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LoRa WAN (Long range wide area network) performance in IoT (Internet of Things) tends to be an effective communication at low power and less cost. It assists all the nodes to interrelate within a range of 5 km if received signal strength is up to − 154 dBm. The calculated link budget of LoRa WAN predict LOS/ NLOS signal in the range of less than − 154 dBm at path loss of maximum 160 dB. Path loss of a signal is calculated with standard model and area specific path loss model is proposed. The real time analysis based on received signal strength resulted a standard deviation of signal in the range of 11.8 dB for a fading environment. Path loss with standard models in deep fading areas varies in between 200 and 360 dB. Area specific path loss model for free space is proposed within the range of LoRa WAN and it varies between 100 and 154 dB. The outage in deep fading area tends to deep almost 80% at 1 km range and data transfer rate is about 17 % at 3 dB noise figure. The received parameters are also compared with LTE and GSM networks which operate at L band frequency. [ABSTRACT FROM AUTHOR]

The effective performance of LTE network is analyzed using signal strength measurements in fading environments. It is one of the primary experimental methodologies for planning and designing a cellular network for given coverage area. In this paper, we present the divergence of path loss between two environments i.e. indoor and outdoor and its effect on coverage and capacity very effectively. The received signal strength and data transfer rate is analyzed at different locations for user's satisfaction. Standard deviation of signal with path loss exponents are calculated based on received signal strength in the operating network areas. It is in the range of 4 to 5.3 in the vicinity of entire urban areas. Path loss using indoors and outdoors model were analyzed effectively and presented. Based on the received signal strength a new path loss model is proposed to meet the requirements of current environment for tuning the path loss model. It is also suggested that, the removal of permanent object within the vicinity of 200 m in front of antenna is considerably a better solution of propagation of signal. The improvement of 27 dBm signal strength around 14 km area is presented with well-installed network if antenna is free from clutter zone. The analyzed parameter may be very effective for 5G communication considering a future network of this era. [ABSTRACT FROM AUTHOR]

A modified path loss prediction model for deep fading area is presented and compared with standard indoor path loss model. An academician perspective, it may not be feasible to design a network for its maximum capacity & coverage under deep fading environment. The above facts reveals us to carry out real time analysis of network using advance set up and predict minimum detectable signal in deep fading area. In this paper, monitoring of signal at different frequency and power under deep fading condition is carried out to check and access the reality of signal variation. The temporal variation of signal is recorded continuously to check the minimum availability of signalfor mathematical analysis. The statistical analysis on recorded data provides large variation in standard deviation (13.16 to 17.25 dB) and the path loss exponent tends to a new value of 4.8. The received signal strength for LTE network goes beyond − 74 to − 103 dBm.Path loss at different frequency, power and distance is calculated using ITU model, Log Distance model and new model is proposed for fading area. The large variation in path loss (9 to 283 dB) for different networks is plotted for fading area under study.The improvement of signal strength was observed slightly by 10 dBm when base station antenna was down tilted by − 20. The change in signal strength after down tilting the antenna is also recorded and presented. Such small increment in signal strength may allow network to provide better connectivity in fading area with good quality of service (QoS). [ABSTRACT FROM AUTHOR]

Particle swarm optimization (PSO) is a dynamic nature-influenced optimization technique. PSO optimization technique can resolve the best solution in minimum iterations and operates more effectively and efficiently. But, the other optimization techniques like particle swarm optimization with passive congregation (PSOPC) technique and dissipative particle swarm optimization (DPSO) technique gives better solution in fewer iterations as compared to PSO. In this paper, the distance between swarms is optimized and compared to all the optimization techniques. Simulation results demonstrate that the PSOPC optimization technique delivers better results than the PSO and DPSO optimization techniques. [ABSTRACT FROM AUTHOR]

C-V2X (Cellular Vehicle-to-Everything) standard introduced in 3GPP Release-14 is emerging as a potential technology for Cooperative Awareness Message (CAMs) dissemination among connected vehicles. But to attain its full potential, optimal resource scheduling and interference management must be enforced. To address this issue, we propose a weighted exponential averaging based Context-Aware Resource Reselection scheme (CARRs), enabling the periodic exchange of CAMs in a vehicular network. The proposed strategy allows autonomous resource selection by performing continuous power sensing and cooperative learning with the neighbors within the safety zone. CARRs is a two-stage learning process. In the first stage, it learns the exponential weighing factor for each resource available in the Vehicle-to-Vehicle resource pool and performs resource reselection. In the second stage, it learns to select transmit power level based on the interference experienced over the reselected resource. It is established through numerical results that CARRs outperforms the existing strategies. Packet reception ratio, average error rate, average blocking rate and update delay are considered as the performance metrics. CARRs improves packet reception ratio by 3.1% while reducing the average error rate by 28.2% and lowering update delay by 4.5% in comparison to existing schemes. [ABSTRACT FROM AUTHOR]

In Internet of Things (IoT), the massive connectivity of devices and enormous data on the air have made information susceptible to different type of attacks. Cryptographic algorithms are used to provide confidentiality and maintain the integrity of the information. But small size, limited computational capability, limited memory, and power resources of the devices make it difficult to use the resource intensive traditional cryptographic algorithms for information security. In this scenario it becomes impertinent to develop lightweight security schemes for IoT. A thorough study on the lightweight cryptography as a solution to the security problem of resource-constrained devices in IoT has been presented in this work. This paper is a comprehensive attempt to provide an in-depth and state of the art survey of available lightweight cryptographic primitives till 2019. In this paper 21 lightweight block ciphers, 19 lightweight stream ciphers, 9 lightweight hash functions and 5 variants of elliptic curve cryptography (ECC) has been discussed i.e. in total 54 LWC primitives are compared in their respective classes. The comparison of the ciphers has been carried out in terms of chip area, energy and power, hardware and software efficiency, throughput, latency and figure of merit (FoM). Based on the findings it can be observed that AES and ECC are the most suitable for used lightweight cryptographic primitives. Several open research problems in the field of lightweight cryptography have also been identified. [ABSTRACT FROM AUTHOR]

Since the advent of 1G through 5G networks, telecommunication industry has gone through phenomenal transformation in the way we communicate, we work, and we socialize. In dense or ultra-dense mobile communication networks, the users are very frequently handed over to other cells making seamless mobility a challenging and complex problem. Therefore, robust connectivity in such networks becomes a very critical issue. In this paper, we present a data-driven handover optimization approach aiming to mitigate the mobility problems including handover delay, early handover, wrong selection of target cell and frequent handover. The proposal is based on collecting the information from the network and developing a model to determine the relationship between the features drawn from the collected dataset and key performance indicator (KPI) expressed as the weighted average of mobility problem ratios. Handover design parameters- time to trigger and handover margin are optimized to improve KPI. The KPI estimation drawn on time to trigger and hysteresis margin design parameters is estimated through neural network multilayer perception method. It is established through simulation results that the proposed approach yields significantly improved handover performance mitigating mobility problem in ultra-dense cellular networks to notable extent. [ABSTRACT FROM AUTHOR]

Device-to-Device (D2D) communication is seen as a promising technology to offload exponentially increasing cellular data traffic. This also enhances spectral and energy efficiency of the cellular network. However, co-channel interference restricts the potential gain of Underlay-D2D (U-D2D) communication technology. In this paper, we propose a novel resource allocation scheme coupled with distributed power control strategy to reduce co-channel interference and improve overall system sum rate. Resource allocation is based on overlapping coalition formation game model. Overlapping coalitions allow a single D2D pair to utilize multiple resource blocks, which provides enhanced transmission bandwidth per user. But, this improved bandwidth is achieved at the cost of increased co-channel interference. The proposed scheme mitigates this problem by distributed control of D2D transmit power in accordance with the interference sensed on each resource block allocated for that particular D2D pair. It is shown through numerical results that there is a significant improvement in overall U-D2D system performance in terms of system sum rate and D2D transmission ratio in comparison with other existing techniques. [ABSTRACT FROM AUTHOR]

In wireless sensor networks (WSNs), thousands of sensor nodes are deployed to measure various environmental parameters such as temperature, light intensity, humidity and air pressure. All living beings can sense the variation in these parameters; therefore, these parameters are termed as natural signals. The natural signals are highly correlated in time and space; therefore, it can be compressed significantly to achieve the low sampling rates. The correlation property of natural signals is exploited here to compress/decompress these signals for reducing the transmission cost of the networks. The real-time temperature signal is measured using national instruments (NI) WSN platform, which is used for analysis purpose. The signal at first is transformed into sparse signal and then compressed. The compressed signal is transmitted to the receiver, where it is decoded into original sparse signal using algorithms based on greedy iterative approaches, i.e. orthogonal matching pursuit (OMP), stagewise orthogonal matching pursuit (StOMP) and generalized OMP (gOMP). The most popular greedy algorithm, OMP, is compared with StOMP and gOMP. The performance is analysed quantitatively in terms of peak signal-to-noise ratio, root- mean-squared error and execution speed of these greedy algorithms. It is demonstrated through simulation, the computational speed of StOMP and gOMP is much better than OMP, and also, the sparse signal is recovered with accuracy approximately equal to OMP. [ABSTRACT FROM AUTHOR]

Numerous wireless communication technologies have been employed to manage mobile users anywhere, any time and anyhow. Additionally, users are more and more fascinated by multimedia applications such as voice, audio and video, which require Quality of Service (QoS) support. To retain the user with Always Best Connected network in such restrictions is a challenging issue. A contemporary approach for efficient network selection in wireless heterogeneous networks is conferred. The approach composed of two criteria: the first is the cost function comprising of received signal strength, available bit rate, signal to noise ratio, throughput and bit error rate metrics. The metrics' respective weights are being optimized by Particle Swarm Optimization (PSO). The second criterion consists of fuzzy logic system fed with similar metrics as inputs and targeted towards same output. The final decision of network selection is taken by the blend of these two criteria. Simulation results indicated that the proposed scheme based on Cost function, PSO and Fuzzy system (C-P-F) provided better performance in terms of minimizing the unnecessary handoffs (network selection rate), utility degree and load balancing. The proposed algorithm (C-P-F) significantly reduces the network selection rate by 50% as compared to existing algorithm based on cost function and PSO. This reduction indicated higher probability of guaranteed session continuity and good quality of the currently running service, which resulted in high user satisfaction levels. It enhances user satisfaction 55% and reduced network selection rate upto 75% in comparison of existing network selection techniques. [ABSTRACT FROM AUTHOR]

Cooperation among different cognitive radios is used to enhance the sensing performance by exploiting the multiuser diversity. Soft and Hard decision fusion schemes are usually employed at the fusion center to detect the presence or absence of primary user. Soft decision fusion schemes perform better than hard fusion schemes but at the cost of increased bandwidth burden on the control channel. In this context, we propose a semi-soft fusion scheme to achieve a tradeoff between sensing performance and bandwidth cost. Under this scheme, each cognitive radio makes a local decision and sends one or two-bit data to the fusion center based on the observed test statistics. On the basis of received data, fusion center estimates the global test statistics which are then compared to a predetermined threshold to make the final decision. Furthermore, a closed form expression for average bandwidth cost for the proposed scheme is also derived. MATLAB simulation demonstrates that the performance of the proposed semi-soft fusion approaches to that of soft fusion scheme with a remarkable reduction in the bandwidth cost of control channel. [ABSTRACT FROM AUTHOR]

In this paper, we have investigated different vulnerabilities in RC4 and its enhanced variants to overcome the security attacks. It is established that in spite of several proposals, RC4 is not secure enough and a trade-off is always sought between security and network performance for overall provisioning of the secure communication. The main goal of the work presented in this paper is the optimization of security-performance tradeoff. We have proposed three RC4 variants referred to as RC4-M1, RC4-M2 and RC4-M3. Security of the proposed schemes is analyzed in terms of randomness and computational complexity. All the proposed variants qualify the NIST statistical test suite of randomness satisfactorily. The proposed schemes also offer computational complexity in terms of greater number of operations relative to the existing variants. The strength of the proposed schemes has been analyzed against different cryptanalytic attempts and shown the resistance of proposed schemes against attacks. The security-performance tradeoff has been analyzed in terms of run time, CPU cycles consumed, energy cost, and throughput. Encryption time of the proposed schemes-RC4-M1, RC4-M2 and RC4-M3 is 30.1, 10 and 48.7 % less as compared to RC4+ respectively. The results clearly indicate that the computation load of the proposed variants is significantly reduced as compared to the RC4+, concluding that the proposed schemes are computationally efficient. Our results and their analysis also recognize the suitability of the security algorithms for particular application areas. [ABSTRACT FROM AUTHOR]

There has been an extensive and widespread deployment of wireless local area networks (WLANs) for information access. The transmission, being of a broadcast nature, is vulnerable to security threats and hence, the aspect of security provisioning in these networks has assumed an important dimension. The security of the transmitted data over a wireless channel aims at protecting the data from unauthorized access. The objective is achieved by providing advanced security mechanisms. Implementing strong security mechanisms however, affects the throughput performance and increases the complexity of the communication system. In this paper, we investigate the security performance of a WLAN based on IEEE 802.11b/g/n standards on an experimental testbed in congested and uncongested networks in a single and multi-client environment. Experimental results are obtained for a layered security model encompassing nine security protocols in terms of throughput, response time, and encryption overhead. The performance impact of transmission control protocol and user datagram protocol traffic streams on secure wireless networks has also been studied. Through numerical results obtained from the testbed, we have presented quantitative and realistic findings for both security mechanisms as well as network performance. The tradeoff between the strength of the security protocol and the associated performance is analyzed through computer simulation results. The present real time analysis enables the network designers to make intelligent choices about the implementation of security features and the perceived network performance for a given application scenario. [ABSTRACT FROM AUTHOR]

Multi radio, multi hop, self organizing and self configuring wireless technology are the characteristic features of wireless mesh networks (WMNs) to offer last mile access to end users. The emergence of stochastically varying network environments critically affects routing in WMNs. Any routing policy meant for WMNs must be quickly adaptive and evolve in a decentralized self organizing and self configuring manner. This paper firstly proposes formulation of a soft computing i.e. fuzzy logic based hybrid performance metric which includes per flow (throughput, delay and jitter) as well as per node (residual energy of the node) parameters. This fuzzy logic based hybrid performance metric enumerates the integrated link cost (ILC) which is used as distance measure between two adjacent nodes. The paper further proposes three routing algorithms based upon nature inspired computing approaches namely firefly algorithm, Big Bang Big Crunch and Ant Colony Optimization. The proposed routing approaches aim at finding the minimal ILC path within a stipulated time constraint. The time constraint is governed by the mobility of network nodes. Extensive simulations were conducted for various WMN topologies. The results of the proposed approaches have been compared with two commonly used conventional approaches and were found to be far more superior. It was also observed that the self organizing capability of the proposed nature inspired routing approaches effectively reduces the complexity and makes a network quite adaptive to the dynamic network behavior found in WMNs. [ABSTRACT FROM AUTHOR]

In this paper, we present a comprehensive experimental study to analyze the security performance of a WLAN based on IEEE 802.11b/g/n standards in a congested and uncongested roaming and non-roaming scenarios at different packet lengths. Experimental results are obtained for a layered security model encompassing nine security layers in terms of throughput, response time, and encryption overheads, packet loss, frame loss and jitter. The performance impact of TCP and UDP traffic streams on secure wireless networks has also been studied. Through numerical results obtained from the testbed, we have presented quantitative and realistic findings for both security mechanisms as well as network performance. It establishes the fact that there is always a tradeoff between the security strength and the associated network performance that is performance decreases with increase in security strength. It is observed that under all the network scenarios non-roaming network performs better than roaming network. To analyze the benefits offered by a particular security protocol we have presented a relative security strength index model. Further we have presented the statistical analysis of our experimental data. We found that different security protocols have different robustness against mobility. By choosing the robust security protocol, network performance can be improved. The present performance analysis is significant and useful with reference to the assessment of the suitability of security protocols for given real time application. [ABSTRACT FROM AUTHOR]

In wireless communication, new radio access technologies are emerging, capable of supporting larger coverage area and faster data rates. In a wireless heterogeneous environment consisting of disparate radio access technologies, selection of the best network is an important research issue. In this paper, we propose a novel network selection algorithm for a heterogeneous environment consisting of WiMAX and LTE standard. The proposed algorithm is based on received signal strength, signal to noise ratio, available bit rate, achievable throughput and bit error rate. Relative weights of the decision making attributes are optimized by employing particle swarm optimization approach. The number of satisfied users calculated (as per their demand with wireless network selected) by proposed algorithm is optimized by modified PSO and confirmed by Monte Carlo method. From the simulation results it is inferred that the number satisfied users while running multimedia applications has been improved by 50 % as compared to the existing network selection algorithms. [ABSTRACT FROM AUTHOR]

Heterogeneous wireless networks encompass different radio access technologies to offer services as per the requirements of the users at anytime and anywhere. In such networks, mobile users have to undergo vertical and horizontal handovers to realize seamless communication with guaranteed quality of service. In this paper, we propose cross layer based dynamic handover decision algorithm to maximize resource utilization and to attain high QoS. The parameters measured at different layers are used through media independent handover functionality to estimate handover requirement and to select an appropriate target network. Based on user's preferences, different weights are assigned to handover decision parameters using fuzzy analytical hierarchical process. The weights, assigned to decision parameters, are made adaptive to call time, velocity of mobile user, type of application and remaining battery life of the mobile handset. A popular multiple attribute decision making technique, TOPSIS (technique for order preference by similarity to the ideal solution), is adopted to choose the most suitable target network. Numerical results are obtained through computer simulation for preference scores of different networks, security, end to end delay and available data rate, which show that QoS perceived by the end user is maintained consistently in varied conditions of the network and applications. [ABSTRACT FROM AUTHOR]

Network selection in a heterogeneous wireless environment is a major challenge to ensue seamless mobility across different radio air interfaces. To provide the desired quality of service for a given application in a multimedia environment, different parameters, including delay, bandwidth, packet loss and cost per byte, play an important role in network selection. In this paper, we present a novel algorithm for optimal network selection. A heterogeneous environment consisting of four networks, UMTS, WLAN, GPRS and WiMAX has been considered. We propose a network selection algorithm in which weight estimation for the representative set of the network attributes is computed using entropy and technique for order preference by similarity to ideal solution approach. The numerical results show that the proposed model can be effectively implemented to select the desired network in a heterogeneous environment employing triple-play services. [ABSTRACT FROM AUTHOR]

Multi-interface terminal in heterogeneous wireless networks will have network access from diverse access technologies. Multiple attribute for decision making including user preference will increase the complexity of handoff process. Various approaches have been proposed to solve the complexity problem of handoff decision. In this paper, multi attribute decision making algorithms Analytic Hierarchy Process (AHP) method, Simple Additive Weighting (SAW), Total Order Preference by Similarity to the Ideal Solution (TOPSIS), and Grey Relational Analysis (GRA) methods have been proposed for handoff decision in a WiMAX-WLAN environment to facilitate user with better quality of service. AHP has been used for calculation of weights of decision parameters. Numerical results show that SAW, TOPSIS and GRA provide almost similar performance. SAW is very simple to implement but probability of error is less in GRA because values of decision attribute are directly used for ranking of alternatives. TOPSIS is sensitive to the attribute with high score. [ABSTRACT FROM AUTHOR]

This article represents the system performance and its operation stability of a fixed worldwide interoperability for microwave access network operating with point to multipoint technology. It provides broadband access in fixed locations for mixed environments in Greater Noida, UP, India. The Field measurement for its capacity and coverage are recorded simultaneously to optimize a network by raising customer premises equipment (CPE) antenna height. This process is not going to alter any technical parameters of a network. CPE antenna is a directional antenna facing towards base station to achieve optimum LOS reception. The net changes in RSS 10-17 dBm, DTR 512-1.8 Mbps, path loss exponent 0.5-0.9 and standard deviation of 1.2-2.3 were observed by raising CPE antenna height of 2-5 m above the prescribed height. The path loss exponents for different environments are obtained using least squares method based on measured data by MatLab statistics tool. Standard deviations of signal strength variability with distance are derived. Real coverage of a network is presented based upon path loss exponent and standard deviation. Our result suggest that, raising the height of CPE antenna can reduce transmitted power, there for reducing overall maintenance cost and system interference in future. [ABSTRACT FROM AUTHOR]

Field measurements of signal strength is one of the basic techniques for coverage determination of a cellular network. In this paper, we report on the experimental study of the signal strength measurements in a typical worldwide interoperability for microwave access network operating at 2.62 GHz installed for fixed wireless access in the district of Greater Noida, Uttar Pradesh, India. The experimental data are analyzed for deriving characteristic parameters of the radio propagation environment. The characteristic parameters include path loss exponent and standard deviation of shadow fading. Having derived the characteristic parameters, we propose path loss models for the cellular network. The study also aims at the determination of network coverage for the given system parameters. Results and their analysis are utilized for network planning and optimization of the system parameters for the installed cellular network. [ABSTRACT FROM AUTHOR]

4G wireless networks are based on All-IP architecture integrating cellular networks, Wireless local area networks, Worldwide Interoperability for Microwave Access, Wireless ad hoc networks, and Wireless Personal Area Networks etc. This makes seamless handover an important issue for users roaming among these networks. Anticipation of future events based on layer 2 (L2) trigger information is the basic principle of fast handover. It incurs higher signaling costs compared with the other protocols like Mobile IPv6 and Hierarchical Mobile IPv6. L2 trigger is based on fluctuating wireless channel states. Therefore, the handover anticipation using L2 trigger may sometimes be incorrect. Unnecessary buffer space is used for providing a smooth handover in the case of incorrect anticipation. Therefore, it is very important to analyze overhead costs and compare the performance of IP based handover protocols. This paper investigates the impact of L2 triggering time on the signaling cost, packet delivery cost, total overhead cost, and buffer space. Results show that Session to mobility ratio, L2 trigger time and number of subnets are determining parameters for optimizing handover performance. [ABSTRACT FROM AUTHOR]

Mobility management is the most important feature of a wireless cellular communication system. Continuation of an active call is one of the most important quality measurements in the cellular systems. Handover makes it possible for a user to travel between various networks or cells while having a seamless connection. This paper shows that, performance of cellular network can be increased with proposed adaptive soft handoff algorithm, which dynamically calculates the Soft handover margin based on the received signal strength and distance. Performance is evaluated in terms of the performance metrics active set update rate, active set size, soft handover region and probability of outage. Simulation results show that soft handover algorithm gives better performance with adaptive soft handoff margin compared to that of fixed soft handover margin in varied propagation conditions. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new empirical formula for handover rate as a function of base stations separation, standard deviation of shadow fading, path loss exponent, averaging distance, and correlation distance. The handover initiation algorithm is based on averaged signal strength measurements using relative signal strength with hysteresis margin approach. We generate the data through computer simulations for the average number of handovers referred to as handover rate, for the practical range of path loss exponent and standard deviation of shadow fading. The proposed formula provides for a practical design tool to optimize the handover initiation performance under varied propagation environments. [ABSTRACT FROM AUTHOR]