NB-IoT extends LTE by low power WAN functionality for IoT applications. Strengths of the standard lie in the already existing infrastructure, an ubiquitous availability, and the low power consumption and costs. NB-IoT...
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ISBN:
(纸本)9781728125176
NB-IoT extends LTE by low power WAN functionality for IoT applications. Strengths of the standard lie in the already existing infrastructure, an ubiquitous availability, and the low power consumption and costs. NB-IoT supports both TCP and UDP as transport protocols. However, TCP is sensitive to delays and packet losses during data transmission. This affects the commonly used messaging protocol MQTT, as it uses TCP as its underlying transport protocol. In this paper the role of UDP as a possible transport layer protocol for NB-IoT in conjunction with MQTT-SN is discussed and compared to TCP with standard MQTT. Using TCP for a typical NB-IoT application resulted in a packet loss of about 90%, whereas UDP achieved a packet loss of only around 3%. Additionally, the current state of NB-IoT installations in Germany and their functionality are evaluated. Coverage, signal quality and power saving functionality are monitored and analyzed as well.
In IoT scenario, a device can be deployed in a particular environment to serve a particular purpose. It can be any smart device acting as an integral part of any smart system deployed in any environment, which require...
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ISBN:
(纸本)9781728128894
In IoT scenario, a device can be deployed in a particular environment to serve a particular purpose. It can be any smart device acting as an integral part of any smart system deployed in any environment, which requires remote supervision. To facilitate on-demand remote control of such smart systems, from any public server, that sever must be able to propagate the required signal to the appropriate devices. But, these devices are not publicly addressable as they reside behind various Network Address Translators (NAT). These devices even have energy constraints as they are battery powered. Therefore, for such devices, maintaining a TCP connection or performing repeated polling to the public server is not an energy efficient solution. This paper proposes a scheme that facilitates the server to maintain a UDP connection to the client residing behind a NAT, by dynamic determination of that NAT's translation entry lifetime and by maintaining the translation entry on that NAT through periodic keep-alives from the Server. Thus leading to an energy efficient solution towards on-demand acquiring of sensing resources for IoT based cloud services.
The Constrained Application protocol (CoAP) is specifically designed for constrained IoT devices and is being rapidly deployed for the communication needs of the IoT devices. CoAP has been specified with its own conge...
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ISBN:
(纸本)9781538663592;9781538663585
The Constrained Application protocol (CoAP) is specifically designed for constrained IoT devices and is being rapidly deployed for the communication needs of the IoT devices. CoAP has been specified with its own congestion control algorithms because it runs on top of UDP that does not include any congestion control measures. These algorithms aim at taking into account the specific needs of the IoT communication. The need of running CoAP also over TCP has arised recently and is expected to be increasingly deployed alongside with CoAP over UDP. To understand the benefits and shortcomings of both CoAP over TCP and CoAP over UDP, we run an extensive set of experiments in different network settings and compare the performance of CoAP over TCP to the existing congestion control algorithms for CoAP over UDP. Our results reveal that even though CoAP over TCP has its known limitations it scales well and performs even better than expected in certain wireless settings that CoAP over UDP algorithms are specifically designed for, often even outperforming CoAP over UDP.
High resolution and dimensional hyperspectral data are required to develop high performance platforms for processing. FPGA provides a very effective approach for accelerating hyperspectral image analy
ISBN:
(纸本)9781467389808
High resolution and dimensional hyperspectral data are required to develop high performance platforms for processing. FPGA provides a very effective approach for accelerating hyperspectral image analy
Current networking devices are limited in their capabilities to dynamically adjust their behaviour with respect to the location changes induced by the mobility of communicating partners. This adversely affects the per...
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ISBN:
(纸本)9781509021949
Current networking devices are limited in their capabilities to dynamically adjust their behaviour with respect to the location changes induced by the mobility of communicating partners. This adversely affects the performance of applications running on top of IP-based wireless networks. Software Defined Networks (SDN) provide the strength of network programability which facilitates on-demand customization of underlying network according to the application context. In this paper, we propose our methodology for seamless mobility in IP-based Wi-Fi networks using SDN. Our solution works for both layer-2 and layer-3 mobility scenarios and is able to cater the needs of Wi-Fi networks. We have evaluated our approach with respect to handover delay, route establishment delay, data loss and throughput both for UDP and TCP traffic. Emulation results obtained establish the applicability of our approach.
Random Linear Network Coding (RLNC) theoretical results typically assume that packets have equal sizes while in reality, data traffic presents a random packet size distribution. Conventional wisdom considers zero-padd...
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Random Linear Network Coding (RLNC) theoretical results typically assume that packets have equal sizes while in reality, data traffic presents a random packet size distribution. Conventional wisdom considers zero-padding of original packets as a viable alternative, but its effect can reduce the efficiency of RLNC or other erasure coding techniques. Our goal is to characterize the overhead generated by this zero-padding under real-traffic traces. These include TCP and UDP traces from traffic at core routers from CAIDA and a collection of video traces for different codecs and video resolution compiled by Arizona State University. Our numerical results show the dependence of the zero-padding overhead with the number of packets combined in a generation using RLNC. Surprisingly, medium and large TCP generations are strongly affected with more than 100% of padding overhead. Although all video traces are affected, our results show that higher resolution video has a lower overhead, due in part to the fact that most of the transmitted data packets are of the maximum size of packet in the network.
Active Queue Management (AQM) mechanisms have come a long way, with an initial goal to avoid congestion to the recent most focus on reducing queue delay. The benefits of using AQM mechanisms at routers are being thoro...
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ISBN:
(纸本)9781509021949
Active Queue Management (AQM) mechanisms have come a long way, with an initial goal to avoid congestion to the recent most focus on reducing queue delay. The benefits of using AQM mechanisms at routers are being thoroughly studied nowadays, mainly to avoid the problem of bufferbloat. Although a lot of work has focused on analyzing the behavior of AQM mechanisms, the nature of traffic used while deriving inferences is mainly responsive (TCP), with small numbers of unresponsive flows (UDP) used in the background. The usage of UDP in internet has increased significantly in the recent past, owing to a great demand for time sensitive multimedia applications. Since UDP flows do not respond to congestion signals, controlling the queue length at routers by using AQM mechanisms becomes a non-trivial task. In this paper, we study the robustness of popular AQM mechanisms in the presence of a large number of unresponsive UDP flows using ns-2. Further, we provide guidelines to effectively tune the AQM knobs and enhance their robustness against non-responsive UDP flows.
HTTP has been the protocol for transferring web traffic over the internet since the 90s. However, over the past 20 years websites have evolved so much that today this protocol does not provide optimal delivery over th...
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ISBN:
(纸本)9781479966653
HTTP has been the protocol for transferring web traffic over the internet since the 90s. However, over the past 20 years websites have evolved so much that today this protocol does not provide optimal delivery over the internet and became a bottleneck in decreasing page load times. Google is pioneering in finding better solutions for downloading web pages and they implemented two new protocols: SPDY in 2009 and QUIC in 2013. Since the wide range deployment of SPDY clients and servers it has been revealed that in some scenarios SPDY can negatively affect the page transfer time mainly due to the fact that the protocol is working over TCP. To tackle these obstacles QUIC uses its own congestion control and based on UDP in the transport layer. Since QUIC is a very recent protocol, this paper could help further understand its operation and performance in a wide range of network scenarios. We present a comprehensive study about the performance of QUIC, SPDY and HTTP particularly about how they affect page load time. We found that none of these protocols is clearly better than the other two and the actual network conditions determine which protocol performs the best.
MQTT-SN offers energy efficient data transportation under unreliable wireless environment with limited energy/bandwidth. However, MQTT-SN faces a new set of challenges for service guarantees when operated for a reliab...
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ISBN:
(纸本)9781479963904
MQTT-SN offers energy efficient data transportation under unreliable wireless environment with limited energy/bandwidth. However, MQTT-SN faces a new set of challenges for service guarantees when operated for a reliable or time-critical applications. The impact of various network parameters on the MQTT-SN service assurance requires an end-to-end system study, which are unexplored yet. In this paper we analyze in detail about the end-to-end service assurance parameters such as content delivery delay and probability of content delivery for a MQTT-SN to be used in health care internet of Things (IoT). To model the end-to-end delay, various entities of the MQTT-SN including handshake messages in MQTT-SN Pub/sub architecture over TCP, over UDP and then the queuing delay involved in server have been considered. We model the MOTT content and request server as a round-robin queue scheduler and also model a TOPIC ID based matching station that delivers the content on requested TOPIC ID. With this model we derive the end-to-end content delivery probability and content delivery delay estimate as functions of MQTT-SN system parameters such as content arrival rate, request arrival rate, possession time of content in server, possession time of request in server, number of content arrivals and number of requests arrivals. Both these service assurance parameters will give more insight into the number of content/request arrivals that can be supported for a given service assurance requirement. In addition these service assurance parameters will be of help to design the system more effectively. We carry out a detailed ns2 based simulation to show impacts of various system parameters on the network performances for various QoS services designed for MQTT-SN system.
Recently, high-speed train is rapidly developed as a popular public transportation. How to provide passengers's broadband mobile communication services efficiently, such as voice over IP (VoIP) or other multimedia...
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ISBN:
(纸本)9781479959532
Recently, high-speed train is rapidly developed as a popular public transportation. How to provide passengers's broadband mobile communication services efficiently, such as voice over IP (VoIP) or other multimedia services, is receiving more and more attention. To fulfill the passenger's demand, we consider a heterogeneous network (HetNet) structure consisting track-side access points (TAPs) and cellular networks for the high-speed rail communication system (HRCS). End-to-end delay is one of the most important quality of service (QoS) indicators to evaluate the HetNet performance. Therefore, this paper investigates the joint end-to-end delay of VoIP and multimedia services in this HetNet architecture. Intermittent connectivity of TAPs and scheduling of multiple on-demand services are considered. In order to obtain the theoretic value of queueing delay bounds, we utilize the martingale theory by analyzing the Markov arrival processes. By combing the arrival-martingale and service-martingale concepts, the theoretic delay bounds under the first in first out (FIFO) scheduling scenario are obtained. For the simulation, we use three kinds of real wireless data traces, VoIP, gaming and UDP to evaluate our algorithm by using Nakagami fading channel and LTE fading channel. From the results we can see that the martingale end-to-end delay bounds are tight to the real data trace simulation results.
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