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Wireless Sensor Networks (WSNs) are used for monitoring and data collection purposes. A key challenge in effective data collection is to schedule and synchronize the activities of the nodes with global clock. This paper proposes the Synchronized Data Aggregation Algorithm (SDA) using spanning tree mechanism. It provides network-wide time synchronization for sensor network. In the initial stage algorithm...
Contact discovery is a fundamental premise of information exchange in delay-tolerant networks (DTNs). However, the intermittent connectivity nature of DTNs makes energy-efficient contact discovery a tough challenge. To save energy, a node should work in low-power mode most of the time since contacts with the other nodes may rarely happen. However, such a strategy will probably fail to detect many...
In the case of the Ubiquitous Robot, the robot elements such as sensor, controller and actuator are distributed in the environment. This system aims at supporting robots and human beings by enabling their cooperation. In order to get high customizability, modularized robot elements are desired. For this reason, it is preferred that the functionality of each element is small. When one promotes the...
In IMT-Advanced system, carrier aggregation makes use of continuous or non-continuous spectrum which may be scattered in many channels, and then the individual component carrier frame is combined to form a new frame structure named frame aggregation. In this paper, flexible frame aggregation strategies are designed for different carrier aggregation situation in order to reduce the duplex delay existed...
This work deals with M-sequence UWB Radio architectures for high-precision indoor localization and low data rate radio transmission. So far, UWB M-sequence devices were only used in Radar mode which applies wired synchronization between transmitter and receiver. Radio systems have different architecture since receiver and transmitter are spatially separated from each other. This paper focuses on the...
This paper presents results of the Seventh Framework Programme (FP7) LOLA (achieving LOw LAtency in wireless communications) project about the design of a cooperative broadcast (CB) technique based on a decode and forward (DF) protocol, in the context of a clusterized wireless mesh network (WMN) based on 3GPP LTE PHY/MAC layers. The CB technique is compared to a baseline broadcast technique, obtained...
In this paper, we address the energy-efficient contact discovery issue in Pocket Switched Networks (PSNs), in which the nodes' mobility pattern shows strong social property. In a PSN, although the end-to-end connection may be disconnected most of the time for a given source-destination pair, several nodes periodically gather at certain hot spots and form well connected clusters. Based on such mobility...
This paper presents a method for time base synchronization between independent nodes which communicate over a wireless medium. It is shown that the malicious effects of multipath propagation are minimized and precise time base synchronization is achieved.
This paper presents a method for time base synchronization between independent nodes which communicate over a wireless medium. It is shown that the malicious effects of multipath propagation are minimized and precise time base synchronization is achieved.
The paper introduces a novel software defined radio system named Sora and analyzes its system architecture. For the special characteristics of radio channel in high speed scenario,we research a novel scheme based on wireless cell network WCDMA for channel sounding in High-Speed Railway. According to developing an application that simulates the transmition and reception of WCDMA siganl by User-Mode...
Pulse wave velocity (PWV) has garnered attention as a means to estimate vessel elasticity. This paper presents an approach to measure PWV using two synchronized, wireless pulse oximeters placed on the wrist and fingertip of the same hand. A MATLAB interface acquires and time-aligns these incoming photoplethysmograms (PPGs), and then it calculates PWVs using time differences at three waveform features:...
High-speed data applications over wireless networks have been growing rapidly in recent years. With this increased use of wireless data, services in wireless networks require performance guarantee. This is, therefore, driving the need for regular innovations in wireless technologies to provide more and more capacity and higher quality of service (QoS). These higher performance requirements have motivated...
Orthogonal frequency division multiplexing (OFDM) communication systems require accurate estimation of timing offset and channel impulse response in order to achieve desirable performance. In this paper, we consider the optimal placement of pilot symbols over the OFDM subcarriers in order to minimize a function of the Cramér-Rao bound on these parameters. Previous work has investigated this problem...
In this paper, two estimators are proposed for calculating fine timing and channel impulse response (CIR) of a CD-OFDM based communication system. The proposed low complexity algorithms are designed to operate with asynchronous nodes having independent timing and carrier frequency offsets. These algorithms fully exploit the specially designed structure of time domain preamble used for cooperative...
This paper discusses a wireless control system for cooperative motion of machines, and clarifies the influence of packet loss on the system behavior. In performance evaluation, we focus on the synchronization of the motion of the fellow machines. In addition, using the nature of wireless, a new wireless control method is proposed for maintaining the performance under packet loss conditions. In the...
According to multimedia service distribution such as High-Definition Television (HDTV), Internet Protocol Television (IPTV) and Voice Over Internet Protocol (VoIP), the networks are required to guarantee Quality of Service (QoS) and real-time performance. Power Line Communication Technology is used for data transfer as well as the transfer of electric power. However, power line communication has some...
Host identification, today, can be done at many layers of the network protocol stack depending on the identifiable parameter used for classification. But, these generally include fields from TCP/IP/MAC packets; that can be spoofed or manipulated very easily to misguide the identification process or include intolerable error into. Identification on wireless networks can be done with better precision...
When the ABS supports mixed mode that is it supports both 16e MSs and 16m AMSs, if we have a Software Defined Radio which supports both 16e and 16m modes, then we can take advantage of the extra preamble available from the other mode to do either fast or robust coarse timing synchronization. For 16e mode, if the signal is weak and cannot synchronize on 16e preamble, the MS can first synchronize on...
Along with LTE-Advanced system and standardization investigation progress, the requirement for verifying relevant key technologies become more and more urgent. This article summarizes the progress of Huawei 4G Test-bed “HEART” (Huawei Experimental Advanced Radio Test-bed). CoMP technology is considered as a launch point to build up this test-bed competence. Some initial analysis and results are addressed...
Most research on distributed space-time block coding (D-STBC) has assumed that cooperative relay nodes are perfectly synchronized, for the delay destroys the required spacetime signal structure. However, in most practical distributed scenario, perfect synchronization is hard to achieve. To deal with it, this paper applies front end prefilter (FEP) as a delay synchronization scheme which accomplishes...
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