A Trust-Based Predictive Model for Mobile Ad Hoc Networks

The Internet of things (IoT) is a heterogeneous network of different types of wireless networks such as wireless sensor networks (WSNs), ZigBee, Wi-Fi, mobile ad hoc networks (MANETs), and RFID. To make IoT a reality for smart environment, more attractive to end users, and economically successful, it must be compatible with WSNs and MANETs. In light of this, the present paper discusses a novel quantitative trust model for an IoT-MANET. The proposed trust model combines both direct and indirect trust opinion in order to calculate the final trust value for a node. Further, a routing protocol has been designed to ensure the secure and reliable end-to-end delivery of packets by only considering trustworthy nodes in the path. Simulation results show that our proposed trust model outperforms similar existing trust models.

Design of a Compact Circular Microstrip Patch Antenna for WLAN Applications

This paper presents the design of a compact circular microstrip patch antenna for WLAN applications which covers the band 5.15 to 5.825 GHz. The antenna is designed using 1.4mm thick FR-4 (lossy)substrate with relative permittivity 4.4 and a microstrip line feed is used. The radius of the circular patch is chosen as 7.62mm. To reduce the size and enhance the performance of the proposed antenna, a circular slot is loaded on circular patch and a square slot is etched on the ground plane of dimension 30mm×30mm. Design of the antenna is carried out using CST Microsoft Studio Sonimulation Software. The proposed antenna resonates at 5.5 GHz with a wider bandwidth of 702 MHz and it provides low return loss of -31.58 dB, good gain of 3.23 dB and directivity of 4.28 dBi and high efficiency of around 79% against the resonance frequency. The geometry of the proposed circular antenna with reduced size and its various performance parameters such as return loss, bandwidth, VSWR, gain, directivity, efficiency and radiation pattern plots are presented and discussed

Comparative Performance Assessment of V-Blast Encoded 8×8 MIMO MC-CDMA Wireless System

The bit error rate performance of a V-Blast encoded 8x8 MIMO MC-CDMA wireless communication system for different signal detection (MMSE and ZF) and digital modulation (BPSK, QPSK, DPSK, and 4QAM) schemes for grayscale image transmission has been investigated in this paper. The proposed wireless system employ ½-rated Convolution and cyclic redundancy check (CRC) channel encoding over the AWGN channel and Walsh Hadamard code as an orthogonal spread code. The present Matlab based simulation study demonstrates that the V-Blast encoded 8×8 MIMO MC-CDMA wireless system with the employment of 1⁄2- rated convolution and cyclic redundancy check (CRC) channel encoding strategies shows good performance utilizing BPSK digital modulation and ZF signal detection scheme in grayscale image transmission.

Investigation and Evaluation of IEEE 802.11n WLANs Link Features Performance Under Single Host and Concurrent Communication

For an efficient design of wireless local-area networks (WLANs), the simulation tools are important to accurately estimate the IEEE 802.11n/ac link features for WLANs. However, this true simulation of network behavior is critical in designing high-performance WLANs. Through testing, analysis, and modeling of the proposed scheme repetitively, the design of the WLAN can be enhanced with a small budget before making its practical implementation. Many network simulation tools have been established to give solutions for this request and ns-3 is the most widely used tools among them by the research industry as an open-source network simulator. In this paper, we examine the various link features of the 802.11n WLANs under several conditions. We investigate the effects of 802.11n WLAN modulation and coding schemes (MCSs), 20MHz single channel or 40 MHz bonded channel, guard intervals (GI), frame aggregation, data encoding, number of antennas and their data rate, and link distance features of 802.11n WLAN in ns-3 when only a unique host connects with the access point (AP) and generates data traffic. Besides, the performance for an enterprise scenario proposed by the IEEE 802.11ax study group is evaluated when several hosts are simultaneously creating traffic with their associated APs. The results demonstrate that ns-3 support most of the link features of the 802.11n protocol with significant accuracy.