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In wireless personal area networks (WPANs), the successful design of channel time allocation algorithm is a key factor in guaranteeing the various quality of service (QoS) requirements for the stringent real-time constraints of multimedia services. In this paper we propose a dynamic channel time allocation algorithm for providing delay guarantees to multimedia traffics such as MPEG streams in the IEEE 802.15.3 high-rate WPANs. The dynamic algorithm exploits the characteristics of MPEG stream, wherein devices (DEVs) send their channel time requests near at the end of superframe. The algorithm uses mini packets for feedback control in order to deliver dynamic parameters for channel time requests from DEVs to the piconet coordinator (PNC). In this scheme, the duration of channel time allocated to a DEV during a superframe is changed dynamically depending on the MPEG frame type, traffic load and delay bound of the frame, etc. Performance of the proposed scheme is investigated by simulation. Our results show that compared to conventional scheme, the proposed scheme is very effective and has high performance while guaranteeing the delay bound. [ABSTRACT FROM AUTHOR]

Multiple input multiple output-orthogonal frequency division multiplexing (MIMO-OFDM) is regarded as a promising technology enabling higher data rate wireless communications in frequency selective fading channels. This paper proposes the next generation wireless local area network (WLAN) physical (PHY,) layer transmission technology using dual-band and MIMO-OFDM schemes and discusses test results of MIMO-OFDM prototype system implemented with field programmable gate arrays (FPGA). This design targets over 200Mbps of the maximum PHY data rate in 40MHz bandwidth and compatibility with the legacy IEEE 802.11a. For a cost-effective implementation and improved packet error rate (PER) performance, 2 transmit and 3 receive antennas and 40MHz channel are used to achieve the desired PER and throughput performance in the 5GHz band. [ABSTRACT FROM AUTHOR]

This paper introduces a cost-effective video demosaicking solution suitable for mobile phones with video capturing capabilities. The proposed solution is a spatiotemporal demosaicking scheme which operates over three subsequent frames of the acquired video sequence. To rapidly demosaick the raw, color filter array (CFA), spatiotemporal video data our solution uses multi-stage processing concepts and builds on the principles of refined spectral modeling and self-adaptation to varying spatiotemporal characteristics. The proposed solution accommodates cost-effective considerations inherent in mobile phone imaging and produces a visually pleasing demosaicked video sequence. [ABSTRACT FROM AUTHOR]

In this paper, an efficient decision feedback equalizer (DFE) is presented for sparse channels with large delay echoes, which are encountered in many high-speed wireless communication applications. Unlike the conventional DFE, this proposed equalizer considers that the channel is sparse and large number of DFE taps lead to noise accumulation problem. The new method can achieve efficient equalization by setting the active group for equalization taps and clearing the abandoned taps mechanism. As a result, it can both reduce hardware implementation complexity effectively and improve the performance compared to the conventional DFE. Brief analysis about noise accumulation effects in large-scale equalizer and working mechanism description of this effective algorithm exhibits us where the performance gain lies. Simulation results show that this modified DFE exhibits considerable computational savings, faster convergence, and better performance and improved tracking capabilities than the conventional ones. It is quite fit for applications in high-speed systems, such as high definition television (HDTV) and broadband mobile communication. [ABSTRACT FROM AUTHOR]

This paper describes the problems of wireless LAN usage in the user's home with focus on high quality, real-time media transmission. Results of physical channel measurements with respect to fading effects and channel power are analyzed and experimentally obtained link data rates are presented Methods for a transmitter based link adaptation are described and evaluated to increase the reliability of the physical data transmission. [ABSTRACT FROM AUTHOR]

Adaptive modulation is proposed by many researchers for future generation wireless networks based on multi-carrier transmission technologies. In this paper, we propose and investigate some blind mechanisms at the receiver of adaptive modulation based coded OFDM-CDMA systems in Rayleigh fading channels, for enhancement of the systems both in terms of practical implementation and data throughput capacity. In this respect, blind techniques to estimate the channel impulse response and modulation scheme are proposed and investigated and their effect on the BER performance of the systems are also analyzed A subspace based algorithm is proposed to estimate the channel impulse response blindly. This estimate is then used to coherently demodulate the OFDM-CDMA signals and adaptively switch the modulation schemes for varying channel conditions. Furthermore, an algorithm to estimate the modulation scheme at the receiver is also proposed Results show error free estimation of modulation scheme for a maximum 7 number of active users in the system at a channel condition of 20 dB. Simulation results show that in some situations, the systems based on blind channel estimation show little degradation in terms of the BER performance compared to the pilot based scheme. However, the advantages of blind estimation schemes far outweigh this degradation. [ABSTRACT FROM AUTHOR]

With great advances in the mobile technology and wireless communications, users expect to access the Internet anytime anywhere. However, resources on the mobile information appliances and wireless links are obviously inferior to the fixed peers. To save limited resources, actively push updated information from the data sources to the mobile users can be a good choice. However, due to particularities of mobile communications, kinds of problems are partially solved to achieve pushing timely information to the mobiles. In this paper, we present a push system with intelligence for delivering updated information to the mobile subscriber. By using the proposed push system, mobile users can obtain latest information anytime anywhere using any available appliances with personalized presentation. Experiment results show that the proposed push system can timely deliver information to the mobiles with satisfying efficiency. [ABSTRACT FROM AUTHOR]

In this paper, we present an open source network storage protocol, HyperSCSI, which can be applied to build a home storage network. HyperSCSI is designed for transmission of SCSI (Small Computer System Interface) protocol data across Ethernet based network With HyperSCSI, a home user can access SCSI or non-SCSI storage device (like IDE, USB) natively through the network as if the storage device is attached locally. We describe HyperSCSI protocol architecture, operations, as well as some key protocol features that make it distinct from conventional solutions. We also demonstrate the experiment and applications that integrated HyperSCSI protocol with Fast Ethernet and IEEE 802.11b/g WLAN (Wireless Local Area Network) environment The results show that it is promising to build efficient and cost-effective HyperSCSI based home storage network that utilizes common-off-the-shelf storage hardware and well deployed network infrastructure. [ABSTRACT FROM AUTHOR]

In this paper, the design and experimental testing of a Direct-Sequence Spread Spectrum (DSSS) system for wireless infrared LAN is presented This method improves the wireless IR communications performances against multipath propagation and narrowband interference. We have implemented a IR-DSSS prototype with 100 MHz code frequency and 6 Mbps bit rate. We have also studied the effects of both gaussian and sinusoidal signal conformation over wireless optical DSSS systems. These results show that these techniques reduce the adjacent-channel interference without loss of process gain or substantial reductions of BER vs. S/N performances. We also present some results about a simplified synchronization structure so as to be used on reduced-cost domestic equipment. These systems are suitable for different applications at low and medium rates, especially for In-house. [ABSTRACT FROM AUTHOR]

This paper presents a frame synchronization and two frequency synchronization techniques for high-rate wireless LANs (Local Area Networks). Also, to improve the reliable communication under the multipath fading channel, we propose the wireless LAN system employing the space-time code. The proposed frame synchronization technique using the threshold checking scheme is directly based on the correlation method. We then describe a coarse frequency synchronization technique combining two conventional synchronization techniques to estimate an integral frequency-offset and a frequency synchronization technique employing interpolation method to estimate the integral and fractional frequency- offsets at the same time, respectively. Finally, by simulation, the performance of the proposed techniques is evaluated. [ABSTRACT FROM AUTHOR]

Designing reliable and flexible Home Energy Controllers (HECs) is the pivotal part for Energy Information Network System (ENJS). This paper presents a hybrid channel data concentrator for reliable Internet access control. The concentrator is composed of Power Line Carrier (PLC) and wireless front-end modules, and an Embedded system. The selection of either PLC or RE channel is based on a channel reliability level estimation method. To verify the reliability and robustness of the proposed system, line-spread and radial- spread test sites have been installed for link performance tests. The experimental results show the feasibility of deploying a reliable PLC and wireless data concentrator for ENIS in areas of high or low population density residential apartments. [ABSTRACT FROM AUTHOR]

In this paper, we introduce a novel home network system for creating new network and service architecture by connecting home appliances networked using Bluetooth technology with the Internet. In the system, we mainly propose a new method of home network formation using Bluetooth devices and a method to control/monitor networked home appliances with commands that are implicitly integrated within service contents offered by an application service provider to a user. Finally, we show the implementation and evaluation results, and we discuss the advantages of this system for white appliance networking. [ABSTRACT FROM AUTHOR]

This paper proposes a novel approach for robust transmission of JPEG2000 (JP2) images over wireless channels. It relies on using a wavelet transmultiplexer that allows for a proper unequal distribution of the transmission power among JP2 coding units according to their contribution to the decoded image quality. In the proposed system, the JP2 stream is divided into a certain number of packet groups and each group is transmitted through a separate sub-channel at a different rate and power. Packet grouping and power distribution is driven by the native JP2 rate-distortion Junction The major strength of the proposed method is the flexibility on assigning a different protection level to each source JP2 packet by selecting the transmission power from a continuous range of possible values. The performance of this technique is evaluated in case of AWGN and Rayleigh channels. [ABSTRACT FROM AUTHOR]

Presents a study which discussed a novel optimal decoding method for receiver antenna diversity combining for Coded Orthogonal Frequency Division Multiplexing system. Overview of the channel model, IEEE 802.11a transceiver and Zehavi's soft metrics calculation algorithm; Theoretical analysis; Simulation results.

Focuses on a study which presented a multiple symbol differential detection method for the differential encoding scheme of MPSK signals by using several transmit antennas. Multiple antennas in wireless communications; Differential encoding; Simulation results.

This paper describes the design and implementation of a multimedia home gateway for threescreen television (3STV) service. The proposed in-home wireless network uses scalable video coding (SVC) and unequal error protection with Raptor forward error correction (FEC) for maximizing the quality of experience (QoE) over the variable-bandwidth, error-prone wireless network. The gateway incorporates (a) dynamic SVC layerswitching, which enables the server to perform selecting appropriate layers from SVC bitstreams, (b) adaptive Raptor FEC, which controls the overhead of Raptor FEC according to packet loss rate (PLR), (c) an efficient combination of (a) and (b), and (d) slice group-based selective streaming in the overall gateway architecture. The paper explains the home gateway architecture as well as experiments for performance evaluation as compared to that of traditional SVC streaming. In the experiments conducted, gains in video quality vary from 2 to 5dB in peak signal-to-noise ratio (PSNR), with corresponding subjective improvements. Overall reductions of bit rate at the input to the home gateway vary from 28% to 36%1. [ABSTRACT FROM AUTHOR]

Mobile RFID, the technology of a cellular phone equipped with a RFID reader, allows users to read RFID tags anywhere. However, signals from more than two readers can interfere with one another, i.e., reader collision problem; reliable tag reading is necessary. This paper proposes GENTLE protocol to use beacon messages and multi-channel for increasing throughput. GENTLE protocol can also put tag ID information into the beacon message and share it among close readers. In addition, we suggest LSWBT protocol that reduces reader collision without beacon messages. Simulation results show that GENTLE and LSWBT protocols outperform existing reader anti-collision protocols. [ABSTRACT FROM PUBLISHER]

This paper presents cooperative spectrum sensing techniques for cognitive radio (CR) systems. The spectrum sensing detects the presence of a primary user (service) on an associated spectrum. The accuracy of spectrum sensing depends on both sensing time and number of sensing nodes (i.e. secondary users) participating in the sensing process. We derive optimal number of secondary users for cooperative spectrum sensing to minimize spectrum detection error probability and optimal spectrum sensing time to maximize data transmission throughput. A system model which consists of a primary TV spectrum and multiple Wi-Fi secondary users is considered. The proposed CR scheme can solve recent spectrum shortage problem in Wi-Fi networks due to traffic explosion by smart phones. We propose K-out-of-N-rule which is the most efficient cooperative sensing rule by analytical and numerical results. [ABSTRACT FROM PUBLISHER]

Along with the rapid growth in consumer adoption of modern portable devices, video streaming is expected to dominate a large share of the global internet traffic in the near future. In the wireless communications domain, this trend creates considerable challenges to consumers? quality of experience (QoE). From a consumer-focused vision, predicting perceptual video quality is extremely important for QoE-based service provisioning. However, available QoE measurement techniques that adopt a full reference model are impractical in real-time transmission since they require the original video sequence to be available at the receiver?s end. Therefore, the primary aim of this study is to present a cross-layer no-reference prediction model for the perceptual quality of 3D video in the wireless domain. The contributions of this study are twofold: first, the impact of selected quality of service (QoS) parameters from both encoding and network levels on QoE is investigated. Also, the obtained QoS/QoE correlation is backed by thorough statistical analysis. Second, a prediction model based on fuzzy logic inference systems (FIS) is developed by mapping chosen QoS parameters to the measured QoE. This model enables a non-intrusive prediction of 3D visual quality. Conclusive results show a significantly high correlation between the predicted video quality and the objectively measured mean opinion scores (MOS). Objective MOS is also validated through methodical subjective assessments. For consumer?s QoE, this study advances the development of reference-free video quality prediction models and QoE control methods for 3D video streaming. [ABSTRACT FROM AUTHOR]

With the fast development of the Internet, wireless communications and semiconductor devices, home networking has received significant attention. Consumer products can collect and transmit various types of data in the home environment. Typical consumer sensors are often equipped with tiny, irreplaceable batteries and it therefore of the utmost importance to design energy efficient algorithms to prolong the home network lifetime and reduce devices going to landfill. Sink mobility is an important technique to improve home network performance including energy consumption, lifetime and end-to-end delay. Also, it can largely mitigate the hot spots near the sink node. The selection of optimal moving trajectory for sink node(s) is an NP-hard problem jointly optimizing routing algorithms with the mobile sink moving strategy is a significant and challenging research issue. The influence of multiple static sink nodes on energy consumption under different scale networks is first studied and an Energy-efficient Multi-sink Clustering Algorithm (EMCA) is proposed and tested. Then, the influence of mobile sink velocity, position and number on network performance is studied and a Mobile-sink based Energy-efficient Clustering Algorithm (MECA) is proposed. Simulation results validate the performance of the proposed two algorithms which can be deployed in a consumer home network environment1. [ABSTRACT FROM PUBLISHER]

In this paper we propose a design using a guiding system, Radio Frequency Identification (RFID), IEEE 802.15.1 short-range wireless transmission technology and the Internet to fabricate a blood pressure measurement (BPM) which works in cooperation with a health management system. Our design has many advantages, including being easy to use by the aged, low cost and wireless connectivity. It allows the early detection of high blood pressure and provides a doctor with a means for observing a patient's health over a long period. The guiding system provides video guide features for the measuring steps, reminds the patient of the measurement results and makes suggestions. We propose here a new design to determine the BPM posture in order to increase the BPM reliability. [ABSTRACT FROM PUBLISHER]

Wireless Body Area Network (WBAN) in recent years have received significant attention, due to their potential for increasing efficiency in healthcare monitoring. Typical sensors used for WBAN are low powered single transceiver devices utilizing a single channel for transmission at the Medium Access Control (MAC) layer. However, performance of these devices usually degrades when the density of sensors increases. One approach to counter this performance degradation is to exploit multiple channels at the MAC layer, where optimal usage of the channels is achieved through cooperation between the sensor nodes. In this paper we propose a cooperative WBAN environment that supports multi-hop transmission through cooperation involving both environmental sensors and WBAN nodes. Our solution extends the cooperation at the MAC layer to a cross-layered gradient based routing solution that allows interaction between WBAN and environmental sensors in order to ensure data delivery from WBANs to a distant gateway. Extensive simulations for healthcare scenarios have been performed to validate the cooperation at the MAC layer, as well as the cross-layered gradient based routing. Comparisons to other cooperative multi-channel MAC and routing solutions have shown the overall performance improvement of the proposed approach evaluated in terms of packet loss, power consumption and delay. [ABSTRACT FROM PUBLISHER]

A wireless network of consumer electronic (CE) devices in a modern home, is typically running streaming services with heterogeneous bandwidth demands. Satisfying these demands offers the challenge of mapping them efficiently onto scarce wireless channel bandwidth. This mapping is supported by the IEEE 802.11e standard which provides cooperative and competitive distributed control for bandwidth assignment through a set of medium access control (MAC) mechanisms. While these mechanisms leverage priority arbitration for wireless channel usage, they are typically configured without taking the knowledge of streaming services into account thus resulting in suboptimal bandwidth utilization. This paper presents a streaming-aware wireless channel utilization policy. For defining and understanding the policy, a previous analytic model, which focuses mainly on the aspect of obtaining control of the channel, is extended with the aspect of retaining control according to application requirements. The model is simpler than previous works; it is compared with simulations and shown to be accurate. A utilization improvement of up to 18% is observed to be possible showing that such cross-layer optimization improves resource use1 [ABSTRACT FROM AUTHOR]

This paper focuses on the integration of Digital Addressable Lighting Interface (DALI) devices in wireless sensor networks. Since different manufacturers usually deal with one aspect of building automation - e.g. heating ventilation and air conditioning, lighting control, different kinds of alarms, etc. - final building automation system has different subsystems which are finally taken to an integrated building management system. The cost of this process is consequently increased due to additional hardware investment. Our main purpose is to provide the end consumer with an economical fully centralized system in which home appliances are managed by an IEEE 802.15.4-based wireless sensor network. Not only is it necessary to focus on the initial investment, but maintenance and energy consumption costs must also be considered. This paper explains the developed system along with a brief introduction to usual building automation protocols. Finally it presents future work in this field. [ABSTRACT FROM AUTHOR]

This paper presents the implementation and experimental evaluation of an advanced MIMO detector for wireless LAN systems. The proposed detector architecture is based on the well-known lattice-reduction aided MMSE method. Several optimizations at both algorithmic and architectural level are presented which result in an efficient VLSI design able to meet the timing requirements of a practical OFDM-based wireless LAN receiver while keeping complexity at moderate levels. Moreover, the detector offers built-in compensation for transmitter impairments such as nonlinear power amplifier characteristics, hence providing a full and cost-effective solution for practical systems. The described solution is implemented on an FPGA-based IEEE802.11n prototype and evaluation results comparing performance of both conventional MMSE and reduced-lattice detection under several propagation scenarios are presented. Experimental results show significantly lower error rates at the receiver for the advanced detector, or equivalently a lower number of required receiver antenna elements for a given performance target, hence resulting in lower cost, physical size and energy consumption,sup>1. [ABSTRACT FROM AUTHOR]

Selected mapping (SLM) is an efficient peak-toaverage power ratio (PAPR) reduction scheme without signal distortion in orthogonal frequency division multiplexing (OFDM) systems. Therefore, it can be applied to mobile consumer electronics that are sensitive to high PAPR because of the limitation of the linear area of a power amplifier. However, enormous inverse fast Fourier transforms (IFFTs) are needed for the sufficient PAPR reduction performance, which cause the mobile devices with SLM scheme to become quite complex and reduce battery power consumption. In this paper, we propose a new SLM scheme that replaces the additional IFFT operations with a conversion of the other candidate OFDM signal. Simulation results show that the proposed scheme significantly reduces the computational complexity, while it obtains the better PAPR reduction performance than the dummy sequence insertion (DSI)-partial transmit sequence (PTS) scheme1. [ABSTRACT FROM AUTHOR]

Wireless data transmission standards like 802.16e, 802.11n, employ Low Density parity Check (LDPC) codes for error control coding. The bit flipping decoding algorithms presents a tradeoff between the error correcting capability, decoding resources and the decoding time. Software based LDPC decoders provide adaptation capabilities in system parameters such as block size and code rate. In a real-time, low-power mobile environments, the Single-Instruction Multiple-Data (SIMD) processor currently used for video processing, could also be used for the LDPC decoding. In this paper, the implementationefficient, reliability ratio-based, weighted bit flipping (IRRWBF) algorithm is presented using a flexible softwarebased LDPC decoder. Compact data structures are proposed for performing the decoding using SIMD architecture. Based on the implementation on two commonly used SIMD architecture for mobile platform, it was found that the decoding speed can be increased by more than 2000% (using 64 bit SIMD registers with vector integer calculation) and 1800% (using 128 bit SIMD registers with vector floating point calculation). Experimental results for different code lengths of 802.16e and 802.11n show that decoding time in order of 1?10-3~10?10-3 seconds is achievable. Due to significantly high throughput and flexibility, the proposed design algorithm and data structure can easily be adapted to any energy-sensitive mobile devices employing SIMD processors1. [ABSTRACT FROM PUBLISHER]

This paper investigates the problem of packet scheduling and resource allocation for multi-user wireless video transmission. The problem is first formulated as an optimization problem with the objective of minimizing the reconstructed video distortion of each user under the radio resource constraints. In order to solve the optimization problem, a crosslayer algorithm with low complexity is proposed by taking the radio resource constraints and the fairness across multi-user into account. Simulation results show that the proposed crosslayer algorithm outperforms the state-of-the-art packet scheduling and resource allocation algorithms by up to 1.2 dB in terms of the quality of the reconstructed video, and the fairness across different users is also maintained. [ABSTRACT FROM AUTHOR]

New communication services among nearby passing people are growing rapidly thanks to the advance of short-range wireless communication technologies and the widespread use of mobile devices that use them. Time-offset communication capability will engender a new service paradigm and promote new service emergence. This paper presents a proposal of a new distributed mobile cache system to cache data temporarily in a designated local area. The system is realized through collaborative consumer electronics mobile devices which use no infrastructure network. The system overview and its middleware on the mobile devices are explained. Furthermore, new relay data algorithms are proposed to provide lower-overhead communication and a more robust caching capability. Finally, results of simulation experiments underscore the effectiveness of the proposed control algorithm in terms of the communication cost and the length of the cache time. [ABSTRACT FROM PUBLISHER]

This paper describes the design and implementation of a new consumer product, namely a generic intelligent iWBC client application. This application sits on a mobile terminal (MT) and operates in the background in support of the mobile consumer-user becoming fully aware of all relevant wireless services available in the location of the MT and which are advertised according to a structured format over wireless billboard channels (WBCs) which are broadcasted and receivable in the same location. The WBCs' role primarily is to facilitate wireless access networks advertising their wireless communication access services to consumers, on their MTs and do this in a background neartransparent way. Information about available services is proactively pushed to users' MTs. The MTs can thus discover the services and all the necessary details about these service offerings sufficient to make informed `always best connected and best served? (ABC&S) decisions about using them, including knowing how to associate with the access networks to obtain these services in the best possible way through an advertisement, discovery and association (ADA) procedure. Other teleservice providers can also advertise their service offerings via WBC and have them handled by this iWBC application in a similar way. Hence this novel iWBC application amounts to a significant advance in consumerdriven ABC&S capabilities and services. [ABSTRACT FROM PUBLISHER]

Intention of this work is to investigate the opportunity and feasibility of more energy efficient networking in wired Home and Building Automation Systems, which have traditionally devoted a relatively little attention to this issue, especially if compared to wireless networks. This paper will propose a solution to address the problem by evaluating the introduction of power state switching in a real scenario and defining the concept of functional and spatial adjacency among packets. The impact of adopting such approach will be assessed through a simulation aimed at determining the best trade-off between energy and Quality of Service. [ABSTRACT FROM PUBLISHER]

One of the effective methods used for reducing peak to average power ratio (PAPR) in OFDM systems is partial transmit sequence (PTS). In the conventional PTS (CPTS) several inverse fast Fourier transform (IFFT) operations and complicated calculation to obtain optimum phase sequence, increase the computational complexity of C-PTS. In this paper, we propose a technique to reduce the number of IFFT operations to half at the expense of a slight PAPR degradation. Simulations are performed with QPSK modulation with OFDM signal and Saleh model power amplifier. The effects of digital predistortion (DPD) to increase the linearity and efficiency of the Saleh model power amplifier (PA) are also examined. [ABSTRACT FROM PUBLISHER]

Wireless Body Area Networks (WBANs) are considered to be a new method for short range wireless communication. Channel characteristics of WBAN are different from those of other wireless channels; specifically, when the human body rotates, the WBAN channel between the body surface and the wireless access point is changed via body shadowing. This paper analyzes the characteristics of recently proposed off-body WBAN channels and bit error performances when the human body rotates. In order to avoid inadequate channels and to improve the bit error performances, the receive antenna is attached to the back side, additionally. And the performance for each diversity scheme is evaluated. [ABSTRACT FROM PUBLISHER]

With the advance of wireless communications technology, home automation based on home networks has regained attention. This paper proposes a wireless network protocol and a control device, which make it possible to control legacy home appliances in an interactive way. The proposed wireless network protocol provides a bidirectional communication channel between a gateway and control devices. The control device hooked up to the wireless network controls a legacy home appliance requested by a user using IR signals and returns the result of the control action as a digested image so that the user can determine if the control operation has been conducted properly. The feasibility of the network protocol and control device is demonstrated by an experiment in which a wireless network is constructed using the proposed network protocol and TVs and air conditioners are controlled via the wireless network and the result is fed back to the user 1. [ABSTRACT FROM AUTHOR]

The demand for broadband communications for high data-rate applications has pushed towards the development of novel access technologies. Even if wireless access networks have gained more importance in the last years, wired access networks still remain the most common alternative for in-home access. In particular, xDSL technology allows a broadband access in domestic environment by exploiting the already deployed Public Switched Telephone Network (PSTN). Within this scenario, one of the most significant drawbacks is the presence of the impulse noise in wired connections. In particular, this is fundamental whenever xDSL is used for carrying high datarate real-time services (e.g., video streaming). Aims of this paper are to present results derived by a measurement campaign over an actual SOHO telephone line and, in addition to this, to propose a suitable detection and mitigation technique for applications in xDSL in-home receivers. Performance comparisons with alternative techniques will be also provided by focusing on real impulses as result of an actual measurement campaign to validate the effectiveness of the proposed solutions.1. [ABSTRACT FROM AUTHOR]

In this article, the device-free human presence detection method based on radio signal strength variations is proposed. The method exploits the known fact that human body interferes with radio signals by causing fading and shadowing effects. Introduced irregularities in the radio propagation pattern indicate possible presence of a human. The proposed method is incorporated into the existing platform for intelligent residential energy management. As opposed to conventional solutions which utilize a complex set of sensors for human detection, the proposed approach achieves the same only by analyzing and quantifying radio signal strength variations incorporated in messages exchanged between 2.4 GHz radio transceivers. One of the key benefits of the proposed solution is the integration of the detection algorithm into the smart power outlets and smart light switches. Such an approach improves interactions in smart home systems, enables intelligent power consumption management and low installation cost. [ABSTRACT FROM PUBLISHER]

For efficient variable-rate speech coding, Karhunen-Loève transform based adaptive entropy- constrained vector quantization (KLT-AECVQ) is proposed. The proposed method consists of backward-adaptive linear predictive coding (LPC) analysis, KLT estimation based on LPC coefficients, and lattice vector quantization followed by Huffman coding according to KLT statistics. As different statistics in an original-signal domain can be mapped into identical statistics in a KLT domain, only a few classified Huffman codebooks are sufficient to represent KLT-domain source statistics. KLT-AECVQ with 32 Huffman codebooks has comparable rate-distortion performance with theoretically optimal AECVQ with infinite number of Huffman codebooks. KLT-AECVQ also produces superior perceptual quality to KLT-based classified vector quantization (KLT- CVQ) that yielded better quality than conventional code- excited linear predictive (CELP) codec. Under five-sample delay constraints, KLT-AECVQ has also three times lower complexity than CELP codec. [ABSTRACT FROM AUTHOR]

Long term evolution (LTE) of 3GPP provides high bandwidth for data transfer. In the viewpoint of the LTE terminal baseband modem chip, these high data rates require more complex logics and memories than previous baseband modem chips in preceding technologies such as Wideband Code Division Multiple Access (W-CDMA), High Speed Down/ink Packet Access (HSDPA), and High Speed Packet Access (HSPA). it may exhaust user equipment (UE)'s battery power quickly. Thus, LTE provides an enhanced discontinuous reception (DRX) to extend the UE's battery lifetime. in this work, we propose an adjustable power management using a hierarchical cascaded power gating (HCPG) and a hierarchical multi-level clock gating (HMLCG) with special regard for DRX framework. The test results from the designed ASIC show that optimal power saving was achieved by using the proposed adjustable power management. [ABSTRACT FROM AUTHOR]

Recent developments in ad-hoc wireless networks, single-chip embedded systems and the wide-spread availability of Internet in homes has made it possible to remotely monitor status of external data sources and home appliances using small, independent wireless devices. This paper presents an open-architecture and an implementation of such a system called the Infopods System. This architecture is based on a Zigbee-based controller. The architecture allows multiple family members to simultaneously monitor their home appliances as well as external Internet resources using cheap, stand-alone hand-held mobile wireless devices. The proposed architecture can be easily integrated with existing smart-home systems. The architecture is implemented and demonstrated in the context of an existing Java-based smart-home architecture. [ABSTRACT FROM AUTHOR]

Among the most promising applications provided by interactive Digital Television Systems (iDTV) are the ones that enable TV-Sets to work as the central processing unit of a house. This is supported by the extending of iDTV common functionalities making use of its processing power not only to deal with image and audio but also to execute interactive software applications. This paper proposes a new infrastructure that allows the exchange of data from the iDTV to Home Automation devices, such as sensors, mobile devices, and so on. The integration process among the involved technologies as well as each element in the proposed infrastructure is described in details. This model is supported by Open Services Gateway initiative (OSGi), as a framework for networked devices, and the Brazilian reference middleware, Ginga. Thus it is possible to use devices services in OSGi-based Home Networks, through the Digital TV. in order to prove the model functionalities, we created validating scenarios of service management involving iDTV interaction with mobile phones and electronic sensor devices using WiFi and Bluetooth technologies. [ABSTRACT FROM AUTHOR]

Car navigation systems (CNS) have become an interesting research and industrial topic due to their wide deployment. However, updating and distribution of the road map database is a complex and high cost process. In this paper, we propose a real-time map generation and updating algorithm, which fulfills or corrects the unknown road area of the conventional road map database by using global positioning system (GPS) information and wireless communication technologies. To generate the road map of unknown roads, the proposed algorithm uses road images, which can be obtained when a driver travels unknown roads. When a driver travels unknown roads, which do not appear on the map of the car navigation system, the car navigation system extracts GPS and image information of the unknown roads. Then, the car navigation system generates the road map for the unknown roads by extracting location and road information, and updates the road map database in the car. After updating the local road map database, the car navigation system updates the master road map database, which is located at the network and is distributed to other car navigation systems. Thus, the road map database provider can update the road map database of other car navigation systems, which share the same master road map database. The proposed algorithm provides an efficient updating process of the road map database with a simplified process and reduced time for unknown road areas. [ABSTRACT FROM AUTHOR]

Duty cycling is a common mechanism for achieving energy efficiency in WSNs. Over the past several years a number of researchers have proposed low-power duty-cycle MAC protocols, but the tradeoff between energy efficiency and latency has been remained a challenging issue. We propose the Express-MAC protocol (EX-MAC) which can guarantee the requirement of the end-to-end transmission latency while conserving energy in a wireless sensor network using asynchronous duty cycling. To achieve low latency operation, EX-MAC employs a wakeup time reservation that utilizes a short preamble scheme to reduce end-to-end latency and to minimize energy consumption. Also, EX-MAC supports multi-hop applications through a cross-layering API, and it provides convergecast packets with unidirectional interfaces to optimize performance and to support reconfiguration routing. In this paper, we first introduce WSNs and the problems in existing MAC protocols. Then we propose the EX-MAC protocol for low end-to-end latency and power efficiency in WSNs. From simulation results, it is proven that EX-MAC is able to adjust its wakeup time reservation for convergecast traffic and to guarantee the requirement of end- to-end latency. [ABSTRACT FROM AUTHOR]

Digital Video Broadcasting for Handheld (DVB-H) is one of the wireless technologies that provide modern digital television services. The main objective of this paper is to propose a method to evaluate the performance of mobile rebroadcaster in terms of symbol error rate, taking into account antenna effects and the Angle of Arrival statistics. A correction factor is derived from concepts as the Mean Effective Gain, which joined to a closed-form expression for the symbol error probability, allows predictions about the antenna impact on the broadcaster. The quantitative evaluation of the analysis identifies an important SNR reduction from 4 dB to 10 dB, depending on the environment. [ABSTRACT FROM AUTHOR]

This paper presents an improved, scattered pilot synchronization (SPS) scheme in digital video broadcasting-handheld (DVB-H) systems, which detect the pilot pattern of the currently received orthogonal frequency division multiplexing (OFDM) symbol. To reduce the SPS time, and to mitigate the influence of the sampling frequency offcet (SFO), the proposed SPS method is based on the conventional correlation-based SPS, and adopts a partial correlation. By using computer simulations, the synchronization performances of the traditional SPS and the new proposed SPS algorithms are evaluated in terms of their probabilities of synchronization failure. [ABSTRACT FROM AUTHOR]

A low complexity hierarchical quadrature amplitude modulation (QAM) symbol bits allocation algorithm for unequal error protection of video transmission over wireless channels is proposed in this paper. An unequal error protection (UEP) scheme using hierarchical QAM, which takes into consideration the non-uniformly distributed importance of intracoded frame (I-frame) and predictive coded frame (P-frame) in a group of pictures (GOP), is first proposed. In order to optimally allocate the hierarchical QAM's high priority (HP), medium priority (MP) and low priority (LP) symbol bits to the H.264/AVC video, a generic solution for optimal allocation of hierarchical QAM's high priority (HP), medium priority (MP) and low priority (LP) symbol bits to the H. 264/A VC video is then proposed. Finally, a low complexity symbol bits allocation algorithm, namely ranking search algorithm, which reduces the computational complexity of the proposed optimal symbol bits allocation algorithm, is proposed. Simulation results show that our proposed UEP scheme outperforms the classical equal error protection (EEP) scheme and also the previous UEP scheme. [ABSTRACT FROM AUTHOR]

The adoption of pseudo-noise (PN) sequence instead of cyclic prefix (CP) as guard interval (GI) enables time domain synchronous orthogonal frequency division multiplexing (TDS-OFDM) outperform Cyclic Prefixed-OFDM (CP-OFDM) by spectrum efficiency but at the expense of higher complexity. Up to now, TDS-OFDM is only used in unidirectional data transmission such as downlink broadcasting. The difficulty to eliminate the implicitly mixed interferences between different PN sequences and inverse discrete Fourier transform (IDFT) blocks caused by multiple users hinders the application of TDS-OFDM in multi-user uplink scenarios. To deal with this problem, this paper proposes a multi-user uplink TDS-OFDM system based on dual PN padding (DPNP) where the cancellation of mixed interference is avoid by joint cyclicity reconstruction for all users. In addition, joint channel estimation and separation is also proposed to restore the transmitted signal for each user. Theoretical analysis and computer simulation not only verify the feasibility of the proposed system, but also show that, compared with the conventional single-user TDS-ODFM system, it holds lower implementation complexity yet even better system performance in mobile environments. [ABSTRACT FROM AUTHOR]

This paper describes an optical wireless system based on time-hopping spread-spectrum techniques, as a first approach, at infrared wavelengths. It can be used either for low-speed sensor interconnections or as a return channel in a Visible Light Communications system. The main advantage of this scheme is an improvement in the narrowband interference rejection capability and the number of simultaneous users supported, compared with other wireless optical standards. Moreover, a wide analysis is carried out about the mutual interference between time-hopping spread-spectrum systems and other infrared ones. Finally, some conclusions are drawn about some design parameters of the time-hopping system in order to allow its compatibility with preexisting optical devices. [ABSTRACT FROM AUTHOR]

In this paper, a novel constellation extension algorithm, named as Peak-restricted Constellation Extension (PCE), is proposed for peak-to-average power ratio (PAPR) reduction in Orthogonal frequency division multiplexing (OFDM) system. This algorithm actively selects outer constellation points which contribute to the large peak magnitudes, and dynamically alter the amplitudes of these points to reduce PAPR. It does not require transmitting any side information to the receiver and there is no loss in data rate. As radio-over-fiber (ROF) network is proved to be one of the best solutions for the wireless-access technology, this algorithm is verified in an OFDM-ROF system. It is shown that this algorithm significantly reduces the PAPR of OFDM signals. The performances of the system with and without the algorithm are also compared. [ABSTRACT FROM AUTHOR]

Ubiquitous smart space consists of various ubiquitous objects (devices and applications) and their collaborations that provide convenient and intelligent services for users. Many studies have focused on developing convenient ubiquitous systems and their applications. However, to provide smooth and satisfactory services to users, a ubiquitous system must be aware of the real-time context of its ubiquitous objects and their collaborations during execution. Therefore, monitoring and analyzing must be provided, not only for the status of the functions and performance of individual ubiquitous objects, but also for their collaborative status. This paper discusses the challenges of monitoring systems for ubiquitous smart space, and proposes seven prerequisites for a monitoring system that examines and diagnoses ubiquitous smart space. We also developed a monitoring system for a ubiquitous smart space scenario, to verify our proposal. [ABSTRACT FROM AUTHOR]

Video-on-demand (VoD) services allow users to receive real-time multimedia contents from afar distance. Yet, current architectures still require a context-aware indexing system to help users learn about story details. In this paper, we present a semantic processing system that offers structuralized video contents based on four basic entities: who, what, where, and when. Thus, users can select clips of interest among a video according to the guided clues. At the same time, we also present an SVC-compatible coding that improves spatial scalability in order to transmit the structuralized results for mobile devices efficiently. Users can, therefore, get a higher PSNR in low bit-rate applications. The experimental results have demonstrated the feasibility and effectiveness of our proposed system. [ABSTRACT FROM AUTHOR]