The Experts below are selected from a list of 3330 Experts worldwide ranked by ideXlab platform

J D Gibson - One of the best experts on this subject based on the ideXlab platform.

  • Payload Length and rate adaptation for multimedia communications in wireless lans
    IEEE Journal on Selected Areas in Communications, 2007
    Co-Authors: Sayantan Choudhury, J D Gibson
    Abstract:

    We provide a theoretical framework for cross-layer design in multimedia communications to optimize single-user throughput by selecting the transmitted bit rate and Payload size as a function of channel conditions for both additive white Gaussian noise (AWGN) and Nakagami-m fading channels. Numerical results reveal that careful Payload Length adaptation significantly improves the throughput performance at low signal to noise ratios (SNRs), while at higher SNRs, rate adaptation with higher Payload Lengths provides better throughput performance. Since we are interested in multimedia applications, we do not allow retransmissions in order to minimize latency and to reduce congestion on the wireless link and we assume that packet loss concealment will be used to compensate for lost packets. We also investigate the throughput and packet error rate performance over multipath frequency selective fading channels for typical Payload sizes used in voice and video applications. We explore the difference in link adaptation thresholds for these Payload sizes using the Nafteli Chayat multipath fading channel model, and we present a link adaptation scheme to maximize the throughput subject to a packet error rate constraint.

  • effect of Payload Length variation and retransmissions on multimedia in 802 11a wlans
    International Conference on Wireless Communications and Mobile Computing, 2006
    Co-Authors: Sayantan Choudhury, Irfan Sheriff, J D Gibson, Elizabeth M Beldingroyer
    Abstract:

    Multimedia transmission over wireless local area networks is challenging due to the varying nature of the wireless channel as well as the inherent difference between multimedia and data traffic. In the MAC layer, a single bit error in the packet can lead to the entire packet being discarded. This results in a higher packet error rate for larger Payload sizes. Retransmission due to packet errors causes the contention window to double, and this leads to a decrease in throughput if the wireless channel does not improve for the retransmitted packets. Hence, throughput is a function of packet Payload Length as well as the maximum number of allowable retransmissions. In this paper, we investigate the effect of Payload Length adaptation and retransmissions on the throughput and capacity of multimedia users. Numerical results and simulations reveal that careful Payload adaptation significantly improves the throughput performance at low signal to noise ratios (SNRs). It is also observed that excessive retransmissions reduce the effective throughput, thereby decreasing the capacity of multimedia users in the presence of data users. Since multimedia traffic is more latency constrained and less error constrained, by carefully selecting the Payload Length and maximum number of allowable retransmissions based on the channel conditions, a greater number of multimedia users can be supported.

Luca Enini - One of the best experts on this subject based on the ideXlab platform.

  • nb iot versus lorawan an experimental evaluation for industrial applications
    IEEE Transactions on Industrial Informatics, 2020
    Co-Authors: Massimo Allerini, Tommaso Polonelli, Davide Unelli, Michele Magno, Luca Enini
    Abstract:

    Low power and long-range communications are crucial features of the Internet of Things (IoT) paradigm that is becoming essential even for industrial applications. Today, the most promising long-range communication technologies are LoRaWAN and Narrow Band IoT (NB-IoT), which are driving a large IoT ecosystem. In this article, we evaluate the performance of LoRaWAN and NB-IoT with accurate in-field measurements using the same application context for a fair comparison in terms of energy efficiency, lifetime, quality of service, and coverage. The NB-IoT energy transmission is scarcely dependent on the Payload Length. Thus applications that can tolerate buffering and caching techniques on the node are favored. On the other hand, LoRaWAN consumes 10 ×  lower energy compared to NB-IoT for occasional and latency-sensitive communications, for which it enables much end-device lifetime. Finally, this paper provides design guidelines for future industrial applications with stringent requirements of long-range and low power wireless connectivity.

  • experimental evaluation on nb iot and lorawan for industrial and iot applications
    International Conference on Industrial Informatics, 2019
    Co-Authors: Massimo Allerini, Tommaso Polonelli, Davide Unelli, Michele Magno, Luca Enini
    Abstract:

    Low power and long-range communications are essential features of the Internet of Things (IoT) paradigm that is becoming widespread across a spectrum of industrial applications. In this paper, we present performance evaluation of the most promising long-range communication technologies, namely LoRaWAN and NB-IoT. We present accurate in-field measurements using a monitoring application as a testbench for a fair comparison in terms of energy efficiency and lifetime. Experimental results highlight that NB-IoT Payload Length does not impact on transmission energy. Thus, applications that implement buffering and caching techniques are favored. On the other hand, LoRaWAN consumes 10× less energy to transmit a Payload equivalent to that of NB-IoT, thereby allowing longer end-device lifetime.

Sayantan Choudhury - One of the best experts on this subject based on the ideXlab platform.

  • Payload Length and rate adaptation for multimedia communications in wireless lans
    IEEE Journal on Selected Areas in Communications, 2007
    Co-Authors: Sayantan Choudhury, J D Gibson
    Abstract:

    We provide a theoretical framework for cross-layer design in multimedia communications to optimize single-user throughput by selecting the transmitted bit rate and Payload size as a function of channel conditions for both additive white Gaussian noise (AWGN) and Nakagami-m fading channels. Numerical results reveal that careful Payload Length adaptation significantly improves the throughput performance at low signal to noise ratios (SNRs), while at higher SNRs, rate adaptation with higher Payload Lengths provides better throughput performance. Since we are interested in multimedia applications, we do not allow retransmissions in order to minimize latency and to reduce congestion on the wireless link and we assume that packet loss concealment will be used to compensate for lost packets. We also investigate the throughput and packet error rate performance over multipath frequency selective fading channels for typical Payload sizes used in voice and video applications. We explore the difference in link adaptation thresholds for these Payload sizes using the Nafteli Chayat multipath fading channel model, and we present a link adaptation scheme to maximize the throughput subject to a packet error rate constraint.

  • effect of Payload Length variation and retransmissions on multimedia in 802 11a wlans
    International Conference on Wireless Communications and Mobile Computing, 2006
    Co-Authors: Sayantan Choudhury, Irfan Sheriff, J D Gibson, Elizabeth M Beldingroyer
    Abstract:

    Multimedia transmission over wireless local area networks is challenging due to the varying nature of the wireless channel as well as the inherent difference between multimedia and data traffic. In the MAC layer, a single bit error in the packet can lead to the entire packet being discarded. This results in a higher packet error rate for larger Payload sizes. Retransmission due to packet errors causes the contention window to double, and this leads to a decrease in throughput if the wireless channel does not improve for the retransmitted packets. Hence, throughput is a function of packet Payload Length as well as the maximum number of allowable retransmissions. In this paper, we investigate the effect of Payload Length adaptation and retransmissions on the throughput and capacity of multimedia users. Numerical results and simulations reveal that careful Payload adaptation significantly improves the throughput performance at low signal to noise ratios (SNRs). It is also observed that excessive retransmissions reduce the effective throughput, thereby decreasing the capacity of multimedia users in the presence of data users. Since multimedia traffic is more latency constrained and less error constrained, by carefully selecting the Payload Length and maximum number of allowable retransmissions based on the channel conditions, a greater number of multimedia users can be supported.

Massimo Allerini - One of the best experts on this subject based on the ideXlab platform.

  • nb iot versus lorawan an experimental evaluation for industrial applications
    IEEE Transactions on Industrial Informatics, 2020
    Co-Authors: Massimo Allerini, Tommaso Polonelli, Davide Unelli, Michele Magno, Luca Enini
    Abstract:

    Low power and long-range communications are crucial features of the Internet of Things (IoT) paradigm that is becoming essential even for industrial applications. Today, the most promising long-range communication technologies are LoRaWAN and Narrow Band IoT (NB-IoT), which are driving a large IoT ecosystem. In this article, we evaluate the performance of LoRaWAN and NB-IoT with accurate in-field measurements using the same application context for a fair comparison in terms of energy efficiency, lifetime, quality of service, and coverage. The NB-IoT energy transmission is scarcely dependent on the Payload Length. Thus applications that can tolerate buffering and caching techniques on the node are favored. On the other hand, LoRaWAN consumes 10 ×  lower energy compared to NB-IoT for occasional and latency-sensitive communications, for which it enables much end-device lifetime. Finally, this paper provides design guidelines for future industrial applications with stringent requirements of long-range and low power wireless connectivity.

  • experimental evaluation on nb iot and lorawan for industrial and iot applications
    International Conference on Industrial Informatics, 2019
    Co-Authors: Massimo Allerini, Tommaso Polonelli, Davide Unelli, Michele Magno, Luca Enini
    Abstract:

    Low power and long-range communications are essential features of the Internet of Things (IoT) paradigm that is becoming widespread across a spectrum of industrial applications. In this paper, we present performance evaluation of the most promising long-range communication technologies, namely LoRaWAN and NB-IoT. We present accurate in-field measurements using a monitoring application as a testbench for a fair comparison in terms of energy efficiency and lifetime. Experimental results highlight that NB-IoT Payload Length does not impact on transmission energy. Thus, applications that implement buffering and caching techniques are favored. On the other hand, LoRaWAN consumes 10× less energy to transmit a Payload equivalent to that of NB-IoT, thereby allowing longer end-device lifetime.

Yu-hsiang Cheng - One of the best experts on this subject based on the ideXlab platform.

  • Performance of LoRa-Based IoT Applications on Campus
    2017 IEEE 86th Vehicular Technology Conference (VTC-Fall), 2017
    Co-Authors: Shie-yuan Wang, Yo-ru Chen, Tzu-yang Chen, Chia-hung Chang, Yu-hsiang Cheng
    Abstract:

    To promote smart campus, National Chiao Tung University is deploying several location-based IoT applications based on wireless communications technologies including LoRa and NB-IoT. The applications are indoor/outdoor environment conditions monitoring (such as PM2.5, temperature, and humidity), emergency buttons, and so on. This paper uses PM2.5 measurement application as an example to present the performance of LoRa when it is used on campus. We investigated the LoRa transmission performance from LoRa end-devices to the LoRa gateway. We show how packet losses were affected by the distance between the end-device and the gateway, the transmit power, the Payload Length, the antenna angle, the time of day, and the weather conditions. The pattern of LoRa packet losses were also measured and we found that in our long-term PM2.5 monitoring application, more than 99% of LoRa packet losses occurred with three or less consecutive packet losses.