborative in-network processing among sensors emerges as a promising solution: sensors do not only process information at the application layer, but also synchronize their communication activities to exchange partially processed data for parallel processing. However, scheduling computation and communication events is a challenging problem in WSNs due to limited resource availability and shared communication medium. In this work, an application-independent task mapping and scheduling solution in multihop homogeneous WSNs, multihop task mapping and scheduling (MTMS), is presented that provides real-time guarantees. Using our proposed application model, the multihop channel model, and the communication scheduling algorithm, computation tasks and associated communication events are scheduled simultaneously. The dynamic voltage scaling (DVS) algorithm is presented to further optimize energy consumption. Simulation results show significant performance improvements compared with existing mechanisms in terms of minimizing energy consumption subject to delay constraints     

High Reliable In-Network Data Verification in Wireless Sensor Networks

In order to provide efficient and suitable services for users in a ubiquitous computing environment, many kinds of context information technologies have been researched. Wireless sensor networks are among the most popular technologies providing such information. Therefore, it is very important to guarantee the reliability of sensor data gathered from wireless sensor networks. However, there are several factors associated with faulty sensor readings which make sensor readings unreliable. In this paper, we classify faulty sensor readings into sensor faults and measurement errors, then propose a novel in-network data verification algorithm which includes adaptive fault checking, measurement error elimination and data refinement. The proposed algorithm eliminates faulty readings as well as refines normal sensor readings, to increase reliability. Also, to achieve scalability of sensor networks and minimize network overhead, the proposed scheme involves a distributed implementation in a local area. The simulation study shows that the in-network data verification algorithm is highly reliable and its network overhead is very low compared to previous works. Reliability and overhead is improved by a maximum of 10–30% and 70%, respectively.     

Polar Transmitters for Wireless Communications

Future wireless communications will require multimode radio transceivers. This article looks at two possible transmitter architectures: direct upconversion and polar modulation. A brief review of the direct upconversion approach reveals some key limitations. This leads to a detailed study of the polar transmitter focusing on its operation, design challenges, and potential benefits. Its multi- mode capability and low power consumption are illustrated by a prototype design of a GSM, EDGE, and WCDMA polar transmitter. The efficiency of the polar transmitter is shown as a key enabler of future systems using OFDM modulation with high peak-to-average signals.     

跳频与扩频：无线机器对机器接口

无线机器对机器接口代表了计算机发展的第三次浪潮.第一次浪潮是企业计算机、昂贵的主机以及只有大企业才有能力购买的超级计算机.这一阶段为上世纪的六十和七十年代.第二次计算机浪潮开始于1981年,当时IBM推出了个人计算机(PC).这一时期为上世纪的八十和九十年代.新世纪带来了第三次计算机浪潮.在此期间成本降低、新技术不断涌现,使计算机中采用嵌入式处理器及无线通信像烤箱一样普及.这些处理器独立工作时可提供特定的功能,但当它们在无人为干预时,自身间相互通信时作用更大.随着小型廉价计算机的发展,无线技术应运而生.无线移动电话技术的出现领导了这些进步技术.这些技术包括用于手机的无线网络和增长迅速的无线热点现象(图1).     

异构环境下基于3GPP的M2M业务分流算法(英文)

In this study,an explicit adaptive traffic allocation scheme for Machine-to-Machine(M2M)service is proposed to achieve optimum distribution in heterogeneous networks.Based on the characteristics of M2M services,the presented scheme is formulated as a convex optimization problem that maximises the utility of the M2M service,and then determines how to allocate the total rate among the multiple access networks.The analysis and numerical simulations indicate that the proposed scheme makes a significant improvement in performance compared with the traditional schemes.     

Wireless Communication in Mobile Robotics a Case for Standardization

This paper discusses the relevant issues and concerns accompanying the efforts in creating a standard for wireless communication in mobile robotics. It is found, that the application areas of mobile robotics exhibit immense diversity and it is as a prerequisite concluded, that standardization across the entire set of application areas is non productive. Focus in put on the domestic area, i.e. cleaning, personal assistance, surveillance, etc., since this area is assumed to hold the highest market potential. Existing and future use case scenarios are investigated for communication requirements and it is concluded that existing commercially available technologies will meet the requirements. Therefore an architectural framework for integrating a diversity of wireless carrier technologies is proposes. Higher layer issues are discussed with focus on application layer functionality. Communication of the semantics of the application domain of domestic robots should be supported in a standardized application layer protocol.     

Wireless Robotics: A Highly Promising Case for Standardization

Mobile robots are an area of active research with enormous, untapped potential for the future—for household use, for applications in industry and production, for elderly care, in hospitals as well as in a host of other fields. In order to realise the possibilities that future robots hold, there are a number of obstacles to be overcome before mass markets can evolve in these individual segments. This paper discusses the main challenges related to the adoption of wireless robotics and gives a comprehensive overview of the suitability of existing wireless technologies, while arguing the need for standardization in this rapidly advancing area.     

无线激光通信

无线激光通信是利用激光作为信息的载体,直接在大气或外太空进行信号传递的一种通信方式。它具有容量大、高速率、保密性好、机动性强的特点,可以进行语音,数据,电视,多媒体图像的高速双向传递。     

Wireless Robotics: Opportunities and Challenges

Wireless robotics is one of the emerging fields in the world of automation. In-spite of research and standardization efforts around the world, the definition of the term “Robot” is still evolving. Robots have found application in many domains including home automation, industrial automation, health-care, surveillance, reconnaissance, planetary exploration or rescue missions. This paper addresses some of the opportunities, research challenges and standardization issues in wireless robotics with the focus on wireless and networking aspects.     

无线激光通信

无线激光通信是利用激光作为信息的载体,直接在大气或外太空进行信号传递的一种通信方式。它具有容量大、高速率、保密性好、机动性强的特点,可以进行语音,数据,电视,多媒体图像的高速双向传递。     

Wireless Underwater Communications

The depths of the oceans have a high potential for future industrial development and applications. Robotic autonomous systems will greatly depend on a reliable communications channel with operators and equipment either performing joint operations or on the surface. However, communications must face harsh conditions that hinder the performance. Neither electromagnetic nor optical technologies are suitable for communication because of their short range in this medium. Due to this, acoustic equipment is envisaged as the most appropriate technology, even though it suffers several negative effects such as strong attenuation at high (ultrasonic) frequencies, Doppler shifts and a time-varying multipath. In this paper, we describe the characteristics of the acoustic underwater channel and how it impacts the mechanisms at the link and network layers.     

Multitier Wireless Communications

Next-generation computing systems will be highly integrated using wireless networking. The Rice Everywhere NEtwork (RENÉ) project is exploring the integration of WCDMA cellular systems, high speed wireless LANs, and home wireless networks to produce a seamless multitier network interface. We are currently developing a simulation acceleration testbed and a multitier network interface card (mNIC) consisting of DSP processors, custom VLSI ASICs, and FPGAs for baseband signal processing to interact with the various RF units and the host processor. This testbed will also allow us to explore high performance algorithm alternatives through computer aided design tools for rapid prototyping and hardware/software co-design of embedded systems.     

Computation Hierarchy for In-Network Processing

In this paper we explore the network level architecture of distributed sensor systems that perform in-network processing. We propose a system with heterogeneous nodes that organizes into a hierarchical structure dictated by the computational capabilities. The presence of high-performance nodes amongst a sea of resource-constrained nodes exposes new tradeoffs for the efficient implementation of network-wide applications. Our experiments show that even for a low relative density of resource-constrained nodes to high-performance nodes there are certain gains in performance for a heterogeneous and hierarchical network over a homogeneous one. The introduction of hierarchy enables partitioning of the application into sub-tasks that can be mapped onto the heterogeneous nodes in the network in multiple ways. We analyze the tradeoffs between the execution time of the application, accuracy of the output produced and the overall energy consumption of the network for the different mapping of the sub-tasks onto the heterogeneous nodes. We evaluate the performance and energy consumption of a typical sensor network application of target tracking via beamforming and line of bearing (LOB) calculations on the different nodes. Our experiments also include the study of the overall performance and energy consumption of the LOB calculation using two different types of resource constrained sensor nodes (MICA and MICA2 nodes) and show how these metrics are affected by changes in the node architecture and operation. Our results indicate that when using MICA motes as resource-constrained nodes, 85% of the time on average the hierarchical network outperforms a homogeneous network for approximately the same energy budget. When using MICA2 motes as resource-constrained nodes, 54% of the time the hierarchical network performs better than a homogeneous network with approximately the same energy budget. Vlasios Tsiatsis received the BS degree from the Technical University of Crete, Chania, Greece, in 1998, and the MS degree in Electrical Engineering from the University of California, Los Angeles (UCLA), in 2001. He is currently pursuing a PhD degree at UCLA. His research interests include low-power protocol and system design in heterogeneous sensor networks. Ram Kumar is a PhD student in the Electrical Engineering department at UCLA. He received his MS degree from the same department in 2003, and his B.S. degree from the Indian Institute of Technology, Delhi in 2001. His current research interests focus on programming techniques for distributed ad-hoc sensor networks and architectures of heterogeneous networks of sensors. Mani Srivastava (Ph.D., U.C. Berkeley, 1992; M.S., U.C. Berkeley, 1987, and B.Tech., IIT Kanpur, 1985) is Professor at UCLA’s Electrical Engineering Department and the Center for Embedded Networked Sensing. His research is on various technology, fundamental, and application aspects of networked embedded systems such as wireless sensor/actuator networks. Prior to joining the faculty at UCLA he worked at Bell Labs Research in the area of Networked Computing. Among the awards that he has received are the President of India’s Gold Medal, the NSF CAREER Award, and the Okawa Foundation Grant. More information about him and his research group is available at http://nesl.ee.ucla.edu.This revised version was published online in August 2005 with a corrected cover date.     

Utilizing Space-Time Diversity for Wireless Communications

In this paper we consider the use of multiple antennas for wireless communication over fading channels.The fading we consider is quasi-static flat Rayleigh fading. For such a scenario optimal SNR schemes are derived when the transmitter knows the channel and when the transmitter does not know the channel. But in both cases the receiver has to estimate the channel. When the SNR during channel estimation is reasonably high we derive expressions to show the impact of channel estimation errors on SNR.     

Octopus Algorithm for Wireless Personal Communications

Wireless Personal Communications - Bio-inspired computation has opened a new window towards the solution of different computational problems. In this article we propose octopus algorithm for the...