scholarly journals Femtocells Underlaid Macro-cellular Networks

Author(s):  
Joydev Ghosh

<div>This work presents the evaluation of the downlink (DL) performance of a dual-layer cellular networks by using energy efficiency (EE) metric, where femto base stations (FBSs), macro base stations (MBSs) and users (FUs) form independent spatial Poisson point processes (PPPs). The proposed network model is developed by considering number of antennas at each BS alongside a single antenna at each user with the use of the conventional spectrum re-utilization approach. Then, Coverage probability and EE expressions for the duallayer cellular networks are exclusively derived analytically. It is also demonstrated that simulation results are almost in-line with the analytical one in the PPP-based model. While coverage probability deteriorates with less margin in the lower FBS density region compared to the scheme presented in [10] signalled not much turnaround of the network performance, EE in the lower and the upper FBS density regions are likely to remain between 6x10^-3 to 9.2 x10^-3 Bits/Joule and 4.6 x10^-3 to 7.1x10^-3 Bits/Joule, respectively. Proposed scheme tells us that it is firmly on course to match up with Vehicular Ad-hoc NETworks (VANET) applications without incurring high cost as EE, low latency, coverage probability and low power adaptability are back on good growth path. </div>

2021 ◽  
Author(s):  
Joydev Ghosh

<div>This work presents the evaluation of the downlink (DL) performance of a dual-layer cellular networks by using energy efficiency (EE) metric, where femto base stations (FBSs), macro base stations (MBSs) and users (FUs) form independent spatial Poisson point processes (PPPs). The proposed network model is developed by considering number of antennas at each BS alongside a single antenna at each user with the use of the conventional spectrum re-utilization approach. Then, Coverage probability and EE expressions for the duallayer cellular networks are exclusively derived analytically. It is also demonstrated that simulation results are almost in-line with the analytical one in the PPP-based model. While coverage probability deteriorates with less margin in the lower FBS density region compared to the scheme presented in [10] signalled not much turnaround of the network performance, EE in the lower and the upper FBS density regions are likely to remain between 6x10^-3 to 9.2 x10^-3 Bits/Joule and 4.6 x10^-3 to 7.1x10^-3 Bits/Joule, respectively. Proposed scheme tells us that it is firmly on course to match up with Vehicular Ad-hoc NETworks (VANET) applications without incurring high cost as EE, low latency, coverage probability and low power adaptability are back on good growth path. </div>


2018 ◽  
Vol 7 (3.16) ◽  
pp. 76
Author(s):  
Deepak . ◽  
Rajkumar .

Vehicular ad hoc networks is an emerging area for researchers to provide intelligent transportation system to the society. It is due to the wide area of applications of VANETs interest is developed among the people from different countries to be a part of it. Therefore many projects had been started and also presently working to implement VANETs in real world scenario. The main challenge in its implementation is to provide a secure mechanism against the various attacks and threats that have the capability to bring the network performance significantly down. In this paper to overcome different types of authentication based attacks in VANETs an ECDSA based secure routing protocol SE-AODV is proposed with security features incorporated in already existing AODV routing protocol. The performance of SE-AODV is evaluated and compared with original AODV and AODV with black hole attack (BH-AODV). The SE-AODV shows better performance with the parameters used for comparison with the variation in vehicle density, speed of vehicles and simulation time. 


Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2764 ◽  
Author(s):  
Huanhuan Yang ◽  
Zongpu Jia ◽  
Guojun Xie

As an auxiliary facility, roadside units (RSUs) can well improve the shortcomings incurred by ad hoc networks and promote network performance in a vehicular ad hoc network (VANET). However, deploying a large number of RSUs will lead to high installation and maintenance costs. Therefore, trying to find the best locations is a key issue when deploying RSUs with the set delay and budget. In this paper, we study the delay-bounded and cost-limited RSU deployment (DBCL) problem in urban VANET. We prove it is non-deterministic polynomial-time hard (NP-hard), and a binary differential evolution scheme is proposed to maximize the number of roads covered by deploying RSUs. Opposite-based learning is introduced to initialize the first generation, and a binary differential mutation operator is designed to obtain binary coding. A random variable is added to the traditional crossover operator to increase population diversity. Also, a greedy-based individual reparation and promotion algorithm is adopted to repair infeasible solutions violating given constraints, and to gain optimal feasible solutions with the compromise of given limits. Moreover, after selection, a solution promotion algorithm is executed to promote the best solution found in generation. Simulation is performed on analog trajectories sets, and results show that our proposed algorithm has a higher road coverage ratio and lower packet loss compared with other schemes.


Author(s):  
Shaik Shakeel Ahamad ◽  
V. N. Sastry ◽  
Siba K. Udgata

In this chapter, the authors propose a secure payment framework in mobile ad hoc network for disaster areas. In order to enable transactions in a disaster area using existing payment systems, we need infrastructure to communicate such as wired networks and base stations for cellular networks which are damaged by natural disasters. The authors propose to use mobile agent technology and digital signature with message recovery (DSMR) mechanism based on ECDSA mechanism to enable transactions in a disaster area using ad hoc networks.


Author(s):  
Ali Kamil Ahmed ◽  
Mohanad Najm Abdulwahed ◽  
Behnam Farzaneh

<p>Vehicular Ad-hoc Networks (VANETs) are one of the most important types of networks which are widely used in recent years. Along with all the benefits of Quality of Service (QoS) improvements, vulnerability analysis for this type of networks is an important issue. For instance, a Gray-hole attack decreases network performance. We proposed a novel solution to help to secure these networks against this vulnerability. The proposed method can detect and prevent the Gray-hole attack. Anywhere in the network, each node (vehicle) can distinguish between the Gray-hole attack and the failed link. Some topology related information helps us to detect attacks more accurately. Also, the proposed method uses the most reliable path in terms of link failure when there is no malicious node. In this paper, we used the TOPSIS method for choosing the most trusted node for routing intelligently. We validated our proposal using a simulation model in the NS-2 simulator. Simulation results show that the proposed method can prevent Gray-hole attack efficiently with low overhead.</p>


2021 ◽  
Author(s):  
Hamed Nassar ◽  
Gehad Taher ◽  
El-Sayed El-Hady

We prove that under stochastic geometric modelling of cellular networks, the coverage probability is <i>not</i> a function of base stations density, contrary to widespread belief. That is, we reveal that the base station density, $\lambda$, that is appears in a plethora of published cellular coverage probability expressions is superfluous.<br>


2021 ◽  
Author(s):  
Hamed Nassar ◽  
Gehad Taher ◽  
El-Sayed El-Hady

We prove that under stochastic geometric modelling of cellular networks, the coverage probability is <i>not</i> a function of base stations density, contrary to widespread belief. That is, we reveal that the base station density, $\lambda$, that is appears in a plethora of published cellular coverage probability expressions is superfluous.<br>


2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Junpeng Yu ◽  
Hongtao Zhang ◽  
Yuqing Chen ◽  
Yaduan Ruan

In 5G ultradense heterogeneous networks, wireless backhaul, as one of the important base station (BS) resources that affect user services, has attracted more and more attention. However, a user would access to the BS which is the nearest for the user based on the conventional user association scheme, which constrains the network performance improvement due to the limited backhaul capacity. In this paper, using backhaul-aware user association scheme, semiclosed expressions of network performance metrics are derived in ultradense heterogeneous networks, including coverage probability, rate coverage, and network delay. Specifically, all possible access and backhaul links within the user connectable range of BSs and anchor base stations (A-BSs) are considered to minimize the analytical results of outage probability. The outage for the user occurs only when the access link or backhaul link which forms the link combination with the optimal performance is failure. Furthermore, the theoretical analysis and numerical results evaluate the impact of the fraction of A-BSs and the BS-to-user density ratio on network performance metric to seek for a more reasonable deployment of BSs in the practical scenario. The simulation results show that the coverage probability of backhaul-aware user association scheme is improved significantly by about 2× compared to that of the conventional user association scheme when backhaul is constrained.


2014 ◽  
Vol 46 (3) ◽  
pp. 832-845 ◽  
Author(s):  
Naoto Miyoshi ◽  
Tomoyuki Shirai

Stochastic geometry models for wireless communication networks have recently attracted much attention. This is because the performance of such networks critically depends on the spatial configuration of wireless nodes and the irregularity of the node configuration in a real network can be captured by a spatial point process. However, most analysis of such stochastic geometry models for wireless networks assumes, owing to its tractability, that the wireless nodes are deployed according to homogeneous Poisson point processes. This means that the wireless nodes are located independently of each other and their spatial correlation is ignored. In this work we propose a stochastic geometry model of cellular networks such that the wireless base stations are deployed according to the Ginibre point process. The Ginibre point process is one of the determinantal point processes and accounts for the repulsion between the base stations. For the proposed model, we derive a computable representation for the coverage probability—the probability that the signal-to-interference-plus-noise ratio (SINR) for a mobile user achieves a target threshold. To capture its qualitative property, we further investigate the asymptotics of the coverage probability as the SINR threshold becomes large in a special case. We also present the results of some numerical experiments.


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