The non-regenerative massive multi-input-multi-output (MIMO) non-orthogonal multiple access (NOMA) relay systems are introduced in this paper. The NOMA is invoked with a superposition coding technique at the transmitter and successive interference cancellation (SIC) technique at the receiver. In addition, a maximum mean square error-SIC receiver design is adopted. With the aid of deterministic equivalent and matrix analysis tools, a closed-form expression of the signal to interference plus noise ratio (SINR) is derived. To characterize the performance of the considered systems, closed-form expressions of the capacity and sum rate are further obtained based on the derived SINR expression. Insights from the derived analytical results demonstrate that the ratio between the transmitter antenna number and the relay number is a dominate factor of the system performance. Afterward, the correctness of the derived expressions are verified by the Monte Carlo simulations with numerical results. Simulation results also illustrate that: 1) the transmitter antenna, averaged power value, and user number display the positive correlations on the capacity and sum rate performances, whereas the relay number displays a negative correlation on the performance and 2) the combined massive-MIMO-NOMA scheme is capable of achieving higher capacity performance compared with the conventional MIMO-NOMA, relay-assisted NOMA, and massive-MIMO orthogonal multiple access (OMA) scheme.

Localization is an important aspect in the field of wireless sensor networks (WSNs) that has developed significant research interest among academia and research community. Wireless sensor network is formed by a large number of tiny, low energy, limited processing capability and low-cost sensors that communicate with each other in ad-hoc fashion. The task of determining physical coordinates of sensor nodes in WSNs is known as localization or positioning and is a key factor in today’s communication systems to estimate the place of origin of events. As the requirement of the positioning accuracy for different applications varies, different localization methods are used in different applications and there are several challenges in some special scenarios such as forest fire detection. In this paper, we survey different measurement techniques and strategies for range based and range free localization with an emphasis on the latter. Further, we discuss different localization-based applications, where the estimation of the location information is crucial. Finally, a comprehensive discussion of the challenges such as accuracy, cost, complexity, and scalability are given.

In order to support seamless mobility in the Information- Centric Networking (ICN) Architecture we propose the Named-Node Network Architecture (3NA). 3NA introduces two independent namespaces to ICN, the 3N namespace used to uniquely identify nodes within a network and the Point of Attachment (PoA) namespace to identify a node's PoA to the network. The mappings between the two namespaces, along with all the necessary mechanisms to keep the mappings updated over time, are used when routing ICN packets to improve delay and the goodput when either the producer or the consumer are mobile. To support simultaneous producer and consumer mobility, we expand on the 3NA by adding a new Protocol Data Unit (PDU), the DU PDU. The DU PDU permits the encapsulation of ICN packets in a header that has source and destination name fields which belong to 3NA's 3N namespace. The new PDU permits seamless connectivity as long as 3NA's point of attachment signaling is strictly followed. We demonstrate the performance of the DU PDU against our previous defined communication methods and Named Data Networking's (NDN) Smart Flooding forwarding strategy using our open source nnnSIM module for the ns-3 framework. The new PDU outperforms all existing alternatives when the producer or both consumer and provider are mobile, obtaining overall lower mean network delay and higher median goodput.

Non-orthogonal multiple access (NOMA), millimeter wave (mmWave), and massive multiple-input-multiple-output (MIMO) have been emerging as key technologies for fifth generation mobile communications. However, less studies have been done on combining the three technologies into the converged systems. In addition, how many capacity improvements can be achieved via this combination remains unclear. In this paper, we provide an in-depth capacity analysis for the integrated NOMA-mmWave-massive-MIMO systems. First, a simplified mmWave channel model is introduced by extending the uniform random single-path model with angle of arrival. Afterward, we divide the capacity analysis into the low signal to noise ratio (SNR) and high-SNR regimes based on the dominant factors of signal to interference plus noise ratio. In the noise-dominated low-SNR regime, the capacity analysis is derived by the deterministic equivalent method with the Stieltjes-Shannon transform. In contrast, the statistic and eigenvalue distribution tools are invoked for the capacity analysis in the interference-dominated high-SNR regime. The exact capacity expression and the low-complexity asymptotic capacity expression are derived based on the probability distribution function of the channel eigenvalue. Finally, simulation results validate the theoretical analysis and demonstrate that significant capacity improvements can be achieved by the integrated NOMA-mmWave-massive-MIMO systems.

In this paper, we introduce a key technology, polarization modulation (PM), which should be taken into account when standardizing outdoor optical wireless communications (OWC), also known as free-space optical communications (FSO). We analyze the distortion of the polarization state when a laser beam propagates through the atmospheric channel. The floating range of the optical polarization was estimated and the necessity of researching the proposed technology was discussed. Moreover, we conducted a comparison between the PM-based FSO system and intensity modulation-based FSO system. The conclusions will be helpful in establishing the FSO standard architectures.

We propose the node name routing (NNR) strategy for information-centric ad-hoc networks based on the named-node networking (3N). This strategy is especially valuable for use in disaster areas because, when the Internet is out of service during a disaster, our strategy can be used to set up a self-organizing network via cell phones or other terminal devices that have a sharing ability, and it does not rely on a base station (BS) or similar providers. Our proposed strategy can solve the multiple-name problem that has arisen in prior 3N proposals, as well as the dead loop problems in both 3N ad-hoc networks and TCP/IP ad-hoc networks. To evaluate the NNR strategy, it is compared with the optimized link state routing protocol (OLSR) and the dynamic source routing (DSR) strategy. Computer-based comprehensive simulations showed that our NNR proposal exhibits a better performance in this environment when all of the users are moving randomly. We further observed that with a growing number of users, our NNR protocol performs better in terms of packet delivery, routing cost, etc.

© 2016 IEEE.Urban surveillance systems are being applied in a rapid pace with mature but inefficient solutions. The inefficiency is revealed with two aspects, too concentrated bandwidth and processing requirement. To solve this problem, we proposed a content oriented surveillance system based on Information-Centric Network. However, we can't simply replace TCP/IP streaming structure with named contents streaming structure because it can't improve the surveillance system's efficiency enough. In this paper, we took the ICN network's profits even further with the named contents. Instead of streaming live video to the central data center and processing multiple data stream in the same time, we have designed the nodes to process the captured raw data and produce objective contents for the central data center. With the extremely size difference in raw data and actual valued contents from it, we could apply the method in investigating area people traffic conditions and even in disaster and anti-terrorism scenarios. There was a field experiment performed to evaluate tourists' densities and dressing habits during winter season of March. The experiment expressed the benefits of our system and compared our method with traditional surveillance systems in saving network bandwidth and functionalities.

© 2017 The Institute of Electronics, Information and Communication Engineers. We propose the node name routing (NNR) strategy for information-centric ad-hoc networks based on the named-node networking (3N). This strategy is especially valuable for use in disaster areas because, when the Internet is out of service during a disaster, our strategy can be used to set up a self-organizing network via cell phones or other terminal devices that have a sharing ability, and it does not rely on a base station (BS) or similar providers. Our proposed strategy can solve the multiple-name problem that has arisen in prior 3N proposals, as well as the dead loop problems in both 3N ad-hoc networks and TCP/IP ad-hoc networks. To evaluate the NNR strategy, it is compared with the optimized link state routing protocol (OLSR) and the dynamic source routing (DSR) strategy. Computer-based comprehensive simulations showed that our NNR proposal exhibits a better performance in this environment when all of the users are moving randomly. We further observed that with a growing number of users, our NNR protocol performs better in terms of packet delivery, routing cost, etc.

<p>In order to support seamless mobility in the Information-Centric Networking (ICN) Architecture we propose the Named-Node Network Architecture (3NA). 3NA introduces two independent namespaces to ICN, the 3N namespace used to uniquely identify nodes within a network and the Point of Attachment (PoA) namespace to identify a node's PoA to the network. The mappings between the two namespaces, along with all the necessary mechanisms to keep the mappings updated over time, are used when routing ICN packets to improve delay and the goodput when either the producer or the consumer are mobile. To support simultaneous producer and consumer mobility, we expand on the 3NA by adding a new Protocol Data Unit (PDU), the DU PDU. The DU PDU permits the encapsulation of ICN packets in a header that has source and destination name fields which belong to 3NA's 3N namespace. The new PDU permits seamless connectivity as long as 3NA's point of attachment signaling is strictly followed. We demonstrate the performance of the DU PDU against our previous defined communication methods and Named Data Networking's (NDN) Smart Flooding forwarding strategy using our open source nnnSIM module for the ns-3 framework. The new PDU outperforms all existing alternatives when the producer or both consumer and provider are mobile, obtaining overall lower mean network delay and higher median goodput.</p>

<p>In order to support seamless mobility in the Information-Centric Networking (ICN) Architecture we propose the Named-Node Network Architecture (3NA). 3NA introduces two independent namespaces to ICN, the 3N namespace used to uniquely identify nodes within a network and the Point of Attachment (PoA) namespace to identify a node's PoA to the network. The mappings between the two namespaces, along with all the necessary mechanisms to keep the mappings updated over time, are used when routing ICN packets to improve delay and the goodput when either the producer or the consumer are mobile.</p><p> To support simultaneous producer and consumer mobility, we expand on the 3NA by adding a new Protocol Data Unit (PDU), the DU PDU. The DU PDU permits the encapsulation of ICN packets in a header that has source and destination name fields which belong to 3NA's 3N namespace. The new PDU permits seamless connectivity as long as 3NA's point of attachment signaling is strictly followed. We demonstrate the performance of the DU PDU against our previous defined communication methods and Named Data Networking's (NDN) Smart Flooding forwarding strategy using our open source nnnSIM module for the ns-3 framework. The new PDU outperforms all existing alternatives when the producer or both consumer and provider are mobile, obtaining overall lower mean network delay and higher median goodput.</p>

In order to address the energy issue and enhance the feasibility of Information-Centric Networking (ICN) in the case of access networks, this research proposes a novel Green ICN design which can adapt power consumption of network devices to their optimized real-time link-utilizations based on content popularity levels. We utilize dynamic ALR (Adaptive Link Rate) based scheme for content nodes to provide efficient content delivery as a realistic approach for the economically viable green network. We also develop a game-theoretical model to study the interaction between an ISP and a network equipment company in the context of green networking. Specifically, we present the system concept and some demonstration results of game-based Green ICN model to analyze the economic incentives of players. Moreover, we discuss ICN deployment and standardization challenges, then show that the proposal is robust, easy to deploy and practically relevant for the network players.

Besides the prior study of energy efficiency (EE) that focuses on single component (antenna, radio frequency (RF) chain, circuit, etc.), or limited to one base station (BS) area, in this paper, EE is integrated, investigated with various components (antenna, RF chain, circuit, coverage area) considering in, based on an optimized system model. That is, one optimized multi-BS system model is introduced beforehand with the cloud radio access network (C-RAN) for easier deployment of the selecting/sleeping mechanism. In addition, the system EE is described by an optimization problem while taking more component factors into consideration. While solving, this integrated optimization problem in all time intervals of all BS areas is proved to be equal to an optimization problem of each single BS area within each single time interval. After that, the integrated optimization solution is obtained while adding up the single-BS-single-interval optimization solutions, whereas the later solution is addressed by an offline decision method plus a convex optimization strategy. Observation from the numerical results demonstrates that the antenna power consumption is the dominant factor of the power consumption, which therefore, the dominant factor of EE performance.

Besides the prior study of energy efficiency (EE) that focuses on single component (antenna, radio frequency (RF) chain, circuit, etc.), or limited to one base station (BS) area, in this paper, EE is integrated, investigated with various components (antenna, RF chain, circuit, coverage area) considering in, based on an optimized system model. That is, one optimized multi-BS system model is introduced beforehand with the cloud radio access network (C-RAN) for easier deployment of the selecting/sleeping mechanism. In addition, the system EE is described by an optimization problem while taking more component factors into consideration. While solving, this integrated optimization problem in all time intervals of all BS areas is proved to be equal to an optimization problem of each single BS area within each single time interval. After that, the integrated optimization solution is obtained while adding up the single-BS-single-interval optimization solutions, whereas the later solution is addressed by an offline decision method plus a convex optimization strategy. Observation from the numerical results demonstrates that the antenna power consumption is the dominant factor of the power consumption, which therefore, the dominant factor of EE performance.

To further enhance the energy efficiency (EE) performance of fifth generation (5G) Internet of Things systems, an integrated structure is proposed in this paper. That is, other than prior studies that separately study the wireless and wired parts, the wireless and wired parts are holistically combined together to comprehensively optimize the EE of the whole system. The integrated system structure is introduced beforehand with the proposed unified control center components for better deployment of the select-and-sleep mechanism. In addition, in the wireless part, one cellular partition zooming (CPZ) mechanism is proposed. In contrast, in the wired part, a precaching mechanism is introduced. With these proposals, the proposed system EE performance is investigated. Comprehensive computer-based simulation results demonstrate that the proposed schemes display better EE performance. This is due to the fact that system power consumption is further reduced with these schemes as compared to the prior work.

In order to provide high-quality and highly reliable video delivery services for mobile users, especially train passengers, we propose a proactive content caching scheme that uses transportation systems. In our system, we place content servers with cache capability [e.g., content centric networking/named data networking (CCN/NDN)] in every train and station. Video segments encapsulated by MPEG-Dynamic Adaptive Streaming over HTTP (MPEG-DASH) are distributed and pre-cached by the station servers before the trains arrive at the stations. The trains receive content via high-speed wireless transport, such as wireless LANs or millimeter waves, when they stop at the stations. We developed prototype systems based on hypertext transfer protocol and CCN/NDN protocol, evaluate their performance through two field experiments that uses actual trains, and compare with traditional video streaming over cellular networks. Such evaluations indicate that our system can achieve high-quality video delivery without interruption for up to 50 users simultaneously.

Energy efficient object detection and image transmission are one of the key issues in wireless multimedia sensor networks (WMSN). Recent approaches in the WMSN propose in-node object detection and tracking algorithms. However, a little effort has been made to effectively detect object presence and absence in images in the WMSN. Since object detection has a direct relation with image transmission, therefore effective object detection algorithm would provide a reduction in the false transmission of image information. In this paper, a novel object presence model and an image transmission scheme are proposed for the WMSN. This scheme uses the transmission of image segments rather than a complete image. It guarantees in-node energy conservation and minimal image content transmission to the sink node. The proposed scheme is evaluated based on in-node energy consumption and reconstructed image peak signal-to-noise ratio (PSNR). Simulation results show that the proposed approach saves 95% of the node energy with the received image PSNR of 46 dB as compared with other state-of-the- art approaches.

In this paper, we propose to implement a consecutive polarization modulation (CPolM) scheme to transmit orthogonal frequency division multiplexing (OFDM) signal over the turbulent free-space optical (FSO) links. We analyze the fluctuation of polarization states of an optical wave while propagating through the turbulence channel of which the refractive-index property is described by Kolmogorov spectrum. The transmission performance in terms of signal-to-noise-ratio (SNR), symbol-error-ratio (SER) and outage probability of the proposed system are evaluated. The proposed system provides a more efficient way to compensate scintillation effects in a comparison with the intensity modulation (IM) based OFDM FSO system under a varying degrees of turbulence strength regimes. (C) 2016 Elsevier B.V. All rights reserved.

The information revolution process is boosting the development of social big data. Other than the use of traditional sampling of statistical methods to analysis data, people nowadays shifts to use the real-time data. And the transmission of massive data puts forward new demands. Here in this paper, to cater this trend, with the proposed new way of packets transmission management with Information-Centric Network (ICN), the transmission is compared with traditional IP based transmission, which simulation results demonstrated that both the network transmission speed and efficiency improved significantly by our method.

© 2015 IEEE.Providing robust content delivery service, such as Video on Demand, with efficient wireless resource usage is important for mobile users. To achieve this, we have proposed a proactive content caching scheme utilizing transportation systems (e.g., train.) Because our previous prototype is immature and has a scalability issue, in this paper, we introduce efficient transmission mechanism of Interest messages in order to improve throughput efficiency in mobile NDN. We develop two prototypes based on HTTP and NDN and then evaluate prototype performance by performing larger-scale field experiments on actual commercial railroad line. Evaluations conclude that our system can achieve high efficient content transfer and fully utilize wireless network bandwidth. Therefore, our system can provide high-quality video streaming for up to 50 users simultaneously.

In this article, we construct a concrete model as the prototype of efficient and reliable wireless Information Centric Networking (ICN) within the context of Intelligent Transport System (ITS). This research proposes a novel proactive-caching technique in ICN providing the robust and effective content delivery to the mobile nodes (commuters) for transportation system and fitting numerous ICN mobility scenarios of transportation system thanks to our "smart scheduler". We also propose a wireless ICN architecture which can adapt the power consumption of network nodes to the actual values of their optimized utilizations for greening the transportation communication network. Moreover, we identify that there are currently various ICN-based models and emphasize the need of an official international standard for wireless communication in general and transportation system in particular. Then by evaluating our proposal, we show that our proposal is a promising and feasible contribution for the ITU standardization process of Data Aware Networking (DAN) by integrating Green networking into DAN to combine the benefits of innovated rate-adaptivity and proactive-caching based schemes for achieving highly scalable, reliable and energy-efficient network performance in future transportation Information-centric communication system with data-awareness.

Recently, miniaturization, low cost and standardization activates of the wireless sensor network technologies has been remarkably advanced, because of advancement of the wireless technologies. Especially smart grid is important application of the wireless sensor network technologies. In the smart grid network, the network congestion occurs caused by huge traffic in real time transmission of energy usage data or environment information data in the house or building. It is required to effectively collect the data and improve the network efficiency. We describes the scheme and the results in this paper since we clarified the efficient data transmission based on data fusion method for the energy usage data using Back Propagation (BP) algorithm with Artificial Neural Network.

A Pseudo Double Scattering Channel (PDSC) Matrix assumption is proposed here for downlink Non-Orthogonal Multiple Access (NOMA) within massive Multi-Input Multi-Output (MIMO) systems. Afterwards, outage probability analysis of such a system is investigated. That is, with the aid of random matrix and statistics theories, the Cumulative Probability Distribution (CDF) and also the outage probability performance are addressed. After that, the mathematics derivations obtained here are verified through numerical simulation results, wherein we further find out that with antenna number increasing, the system outage probability performance is reduced.

Based on the Cloud-Radio Access Network (C-RAN) structure and massive Multi-Input Multi-Output (MIMO), we propose one comprehensive system model and give the Energy Efficiency (EE) analysis of this system. The C-RAN structure is amended for better antenna control in massive MIMO based C-RAN system model. Furthermore, system EE optimization problem is modeled from a comprehensive way, and its solution is addressed with a convex optimization method plus an offline decision. In EE analysis, apart from the prior literature, Carrier Capacity (CC), antenna, Radio-Frequency (RF) chain, machine room and also the electron circuits are integrally taken into consideration. A positive correlation is observed between CC and the EE performance prior to the optimal value, after this optimal value, further increase CC has little help to EE enhancement.

This paper presents a novel model of heterodyne-detected optical code-division multiple-access (OCDMA) systems employing polarization shift keying (PolSK) modulation over a free-space optical (FSO) turbulence channel. In this article, a new transceiver configuration and detailed analytical model for the proposed system are provided and discussed, taking into consideration the potential of heterodyne detection on mitigating the impact of turbulence-induced irradiance fluctuation on the performance of the proposed system under the gamma-gamma turbulence channel. Furthermore, we derived the closed-form expressions for the system error probability and outage probability, respectively. We determine the advantages of the proposed modeling by performing a comparison with a direct detection scheme obtained from an evaluation of link performance under the same environment conditions. The presented work also shows the most significant impact factor that degrades the performance of the proposed system and indicates that the proposed approach offers an optimum link performance compared to conventional cases.

© 2015 American Physical Society.We studied the physical properties of hollandite titanates, BaxTi8O16+δ, which have double chains of edge-sharing TiO6 octahedra with d electrons in the t2g states. We found that there is an electronic phase transition at ∼220 K, at which various properties exhibit anomalies. This phase transition is characterized by a modulation in the TiO6 chains and a spectral weight transfer of over 2 eV in the optical conductivity spectrum, which are presumably caused by charge and orbital ordering of the Ti t2g electrons.

Information Centric Networking (ICN) had merits in terms of mobility, security, power consumption and network traffic. When a large-scale disaster occurred, the current communication system might be fragile and the server based network service might be unavailable due to the damages, network congestions, and power failure, etc. In this paper, we proposed an ICN based Disaster Information Sharing Service (DISS) [1], [2] system. DISS could provide robust information sharing service. Users could publish disaster information as a content message with the help of our DISS. In addition, by utilizing DISS's message naming strategy, users could retrieve disaster information even without a server connection. The ICN based DISS could reduce the probability of network congestion when a large number of simultaneous connections occurring. It could provide server-less service in poor network condition. DISS allows users retrieve disaster information from terminals or ICN nodes. During disasters, sharing information timely and effective could protect people from disaster, ensure people's safety.

Information Centric Networking (ICN) had merits in terms of mobility, security, power consumption and network traffic. When a large-scale disaster occurred, the current communication system might be fragile and the server based network service might be unavailable due to the damages, network congestions, and power failure, etc. In this paper, we proposed an ICN based Disaster Information Sharing Service (DISS) [1], [2] system. DISS could provide robust information sharing service. Users could publish disaster information as a content message with the help of our DISS. In addition, by utilizing DISSïs message naming strategy, users could retrieve disaster information even without a server connection. The ICN based DISS could reduce the probability of network congestion when a large number of simultaneous connections occurring. It could provide server-less service in poor network condition. DISS allows users retrieve disaster information from terminals or ICN nodes. During disasters, sharing information timely and effective could protect people from disaster, ensure peopleïs safety.

Despite the numerous benefits brought by device-to-device (D2D) communications, the introduction of D2D into cellular networks poses many new challenges in the resource allocation design because of the co-channel interference caused by spectrum reuse and limited battery life of user equipment's (UEs). Most of the previous studies mainly focus on how to maximise the spectral efficiency and ignore the energy consumption of UEs. In this study, the authors study how to maximise each UE's Energy Efficiency (EE) in an interference-limited environment subject to its specific quality of service and maximum transmission power constraints. The authors model the resource allocation problem as a non-cooperative game, in which each player is self-interested and wants to maximise its own EE. A distributed interference-aware energy-efficient resource allocation algorithm is proposed by exploiting the properties of the nonlinear fractional programming. The authors prove that the optimal solution obtained by the proposed algorithm is the Nash equilibrium of the non-cooperative game. The authors also analyse the tradeoff between EE and SE and derive closed-form expressions for EE and SE gaps.

In 5G research the spectrum efficiency (SE) and energy efficiency (EE) are two crucial issue. Some scholars propose the Massive Multiple-Input Multiple-Output (Massive MIMO) technology as a essential element to achieve the targets. In addition, the non-orthogonal multiple access (NOMA) and mm Wave technologies are proposed towards SE in 5G. In this paper, apart from the previous studies, we study the EE issue while combining the massive MIMO and NOMA together. Which can take advantage of the NOMA for better SE and antenna selection for better EE performance within the background of massive MIMO in 5G.

In order to provide the robust and energy-efficiency contents delivery to the mobile terminals in Information Centric Networking (ICN), this paper proposes a dynamic proactive-scheme and evaluates its performance as an effective mechanism for green mobility in ICN. In our scheme, when a mobile node expresses an Interest for a content then neighbor Aggregation Nodes (possible future points of attachment) also generate the "fake interest" for this content to the Content Provider. As a result, after the handoff, when the mobile node re-issues the same interest, the desired content can be found en-route and can be retrieved immediately. To diminish the ICN energy consumption by utilizing this scheme (the interest needs not to travel to the Content Server), we design different operating modes for the server based on the interest traffic. We verify the effectiveness and reliability of our proposed scheme by simulating the model with ndnSIM.

The information exchange in the power grid has been undergoing through crucial changes. With the application of advanced Information and Communication Technologies (ICT) to the existing power network; the future grid sees incredible enhancements. However the huge amount of data to transfer over the network becomes challenging. Many literatures show the benefits of applying Information-Centric Network to the power system. In this paper we propose an application of 1CN to Smart Grid system. We evaluate the robustness of the ICN over IP.

Information Centric Networking (ICN) had merits in terms of mobility, security, power consumption and network traffic. When a large-scale disaster occurred, the current communication system might be fragile and the server based network service might be unavailable due to the damages, network congestions, and power failure, etc. In this paper, we proposed an ICN based Disaster Information Sharing Service (DISS) [1], [2] system. DISS could provide robust information sharing service. Users could publish disaster information as a content message with the help of our DISS. In addition, by utilizing DISSs message naming strategy, users could retrieve disaster information even without a server connection. The ICN based DISS could reduce the probability of network congestion when a large number of simultaneous connections occurring. It could provide server-less service in poor network condition. DISS allows users retrieve disaster information from terminals or ICN nodes. During disasters, sharing information timely and effective could protect people from disaster, ensure peoples safety.

This paper aims to focus on the standardization process and its consequences in the field of information and communication technologies (ICT) , with a view to understanding the significance of the standardization in academia and inclusion to this subject in academic curricula. Particularly, we take the scenario of cellular communication industry and as an evolutionary technology we take CDMA (Code Division Multiple Access) as a case study. Game theory is chosen as a tool for analysis of the business decision of stakeholder of an innovative technology. CDMA' s spread spectrum approach was unique. However, the good technology doesn' t always win out. A good example is VHS ; which is successful and won out the market though technically inferior to Betamax. For the case of CDMA, we explain the case of good technological innovation, strategic management by the innovator and the role of standardization as a pre-requisite to win the market. We designed the game based on the scenario while a technology licensor (Qualcomm) simultaneously works as a product manufacturer and make a role overlapping with the licensee (Motorola, Nokia, Ericson etc) . We also give a brief mathematical analysis with the Stackelberg leadership Game Model for the Qualcomm' s Royalty and Chip business.

In order to address the energy flaw and enhance the energy efficiency of Information Centric Networking (ICN) Architecture, this research proposes an innovated optimal ICN model with adaptive power consumption ability based on the popularity of the content to adapt content router link rate to its real-time utilization for optimizing the ICN router operating power value and based on the interest traffic to the server to select the optimal working mode for the server/content provider. With this dynamic control/adaptive mechanism, the proposed architecture can provide higher reliability with dynamic energy efficiency consumption and better cost-effectiveness for the future ICN infrastructure system to reduce electricity usage, cost and greenhouse gases, then solve global warming issues.

Massive Multiple-Input Multiple-Output (Massive MIMO) has been realized as a promising technology element for 5G wireless mobile communications, in which Spectral Efficiency (SE) and Energy Efficiency (EE) are two critical issues. Prior estimates have indicated that 57% energy consumption of cellular system comes from the operator, mostly used to feed the base station (BS). Yet previously, the User Equipment (UE) is focused on while studying the EE issue instead of BS. In this case, in this paper, an EE scheme that focuses on the optimization of BS energy consumption is proposed. Apart from the previous studies, which divides the coverage area by circuit section, the coverage area is divided by fan section with the help of Propagation theory for zoom in or zoom out. In the proposal, transmission model and parameters related to EE is deduced first. Afterwards, the Cellular Partition Zooming (CPZ) scheme is proposed where the BS can zoom in to maintain the coverage area or zoom out to save the energy. Comprehensive simulation results demonstrate that CPZ presents better EE performance with negligible impact on the transmission rate.

The Large Scale Antenna System is expected to bring significant improvements to overall Communication System Performance. However the use of so many antennas in Massive Multiple Inputs Multiple Outputs (Massive MIMO) architectures highlights the cost implication of the technology. It is therefore possible that Massive MIMO may be deployed using low cost equipment to avoid HUGE implementation costs. The use of Low Cost Equipment will results into significant Radio Frequency Impairments (RF-Impairments) such as Phase Noise, IQ Imbalance and Nonlinearities, which will affect the overall system performance. Among other aspects channel estimations will also be affected since the signal used for these estimations will be affected by the RF-Impairments. This paper analyzes a way to exploit correlation during Minimum Mean Square Error (MMSE) Channel Estimation of a Massive MIMO System in presence of aggregated RF-Impairments (i.e. combined effects of the impairments). Specifically it derived the statistical distribution of the equivalent aggregated error/noise term using statistical identities and uses the derived term to obtain temporal channel estimation error and consequently the correlation matrix necessary to minimizes the channel Mean Square Error (MSE) of the channel estimate.

移動中での高速インターネット環境が整備される中,新幹線やリニア新幹線での実用化に向けて無線問題が上がった.今後更なる普及が見込まれるクラウドサービスを支えるためには,更なる安定かつ高速な無線通信環境が要求される.本稿では,GPS(Global Positioning System)の測位誤差を考慮する事で,移動局の位置情報の誤差に対するスループットの低下を補償する一手法を提案する.通信状態に応じて送信および受信アンテナ数を適応的に切り換えるビームマネージメント・アルゴリズムにより,移動局の測位誤差による影響を最小限に抑える事で,平均スループットの改善を得た.

筆者らは,近年のモバイルトラフイックの爆発的な増加に対処するために,交通機関を活用したコンテンツ先回り配信システムを提案している.本稿では,その性能評価をするために,フィールド実験として,試験線を用いた実車両実験を行った.従来の CDN を想定したセルラーによる配信と比較し,先回り配信システムの有効性を明らかにした.

筆者らが研究するSSB-QPSK変復調方式に多値化対策を提案し、SSB-QAM方式を提案した。QPSKモードではrolloff率を0に近づけた場合に4bit/s/Hzとなる。また多値化変調16QAM、64QAMにおいてもOFDMの性能の2倍になることを原理的に示せるとした。本報告では、本提案方式がBit誤り率の劣化要因として及ぼす範囲を検証した。またAWGNに対しては本方式が相関検波と同様の作用を有することで、SSBとしてのCNR劣化作用を克服できることを示した。

筆者らは,近年のモバイルトラフイックの爆発的な増加に対処するために,交通機関を活用したコンテンツ先回り配信システムを提案している.本稿では,その性能評価をするために,フィールド実験として,試験線を用いた実車両実験を行った.従来の CDN を想定したセルラーによる配信と比較し,先回り配信システムの有効性を明らかにした.

コンテンツセントリックネットワーク(Contents Centric Network; CCN)は、従来、ノードを基準として行われていた通信形態をコンテンツを主体として行う形態へと変革させる新しい通信パラダイムである.本文はその特徴を利用して、CCNにおけるVoDサービスについて研究している.そして、新たな効率的キャッシュアルゴリズムの検討を行った。

本論文では、情報通信技術(ICT)のアプローチの近代的な概念を使用して、災害シナリオのコンテンツ中心ネットワーク(CCN)スキームを提示する。コンテンツ中心ネットワークは必要がある場所に関連するコンテンツをプッシュすることを特徴として新しいネットワークである。そのキャッシュとリポジトリ機能を使用して、バックボーンネットワークの輻輳や遅延を低減することができる。災害シナリオでは、完備していないネットワーク環境のため、通信障害が発生しやすい。また、被災地の内と外両側から通常より災害に関する情報配信の高い需要、がバックボーンネットワークに大きな圧力をもたらす。事前キャッシュされた内容を詰め込みするリポジトリ機能を持つコンテンツ中心ネットワークは、キャッシュヒットとホップ距離で、堅牢性と高い性能を表す。バックボーンネットワークにおける輻輳やスループットの圧力を解放に活用できる。

筆者らが研究するSSB-QPSK変復調方式において、新たな検波方式を考案した。この結果、最大の課題の一つであった隣接シンボル間干渉を理論的に皆無にした。これにより希望波の振幅情報をほぼ干渉なく復調できることとなり、シンボル信号の多値化が可能となり、OFDM方式の持つ周波数利用効率2bit/s/Hzに匹敵する新たな変復調方式を具現化した。NyquistフィルタのRolloff率を0に近づけた場合の周波数利用効率は4bit/s/Hzとなる。今後、SSBキャリアのインターリーブ化を図りOFDMタイプのマルチキャリア化による新変復調方式を検討する。

© 2014 IEEE. The Advanced Metering Infrastructure (AMI) is the core component in Smart Grid. The cyber security is one of the major concerns and challenges should be prior considered. The Information Centric Networking (ICN) is a promising architecture for the future Internet that disseminates content based on named data instead of named hosts. It will be involved into Smart Grid because its excellent congestion control and self-security can enable more scalable, secure, collaborative and pervasive networking. This paper aims at proposing an Information Centric AMI (ICN-AMI) structure and a novel key management scheme (KMS) for a large number of smart meters (SMs) in this system to ensure confidentiality, integrality and authentication. To validate the scheme, the security analysis, comparisons and NDNsim simulation are done to demonstrate that the proposed ICN-KMS is possible solution for ICN-AMI system.

Providing robust content delivery along with efficient wireless resource usage is important for next generation wireless networks. To achieve this, we propose a proactive content caching scheme utilizing transportation systems, especially trains. In our system, we place content servers with CCN capability to every train and station. Segments of video contents are pre-cached by the station servers before trains arrive at stations. Trains receive the contents via high-speed wireless transport while they stop at the stations. We develop a prototype system based on IP and CCN Hybrid protocols. We evaluate its performance by field experiment and compare with traditional CDN scenarios using cellular networks. Evaluations conclude that our system can achieve high-speed and high-reliable video delivery without freezing.

© 2014 IEEE. In the long term evolution (LTE), Relay node architectures included in order to increase the coverage and system capacity. But designed in the LTE-A and release 12, the Relay node architectures supported mobility. An LTE system based on the network-controlled hard handoff and handoff reuses existing user equipment. In this paper, we propose an adaptive handoff hysteresis scheme with a simplified cost function considering some dominant factors for Mobile Relay such as the load difference target cells, the velocity, and the service type. The performances of the traditional handoff scheme and the proposal are analyzed and compared in details.

In Japan a feed-in tariff scheme has promoted the utilization of photovoltaic power generators in combination with electric batteries. Although many researchers have assessed the operations of grid-connected photovoltaic systems with electric batteries, little attention has been paid to the impact of the electric batteries' degradation characteristics. This paper presents an evaluation of the operation of a grid-connected photovoltaic/electric battery system in a house from energy saving and economy viewpoints. We constructed a long-term operational optimization model considering the degradation characteristics of the electric battery. This model contains two objective functions: energy saving and operating cost. We set a scenario of power rate and photovoltaic/battery system configurations. In order to reveal the optimal operational strategy of the photovoltaic/battery system, the multi-objective optimization problem was solved. As a result, pareto optimal solutions were obtained, and trade-off relationships between economy and energy saving are presented. In this study, the utilization of the grid-connected photovoltaic system with an electric battery was expected to be effective in an energy saving priority operation.

© 2014 IEEE. Advanced Metering Infrastructure (AMI), as the totality of systems and networks to measure, collect, store, analyze, and use energy usage data, is supposed to the key component that should be preferentially constructed for smart grid. In the meanwhile, content-centric networking (CCN) is perceived as a promising approach where the content itself becomes the core of communication instead of the address or location in the future internet research. Based on its caching advantage, it is widely believed that CCN can effectively reduce the AMI network bandwidth. This paper aims to apply the CCN approach on AMI system, which is called CCN-AMI. To the best of our knowledge, this is the first attempt to distribute contents or requests based on CCN in AMI system. Moreover, a simulation-based performance evaluation is employed to evaluate the effectiveness of the proposed CCN-AMI approach in traffic control for developing AMI system in smart grid.

The contributions of this paper are twofold. Firstly, we analyze the decision making problem of caching contents by the network players of Information Centric Networking (ICN) from a game theoretic perspective. We also mention a possible content distribution model for ICN. By our proposed game theory, different network players can find the optimality taking into consideration which benefits them with optimum revenue. Secondly, we present a solution for Live Streaming Media broadcast in ICN and analyze the economic part with a decision tree. We believe, our paper clearly shows the economic incentives for major network players which can stand as a motivation to achieve the faster accommodation of ICN architecture. Besides, we identify some standardization issue in ICN architecture and we emphasize on the need for a common standard for content routers (CR) so that as a node in the ICN, CR ensure scalable content delivery as well as its functionalities match with the Internet open standard philosophy. © 2014 ITU.

The extensive deployment of femtocells introduces co-channel interference to the macro cell-edge users (MCEUs), which degrades the throughput improvement of the total network. In this paper, we consider the scenario in which the femtocell base station (FBS) allows the hybrid access of MCEUs on the condition that the MCEUs rent the power resource from it. However, the FBS is power limited. If almost all of its power is used to serve the MCEUs and its original femtocell users (FUEs), when newly authoritized FUEs are switched on, there will be little power left to serve these newly authoritized FUEs. In this situation, the FBS can select one MCEU as a relay to coordinate its information transmission to the FUE. To reward the cooperation of the MCEUs, the FBS will agree to support the service of MCEUs without charging. Stackelberg game is used to find the optimal power and price value for this procedure. An MCEU relay selection criterion is proposed for the FBS. The optimal power that the MCEU can obtain from the FBS and the power that the MCEU can obtain from the FBS and the power that the MCEU can share with the FUEs are obtained. The simulation results show that the throughputs of both the FUEs and the MCEUs are improved. © 2013 IEEE.

災害時には災害情報の発信と受信のために,膨大なアクセスが短時間にネットワークに対して行われる.それら通信サービスに対応するための通信処理能力が大幅に不足することから,通信途絶等の状態が生じたことを踏まえ,通信ネットワークの耐災害性強化に向けるネットワークを統合的に構成することが必要である.本研究では,ネットワーク全体のトラヒックを削減するには,コンテンツ中心ネットワークを用い,ルータ上でキャッシュを行う方法を検討する.さらに,キャッシュヒット率の向上を図るために,パスキャパシティとコンテンツ人気度を考慮するキャッシュを適切に多重化するキャッシュデシジョンポリシの提案とその評価を行う.

In this paper, we present the Intelligent Hybrid MAC (IH-MAC), a novel low power with quality of service guaranteed medium access control protocol for wireless sensor networks (WSNs). The IH-MAC achieves high energy efficiency under wide range of traffic load. It ensures shorter latency to critical and delay-sensitive packets. The IH-MAC protocol achieves high channel utilization during high traffic load without compromising energy efficiency. The IH-MAC does it by using the strength of CSMA and TDMA approach with intelligence. The novel idea behind the IH-MAC is that it uses both the broadcast scheduling and link scheduling. Depending on the network loads, the IH-MAC protocol dynamically switches from broadcast scheduling to link scheduling and vice versa in order to achieve better efficiency. The scheduling is done in the IH-MAC with a novel decentralized approach where the nodes locally use the clock arithmetic to find the time slot, allocated for it. Furthermore, the IH-MAC uses Request-To-Send, Clear-To-send handshakes with methods for adapting the transmit power to the minimum level necessary to reach the intended neighbor. Thus, the IH-MAC reduces energy consumption by suitably varying the transmit power. The IH-MAC also uses the concept of parallel transmission that further reduces delay. The analytical and simulation results corroborate the theoretical idea, and show the efficiency of our proposed protocol.

In this paper, we present the Intelligent Hybrid MAC (IH-MAC), a novel low power with quality of service guaranteed medium access control protocol for wireless sensor networks (WSNs). The IH-MAC achieves high energy efficiency under wide range of traffic load. It ensures shorter latency to critical and delay-sensitive packets. The IH-MAC protocol achieves high channel utilization during high traffic load without compromising energy efficiency. The IH-MAC does it by using the strength of CSMA and TDMA approach with intelligence. The novel idea behind the IH-MAC is that it uses both the broadcast scheduling and link scheduling. Depending on the network loads, the IH-MAC protocol dynamically switches from broadcast scheduling to link scheduling and vice versa in order to achieve better efficiency. The scheduling is done in the IH-MAC with a novel decentralized approach where the nodes locally use the clock arithmetic to find the time slot, allocated for it. Furthermore, the IH-MAC uses Request-To-Send, Clear-To-send handshakes with methods for adapting the transmit power to the minimum level necessary to reach the intended neighbor. Thus, the IH-MAC reduces energy consumption by suitably varying the transmit power. The IH-MAC also uses the concept of parallel transmission that further reduces delay. The analytical and simulation results corroborate the theoretical idea, and show the efficiency of our proposed protocol.

近年、無線技術の進歩に伴い無線センサ端末の小型化,低価格化および標準化の進展が著しいである.スマートグリッド分野において、膨大な数の住宅やビルに対して、情報を収集する無線センサネットワーク技術が注目を集めている.私は各家庭やビルなどにある環境清報を長期間の観測及び監視をするため、大規模なセンサネットワークに対応できるデータの処理方法が必要だと考えている.スマートグリッド分野における、センサ収集データの処理方法による高精度のデータを取得し、最適な省エネルギー手法やデマンドレスポンス手法が生み出すことができる.本提案は、スマートグリットのHEMSとBEMS分野における、センサ収集データの処理方法に注目し、従来の処理方法より高い精度なデータ処理を提案し、提案する処理方法で評価を行い、従来型のデータ処理方法より優れた事が分かった.

過去、日本の農業の70%以上を占めしていた里山は、天然資源の使用変化と社会問題により相次いて消失した。里山の復興に目を置き、筆者は農業におけるワイヤレス・センサ・ネットワークを用いた温度、湿度の監視と制御を提案する。本稿では、効果的なデータ収集や省エネーのクラスタリングスキームを確保できる方法について研究を行った結果、センサノートが定期的なデータ収集により良く対応できることを明らかにした。その結論によって、人口の減少に対応し里山の生産性と効率性を向上させることが可能になった。

本稿では、情報通信技術(ICT)のアプローチの近代的な概念を使用して情報共有システムを提案する。濃縮された首都圏の災害は、人間の生命や財産に深刻な被害の重大な損失を引き起こす。災害が発生すると被害地域外の救助者は避難所の場所はそれほど頻繁に提供されるより集約された情報を必要とするなどのサービスを提供しながら、被害者は、リアルタイムで離散的事件の情報を受信する必要があります。スマートフォンの需要は驚異的な成長、私たちの災害管理システムのウェブサービスは、スマートフォンに提供することができたので。さらに救助を評価するために、モバイルユーザーがワイヤレス測位技術を通じて現在位置を取得し、システムに災害関連情報をアップロードすることもできますが、この論文では、情報共有システムの設計について説明し、損傷領域外の救助者かウェブサイト上でこれらのデータを確認する操作。

In this paper, we propose an average connectivity degree cluster (ACDC) scheme gossip algorithm to improve the convergence speed and the accuracy of the consensus, when a common decision is needed for a certain phenomenon in a distributed network. We analyze the effects of the initial value, the network topology (regular and irregular), and the number of clusters on the algorithm convergence rate as well as the accuracy of the value when reaching consensus. A utility function is developed based on two parameters, iteration and relative error, to help the network designers make an optimal decision based on their requirements. An irregular sensor model which is based on the degree of irregular (DOI) radius is introduced to evaluate the robustness of the algorithm. The simulation results demonstrate that for any initial value and network topology, the proposed ACDC gossip algorithm can yield results that are 50% closer to the real average value than the referenced standard gossip and grid cluster gossip algorithms. With different DOI values, our ACDC gossip algorithm can still reach lower relative error compared with other gossip algorithms, which demonstrates that our algorithm is robust enough to be executed in the network. © 2013 Yanwei Li et al.

In this paper, we propose an average connectivity degree cluster (ACDC) scheme gossip algorithm to improve the convergence speed and the accuracy of the consensus, when a common decision is needed for a certain phenomenon in a distributed network. We analyze the effects of the initial value, the network topology (regular and irregular), and the number of clusters on the algorithm convergence rate as well as the accuracy of the value when reaching consensus. A utility function is developed based on two parameters, iteration and relative error, to help the network designers make an optimal decision based on their requirements. An irregular sensor model which is based on the degree of irregular (DOI) radius is introduced to evaluate the robustness of the algorithm. The simulation results demonstrate that for any initial value and network topology, the proposed ACDC gossip algorithm can yield results that are 50% closer to the real average value than the referenced standard gossip and grid cluster gossip algorithms. With different DOI values, our ACDC gossip algorithm can still reach lower relative error compared with other gossip algorithms, which demonstrates that our algorithm is robust enough to be executed in the network. © 2013 Yanwei Li et al.

The involvement of smart grid in home and building automation systems has led to the development of diverse standards for interoperable products to control appliances, lighting, energy management and security. Smart grid enables a user to control the energy usage according to the price and demand. These standards have been developed in parallel by different organizations, which are either open or proprietary. It is necessary to arrange these standards in such a way that it is easier for potential readers to easily understand and select a suitable standard according to their functionalities without going into the depth of each standard. In this paper, we review the main smart grid standards proposed by different organizations for home and building automation in terms of different function fields. In addition, we evaluate the scope of interoperability, benefits and drawbacks of the standard. © 2012 IEEE.

This paper aims at improving the demodulation performances of Four-element Single Sideband signals by proposing a new receiver structure involving an Inter-Signal Interference cancellation filter. The filter makes use of the estimated symbols generated by the receiver to approximate the interference between multiplexed signals inherent to the use of low complexity Hilbert Transform filters at the transmitter. Simulation results show that the new receiver structure performs better than the one formerly proposed in early works on this topic. © 2012 IEEE.

We propose a resource allocation method which guarantees a throughput of each mobile station (MS) in a Base Station (BS) cooperated MIMO. A previously proposed method for guaranteeing MS throughputs allocates resource to MSs which can not guarantee throughput with a bad channel quality. Our method excludes MSs with a bad channel quality and allocates resource to the other MSs with a good channel quality. The simulation result showed our method guaranteed more MSs' throughput and achieved a higher system throughput than the previous method.

In previous works, a blind single antenna interference cancellation (SAIC) algorithm named least mean squareblind joint maximum likelihood sequence estimation (LMS-BJMLSE) has been proposed for OFDM systems. It is blind with respect to interference and is able to cancel interference by only one receive antenna. However, LMS-BJMLSE requires a long training sequence (TS) for channel estimation, which greatly reduces the transmission efficiency. Furthermore, since TS is not available in 4G LTE systems, LMS-BJMLSE can not be applied directly. In this paper, in order to solve this problem, a SINR and symbol position weight adaptive algorithm is proposed, and named as adaptive LMS-BJMLSE (ALMS-BJMLSE). For each slot, ALMS-BJMLSE dynamically decides the number of antennas used for interference cancellation and adjusts the step size, based on estimated SINR conditions and symbol position weight. Simulation results demonstrate that ALMS-BJMLSE achieves a much better balance between performance and transmission efficiency compared to the conventional LMS-BJMLSE algorithm, and can be applied for 4G LTE systems.

This paper proposes a study of performances of the Orthogonal Four Single Sideband elements modulation previously proposed by Ohta [1]. Realistic parameters such as receiver noise and various channel effects are introduced in the derivation of the modulation. Transmission of two QPSK signals multiplexed in one 4-SSB (Single Sideband) signal over OFDM (Orthogonal frequency-division multiplexing) is considered and a demodulation process exploiting a turbo equalizer is presented. Computer simulations are used to verify the performances of the proposed modulation scheme. Results show that 4-SSB QPSK signal over OFDM can achieve performances close to QPSK-OFDM scheme while carrying twice more information, provided perfect channel equalization. However, we also show that in a non-ideal equalization case, performances of 4-SSB QPSK OFDM become highly sensitive to channel effects. © 2011 IEEE.

Energy efficient data gathering is a common but critical operation in many applications of Wireless Sensor Networks (WSNs). Innovative energy efficient schemes that improve the sensor network lifetime are highly desirable. One of the energy efficient schemes in sensor network is clustering, which is an effective topology control strategy to increase network scalability and lifetime. In this paper we propose effective data gathering and energy efficient clustering scheme (EDGE) which ensures the equal distribution of cluster head responsibility among the sensor nodes and better suits the periodic data gathering applications. Our approach selects cluster head based on three metrics: sensor nodes current energy level, distance to base station and LEACH's probabilistic approach. We also propose two hop communication by selecting one gateway node. We simulate EDGE with two hop communication and without two hop communication. Simulation results shows that our approach significantly improve the network lifetime over Low Energy Adaptive Clustering Hierarchy (LEACH), LEACH-Centralized (LEACH-C) and Energy-LEACH (E-LEACH) algorithm especially when the first node runs out of energy. © 2011 National Institute of Inform.

The involvement of IEEE 802.15.4 Wireless Sensor Networks (WSNs) in diverse applications has made the realistic analysis of sensor power dissipation in distributed network environments an essential research issue. In this paper, we propose and thoroughly analyze a power dissipation model for Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) based IEEE 802.15.4 distributed multi-hop WSNs. Our model takes the loss rate of frames, neighbor sensors density in communication range of a sensor, number of hops, distance of source to the sink, and density of the network into account. We evaluate the impact of these factors on overall power dissipation. We also perform comprehensive analysis of overheads caused by message routing through multi-hop distributed networks. We validate our proposed model through Monte Carlo simulations. Results show that our power dissipation model is more realistic compared to other proposed models in terms of accuracy and multiplicity of the environments.

本論文は,複数基地局環境において,個々の端末のスループットを保証可能な基地局制御装置(RNC:Radio Network Controller)を用いた集約的な動的チャネル割当方式(DCA:Dynamic Channel Allocation)について提案する.これまで複数基地局環境において提案されたDCAとしては,個別の端末のスループットを考慮せずにシステム全体の端末のスループットの和を最大化する方式や,ある大きさ以上の基地局間干渉波を抑止する条件のもとでシステム全体の端末のスループットを最大化する方式はあったが,個々の端末のスループットを保証した上でシステム全体における端末のスループットの和を最大化するようなDCAの方式は提案されていなかった.本論文では,提案方式についてシミュレーションを実施し,あらかじめ設定したスループットを保証するチャネル割当が実現可能なことを示す.また従来方式によるシミュレーション結果と比較を行い,提案方式の有効性を示す.

With Wireless Sensor Networks (WSNs) involving in diverse applications, the realistic analysis of energy consumption of a sensor node in an error-prone network environment is emerging as an elementary research issue. In this paper, we introduce a Distributed Communication Model (DCM) that can accurately determine the energy consumption through data communication from source to destination in error-prone network environments. The energy consumption is affected with the quality of link, which is characterized by symmetry, directivity, instability, and irregularity of the communication range of a sensor node. Due to weak communication links, significant packet loss occurs that affects the overall energy consumption. While other models unable to determine energy consumption due to lossy links in error-prone and unstable network environments, DCM can accurately estimate the energy consumption in such situations. We also perform comprehensive analysis of overheads caused by data propagation through multi-hop distributed networks. We validate DCM through both simulations and experiments using MICAz motes. Similarity of the results from energy consumption analysis with both simulations and experimentations shows that DCM is realistic, compared to other models in terms of accuracy and diversity of the environments.

Many sensor applications are aimed for mobile objects, where conventional routing approaches of data delivery might fail. Such applications are habitat monitoring, human probes or vehicular sensing systems. This paper targets such applications and proposes lightweight proactive distributed data collection scheme for Mobile Sensor Networks (MSN) based on the theory of thermal fields. By proper mapping, we create distribution function which allows considering characteristics of a sensor node. We show the functionality of our proposed forwarding method when adapted to the energy of sensor node. We also propose enhancement in order to maximize lifetime of the sensor nodes. We thoroughly evaluate proposed solution and discuss the tradeoffs.

Due to the reuse factor reduction, the same frequencies are reused in adjacent neighboring cells, which causes an attendant increase in co-channel interference (CCI). CCI has already become the limiting factor in the performance of orthogonal frequency division multiplexing (OFDM) based cellular systems. Joint maximum likelihood sequence estimation (JMLSE) based interference cancellation algorithms have been under intense research. However, despite the fact that the error probability of JMLSE is critical for analyzing the performance, to the best of our knowledge, the mathematical expression has not been derived for MQAM-OFDM yet. Direct computation of the error probability involves integrating a multi-dimensional Gaussian distribution that has no closed-form solution. Therefore, an alternative way is to upper and lower bound the error probability with computable quantities. In this paper, firstly, both the upper and the conventional lower error probability bounds of JMLSE are derived for MQAM-OFDM systems based on a genie-aided receiver. Secondly, in order to reduce the gap between the conventional lower bound and the simulation results, a tighter lower bound is derived by replacing the genie with a less generous one. Thirdly, those derived error probability bounds are generalized to the receiver diversity scheme. These error probability bounds are important new analytical results that can be used to provide rapid and accurate estimation of the BER performance over any MQAM scheme and an arbitrary number of interferers and receive antennas.

Many sensor applications are aimed for mobile objects, where conventional routing approaches of data delivery might fail. Such applications are habitat monitoring, human probes or vehicular sensing systems. This paper targets such applications and proposes lightweight proactive distributed data collection scheme for Mobile Sensor Networks (MSN) based on the theory of thermal fields. By proper mapping, we create distribution function which allows considering characteristics of a sensor node. We show the functionality of our proposed forwarding method when adapted to the energy of sensor node. We also propose enhancement in order to maximize lifetime of the sensor nodes. We thoroughly evaluate proposed solution and discuss the tradeoffs.

Due to the reuse factor reduction, the attendant increase in co-channel interference (CCI) becomes the limiting factor in the performance of the orthogonal frequency division multiplexing (OFDM) based cellular systems. In the previous work, we proposed the least mean square-blind joint maximum likelihood sequence estimation (LMS-BJMLSE) algorithm, which is effective for CCI cancellation in OFDM systems with only one receive antenna. However, LMS-BJMLSE requires a long training sequence (TS) for channel estimation, which reduces the transmission efficiency. In this paper, we propose a subcarrier identification and interpolation algorithm, in which the subcarriers are divided into groups based on the coherence bandwidth, and the slowest converging subcarrier in each group is identified by exploiting the correlation between the mean-square error (MSE) produced by LMS and the mean-square deviation (MSD) of the desired channel estimate. The identified poor channel estimate is replaced by the interpolation result using the adjacent subcarriers' channel estimates. Simulation results demonstrate that the proposed algorithm can reduce the required training sequence dramatically for both the cases of single interference and dual interference. We also generalize LMS-BJMLSE from single antenna to receiver diversity, which is shown to provide a huge improvement.

:Many sensor applications are aimed for mobile objects, where conventional routing approaches of data delivery might fail. Such applications are habitat monitoring, human probes or vehicular sensing systems. This paper targets such applications and proposes lightweight proactive distributed data collection scheme for Mobile Sensor Networks (MSN) based on the theory of thermal fields. By proper mapping, we create distribution function which allows considering characteristics of a sensor node. We show the functionality of our proposed forwarding method when adapted to the energy of sensor node. We also propose enhancement in order to maximize lifetime of the sensor nodes. We thoroughly evaluate proposed solution and discuss the tradeoffs.

Peer-to-Peer file sharing, computing and communication services are widely used by internet community and thoroughly studied by academia. However, main utilization of such services is in the wired networks due to several significant issues in the wireless world like connectivity, bandwidth, battery, unwillingness of cellular operators, etc. In the recent years, offering femtocell access points to subscribers became very promising business model for cellular operator. It also opens space for a variety of new services at the users premises. In this paper, we propose novel architecture for mobile peer-to-peer file sharing based on the femtocell deployment and describe a role of the femtocell in such scenario. We also describe traditional architecture and previously proposed solutions for mobile P2P. We evaluate these approaches and clearly show that the femtocell plays significant role and moves mobile P2P services into reality. We also discuss several current issues which can be easily solved by this architecture.

The wireless communication system is evolving towards a ubiquitous wireless network in which multiple-radio devices can roam anytime and anywhere across different access networks. Minimal latency and low packet loss ratio during handover (HO) are the indispensable requirements to reduce service disruption and support real-time services. However, minimizing service disruption is a challenging issue to multiple access networks since HO latency is much higher than that of homogeneous networks. Link layer trigger or layer 2 trigger has been proposed to address this issue. Nevertheless, the precise timing and denitive criteria for initiating L2 trigger which can greatly affect the handover performance is not specified. This paper considers the issue of how to timely initiate handover decision from the link layer by using adaptive filtering algorithm to predict forthcoming received signal. Particularly, we propose Recursive Least Squares (RLS) as the predictive method for layer 2 triggering and compare its performance with various conventional filtering techniques. A simulation in which the proposed predictive algorithm is implemented to a handover scenario from Wi-Fi to WIMAX is also presented. Our numerical analysis and simulation results show that the proposed algorithm can achieve better performance than that of the other algorithms and can be used to enhance the handover performance in heterogeneous wireless networks. © 2011 IEEE.

In the previous work, a single antenna interference cancellation (SAIC) algorithm named least mean square-blind joint maximum likelihood sequence estimation (LMS-BJMLSE) has been proposed. However, LMS-BJMLSE requires a long training sequence (TS) for channel estimation, which reduces the transmission efficiency. In another work, in order to solve this problem, a subcarrier identification and interpolation algorithm was proposed, in which the slowly converging subcarriers are identified by exploiting the correlation between the mean-square error (MSE) produced by LMS and the mean-square deviation (MSD) of the desired channel estimate. However, this correlation relationship was only found based on simulation results and no clear mathematical proof was given. The performance of the algorithm was only evaluated for the case of single interference. In this paper, the mathematical proof of the correlation relationship between MSE and MSD is given. Furthermore, we generalize LMS-BJMLSE from single antenna to receiver diversity, which is shown to provide a huge improvement over single antenna. The performance of LMS-BJMLSE is also evaluated for the case of dual interference. © 2011 IEEE.

Performance evaluation in terms of energy conservation and data reliability of the IEEE 802.15.4 multi-hop communications in error-prone Wireless Sensor Networks (WSNs) is an emerging research issue. In order to accurately evaluate the energy consumption of a sensor node and ultimately the lifetime of WSNs, it is highly desired to thoroughly analyze data reliability through variety of aspects. In this paper, we analyze data reliability in the IEEE 802.15.4 multi-hop communications in error-prone WSNs, by assessing the channel quality using both physical and logical channel quality estimators with different set of parametric values of IEEE 802.15.4 Medium Access Control (MAC) protocol. On the basis of these estimators, we approximate the energy consumption of a sensor node. We also analyze the overheads caused by packet forwarding in the multi-hop WSNs. Simulation results indicate that although physical channel quality estimators are dependent on hardware characteristics, they show better performance in terms of energy consumption and successful data delivery compared to logical channel quality estimators.

This paper proposes a hybrid network scheme combining ad-hoc networks into cellular networks. The scheme is aimed to help the networks to recover to service as much as possible after a disaster strike, by maintaining the connection between Base Stations (BSs) and nodes via multi-hopping, where if a node cannot connect to a BS directly, it switches its working mode from cellular mode to ad-hoc mode. A location-based routing protocol has been proposed for building a route from the node to the BS. Simulation results shows that even if only a small part of the nodes can directly connect to a BS, most of the nodes can find a route to a BS via multi-hopping. And it is found that it outperforms a previously proposed solution which is via beaconing in terms of resistance to mobility.

In orthogonal frequency division multiplexing (OFDM) based cellular systems, co-channel interference (CCI) from adjacent interfering base stations (BSs) would greatly degrade the bit error rate (BER) performance of cell-border users. In the previous work, a blind single antenna interference cancellation (SAIC) algorithm named least mean square-blind joint maximum likelihood sequence estimation (LMS-BJMLSE) has been proposed. The proposed LMS-BJMLSE algorithm is blind with respect to interfering signals and neither the training sequence (TS) nor pilot signal from interferers is needed. However, the conventional LMS-BJMLSE requires a long training sequence (TS) for channel estimation. In this paper, we propose a TS reduction scheme in which the subcarriers are divided into small groups based on the coherence bandwidth, and the slowest converging subcarrier in each group is identified by exploiting the correlation between the mean-square error (MSE) produced by LMS and the mean-square deviation (MSD) of the desired signal. The identified subcarrier's channel estimate is replaced by the interpolation result using the adjacent subcarriers' channel estimates. Simulation results demonstrate that the proposed algorithm could reduce the required TS length by 80%. ©2010 IEEE.

Mobile Sensor Networks (MSN) are used for network load balancing, prolonging network lifetime, and improving network coverage by monitoring critical areas where manual sensor deployment cannot be performed. Addressing the problem of how to achieve maximum network coverage and network uniformity, after deploying sensors in critical areas randomly, is of significant importance recently. In this paper, we design an energy efficient distributed self-deployment algorithm, which is based on the diffusion of mobile sensors in the Region of Interest (ROI). Mobile sensors are diffused from denser sensors area to lesser or uncovered area in ROI, on the basis of localized information. Our algorithm considers ROI with the absence as well as presence of obstacles. Resemblance in the numerical and simulation analysis confirms the concreteness of our algorithm. ©2010 IEEE.

Mobile sensor networks have received significant attention recently. Mobile sensors are deployed to achieve network load balancing, prolonging network lifetime, and improving network coverage, by monitoring critical areas where manual sensor deployment cannot be performed. To achieve these goals, energy estimation is one of the main constraints and concerns to consider, while deploying mobile sensors in a sensor field. Most of the energy models designed for sensor networks assumed static sensors. In this paper, we propose a comprehensive energy model to estimate the overall energy consumption through power dissipation, for both static and mobile sensors in the potential sensor fields. We calculate the total remaining lifetime of mobile sensor networks from the total power dissipation. By predicting the remaining lifetime of any network in different network scenarios at a given instance of time, an optimum network strategy can be designed for a given application.

The performance of a proposed handoff algorithm based on both the distance of a mobile station to neighboring base stations and the relative signal strength measurements is evaluated. The algorithm performs handoff when the measured distance from the serving base station exceeds that from the candidate base station by a given threshold and if the measured signal strength of the adjacent base station exceeds that of the serving base station by a given hysteresis level. The average handoff delay and average number of handoffs are used as criteria for performance. Numerical results are presented to demonstrate the feasibility of the distance-based handoff algorithm, including results for an additional criterion based on relative signal strength. The proposed algorithm is compared with an algorithm based on absolute and relative signal strength measurements and with a solely distance-based algorithm. It is found that the proposed handoff algorithm performs well in a log-normal fading environment when the distance estimate error is modeled by wide-sense stationary additive white Gaussian noise.

This paper assesses the performance of the handoff algorithm based on distance and RSSI measurements in a multi-cellular environment by computer simulation. The algorithm performs a handoff if handoff initiation conditions, handoff possible conditions, and handoff selective conditions are met. The performance criteria are based on the average number of handoffs, the crossover points and the average number of outages. Numerical results are presented to demonstrate the feasibility of the algorithm. The performance of the distance-assisted handoff algorithm is compared with that of a conventional algorithm that utilizes signal strength alone. Overall, the distance-assisted algorithm exhibits higher performance in average number of handoffs and the crossover points, yet exhibits a higher number of outages on average than the conventional algorithm.

In this paper, the performance of a higher data rater OFDM system based on IEEE802.11a is described. The performance of the OFDM system which is applied 256QAM and 1024QAM to obtain higher data rate than 64QAM, are evaluated in A WGN and multi path fading environment. Also the system with ADC performance and required SNR are given. This shows 1024QAM OFDM system has capability of an candidate of the higher data rate wireless LAN system, target to 100Mbps.

We analyzed the handoff performance of a multihop-based wireless LAN that uses Access Points (APs) for communication. When a mobile terminal isn't able to communicate with any APs, it uses other mobile terminals as Terminal Repeaters (TRs). The handoff criteria are based on absolute and relative signal strengths. The performance criteria are the average number of handoffis and the average handoff delay. We investigated the relation between the handoff criteria and the performance criteria when both the mobile terminal and the terminal repeaters are moving. Numerical results are presented to show that the average handoff delay decreases but the average number of handoffis increases as the TRs' moving speed is increased.

This paper clarifies an estimation method of a carrier offset frequency of an orthogonal coding multi-carrier CDMA system under a multi-path fading. This paper analyzes an inter channel interference and an inner channel interference which are caused by the multicarrier offset frequency. An estimation method of the carrier offset frequency adopts a prediction method. Prediction coefficients are obtained by Burg algorithm of a Maximum entropy method. As a result of a simulation, it shows that Bit Error Rate (BER) is 3.5x10(-2) at 15 dB of E-6/N-0 for 32 kbit/sec of data rate and 16 subchannels of the orthogonal coding multi-carrier CDMA under a multi-path fading environment.

Group 3 error-free facsimile terminal for use in an analog cellular network has been developed. This facsimile terminal is provided with the International Telecommunication Union (ITU-T, formerly CCITT) T.30 recommendation protocol and an adaptive error control scheme (AECS) for Group 3 communication and error-free communication. The AECS monitors the channel conditions and selects the optimum error correction code. ITU-T V.27ter is used as the modulation method and the transmission rate is 4800 bps. This system is compatible with the modified Huffman (MH), modified READ (MR), and modified modified READ (MMR) image data compression codes. The average communication time of this facsimile terminal is 40 s per page under moving condition through the analog cellular network. © 1996 IEEE.

This paper describes the evaluation results for Group 3 (G3) facsimile transmission in the transparent mode over the digital cellular system. Effectiveness of a convolutional code is clarified for encoding the G3 facsimile data from analysis of error correction capability for the transparent mode. The 1/2 convolutional code is used as the error correction code in the digital cellular circuit, and a simulation experiment is conducted at the data transmission speed of 4,800 bit/sec in a G3 facsimile. It has been clarified that the transparent transmission system is applicable up to a fading frequency of 80 Hz, a received power of -100 dBm and a handoff occupancy frequency of 4 times per minute on asumption of handoff occurrence probability in a Poisson distribution. This scheme presents the high reliable G3 facsimile transmission which does not depend on delay time of the digital cellular system.