Correct and Control Complex IoT Systems: Evaluation of a Classification for System Anomalies

In practice there are deficiencies in precise interteam communications about system anomalies to perform troubleshooting and postmortem analysis along different teams operating complex IoT systems. We evaluate the quality in use of an adaptation of IEEE Std. 1044-2009 with the objective to differentiate the handling of fault detection and fault reaction from handling of defect and its options for defect correction. We extended the scope of IEEE Std. 1044-2009 from anomalies related to software only to anomalies related to complex IoT systems. To evaluate the quality in use of our classification a study was conducted at Robert Bosch GmbH. We applied our adaptation to a postmortem analysis of an IoT solution and evaluated the quality in use by conducting interviews with three stakeholders. Our adaptation was effectively applied and interteam communications as well as iterative and inductive learning for product improvement were enhanced. Further training and practice are required.Comment: Submitted to QRS 2020 (IEEE Conference on Software Quality, Reliability and Security

Sleep Period Optimization Model For Layered Video Service Delivery Over eMBMS Networks

Long Term Evolution-Advanced (LTE-A) and the evolved Multimedia Broadcast Multicast System (eMBMS) are the most promising technologies for the delivery of highly bandwidth demanding applications. In this paper we propose a green resource allocation strategy for the delivery of layered video streams to users with different propagation conditions. The goal of the proposed model is to minimize the user energy consumption. That goal is achieved by minimizing the time required by each user to receive the broadcast data via an efficient power transmission allocation model. A key point in our system model is that the reliability of layered video communications is ensured by means of the Random Linear Network Coding (RLNC) approach. Analytical results show that the proposed resource allocation model ensures the desired quality of service constraints, while the user energy footprint is significantly reduced.Comment: Proc. of IEEE ICC 2015, Selected Areas in Communications Symposium - Green Communications Track, to appea

Satellite-aided mobile communications limited operational test in the trucking industry

An experiment with NASA's ATS-6 satellite, that demonstrates the practicality of satellite-aided land mobile communications is described. Satellite communications equipment for the experiment was designed so that it would be no more expensive, when mass produced, than conventional two-way mobile radio equipment. It embodied the operational features and convenience of present day mobile radios. Vehicle antennas 75 cm tall and 2 cm in diameter provided good commercial quality signals to and from trucks and jeeps. Operational applicability and usage data were gathered by installing the radio equipment in five long-haul tractor-trailer trucks and two Air Force search and rescue jeeps. Channel occupancy rates are reported. Air Force personnel found the satellite radio system extremely valuable in their search and rescue mission during maneuvers and actual rescue operations. Propagation data is subjectively analyzed and over 4 hours of random data is categorized and graded as to signal quality on a second by second basis. Trends in different topographic regions are reported. An overall communications reliability of 93% was observed despite low satellite elevation angles ranging from 9 to 24 degrees

On Interference Cancellation and Iterative Techniques

Recent research activities in the area of mobile radio communications have moved to third generation (3G) cellular systems to achieve higher quality with variable transmission rate of multimedia information. In this paper, an overview is presented of various interference cancellation and iterative detection techniques that are believed to be suitable for 3G wireless communications systems. Key concepts are space-time processing and space-division multiple access (or SDMA) techniques. SDMA techniques are possible with software antennas. Furthermore, to reduce receiver implementation complexity, iterative detection techniques are considered. A particularly attractive method uses tentative hard decisions, made on the received positions with the highest reliability, according to some criterion, and can potentially yield an important reduction in the computational requirements of an iterative receiver, with minimum penalty in error performance. A study of the tradeoffs between complexity and performance loss of iterative multiuser detection techniques is a good research topic

Supervised Collective Classification for Crowdsourcing

Crowdsourcing utilizes the wisdom of crowds for collective classification via information (e.g., labels of an item) provided by labelers. Current crowdsourcing algorithms are mainly unsupervised methods that are unaware of the quality of crowdsourced data. In this paper, we propose a supervised collective classification algorithm that aims to identify reliable labelers from the training data (e.g., items with known labels). The reliability (i.e., weighting factor) of each labeler is determined via a saddle point algorithm. The results on several crowdsourced data show that supervised methods can achieve better classification accuracy than unsupervised methods, and our proposed method outperforms other algorithms.Comment: to appear in IEEE Global Communications Conference (GLOBECOM) Workshop on Networking and Collaboration Issues for the Internet of Everythin

Reliability-Latency-Rate Tradeoff in Low-Latency Communications with Finite-Blocklength Coding

Low-latency communication plays an increasingly important role in delay-sensitive applications by ensuring the real-time exchange of information. However, due to the constraints on the maximum instantaneous power, bounded latency is hard to be guaranteed. In this paper, we investigate the reliability-latency-rate tradeoff in low-latency communications with finite-blocklength coding (FBC). More specifically, we are interested in the fundamental tradeoff between error probability, delay-violation probability (DVP), and service rate. Based on the effective capacity (EC) and normal approximation, we present several gain-conservation inequalities to bound the reliability-latency-rate tradeoffs. In particular, we investigate the low-latency transmissions over an additive white Gaussian noise (AWGN) channel, over a Rayleigh fading channel, with frequency or spatial diversity, and over a Nakagami-$m$ fading channel. To analytically evaluate the quality-of-service-constrained low-latency communications with FBC, an EC-approximation method is further conceived to derive the closed-form expression of quality-of-service-constrained throughput. For delay-sensitive transmissions in which the latency threshold is greater than the channel coherence time, we find an asymptotic form of the tradeoff between the error probability and DVP over the AWGN and Rayleigh fading channels. Our results may provide some insights into the efficient scheduling of low-latency wireless communications in which statistical latency and reliability metrics are adopted.Comment: Submitted to IEEE Trans. Inf. Theor

Marisat -A New Commercial Application Of Communications Satellite Technolgy

A new type of commercial satellite communications system called MARISAT is in its final stages of deployment for operational service beginning this year. This system will provide two different communications services by using two different types of communications repeaters on a single satellite. One service is dedicated to U.S. Navy requirements; the second service is the first commercial offering of maritime mobile satellite communications. Through this latter service the quality and reliability of commercial satellite communications will be extended to ships operating on the high seas. This will be the first step in the evolution of an international global maritime satellite communications system. This paper summarizes the composition and design of the MARISAT System and gives a progress report on the status of its development and deployment

Multihop Diversity for Fading Mitigation in Multihop Wireless Networks

The concept of multihop diversity is proposed, where all the nodes of a multihop link are assumed to have buffers for temporarily storing their received packets. During each time-slot, the best hop having, for example, the highest signal-to-noise ratio (SNR), is selected from the set of those hops that have packets awaiting transmission in the buffer. The packet is then transmitted over the best hop. This hop-selection procedure yields selection diversity, but it requires the global channel knowledge of the hops’ channel quality. In this paper, we assume having perfect channel knowledge and focus our attention on the principles and performance bounds of the error probability and outage probability. Our studies show that relying on multiple hops has the potential of providing a significant diversity gain, which may be exploited for enhancing the reliability of wireless multihop communications