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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.

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.

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.

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 − 2 0 . 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).

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.

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.

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.

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.

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.

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.