The impact of mobility models on the performance of mobile Ad Hoc network routing protocol

A mobility model represents nodes distribution and movement over the network. Several research works have shown that a selection of mobility model can affect the outcome of routing performance simulation in Mobile Ad Hoc Networks. Thus, a routing protocol may only be effective in a particular mobility model or scenario but performs inferiorly in another. As a result, analyses of routing protocol performance are often based on inadequate information leading to inaccurate argument and conclusion. In this paper, three different mobility models have been selected, where each of them is highly distinctive in terms of nodes movement behavior. In addition, a new measurement technique called probability of route connectivity is introduced. The technique is used to quantify the success rate of route established by a routing protocol. Extensive simulation runs are done and results are compared between each mobility model

Hybrid routing scheme for vehicular delay tolerant networks

In Vehicular Delay Tolerant Networks (VDTN) connection from source to destination at any required period is not necessarily available. Therefore, the node with the message, save it in its own buffer and carry it until an opportunity comes across for forwarding. Fix nodes enhances the performance of VDTN. It helps in message storage and relaying messages. Due to mobility the bit error rate is high in mobile nodes connection but it is not considered in any of the previous routing schemes for VDTN. The connection between fix nodes will always have low bit error rate as compared to connection involving mobile nodes. All the pervious schemes are one dimensional. Environmental hindrances are not taken under consideration as well. Its effect can be both negative and positive. In this paper, a scheme titled Hybrid routing scheme is suggested to overcome the above stated problems. Features of another vehicular network called Vehicular Ad Hoc Networks (VANETs) are added to Maximum Priority (MaxProp) routing scheme for VDTN. Different propagation models of VANETs are implemented for both with and without mobile node communication for VDTN. The concept of bit error rate is also featured in Hybrid routing scheme. This makes Hybrid routing scheme two dimensional and more intelligent. The implementation and performance assessment of the proposed scheme is evaluated via Opportunistic Network Environment (ONE) Simulator. The Hybrid routing scheme outperform MaxProp in terms of the delivery probability and delivery delay

Smart Relay Selection Scheme Based on Fuzzy Logic with Optimal Power Allocation and Adaptive Data Rate Assignment

In this paper fuzzy logic-based algorithm with improved process of relay selection is presented which not only allocate optimal power for transmission but also help in choosing adaptive data rate. This algorithm utilizes channel gain, cooperative gain and signal to noise ratio with two cases considered in this paper: In case-I nodes do not have their geographical location information while in case-II nodes are having their geographical location information. From Monte Carlo simulations, it can be observed that both cases improve the selection process along with data rate assignment and power allocation, but case-II is the most reliable with almost zero probability of error at the cost of computational complexity which is 10 times more than case-I

Spectral and Energy Efficient Low-Overhead Uplink and Downlink Channel Estimation for 5G Massive MIMO Systems

[EN] Uplink and Downlink channel estimation in massive Multiple Input Multiple Output (MIMO) systems is an intricate issue because of the increasing channel matrix dimensions. The channel feedback overhead using traditional codebook schemes is very large, which consumes more bandwidth and decreases the overall system efficiency. The purpose of this paper is to decrease the channel estimation overhead by taking the advantage of sparse attributes and also to optimize the Energy Efficiency (EE) of the system. To cope with this issue, we propose a novel approach by using Compressed-Sensing (CS), Block Iterative-Support-Detection (Block-ISD), Angle-of-Departure (AoD) and Structured Compressive Sampling Matching Pursuit (S-CoSaMP) algorithms to reduce the channel estimation overhead and compare them with the traditional algorithms. The CS uses temporal-correlation of time-varying channels to produce Differential-Channel Impulse Response (DCIR) among two CIRs that are adjacent in time-slots. DCIR has greater sparsity than the conventional CIRs as it can be easily compressed. The Block-ISD uses spatial-correlation of the channels to obtain the block-sparsity which results in lower pilot-overhead. AoD quantizes the channels whose path-AoDs variation is slower than path-gains and such information is utilized for reducing the overhead. S-CoSaMP deploys structured-sparsity to obtain reliable Channel-State-Information (CSI). MATLAB simulation results show that the proposed CS based algorithms reduce the feedback and pilot-overhead by a significant percentage and also improve the system capacity as compared with the traditional algorithms. Moreover, the EE level increases with increasing Base Station (BS) density, UE density and lowering hardware impairments level.This research work is supported by Hankuk University of Foreign Studies research fund 2017.Khan, I.; Zafar, MH.; Jan, MT.; Lloret, J.; Basheri, M.; Singh, D. (2018). Spectral and Energy Efficient Low-Overhead Uplink and Downlink Channel Estimation for 5G Massive MIMO Systems. Entropy. 20(2). doi:10.3390/e20020092S20

Global, regional, and national incidence, prevalence, and years lived with disability for 354 diseases and injuries for 195 countries and territories, 1990–2017: A systematic analysis for the Global Burden of Disease Study 2017

Background: The Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017) includes a comprehensive assessment of incidence, prevalence, and years lived with disability (YLDs) for 354 causes in 195 countries and territories from 1990 to 2017. Previous GBD studies have shown how the decline of mortality rates from 1990 to 2016 has led to an increase in life expectancy, an ageing global population, and an expansion of the non-fatal burden of disease and injury. These studies have also shown how a substantial portion of the world's population experiences non-fatal health loss with considerable heterogeneity among different causes, locations, ages, and sexes. Ongoing objectives of the GBD study include increasing the level of estimation detail, improving analytical strategies, and increasing the amount of high-quality data. Methods: We estimated incidence and prevalence for 354 diseases and injuries and 3484 sequelae. We used an updated and extensive body of literature studies, survey data, surveillance data, inpatient admission records, outpatient visit records, and health insurance claims, and additionally used results from cause of death models to inform estimates using a total of 68 781 data sources. Newly available clinical data from India, Iran, Japan, Jordan, Nepal, China, Brazil, Norway, and Italy were incorporated, as well as updated claims data from the USA and new claims data from Taiwan (province of China) and Singapore. We used DisMod-MR 2.1, a Bayesian meta-regression tool, as the main method of estimation, ensuring consistency between rates of incidence, prevalence, remission, and cause of death for each condition. YLDs were estimated as the product of a prevalence estimate and a disability weight for health states of each mutually exclusive sequela, adjusted for comorbidity. We updated the Socio-demographic Index (SDI), a summary development indicator of income per capita, years of schooling, and total fertility rate. Additionally, we calculated differences between male and female YLDs to identify divergent trends across sexes. GBD 2017 complies with the Guidelines for Accurate and Transparent Health Estimates Reporting. Findings: Globally, for females, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and haemoglobinopathies and haemolytic anaemias in both 1990 and 2017. For males, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and tuberculosis including latent tuberculosis infection in both 1990 and 2017. In terms of YLDs, low back pain, headache disorders, and dietary iron deficiency were the leading Level 3 causes of YLD counts in 1990, whereas low back pain, headache disorders, and depressive disorders were the leading causes in 2017 for both sexes combined. All-cause age-standardised YLD rates decreased by 3·9% (95% uncertainty interval [UI] 3·1-4·6) from 1990 to 2017; however, the all-age YLD rate increased by 7·2% (6·0-8·4) while the total sum of global YLDs increased from 562 million (421-723) to 853 million (642-1100). The increases for males and females were similar, with increases in all-age YLD rates of 7·9% (6·6-9·2) for males and 6·5% (5·4-7·7) for females. We found significant differences between males and females in terms of age-standardised prevalence estimates for multiple causes. The causes with the greatest relative differences between sexes in 2017 included substance use disorders (3018 cases [95% UI 2782-3252] per 100 000 in males vs 1400 [1279-1524] per 100 000 in females), transport injuries (3322 [3082-3583] vs 2336 [2154-2535]), and self-harm and interpersonal violence (3265 [2943-3630] vs 5643 [5057-6302]). Interpretation: Global all-cause age-standardised YLD rates have improved only slightly over a period spanning nearly three decades. However, the magnitude of the non-fatal disease burden has expanded globally, with increasing numbers of people who have a wide spectrum of conditions. A subset of conditions has remained globally pervasive since 1990, whereas other conditions have displayed more dynamic trends, with different ages, sexes, and geographies across the globe experiencing varying burdens and trends of health loss. This study emphasises how global improvements in premature mortality for select conditions have led to older populations with complex and potentially expensive diseases, yet also highlights global achievements in certain domains of disease and injury

Global, regional, and national age-sex-specific mortality and life expectancy, 1950-2017: a systematic analysis for the Global Burden of Disease Study 2017

Background: Assessments of age-specific mortality and life expectancy have been done by the UN Population Division, Department of Economics and Social Affairs (UNPOP), the United States Census Bureau, WHO, and as part of previous iterations of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD). Previous iterations of the GBD used population estimates from UNPOP, which were not derived in a way that was internally consistent with the estimates of the numbers of deaths in the GBD. The present iteration of the GBD, GBD 2017, improves on previous assessments and provides timely estimates of the mortality experience of populations globally. Methods: The GBD uses all available data to produce estimates of mortality rates between 1950 and 2017 for 23 age groups, both sexes, and 918 locations, including 195 countries and territories and subnational locations for 16 countries. Data used include vital registration systems, sample registration systems, household surveys (complete birth histories, summary birth histories, sibling histories), censuses (summary birth histories, household deaths), and Demographic Surveillance Sites. In total, this analysis used 8259 data sources. Estimates of the probability of death between birth and the age of 5 years and between ages 15 and 60 years are generated and then input into a model life table system to produce complete life tables for all locations and years. Fatal discontinuities and mortality due to HIV/AIDS are analysed separately and then incorporated into the estimation. We analyse the relationship between age-specific mortality and development status using the Socio-demographic Index, a composite measure based on fertility under the age of 25 years, education, and income. There are four main methodological improvements in GBD 2017 compared with GBD 2016: 622 additional data sources have been incorporated; new estimates of population, generated by the GBD study, are used; statistical methods used in different components of the analysis have been further standardised and improved; and the analysis has been extended backwards in time by two decades to start in 1950. Findings: Globally, 18·7% (95% uncertainty interval 18·4–19·0) of deaths were registered in 1950 and that proportion has been steadily increasing since, with 58·8% (58·2–59·3) of all deaths being registered in 2015. At the global level, between 1950 and 2017, life expectancy increased from 48·1 years (46·5–49·6) to 70·5 years (70·1–70·8) for men and from 52·9 years (51·7–54·0) to 75·6 years (75·3–75·9) for women. Despite this overall progress, there remains substantial variation in life expectancy at birth in 2017, which ranges from 49·1 years (46·5–51·7) for men in the Central African Republic to 87·6 years (86·9–88·1) among women in Singapore. The greatest progress across age groups was for children younger than 5 years; under-5 mortality dropped from 216·0 deaths (196·3–238·1) per 1000 livebirths in 1950 to 38·9 deaths (35·6–42·83) per 1000 livebirths in 2017, with huge reductions across countries. Nevertheless, there were still 5·4 million (5·2–5·6) deaths among children younger than 5 years in the world in 2017. Progress has been less pronounced and more variable for adults, especially for adult males, who had stagnant or increasing mortality rates in several countries. The gap between male and female life expectancy between 1950 and 2017, while relatively stable at the global level, shows distinctive patterns across super-regions and has consistently been the largest in central Europe, eastern Europe, and central Asia, and smallest in south Asia. Performance was also variable across countries and time in observed mortality rates compared with those expected on the basis of development. Interpretation: This analysis of age-sex-specific mortality shows that there are remarkably complex patterns in population mortality across countries. The findings of this study highlight global successes, such as the large decline in under-5 mortality, which reflects significant local, national, and global commitment and investment over several decades. However, they also bring attention to mortality patterns that are a cause for concern, particularly among adult men and, to a lesser extent, women, whose mortality rates have stagnated in many countries over the time period of this study, and in some cases are increasing

Multipath routing and quality of service support for mobile ad hoc networks

Mobile Ad hoc Networks (MANETs) are a key part of the ongoing evolution of wireless communications. MANETs are a collection of wireless mobile nodes that dynamically form a temporary wireless network without an infrastructure. The design of an efficient and reliable routing scheme and Quality of Service (QoS) support for MANETs is a major challenge. Unlike traditional routing schemes that seek only single path, multipath routing allows the establishment of multiple paths for routing between a source-destination pair. Multipath routing exploits the resource redundancy and diversity in the underlying network to provide benefits such as fault tolerance, load balancing, capacity aggregation and the improvement in QoS metrics such as delay. In the first part of the thesis, a multipath routing scheme, referred to as Shortest Multipath Source (SMS) routing based on Dynamic Source Routing (DSR) protocol is proposed. The mechanism has two novel aspects compared to other on-demand multipath routing schemes: it achieves shorter multiple partial-disjoint paths and allows more rapid recovery from route breaks. This scheme addresses the problem of wireless broadcast storms by simple hop count mechanism. The performance differentials are investigated using Network Simulator version 2 (NS-2). Results show the superiority of SMS under certain scenarios in terms of goodput of up to 85% and end-to-end delay of up to 99% when compared to the competing schemes. Although SMS is designed to find multiple shorter routes, these routes have no information about the network traffic or application requirements. The second aspect of the thesis addresses QoS support. Two novel capacity-constrained routing schemes based on SMS, which allow nodes to depend on their estimation of the residual capacity to make correct admission control decisions, are presented. The performance evaluation demonstrates the merits of the proposed schemes with a 20% increase in goodput while end-to-end delay is reduced by 47% and the necessity of QoS-aware multipath routing schemes in Mobile Ad hoc Networks becomes more apparent.Mobile Ad hoc Networks (MANETs) are a key part of the ongoing evolution of wireless communications. MANETs are a collection of wireless mobile nodes that dynamically form a temporary wireless network without an infrastructure. The design of an efficient and reliable routing scheme and Quality of Service (QoS) support for MANETs is a major challenge. Unlike traditional routing schemes that seek only single path, multipath routing allows the establishment of multiple paths for routing between a source-destination pair. Multipath routing exploits the resource redundancy and diversity in the underlying network to provide benefits such as fault tolerance, load balancing, capacity aggregation and the improvement in QoS metrics such as delay. In the first part of the thesis, a multipath routing scheme, referred to as Shortest Multipath Source (SMS) routing based on Dynamic Source Routing (DSR) protocol is proposed. The mechanism has two novel aspects compared to other on-demand multipath routing schemes: it achieves shorter multiple partial-disjoint paths and allows more rapid recovery from route breaks. This scheme addresses the problem of wireless broadcast storms by simple hop count mechanism. The performance differentials are investigated using Network Simulator version 2 (NS-2). Results show the superiority of SMS under certain scenarios in terms of goodput of up to 85% and end-to-end delay of up to 99% when compared to the competing schemes. Although SMS is designed to find multiple shorter routes, these routes have no information about the network traffic or application requirements. The second aspect of the thesis addresses QoS support. Two novel capacity-constrained routing schemes based on SMS, which allow nodes to depend on their estimation of the residual capacity to make correct admission control decisions, are presented. The performance evaluation demonstrates the merits of the proposed schemes with a 20% increase in goodput while end-to-end delay is reduced by 47% and the necessity of QoS-aware multipath routing schemes in Mobile Ad hoc Networks becomes more apparent

Improved End-to-end service assurance and mathematical modeling of message queuing telemetry transport protocol based massively deployed fully functional devices in smart cities

QoS is an arguable feature of Message Queuing Telemetry Transport Protocol (MQTT) that is employed under constrained environment for communication over an unreliable network in smart cities. It gives extra control to the client for matching its needs according to the application but with confiscated network performance. For a reliable end-to-end service assurance, guaranteed QoS and controlled scalability, MQTT based IoT must be examined for various network parameters. In this work, an improved TCP based transparent MQTT network is proposed for massively deployed connected devices in smart cities. The mathematical modeling is carried out by analyzing end-to-end quality assurance. Network latency, content delivery rate, number of subscribe/publish requests and services offered by the MQTT broker for various topic IDs are then verified on physical network. These parameters are examined over a transparent gateway-based network for verifying the agreement of devised probability based mathematical model with the actual content delivery, service rate and request hold time at virtual machine based MQTT broker, local network broker and remote server respectively. The Improved MQTT model surpasses Apollo, RabbitMQ and Mosquitto server by evidencing the message queueing delay of 3.5 ms for QoS-0 and 3.6 ms for QoS-1 service IoT

Efficient Routing Scheme for Unidirectional links in Multi-hop Networks

This paper presents an efficient routing scheme for Multi-hop Network in the presence of unidirectional links. The distinct feature of this routing scheme is the capability to actively provide routing paths even though a large number of unidirectional links are present in the network. The results depicts that the routing scheme is able to reduce the delay and routing overhead compared with the already available routing scheme like AODV and AODV-Blacklist. The performance of proposed routing scheme called Active Reverse Route (ARR) scheme is compared with AODV and AODV-Blacklist routing protocols in Multi-hop networks. The performance analysis when compared with the three routing protocols to manage unidirectional links shows that our proposed ARR scheme is superior to the AODV and AODV-Blacklist

An efficient resource optimization scheme for D2D communication

With the rapid development of wireless technologies, wireless access networks have entered their Fifth-Generation (5G) system phase. The heterogeneous and complex nature of a 5G system, with its numerous technological scenarios, poses significant challenges to wireless resource management, making radio resource optimization an important aspect of Device-to-Device (D2D) communication in such systems. Cellular D2D communication can improve spectrum efficiency, increase system capacity, and reduce base station communication burdens by sharing authorized cell resources; however, can also cause serious interference. Therefore, research focusing on reducing this interference by optimizing the configuration of shared cellular resources has also grown in importance. This paper proposes a novel algorithm to address the problems of co-channel interference and energy efficiency optimization in a long-term evolution network. The proposed algorithm uses the fuzzy clustering method, which employs minimum outage probability to divide D2D users into several groups in order to improve system throughput and reduce interference between users. An efficient power control algorithm based on game theory is also proposed to optimize user transmission power within each group and thereby improve user energy efficiency. Simulation results show that these proposed algorithms can effectively improve system throughput, reduce co-channel interference, and enhance energy efficiency