Current Issue : July - September Volume : 2019 Issue Number : 3 Articles : 5 Articles
In recent years, using smartphones for indoor positioning has become increasingly popular\nwith consumers. This paper presents an integrated localization technique for inertial and magnetic\nfield sensors to challenge indoor positioning without Wi-Fi signals. For dead-reckoning (DR), attitude\nangle estimation, step length calculation, and step counting estimation are introduced. Dynamic time\nwarping (DTW) usually calculates the distance between the measured magnetic field and magnetic\nfingerprint in the database. For DR/Magnetic matching (MM), we creatively propose 3-dimensional\ndynamic time warping (3DDTW) to calculate the distance. Unlike traditional DTW, 3DDTW extends\nthe original one-dimensional signal to a two-dimensional signal. Finally, the weighted least squares\nfurther improves indoor positioning accuracy. In the three different experimental scenarios-teaching\nbuilding, study room, office building-DR/MM hybrid positioning accuracy is about 3.34 m....
With the deployment of multimedia services over VANETs, there is a need to develop new techniques to insure various levels of\nquality of services (QoS) for real time applications. However, in such environments, it is not an easy task to determine adequate\nroutes to transmit data with specific application QoS requirements. In this paper, we propose CBQoS-Vanet, a new QoS-based\nrouting protocol tailored towards vehicular networks in a highway scenario. This protocol is based on the use of two techniques:\nfirst a clustering technique which organizes and optimizes the exchange of routing information and, second, a bee colony inspired\nalgorithm, which calculates the best routes froma source to a destination based on given QoS criteria. In our approach, clusters are\nformed around cluster heads that are themselves elected based on QoS considerations. The QoS criteria here are based on the two\ncategories of metrics: QoSmetrics andmobility metrics.The QoS metrics consists of the available bandwidth, the end-to-end delay,\nand the jitter.Themobility metrics consists of link expiration time and average velocity difference.We have studied the performance\nof CBQoS-Vanet through simulation and compared it to existing approaches. The results that we obtained show that our technique\noutperforms, in many aspects, the approaches that it was compared against....
There has been a great increase in the use of wireless communication since a decade. The development of many new devices has lead to a conflict of the application of available resources to perform the communication with efficiency. To have control over these problems and for the proper usage of the available spectrum the concept of cognitive radio is used and developments are made in order to counter the existing problems. Cognitive radio helps in proper spectrum management and allows the secondary user to utilize the white spaces without hindering the primary user. Software defined radio platform helps in controlling and reconfiguration of the parameters according to the environment. SDR helps in reconfiguring the secondary user to allow it to establish itself in the environment. Cognitive radio is the future of wireless communication where the advances in the use of new communication devices and increased number of users can be handled more effectively by using SDR than the conventional radio....
Short-range wireless technologies are known to transmit voice, audio, image, and video messages in real time. Energy consumption\nand transmission reach are critical in such networks, especially for portable and power autonomous devices. The\npurpose of the Voice over Zigbee technology is to provide a competitive offering that excels in these performance aspects. Due to\nthe CSMA-CA mechanism implemented in the 802.15.4 layer, a well-designed strategy must be considered in Zigbee to create a\nrobust, reliable, and full-duplex conversation. In past efforts, we proved that the radio channel of Zigbee has enough bandwidth to\nsupport a full-duplex conversation with narrow-band voice codecs. Our embedded implementation of the Speex voice codec\ntargeted the development of a low-cost, ultralow-power, long-range wireless headset using Zigbee technology to transmit voice in\nfull-duplex mode for use with leading PC VoIP programs. Furthermore, we presented the real environment performance\nevaluation and power consumption tests involving the developed headset prototype. Talk time is comparable to Bluetooth\nincluding at the power budget, the codec processing, and analogue audio interface, but its deep-sleep lifetime more than doubles\nthe Bluetooth performance. This was one of the very few successful efforts to port a voice codec on an ultralow-power DSP for use\nwith power sensitive Zigbee applications, which is highly cited in the literature, proving additionally that using an open-source\ncodec can deliver similar voice quality, reducing the total system cost.Thecurrent paper elaborates on the embedded parallelism of\nthe Speex implementation and the exploitation of the DSP architectural parallelism which critically enabled the Voice over Zigbee\napplication on the ultralow-power DSP platform. Another significant contribution of this work is towards understanding and\nresolving the challenges faced when trying to achieve good quality transmission of media over constrained devices and networks.\nThe way to new ultralow-power voice-related Zigbee and constrained network applications is open....
Every year around 200 million people are affected by hazards of different nature. In most of these situations public protection\nand disaster relief personnel are usually the first responders to provide help. To provide differential relief coverage in these\nscenarios, novel communication and network functionalities are being demanded, relegating todayâ??s narrowband private radio\n(PMR) emergency systems to the background.These are data-support, increased coverage, broadband communication, and high\nreliability which will be addressed by novel communication technologies such as Long Term Evolution (LTE), LTE Advanced-pro,\nand future 5G. In this work we tackle two key technological solutions for future emergency communication networks such as\nan architecture based on relay nodes and enhanced user equipment by means of multiple-input-multiple-output (MIMO) techniques....
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